Archive TRICKLE-L: file log9504, part 1/1, size 162800 bytes:

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Netafim Irrigation, Inc. is currently actively seeking an agronomist to fill
a position in the Western United States.

The successful candidate should have field experience dealing in an
irrigation/agronomy field with special emphasis in the area of drip/micro
irrigation. Graduate degrees are desirable although not necessary depending
on experience.

The purpose of this open position is to assist new and existing customers
throughout the Western United States make the most profit from best
management practices of their newly purchased Netafim drip systems. This
person should also possess excellent written and verbal skills to relate
success stories into marketing pieces for future business development. The
candidate should feel comfortable in working with irrigation dealers and
international colleagues.

The candidate should be willing to relocate to the Central Valley region of
Central California and be willing to travel ~50% throughout the Western
United States.

The position reports to the Western Regional Marketing Director.

Any interested parties should send their resume's to Tx Gator or fax to
Netafim Irrigation, Inc. @ 209-453-6803 and 512-261-3402, attn. Jeff
Bradshaw.

If there are any questions, please direct them to Tx Gator@aol.com.

Netafim Irrigation, Inc. is an equal opportunity employer.

Tomorrow, Richard Mead (list manager of Trickle-L) will arrive in
Orlando, Florida, for the Microirrigation Congress. He will give
a presentation about irrigation on the Internet.
He will also be present with a computer, hooked up to the Internet,
so that people present at the congress can follow discussions from
Irrigation-L and Trickle-L. It is even possible to subscribe to these
mailing lists during the congress.

The people who stay at home, but want to follow the congress as close
as possible can visit the World-Wide-Web pages for the Microirrigation
Congress. All the abstracts (156) from articles in the proceedings
are available on-line, and each day during the congress a summary of
that day will be made available.

The address for the Microirrigation page is:

http://asset.arsusda.gov/micro.html

==========================================================================
Richard Soppe subscribe to
Water Management Research lab TRICKLE-L@UNL.EDU
ARS/USDA or visit
2021 S. Peach Ave http://asset.arsusda.gov/WMRL.html
Fresno CA 93727-5951 for the latest in drip irrigation
phone: (209)453-3119
fax: (209)453-3122
==========================================================================

There is quite a difference of opinion on several key aspects of the
installation and management of subsurface drip irrigation. I would like to
pose a few questions to growers and industry people associated with
subsurface drip:

1) During installation, what is the placement of the drip line?

2) What crops are you mainly growing on subsurface drip?

3) With row crops, depending on the crop, what type of beds are you
planting on? where is the placement of the dripline, center of the bed
or in the furrow?

4) With shallow placement, do you have problems with cultural
practices? i.e: working in crop residue...

I'm trying to get an idea what methods are being regularly used throughout
the industry and why.

You can respond to me directly or share your comments with the rest of the
internet group. I'll keep you posted on the responses received.
Thanks...

Carl Hawk
chawk660@aol.com

> 1) During installation, what is the placement of the drip line?

8 to 9 inches below surface. Below the bottom of the furrow.
>
> 2) What crops are you mainly growing on subsurface drip?
>
Lettuce, Cauliflower, artichokes, and celery

> 3) With row crops, depending on the crop, what type of beds are you
>planting on? where is the placement of the dripline, center of the bed
>or in the furrow?

40 inch rows. seedlines are 11 inches apart. tape in center of bed
>
> 4) With shallow placement, do you have problems with cultural
> practices? i.e: working in crop residue...
>

There are several theoretical advantages in very sand soils, but the mechanical problems are too great for now.

>

I posted a question to the BBS about soaker hoses and drip irrigation
systems. Overwhelmingly, everyone recommended "drip tape" or "t-tape".
I am not familiar with this term. Can someone answer my questions?

1) What does srip tape look like? How does it deliver water? Through
holes, or like a soaker system?

2) Who are some of the suppliers of such equipment? What brands would
you recommend? Where can I call, write, or e-mail to get catalogs or
information? What's a good competetive price per foot?

3) I'm looking into running a drip system through mulched, raised beds.
Will this tape work well just under two inches of mulch, or should it be
buried a few inches into the soil?

4) Is the distribution even? What kind of regulator equipment might be
neccessary? The plot would be a small garden, perhaps no larger than 40k
square feet, with a level topography.

5) Most importantly, what are the special problems, benefits, tricks, or
techniques that you have encountered with your systems? Does it tend to
benefit some crops or cultivars more than others? And tricks for
reducing algae problems? Any special pressures that work for you?

Thanks for reading. I need some answers. :)

Yours Truly,

Eiko Naito

April 3, 1995

Dr. Dale Bucks presented a talk which concerned the Historical
Developments of Microirrigation. Stats quoted were:
land under microirrigation throughout the world is likely to reach 3
million ha by the year 2000. This represents ~ 2% of the total irrigated
area in the world. Nearly half of the microirrigated areas in the world
are in tree crops primarily in the U.S. Greater use of reclaimed
wastewaters and other impaired water qualities along with
microirrigation is also anticipated to increase.(See abstract for more
info*.)
Dr. Phene spoke of three main areas which SDI are of significance:
a) Reduced surface evaporation
b) Difference in geometry between surface and subsurface drip (hemisphere
vs sphere) This has been discussed on Trickle-L before.
c) Deep root system, especially for tree crops the deeper the better (up
to a point)

April 4, 1995

The second day of the congress had more indivduals registering.
The count at 3 p.m. was 330 delegates. Sessions were very busy
and during breaks the exhibit area was very busy. Interest in the
Internet was very high. About 1/3 of individuals interested in Trickle-L
did not even have email access, but were waiting for access in their
country or looking foward to obtaining an email system once they were home.

Felix Reinders and Adriaan Van Niekerk will announce tonight that the
sixth Microirrigation congress will be in in South Africa in the year
2000. The focus of the congress will be on the ever-increasing demand
for food and the resulting need for the optimisation of water resources.
A strong emphasis will be placed on the adaptation to technology to the
requirments of emergent small-farm irrigators world-wide.

Their flyer will be posted on our WMRL homepage soon**.

As a last note for the day, a delegate asked me to post the following
question:

Is there anyone that has subsurface drip irrgation experience with
floriculture, specifically roses and their fertility requirments?
Please post reponses to Trickle-L or to me at: rmead@asrr.arsusda.gov

That's it for today. Tomorrow will be slowing down to half a day session.
I probably will be posting what transpired on that day and overall
impressions of the Congress.

Richard Mead
Trickle List owner/manager
Orlando, Florida

Notes:
* The abstract of Dr. Dale Bucks is available via the World Wide Web
at the URL: http://asset.arsusda.gov/micro.html
**This will be after the Congress in Orlando is finished. The URL for
the Water Management Research Lab is: http://asset.arsusda.gov/wmrl.html

The summaries of the day are also available at the world wide web under
the URL of the microirrigation Congress. To obtain the information by
email, send a message to Agora@mail.w3.org with in the body of the message
the URL that you want to retrieve

==========================================================================
Richard Soppe subscribe to
Water Management Research lab TRICKLE-L@UNL.EDU
ARS/USDA or visit
2021 S. Peach Ave http://asset.arsusda.gov/WMRL.html
Fresno CA 93727-5951 for the latest in drip irrigation
phone: (209)453-3119
fax: (209)453-3122
==========================================================================

I just wanted to thank you for the time you put into this list.

>>Is there anyone that has subsurface drip irrgation experience with
>floriculture, specifically roses and their fertility requirments?
>Please post reponses to Trickle-L or to me at: rmead@asrr.arsusda.gov

My neighbor tried to grow cut flowers by drip. Not roses, but stocks. the problem as I see it is that flowers should not be too lush. Drip might cause the flowers to be too vegetative. It is a management problem, and not impossible

Unsubscribe

Closing comments about the Fifth International Microirrigation Congress and
the future of Trickle-L

The Fifth International Miroirrigation Congress in Orlando this past week
impressed me in several areas:

1) The potential for microirrigation to expand in the irrigated and
semi-irrigated regions of the world is enormous. Due to its water use
efficiency and environmental benefits, microirrigation could contribute
tremendously to feeding people of the next millennium. The emerging economic
growth in developing countries will help accelerate this potential.
2) The amount of subsurface drip research and real practice is more extensive
nationally and internationally than I thought. Not only is this practice of
microirrigation catching on world wide, but other aspects such as using waste
water via subsurface drip is becoming a new technology all on its own.
3) The interest and enthusiasm in Trickle-L as a communicating medium for
microirrigation technology was more than I expected. I was flattered by all
the positive comments and questions about mircoirrigation on the Internet.
Since microirrigation will be a key player in the future of agriculture, our
international group of scientists, engineers, farmers, students, gardeners
and industry reps will hopefully gain knowledge faster and more efficiently
using the Internet.

While in Orlando, some suggestions were offered to help extend and diversify
the Trickle-L discussion group. Among them were:

- Post a question of the week concerning drip (or microspray) irrigation.
- Post major problems of a certain aspects of drip irrigation and have
individuals contribute comments for problem solving.
- Continue adding to the extensive drip irrigation bibliography on the WMRL
homepage
- Link more and more agriculturally related Web sites to the WMRL homepage
and the Virtual Irrigation Library.
(As a side note concerning the World-Wide Web, individuals connected to the
"Web" will increase in the next five years from 2 million to 22 million).
For those of you who don't have access to the Web, just be patient, it will
get to you soon at this rate.

The Web is a nice feature, but our electronic mailing list is the ultimate in
on-line information delivered directly to the user. I assume one day the Web
will merge with listserver technology. Given the speed of Internet growth,
I'll do my best to keep everyone informed of emerging technical uses of the
NET.

Richard Mead
List owner/manager

To Richard Mead (Trickle-L Founder) and all particpants in Trickle-L:

The advent of subsurface drip irrigation is as mundane, but more significant
than the invention of the ball bearing.

As Mr. Mead commented:

>1) The potential for microirrigation to expand in the irrigated and
>semi-irrigated regions of the world is enormous.

The eventual impact of the comunnication that takes place on this seemingly
mundane (to the short sighted) topic WILL HAVE GLOBAL IMPACT. The impact of
SDI (subsurface drip irrigation) will force world-class economists to re-tune
their economic models to account for the increased efficiency of agriculture
to utililize water and fertilizer to produce wholesome sustinance. Imagine
the potential 'quality of life' return on investment if the United Nations
chooses to promote and subsidize this technology in impoverished and arid
nations.

>2) The amount of subsurface drip research and real practice is more
extensive
>nationally and internationally than I thought. Not only is this practice of
>microirrigation catching on world wide, but other aspects such as using
waste
>water via subsurface drip is becoming a new technology all on its own.

Furthermore, by using SDI to recycle liquid waste to agriculture, we are for
the first time ABLE to close the nutrient loop and sustainably produce food
and fiber to meet humanities basic needs.

'And we all thought we were way ahead of everybody else' ... no ... the fact
of the matter is that great minds think alike! ... and the advantages of SDI
technology are not only possible, but are being implemented RELIABLY. In
other words, we can count on the results.

>3) The interest and enthusiasm in Trickle-L as a communicating medium for
>microirrigation technology was more than I expected. [ommitted] Since
microirrigation will >be a key player in the future of agriculture, our
international group of scientists, engineers, >farmers, students, gardeners
and industry reps will hopefully gain knowledge faster and >more efficiently
using the Internet.

The knowledge and technology have been available for some time now ... what
has been lacking is confidence ... and that is what this communication medium
offers ... the ability to have peer to peer interaction with people who are
actually making it work. This interaction will undoubtedly have the impact
of giving people like us individual farmers the confidence to give the
technology a try in our on fields ... and the needed 'hand holding' support
when problems occur in our seemingly unique circumstances. It is that
confidence that will lead to the widespread adaptation of SDI technology.

I believe impact of the discussions held here on the Trickle-L will have
significant world wide ramifications. This is a global group, and I have
noticed that this group consists of the world leaders of the technology side
by side with us miniscule lowly group of 'early adopters' ... we folks who
are puttting the technology to work in our own fields. It is world wide
adaptation by INDIVIDUALS of SDI that makes the differance.

For every one of us 'speaking' here, there are at least several more
'listening' and learning. I am certain that each of us here are leaders in
our communities, and our practices are being observed and evaluated by our
neighbors.

Mark my words, fellow participants, that the implimentation of SDI will be
looked back in history as one of the most significant steps our continuing
'Green Revolution' that eliminated hunger and water shortage as a fact of
life from our Earth ... and that this 'stupid little maillist called
Trickle-L' significantly facilitated that implementation.

Sincerely,
Craig Thompson
Lodi, CA USA
(many 'attaboys' to Richard Mead and his associates ... a truly usable
product from our United States Federal government @ USDA ... true
achievements only seem to come from individuals who take initative.)

Grazing is cheaper than baling or chopping. Cows are cheaper than balers
or tractors and they don't care about EEO or FICA or the rest of that.

I am interested in potassium use in Alfalfa. Particularly on established
stands. SSDI may be an efficient delivery system in that regard.

You need an ag economist to answer all your questions.

JPO

>1) What does drip tape look like? How does it deliver water? Through
holes, or like a soaker system? <

The drip tape manufacture reps can answer their own product's descriptions
(objectively of course), but basically, drip "tape" is a flat collapsible
hose, 5/8 to 7/8 inchs in diameter (16 to 22 mm) having very thin walls (4 to
25 mil) with emitters* spaced anywhere from 4 to 40 inches (10cm to 1 m)
apart, each with flow rates usually ranging from 1 to 4 liters/hour. More
commonly, flow rate is based on liters per hour per 100 m.

*Emitters are designed for a specific drip rate using built-in tortuous
paths/groves to slow water down to emit flow of precise number of drips per
unit of time.

>2) Who are some of the suppliers of such equipment? What brands would
you recommend? Where can I call, write, or e-mail to get catalogs or
information? What's a good competitive price per foot?<

I'll only answer the first question and let the manufacturer reps answer the
remaining part of #2 (again, objectively and discreetly, please).......
Chapin Watermatics, Drip In Irrigation, Hardie Irrigation, Irridelco,
Netafim Irrigation, Roberts Irrigation Products, T-Systems International,
Wade Manufacturing.
Note I have placed these alphabetically and not in any order of importance.
If I have left any company out, my apologies.

>3) I'm looking into running a drip system through mulched, raised beds.
Will this tape work well just under two inches of mulch, or should it be
buried a few inches into the soil?<

Depending on your cultural practice, I would think both options are open, but
burying it 2 to 10 inches (5 to 25 cm) below the soil is more common.

>4) Is the distribution even?<

If the system is designed correctly, distribution uniformity can be very high
(above 90%).

>What kind of regulator equipment might be necessary?<

Pressure regulators (another list of manufacturers I would give, but won't at
this time) are usually installed up stream of the drip tape system. Pressures
normally range from 10 to 15 psi (69 - 103 kpa).

>5) Most importantly, what are the special problems, benefits, tricks, or
techniques that you have encountered with your systems?<

That is a loaded question!! The main problems of burying the system are root
intrusion, clogging, salinity and soil ingestion. There are numerous
techniques to eliminate certain problems. Please refer to the archives of
Trickle-L for more detail (e.g. send GET TRICKLE-L LOG94XX, where XX would
be 07 for July, 08 for August of last year etc. to: LISTSERV@UNL.EDU)

>Does it tend to benefit some crops or cultivars more than others?<

Buried tape usually is implemented on row crops, annuals mostly.

>And tricks for reducing algae problems?<

Chlorine injections, maybe some algaecides if drip systems are labeled for
its use.

These are some cursory answers to the questions posed. I hope others will
contribute, especially if I was in error on company names or technical
specifics. I don't work with EVERY drip system.

Richard Mead
List owner/manager

Question.....last year I used a fire hydrant for water source on 4 acres of
peppers on plastic with a drip tube I have had people tell me I would
encounter problems because of chlorine levels I didn't see any.... yields
were about 1000 packed out boxes per acre.... I want to do it again this year
because the fields are far away from my pond. was i lucky last year....or is
this an opinion based on unproven data......Russ

What were the chlorine levels in ppm?

RM

> Date sent: Thu, 23 Mar 1995 20:32:08 -0600
> Send reply to: <trickle-l@unl.edu>
> From: sjordan@seldon.terminus.com
> To: Multiple recipients of list <trickle-l@unl.edu>
> Subject: Re: Introduction from new member

> >Root intrusion:
> >
> >Tough situation at times:
> >
> >Make certain that your drip laterals are well drained and that
> >residual fertilizers are flushed from the system. Not a complete
> >guarantee, but it helps. Some products exist that use Treflan as an
> >inhibitor to root intrusion.
> >
> >Gary Clark
> >BAE Dept. - Kansas State Univ.
> >
>
> Is Treflan _legal_. I would think the potential harm to be deminimus, but complying with pesticide laws is important. If not properly registered, there may be no incentive to do so from the manufa

>
> Is this something for IR 4?
>
Contact Rodney Ruskin with Geoflow 1-800-828-3388 or 415-621-6008
(Calif). He has products with this technology.

Gary Clark.

> Date sent: Sun, 2 Apr 1995 21:03:51 -0500
> Send reply to: <trickle-l@unl.edu>
> From: Eiko Naito <eqn7918@is2.NYU.EDU>
> To: Multiple recipients of list <trickle-l@unl.edu>
> Subject: Drip tape question

> I posted a question to the BBS about soaker hoses and drip irrigation
> systems. Overwhelmingly, everyone recommended "drip tape" or "t-tape".
> I am not familiar with this term. Can someone answer my questions?
>
> 1) What does srip tape look like? How does it deliver water? Through
> holes, or like a soaker system?
>
> 2) Who are some of the suppliers of such equipment? What brands would
> you recommend? Where can I call, write, or e-mail to get catalogs or
> information? What's a good competetive price per foot?
>
> 3) I'm looking into running a drip system through mulched, raised beds.
> Will this tape work well just under two inches of mulch, or should it be
> buried a few inches into the soil?
>
> 4) Is the distribution even? What kind of regulator equipment might be
> neccessary? The plot would be a small garden, perhaps no larger than 40k
> square feet, with a level topography.
>
> 5) Most importantly, what are the special problems, benefits, tricks, or
> techniques that you have encountered with your systems? Does it tend to
> benefit some crops or cultivars more than others? And tricks for
> reducing algae problems? Any special pressures that work for you?
>
> Thanks for reading. I need some answers. :)
>
> Yours Truly,
>
> Eiko Naito
>
>
Where are you located? (address, phone number, etc) I have several
publications available that will address your questions.

Gary A. Clark
Biological and Agricultural Engineering
147 Seaton Hall
Kansas State University
Manhattan, KS 66502
913.532.5580
gclark@falcon.age.ksu.edu

Dear Group,
I have followed the discussion of using sub-surface drip for fields and
have some basic concerns. I was wondering if sub-surface was a good
choice for hay fields. With all the problems of roots and "bad" water,
I get nervous since the main indication of a problem is when part of your
field is dead due to lack of water. It seems with all the monitoring
equipment, filtering equipment, etc, I would have a hard time justifying
subsurface versus a brute force spraying system. This assumes that I have
enough water to "waste" by spraying. In a good hay field, I would need
the drip line to work good for at least 10 years to make it economical.
I would hate to have to tear up the field every other year to fix problems.
Is there any hope for this kind of application for the sub-surface drip?
I have a good creek, a field, some money and very little time to invest in
this appplication.

Thanks for the input.

Jeff McSpadden
jeff@isd.tandem.com

Jeff,
We are completing a five year study on hay alfalfa this year. Although I
can't give you specifics until the project is written up, I can verify that
yield increases occur, protein levels can improve and water use efficiency is
better with subsurface drip. All this with poor quality water on a very heavy
soil in one of the most harshest climates in the country (Imperial valley,
CA.). When we finish the paper(s), we'll let the specifics be known.

Richard Mead
List owner/manager
USDA-ARS-WMRL

At 10:12 AM 4/10/95 -0500, Jeff Mcspadden wrote:
>Dear Group,
> I have followed the discussion of using sub-surface drip for fields and
>have some basic concerns. I was wondering if sub-surface was a good
>choice for hay fields. With all the problems of roots and "bad" water,
>I get nervous since the main indication of a problem is when part of your
>field is dead due to lack of water. It seems with all the monitoring
>equipment, filtering equipment, etc, I would have a hard time justifying
>subsurface versus a brute force spraying system. This assumes that I have
>enough water to "waste" by spraying. In a good hay field, I would need
>the drip line to work good for at least 10 years to make it economical.
> I would hate to have to tear up the field every other year to fix problems.
>Is there any hope for this kind of application for the sub-surface drip?
>I have a good creek, a field, some money and very little time to invest in
>this appplication.
>

Hi Jeff,

The USDA headquartered at Fresno has done excellent work on SSD with
alfalfa. Please send me your address and I will mail a package to you
including the interim USDA research reports. If you apply the USDA methods
including the dripperline with a 10 year guarantee against root intrusion
(expected life 20 years), I see no reason for you not to get 20 years out
of the SSD installation. Alternatively just contact Richard Mead, our
Trickle-l leader himself, who is active in this research.

Rodney

chlorine in ppm ? I did the typical farmer thing I didn't check I was growing
peppers not running a test plot......It was a fire hydrant hooked into city
water what do they usually run ?
Russ

Re: Subsurface drip for alfalfa...
I am interested in obtaining any USDA research using subsurface drip
in alfalfa as well. If you could please e mail the address where these
reports are available, I would appreciate it very much. Thanks. Dennis
Roll.

If you are running city water, the chlorine levels should not be above 1 or 2
ppm. This level is NOT high enough to kill damage your peppers.

R Mead

>I am interested in obtaining any USDA research using subsurface drip in
alfalfa as well. If you could please e mail the address where these reports
are available, I would appreciate it very much. Thanks. Dennis Roll. <

I'll look into sending out reports (in-house at the moment) to anyone
interested in SSD on alfalfa. I also don't think I'll get in trouble if I
briefly describe the drip system we have on our alfalfa project:
All drip hose is buried 27 inches (~70 cm) (that's right!) deep. This is a
very clay soil.
We have basically two treatments;
1) lateral spacing of 1 m (40 inches)
2) lateral spacing of 2 m (80 inches)
3) furrow irrigated plots (40 inch beds)
emitters are spaced at 39 inches or 1 m apart (2 L/hr)
There is a lysimeter in the middle of the field which triggers irrigations
when ever a 1 mm (1/25th inch) loss of ET occurs (thereby inducing our
philosophy of high frequency irrigations). In the summer in Imperial valley,
ET levels can be as high as 15 mm (.59 inches).

Since "scalding" using furrow irrigation is a problem in this valley, we have
all the plots on traditional beds, including the drip system. We inject
phos-acid at 15 p.m.m. continually and also inject N-phuric with chlorine gas
on a weekly basis for shocking the system. This is critical!! The water is
fairly saline (~1.4 dS/m) with high levels of calcite (CaCO3).
As stated before on Trickle-L, we have observed higher alfalfa yields and
higher hay protein content in the drip plots, BUT I can't give out ANY
numbers until the research is published. Sorry....... :)

R. Mead
List owner/manager

List members- I am looking for a newsgroup that focuses on
the area of PLANT PATHOLOGY. Any suggestions would be highly appreciated!

Thanks in Advance....

Bob Sheck / Hood College, Frederick, MD
--> Nuclear Families _DO_ Glow in the Dark! BSHECK, ME-SHECK, abendigo!
BSHECK@NIMUE.HOOD.EDU >>>-------==The Sheckinator==------<<< (301) 696-3928
I'd rather have a bottle in front of me than a frontal lobotomy.- Groucho Marx

Please keep me in the picture i am getting a lot of interest. Long time no
hear, international visitors to Orlando really enjoyed and were impressed
with you NET!
Robin

Does anyone in the Trickle-L group have experience or information
regarding gopher control in fields where SSD is being used? Are we
limited to the traditional techniques (trapping, etc.) or is there
anything a person can do utilizing the SSD system?

Information regarding alfalfa would be especially helpful.


Thanks,
Jerry Neufeld

> Does anyone in the Trickle-L group have experience or information
> regarding gopher control in fields where SSD is being used? Are we
> limited to the traditional techniques (trapping, etc.) or is there
> anything a person can do utilizing the SSD system?
>
> Information regarding alfalfa would be especially helpful.

***Info from Freddie Lamm, Kansas State University. We have two field
research sites in Kansas. The one, I control here at Colby has had
very little problems. The other site has had some damage. I would
attribute some of these differences to tillage practices. I reshape
my beds with a primary tillage operation after corn harvest. The
other site has not been as diligent in their efforts in this regard.
At Colby we also take care to remove by hand or till residue near
controls, flushlines, and other obstructions. I had noticed, long
before my involvement with SDI, that in small conservation tillage
research plots, that rodent and large predator burrowing activity was
higher than bare ground in the winter because of the better habitat.
Tilled areas aren't as inviting to rodents.

The other site that has experienced problems has tried to "ring"
their field with poison pellets giving some degree of control. I
think they have also specifically targeted one of their field margins
near an irrigation canal which provides year round habitat for the
rodents.

As to your alfalfa question, many of my ideas can't apply. I have
heard anecdotal reports that the round hard drip hose may be more
effective than drip tape. I would also "guess" (and strictly an
uneducated guess) that deeper installations (where appropriate by
crop and soil considerations) would lessen activity, though
intermittent repairs would be more time consuming. Rodent control
prior to installation, is always a recommendation, along with
subsequent preventive measures to reduce infiltration into the
area. Obviously, alfalfa is a tougher situation. Good luck.

Freddie
**
-------------------------------------------------------------------
Freddie Lamm *
Research Agricultural Engineer *** o
KSU Northwest Research-Extension Center ***** /|\
105 Experiment Farm Road *******\\
Colby, Kansas 67701-1697 *********
Ph. 913-462-6281 ***********
FAX 913-462-2315 *************
Email:flamm@oznet.ksu.edu It's all downhill from here.

------ THERE'S NO DOMAIN LIKE OZ, THERE'S NO DOMAIN LIKE OZ. ------

I am reading some traffic on the list lately about use of chlorine. If you
have ever wondered why you can test your water and read a residual content,
and still have microbio fouling, I would love to post a message explaining
the chlorine chemistry in more detail.

Jim Beshears
Engineering Director
Stranco Engineering Services
Jimb1331@aol.com

Regarding >If you have ever wondered why you can test your water and read a
residual content,and still have microbio fouling, I would love to post a
message explaining the chlorine chemistry in more detail.
>Jim Beshears
>Engineering Director
>Stranco Engineering Services
>Jimb1331@aol.com

Jim,
Go right ahead and explain chlorine chemistry. I was even thinking of doing
a small essay on how chlorine kills bacteria (most recent research in water
chemistry from Johns Hopkins). So, start the discussion, we would be pleased
to see this information!

R. Mead
List owner/manager

please do! I am interested

Jim keane

jneufeld asks:

>Does anyone in the Trickle-L group have experience or information
> regarding gopher control in fields where SSD is being used? Are we
> limited to the traditional techniques (trapping, etc.) or is there
> anything a person can do utilizing the SSD system?

Gophers may not be that much of a problem even with no rodent control
program. We have over 80 miles of Geoflow (hardwall) hose in our vineyards
buried 18 to 22" in sandy loam soils with emitters every 3 1/2'. We began
our second year with around 17 gopher strikes, and suffered an additional
five or six through the growing season. The strikes were easy to find and
repair, and the soil is ALWAYS easy to dig in around them (a bit wet though).
I have no complaints about one strike per four miles per year. We had more
problems with surface animals chewing on the vents and end risers than with
gopher attacks, and far far less maintance with than with our above ground
drip systems.

I speculate the gophers don't like the wet enviornment around the hose during
the irrigation season, and would further speculate that the increased
irrigation demanded by alfalfa would discourage their attacks.

I would imagine that strikes in an alfalfa field might be harder to find than
in a tilled vineyard, as they would be disguised by the growing hay. Maybe
Richard Mead has some comments on this aspect.

Craig Thompson
Lodi, CA

There has been some discussion concerning chlorine use in microirrigation
systems on Trickle-L, yet never has there been an explanation on why chlorine
is effective in reducing bacterial growth.
Researchers at Johns Hopkins University in conjunction with the National
Research Council have just published a paper in the latest proceedings of the
American Society for Microbiology.
They propose that chlorination disrupts the protective outer layer of the
bacterium which leads to cell death. To be more specific, the
lipopolysaccharide (LPS) component of the outer membrane is very sensitive to
chlorine. Divalent cations such as Mg and Ca interact with the LPS for
stability. Introducing chlorine into the environment causes a substitution
reaction whereby the LPS outer membrane barrier is destabalized. In addition,
they suggest that the presence of divalant cations such as Ca during chlorine
exposure could restabilize the outer membrane to allow some bacterial cells
to survive.
I know that the bacterial level in irrigation water is not as critical as in
drinking water, yet I thought this topic to be of interest, especially when
Ca levels of the irrigation water are high or when injecting a calcium
related compound into the system prior to or after a chlorine injection.

Richard Mead
List owner/manager

Enclosed is information from a new member of Trickle-L, Bart Fisher

>1) Briefly, what is your affiliation with trickle irrigation?<

I am a farmer in Blythe, CA with +-400 acres of SDI

>2) What crops or plants do you use drip irrigation on?<

Iceberg lettuce, broccoli, muskmelons, cotton

>3) If using subsurface drip irrigation, what is the average depth of
placement of the drip line?<

12" depth, more recently 8"

>4) What problems have you encountered with subsurface drip?<

Keeping our rows centered over the tape. Uniformly distributing water over
our variable soil types.

>5)What form of N, P and K have you been trying and to what success?<

P in the form of phosphoric acid, 0-52-0. N in the form of UN32. No K.

>6) Have you experienced a reduction in fertilizer and water use?<

We use approx. 60% of what fertilizer we use in conventional culture. About
85-90% of water in conventional.

>7) Do you have water quality problems? If so, how do you tackle the
situation?<

Lots of soluble salts in our Colo. River water. We constantly run H2S04 to
buffer our water to about 6.5, and constantly chlorinate to 1ppm at the last
emitter.

>8) How frequent do you irrigate?<

Frequency depends upon crop, time of year, stage of development, etc.
Typically we favor twice a day irrigation.

>9) Do you have rodent damage? If so, how do you tackle the problem?<

Rodents no factor

>10) Are you pleased with the uniformity of your system or systems? Were they
designed correctly?<

Our systems are well designed, but I am not at all satisfied with the
uniformity.

*****************************************************************

As I told Mr. Fisher upon receiving his survey response, it is great to have
him on
board for us to understand his approach to SDI and see what potential
problems farmers like him have with subsurface drip irrigation.

Richard Mead
List owner/manager

Craig Thompson stated >I would imagine that strikes in an alfalfa field might
be harder to find than in a tilled vineyard, as they would be disguised by
the growing hay. Maybe Richard Mead has some comments on this aspect.<

Gopher 'strikes' (a good term by the way) or any kind of break is difficult
to observe in an alfalfa field due to the camouflaging nature of the crop.
The first 'phase' of our alfalfa experiment at Brawley, California, involved
placing the drip laterals at 15 inches (38 cm) deep, whereby the second phase
of the experiment, laterals were placed 27 inches (69 cm) deep. I do recall
several incidences of gopher strikes during the first (shallower) phase of
the study but I have yet do see (nor hear from our technician) any gopher
damage during the second (deeper) phase . Not being a gopher expert, I would
assume that gophers prefer to live in the upper 1 to 1.5 feet (30-45cm) of
the soil profile, at least in the lower deserts of California. It's also
possible, we've been darn lucky. If there any animal (rodent) experts out
there, please contribute.

Richard Mead
List owner/manager

Prior to planting, you should use a gopher machine( an old Planet Junior
seeder with a shank witha balled piece of steel at the end to form a soft
burrow @ 12-18 inches beneath the topsoil) . this machine drops poison seed
and is very effective as a preplant in and especially around a field. It
will eliminate @95% of the gophers within 3 weeks and if used around the
field will eliminte migration

Uniformity is in high 90's are a way of life that you should be enjoying.
Absence of K and high Nachl of concern.. I will be happy to discuss drip with
you in your inviroment.. Robin Franks.

rev trickle-l

At 6:32 PM 4/15/95 -0500, MEAD2513@aol.com wrote:
>Craig Thompson stated >I would imagine that strikes in an alfalfa field might
>be harder to find than in a tilled vineyard, as they would be disguised by
>the growing hay. Maybe Richard Mead has some comments on this aspect.<
>
>Gopher 'strikes' (a good term by the way) or any kind of break is difficult
>to observe in an alfalfa field due to the camouflaging nature of the crop.
>The first 'phase' of our alfalfa experiment at Brawley, California, involved
>placing the drip laterals at 15 inches (38 cm) deep, whereby the second phase
>of the experiment, laterals were placed 27 inches (69 cm) deep. I do recall
>several incidences of gopher strikes during the first (shallower) phase of
>the study but I have yet do see (nor hear from our technician) any gopher
>damage during the second (deeper) phase . Not being a gopher expert, I would
>assume that gophers prefer to live in the upper 1 to 1.5 feet (30-45cm) of
>the soil profile, at least in the lower deserts of California. It's also
>possible, we've been darn lucky. If there any animal (rodent) experts out
>there, please contribute.

I qote from a study Long Term Biobarriers to Plant and Animal Intrusion of
Uranium Tailings by Cline J.F., Burton F.G., Cataldo D.A., Skiens W.E. and
Gano K.A. Sept. 1982.

Table A2 Burrowing Depths and Habitat Prefence of Some Representative
Burrowing Mammals (extract)

Species Recorded Tunneling depth in cm
Marmota monax 40 -50 marmot
Cynomys Ludovicianus 91-427 Black tailed prarie dog
Spermophilus townsendi 50-80 ground squirrel
Thomomys bottae 5-35 pocket gopher
Thomomys talpoides 10-30 pocket gopher
Geomys bursarius 23 Plains pocket gopher
Perognathus longimembris 52-62 pocket mouse
Perognathus parvus 35-193 Great Basin pocket mouse
Dipodomys spectabilis 40-50 kangaroo rat
Dipodomys microps 25-45 Banner-tailed kangaroo rat
Dipodomys merriami 26-175+ Merriam's kangaroo rat
Taxidea taxus 150+ badger

(I hope that the table above holds its format through the net)

This supports Richard's argument and our growers' experience. Those who
bury their hard hose more than 18" deep have little gopher strike problems.
I would expect that a hard hose will be resistant to the pocket mouse.

Rodney (NOT a rodent expert)

At this point in the discussion of chlorine, I hope somebody could futher
help me understand the differance between 'free chlorine' and 'residual
chlorine.' What is the differance between the two terms, what is the signific
ance of that differance, and how do I accurately test for 'free chlorine'
instead of 'residual chlorine?'

I have been told that 'free chlorine' is what really counts in terms of
biocidal activity ... and that when I use a pool chlorine tester, it is the
level of yellow color that I get in the first two seconds that indicates free
chlorine, and the darker yellow color that result in five to ten seconds that
indicates the amount of residual chlorine. I also have heard that chlorine
test strips (litmus paper style) only reflect residual chlorine, not free
chlorine.

Craig Thompson

I have used infra red technology in large fields with suprisingly low costs
when coupled to other cultural practices. The "strikes" really stand out and
are easily located and dealt with.
Robin Franks

While at the Microirrigation Congress in Orlando several weeks ago, Freddie
Lamm and I discussed the possibility of having "question of the week" on
Trickle-L. I would like to start out with a question relating to a topic I've
been wanting to discuss for several months: Automated Irrigation.

One of the basics of automated irrigation is to have a sensor or sensors to
control or trigger irrigation onset. I'll briefly list the sensors or sensing
systems below used or could be used in microirrigation systems today, and
pose the initial question of the week: What kind of system
(sensors/monitoring system etc.) do you use, IF you are doing automated
irrigations?

Researchers such as myself and others can afford to use sophisticated and
expensive devices such as lysimeters to trigger irrigations of experimental
fields. Yet most agricultural engineers, farmers/growers, greenhouse managers
using drip systems will likely use simpler devices to initiate irrigations
for automated systems.

1) Tensiometers are very common devices which measure the soil matric
potential via a porous ceramic cup in contact with the soil. In the last
several years, electronic pressure transducers have been hooked up to these
devices to continually monitor the readings from the sensor which then can
be relayed to a control system (data logger or control timer). I'll let the
users of this system give the pros and cons of the device. An updated
electronic version of a gypsum block is now available for wider ranges of
measurement than most tensiometers.
2) Evaporation pans have become automated. Using a sensor attached to the
side of conventional evaporation pan, the sensor can monitor pan water
levels and send that microclimate information via a data logger to a control
system for desired field irrigations.
3) Matric potential sensors are another soil matric potential reading device
using the theory of heat dissipation. These sensors can be more accurate and
have a greater range of readings than tensiometers, although calibration is
very tedious. We have some of these sensors buried in a subsurface drip
irrigation experimental field 450 miles (720 km) away from our lab. We have
controlled irrigations via computer/modem setup using a multiple of sensors
which obtain the average matric potential of the field. A program in the
datalogger triggers an irrigation when a certain matric potential threshold
is obtained.
4) Automated atnometers are now available. Canvas or gortex material covers a
flat surface of a ceramic cup which is attached to a column of water. When
evaporation occurs from the cup/material surface, electronic pulses within
the system come close to simulating ET. Users of this device usually place it
near the top of the canopy of the crop being grown.
5) Sap flow or heat balance devices can now be used on tree trunks or plant
stems. Very similar in appearance to a blood pressure apparatus, the device
uses the heat balance method of thermodynamics, heat transfer and energy
conservation to determine mass flow of water through the specific stem.
Until just recently the device was used experimentally. However, some
progressive types are beginning to use this system on their crops.
6) FDR and TDR sensors. This category I'll spend an entire posting on in the
future, but they both are considered evolving technologies in soil moisture
measurement. FDR stands for Frequency Domain Reflectometry and TDR stands for
Time Domain Reflectometry. Both these systems are 'potential' devices to
trigger irrigations in automated systems, but I don't know of any being used
for that purpose today. Let me know if you hear other wise.

The above list of sensors and their technology are not in any particular
order of preference. I merely mentioned all the sensors that I think can be
used in automated drip/trickle irrigation systems. Due to the high frequency
nature of drip, hand sampling and using the neutron probe are not the best
choices in determining many irrigations to obtain near field capacity
conditions. Setting a clock timer is considered 'automated', but doesn't
allow for seasonal anomalies of climate. One could over irrigate on a
unseasonably cool day or under irrigate on a strange hot day. If anyone out
there uses a different system than the six I mentioned above, or disagrees
on my premise of hand sampling, neutron probe readings, and clock-timers,
feel free to let us know. I see things from a narrow researchers perspective
and would love to know what people in the 'real world' do. You don't have to
divulge all your secrets, just give us an idea how you accomplish automated
irrigations.

Richard Mead
List owner/manager

p.s.
I haven't mentioned any canned computer programs for predicting ET primarily
because there are so many of them out there.

Craig Thompson wrote >At this point in the discussion of chlorine, I hope
somebody could further help me understand the difference between 'free
chlorine' and 'residual chlorine.' What is the difference between the
two terms, what is the
significance of that difference, and how do I accurately test for 'free
chlorine'
instead of 'residual chlorine?'<

>I have been told that 'free chlorine' is what really counts in terms of
biocidal activity ... and that when I use a pool chlorine tester, it is the
level of yellow color that I get in the first two seconds that indicates free
chlorine, and the darker yellow color that result in five to ten seconds that
indicates the amount of residual chlorine. I also have heard that chlorine
test strips (litmus paper style) only reflect residual chlorine, not free
chlorine.<

Craig,

That is an excellent question. To befuddle things even further, there is
also 'total chlorine, 'available chlorine' and 'combined chlorine' when
looking through the instrumentation literature for chloride analysis.

Let's put it this way: There is aqueous chlorine (Cl2) and chlorine
compounds (Cl-X). Aqueous chlorine, I think, should be considered 'free
chlorine' or 'available chlorine'. This is the chlorine that is affective
in bacterial annihilation.
Then, there is 'residual' chlorine or 'combined' chlorine, representing
chlorine compounds. In my mind, this is a potential "pool" of chlorine.
Finally, 'total' chlorine is the measure of both free and
combined/residual chlorine species.
Hope this does'nt confuse the issue any more than it already is.

Richard Mead
List owner/manager

p.s.
There are numerous tests to measure all three types of chlorine. The
company HACH sells equipment using reagents and indicator dyes. I have
not heard of the litmus strips, other than simple pool test kits. Maybe
someone on Trickle-L has more experience in this than I do.

For those of you just joining Trickle-L,and want to catch up with what
has been discussed in the last month, the archive of March 1995 is now
available if you send the following message:

GET TRICKLE-L LOG9503

to listserv@unl.edu

The file is 225721 bytes big.

Richard Mead
Trickle-L owner/manager

Thanks for the update. I still use a clock and an irrigator but have been
considering using more accurate devices. Certain times of the crop cycles
requires different water demands. How will we account for this without some
sort of % override on the global operating system or whatever? I am always
listening to these discussions, and find them most useful.

Besides chlorine, there is bromine. A horticulturist here in Maryland is
recommending bromine to a grower to kill diseases in recycled irrigation
water. I have not seen much on bromine for awhile but was asked to help the
grower set up an application system if it is the way to go. There was and
may still be a product on the market. Anyone have experience or information
sources on bromine? Anyone using it over chlorine?
**********************************************************
David S. Ross dr27@umail.umd.edu Voice 301-405-1188
Agricultural Engineering Department FAX 301-314-9023
University of Maryland Dept 301-405-1198
College Park, MD 20742-5711
**********************************************************

We have approached automation in a slightly different fashion that
can give us the flexibility we desire for our research work. WE
COULD PROBABLY ARGUE LONG AND HARD ABOUT WHY WE CHOSE THIS METHOD,
BUT THIS IS WHAT WE WANTED. However, there are much simpler and more
reliable systems for most people. We might call ours
semi-automated.

Anyway our idea, is to predict ET from climatic data, and then use
data monitoring and control to apply a given measured amount of
water. We use municipal residential flowmeters that have electical
remote readouts to the the nearest 100 gallons. We MONITOR these
pulses and CONTROL the applied amount. We do not have this directly
tied to ET, because we have several research treatments and study
areas irrigating at different times. **We want** the high accuracy of
applied amount for our studies rather than timed application. We can
automatically schedule when these irrigations begin. We have manual
backup and verification to the **nearest gallon** from the flowmeter
at the plot. Each plot flowmeter costs about $40-50 and we have 121
plots at Colby. This does not include solenoids, wiring and the
data logging and control devices.

This is our plan, HOWEVER, we have tried to work our way into the
automation portion. We have the flowmeters, solenoid valves, wiring
and remote readouts for all plots and have had these for the duration
of our studies (6 years). HOWEVER, we have had much
difficulty keeping the automation portion protected from
electrical storms on the High Plains. AS A RESULT, we often brute
force many of our studies, by manually getting flow readings and
times and calculating a projected shutoff time and then manually
switching the plot off. This is **not** automation at all, but when
things get hectic, the study data is what is important to me, not the
performance of the automation. We haven't given up on our desire
for automation and are working with an independant hardware and
software supplier to help us develope better protection schemes.

Freddie
**

-------------------------------------------------------------------
Freddie Lamm *
Research Agricultural Engineer *** o
KSU Northwest Research-Extension Center ***** /|\
105 Experiment Farm Road *******\\
Colby, Kansas 67701-1697 *********
Ph. 913-462-6281 ***********
FAX 913-462-2315 *************
Email:flamm@oznet.ksu.edu It's all downhill from here.

------ THERE'S NO DOMAIN LIKE OZ, THERE'S NO DOMAIN LIKE OZ. ------

The biggest problem I have seen in scheduling irrigation is not
the
equipment to schedule but rather dealing with the spatial variability
of
the soil and the crop. Over the years I have developed 2 approaches
to
the problem. In strawberry production, the strawberry plant is its
own
tensiometer through the process of guttation. Irrigation of
strawberries
is very simple to schedule: when guttation is not present in the
early
morning hours then irrigate to a desired depth, if guttation is
present
then delay irrigation. Putting a bucket over the plants in the
evening
and checking the plants in the morning eliminates the problem of
wind
evaporating the guttation droplets. This work is explained in
more
detail in HortScience 24:599-601 (Glenn and Takeda, 1989). We
have
conducted field trials for several years and find that
scheduling
irrigation by the absence of guttation reduces the amount of
irrigation
applied without reducing yield relative to tensiometer or
evaporation
scheduling methods. This work will be published shortly. The beauty
of
this visual system is that a grower can walk the strawberry fields in
the
early morning and see where irrigation is needed. After confidence
is
gained that certain areas are more droughty than others then
more
controlled laterals can be installed to schedule irrigation for
these
areas separate from other areas of the field.

The next approach in dealing with the variability of soils and plants
was
to design a valve that a tensiometer could operate. Irrometer has
a
magnetic valve to operate a solenoid. It works well as long as
lightning
stays away and a person is willing to run electrical cable throughout
a
field. We designed a valve that is a part of the tensiometer and
uses
the vacuum developed as the soil dries to open the valve. The
suction
developed in the tensiometer eliminates the need for electricity
and
electric cable in the field. The tensiometer valve is described
in
Applied Engineering in Agriculture 9:293-297 (Peterson, Glenn,
and
Wolford, 1993). We are currently evaluating the system in peach
orchards
but see a real fit for the nursery container industry,
commercial
landscaping and small fruit and vegetable farms. Incidentally, I
used
one of the valves in my garden one summer and had the best tomatoes
ever
without ever worrying about watering.

There are alot of good ways to determine how much water a plant
canopy
has used but bringing that information down to the level of the
plants
that are growing in a diverse environment is tough. The eastern U.S.
has
very diverse soils and topography. These are 2 examples of how we
are
trying to deal with this diversity. I would appreciate any feedback
on
these ideas and approaches others are taking to cope with
spacial
variability in scheduling irrigation.

Michael Glenn
Soil Scientist
USDA-ARS Appalachian Fruit Research Station
Kearneysville, WV 25430
304-725-3451

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The following is a new member survey response from William Tollner
(btollner@bae.uga.edu)
1) Briefly, what is your affiliation with trickle irrigation? Somewhat
tangential--I have a student who is interested in irrigated irish potato
production in north Georgia. Others here are researching drip irrigation for
vegetable production in south Georgia. Of course, drip has been used in Peach
and Pecan production for quite sometime.
2) What crops or plants do you use drip irrigation on? See above.
3) If using subsurface drip irrigation, what is the average depth of
placement of the drip line? Believe me, this is one of the biggest questions
for the industry, and there is debate among experts as to how deep one should
go. Three dimensional models are in their infancy. There is much work to be
done on this aspect. We are looking for guidance on this one!
7) Do you have water quality problems? If so, how do you tackle the
situation? Yes, especially when surface sources are used.
8) How frequent do you irrigate? Many times a day or just one long session
per day or several days? We are studying this question in Tifton, Ga.

After reading the "Chlorine Confusion" Email and seeing Email talking about
emmiter clogging, bio fouling, etc, even though people in the same breath are
talking about how much residual they are keeping in their systems, I thought
I would throw my 2 cents worth out to the list. If this is too elementary
for some or most of you, please excuse my ignorance of the group, I'm kinda
new to drip irrigation. I also apologize in advance for the length, but this
is important information for anyone who uses chlorine, and we find that even
large water treatment company representatives don't know what you are about
to read.

Basically, residual measurement of an oxidizing biocide like chlorine, ozone,
bromine, and the like is not a good indicator of the killing effect it has on
the bacteria or other organics. It is 40% to 60% directly correlatable to
kill, which is why sometimes it seems to works fine, and you have no fouling,
to the extremes; not enough and fouling, and too much and killing plants and
corroding equipment. A chlorine test kit basically has the accuracy
mentioned before, and actually measures all of the chlorine and it's
components, and the background bromine present in water.

When you introduce chlorine to water, a reaction occurs. The chlorine breaks
into basically two parts, Hypochlorus Acid (HOCl), and Hydrochloric Acid
(HCl).

Cl2 + H2O ->->-> HOCl + HCl

The Hypochlorus form of this reaction, HOCl, has 60 to 120 times the killing
power as the Hypohalite part of the reaction, HCl. The problem lies in the
second reaction, the dissociation of the good guy, HOCl, into the bad guy,
HCl.

HOCL ->->-> H+ + OCL

This reaction is pH dependant, and floats back and forth !!!!! This means at
a residual level of say 1.0 PPM, and a pH of 6.5, you get 92% HOCl, and 8%
OCl, which is a good killing environment. But at the SAME 1.0 PPM at a pH of
9.0, you have only 4% HOCl, and 96% OCl! Still trust your test kit?

Just to give you some real life numbers, and remember the test kit says 1PPM
for each:
7.0 pH you have 79% HOCl and 21% OCl
7.5 pH you have 55% HOCl and 45% OCl
8.0 pH gives you 27% HOCl and 89% OCl

What a difference a pH unit makes!

Like Rich said, the terms Free Chlorine, and Free Available Chlorine, usually
refer to the good guys, HOCl, and Total Chlorine or Residual Chlorine refer
to the combined HOCl and OCl, plus all the other components. As far as test
kits go, if you have to use them, I personally agree with Rich in suggesting
Hach has the best portable equipment on the market for residual measurement.

Some of the conclusions you can make from this are:

1) Even though I control pH pretty good, even a .5 pH shift really changes
my chorine effectiveness.
2) I can't trust my test kit to give me a good picture of what is going on.
3) If I have higher pH water, I'm wasting alot of money on chlorine if I
don't control pH down a bit.
4) If I over chlorinate just to make sure, the leftovers are chloramines,
and we all know about that nasty carcinogen trichloramine. Drinking
water plant people love this one.
5) Changes in demand for chlorine aren't picked up by my test kit until it's
too late.
6) Am trying to kill bugs, or hold a residual. The end doesn't really
justify the means in the case of chlorine control.

ORP technology measures the effect that an oxidizing biocide like chlorine
has on the water. An ORP reading is 99% directly correlatable to kill, as
opposed to the 40% to 60% mentioned before. At Stranco we use a version of
ORP that we call HRR for High Resolution Redox, and is a result of 30+ years
of probe and instrument refinement. It has a very high sensitivity, a couple
of millivolts, as compared to the next best competitor, which is 20 to 50.
Depending on which part of the control curve your on, 10 millivolts can be a
few tenths of a part per million. I design automated chlorination systems
for a living, for Stranco. Because of this and a few other instrument related
innovations, our advantage over every other company that tries this is that
ours works, and nobody elses does, including the big guys. We have 30,000+
installations world wide. All of the major water treating companies in the
world use our equipment, and you'll find it on most or all of the whale tanks
and theme parks in the world. In the agricultural area, our equipment is
used in wash tanks, and if you've ever eaten a McDonalds salad, it was run
through a process controlled by us to sterlize the veggies. If you think
about it, when a truckload of veggies is dumped into a wash tank, or a whale
relieves him self in front of a filter inlet, WHAT A DEMAND CHANGE! Our
equipment is very sensitive to demand changes, and is the reason why we are
where we are today. To go into all the applications we get into would take
up alot of virtual real estate here, I think you all get the idea.

Sorry for the sales pitch, but I was chastized on the Environmental
Engineering list for not doing this sooner for them, as some firms reccomended
residual based control technologies that failed and they didn't look very
competent to their customers.

Now for my questions to the list.

1) If you could put a more sophisticated control equipment on your system,
what would it be?
2) Would it be worth it or are you already using a recirculated source tank
for your water that can have all the fertilizers, chlorine, water
conditioners, etc. added automatically to it?
3) Would a remote battery operated tank gauging system that called you when
it was getting empty, or failed for any reason, like pump failure, no flow,
lost prime, etc. be of any worth?
4) Would it be worth being able to see graphically the entire drip system,
pumps, tanks, flows, whatever on a PC on your desk?

Thanks in advance for your responses, and I hope this helped. We have alot
of really good people here in the field of disinfection control, so if any of
you have any questions, please call us or Email me.

Jim Beshears
Engineering Director
Stranco Engineering Services
800 882-6466
JimB1331@AOL.com

Subject: Response about sensors

From: kajordan@ag.Arizona.EDU

The following is from Ken Jordon:

I dont recognize your handle and you probably dont recognize me. I am
primarily an instrumentation geek here at Univ of Arizona. I have been
involved with several sap flow measuring devices and use of the watermark
block in various theses. A few years ago, Andy Terry working in Pheonix
said that he opposed use of timers as automators of irrigation since they
waste water. I had an undergraduate student and we put together an
overwatering controller. The basic premise is that it would prevent the
solenoid from turning on if the soil conductivity was above some level. The
level of conductivity can be easily adjusted. Thus it adapts to the water
use of the plants depending upon the variable environmental conditions
prevaling. We are presently writing a local grant to field test the idea in
our water use area. The main part of the grant is graduate student support.
The unit is cheap to put together and uses a quartz clock to integrate the
time that the water flows. The quick and dirty way to determine the actual
water use is to multiply the time the solenoid is open by the flow of the
emitters. A refinement would be to use water flow meters at the solenoid.
The power for the circuit is minimal and uses the 24 volt AC power supplied
to the solenoid. Not a really new idea but quick and dirty. For the
researchers interested I would always recommend that the control and the
measurement sensors be different. Use and of the methods you outlined to
measure the result. Contact me in a year or so and I'll refer you to a
thesis. Maybe we'll even publish the idea. Not new but affordable by any
irrigator that can affort the timer system to begin with.

Jim,

Thanks for the information on chlorine and the measurement of its different
forms it assumes in treated water. On the drip system I'm in charge of here
in South Florida, (40 ac. of containerized tropical folliage plants using
surface drips in each of the containers to deliver water and nutrients), I
have another concern about measuring the Cl2 and its different metabolites.
Our water quaility is rather poor with high amounts of Fe, Mg, Ca, etc. and
it is my understanding (from the people that set up our system) that aside
from disenfecting the water, the Cl2 also converts the Fe to a water
insoluable form (Fe(ii) to Fe(iii)?) that our filters are more effective in
removing from the water. What kind of wrench does this throw it to the
'works' when trying to measure Cl2 concentration???? Do we also need to be
looking for all the different metabolites in addition to HOCl and HCl ????

Also is it possible to get an expanded table with the values of HOCl and HCl
concentation vs. pH???

I kind of remeber a research publication from the U of Florida IFAS veg crop
people that was deailing with HOCl and HCl in treating wash tanks and how
HOCl killed different percentages of innoculated critters deppending on the
level of HOCl. Can you recomend a good starting point for HOCl levels for
drip systems???

Thanks again for the infomation.

Scott Good
Scottgood@aol.com

Gee, this exchange of ideas and technology transfer stuff is great!!! ----SMG

I may be way off track, but I just finished a paper this morning
(at 6 am fancy that) about effluent use for irrigation. One of the points
from the journal articles and books I have is that too low of an iron content
(due to activation of sludge, flocating it out, whatever the cause...) will
inhibite the nitrification process. The bacteria can't function without
a base level of iron. I don't know what that level is though. I also
understand that iron is not exactly a good thing for drip. If the above
is all true maybe the solution would be to sink a couple of iron nails in
the pots.
In a way I hope I am wrong or else you will have a nitrogen
problem - but then again, my paper may be wrong in which case I'll find
out soon.

Patricia Beddows
Geography Department - Undergraduate
McMaster University
Hamilton Ontario

On Wed, 19 Apr 1995 ScottGood@aol.com wrote:

> Jim,

snip
> Our water quaility is rather poor with high amounts of Fe, Mg, Ca, etc. and
> it is my understanding (from the people that set up our system) that aside
> from disenfecting the water, the Cl2 also converts the Fe to a water
> insoluable form (Fe(ii) to Fe(iii)?) that our filters are more effective in
> removing from the water. What kind of wrench does this throw it to the
snip
> Scott Good
> Scottgood@aol.com

Scott,

There are several publications and software that have been developed in
Florida by the extension service to address biological problems
in Florida, particularly iron and sulfur related. If you send me
a mailing address I can get theseto you by mail.

The software is available from 904 392 7853 (tel) at the
Software Support Office, IFAS. (Ask for the water management
utilities). This includes an expert systemfordiagnosis and
treatment of cloggin problems in Florida.

This topic is of particular interest to me. I'm not a farmer; just one of
those ivory tower graduate students. My research is in the area of
irrigation scheduling via "remote sensing" of water status/stress in
vineyards using field measurements in conjunction with computer models of
the energy budget and turbulent transport in the vineyard canopy. I have
chosen this approach since in vineyards (and other deciduous tree crops)
the carefully timed imposition of moderate water stress can be a tool for
modifying fruit (and wine) quality.

While there have been many valuable developments in irrigation scheduling
based on ET estimates, I feel that an estimate of plant physiological
stress (i.e. stomatal conductance or leaf water potential) should provide
a more precise feedback mechanism to an irrigation system controller in
cases where a predetermined level of stress is desired. Additionally, I
feel that the micrometeorological approach (weather station with infrared
thermometry) has the advantage of spatially-averaging over heterogeneous
conditions.

I'm not trying to sell anything, mind you, but I am interested to find
out if there are growers that have any interest in the "water stress
management" approach to irrigation scheduling.

Mark

---
Mark D. Greenspan
mdgreenspan@ucdavis.edu
University of California, Davis
Agricultural Engineering / Viticulture & Enology

I have been watching the discussion concerning the remote sensing of crops
for determination of moisture stress.
I am a farmer from the state of washington and am raising hops.
Currently we are determining our moisture level by soil monioring. This
has worked ok for us to give us an idea of what is happening in the soil.
I feel that it is not addressing the plants condition. I have looked at
temp readings of the plant and a few other ideas but nothing seems to offer
everything. The main thing I use now is a visual inspection of the plant
to determine the presence of stress or lack there of. Hops are like
cotton where excess growth is not wanted.
It would great if I could determine stress in the plant at any given
moment.

Leslie

The following is a response from a new member of Trickle-L, Manuel Palada
(mpalada@uvi.edu)

Thank you for sending me the info on joining Trickle-L. I'd like to
respond to some of the questions you asked on our experience with drip
irrigation here in the Virgin Islands. The paper I presented during the
recent Microirrigation Congress in Orlando described some of the results
we obtained from drip irrigation experiments on vegetable crops. You may
refer to that paper in the proceedings.

>1) Briefly, what is your affiliation with trickle irrigation?<

My affiliation with trickle or drip irrigation is through the regional
project S-247 Microirrigation of Horticultural Crops in Humid Regions.
We have been participating in this project since it started in the early
80s. I served as Chair of the Technical Committee last year. Our work
here in Virgin Islands is focused on vegetable crops, although we have
some studies on fruit and ornamental crops.

>2) What crops or plants do you use drip irrigation on?<

Most of our vegetable and fruit crops are under drip irrigation. We
cannot successfully grow a crop without irrigation. The climate of the
Virgin Islands is considered semi-arid and water is the most limiting
resource in crop production.

>3) If using subsurface drip irrigation, what is the average depth of
placement of the drip line?<

We only conducted one related study on subsurface drip irrigation.
This was comparing emitter placement (surface vs. subsurface). Emitter
was buried 5 cm below the surface of the soil. We did not get
significant difference on tomato yield. We need more studies on this
before we can draw any conclusions.

>4) What problems have you encountered with subsurface drip?<

The only problem we encountered with subsurface irrigation is the
extra time or labor of burying the drip line and emitters.

>5) Fertigation is a real advantage of drip irrigation. What form of N, P and
K have you been trying and to what success?<

We only apply N fertilizer by fertigation. We usually use urea or
ammonium nitrate. This form of N fertilizer works just fine.

>6) Have you experienced a reduction in fertilizer and water use?<

Drip irrigation and fertigation definitely reduced our water and
fertilizer use.

>7) Do you have water quality problems? If so, how do you tackle the
situation?<

We don't have water quality problem since we use high quality
municipal water. We don't use filters in our drip system.

>8) How frequent do you irrigate? Many times a day or just one long session
per day or several days?<

Irrigation scheduling for most of our experiments is based on soil
moisture tension as measured by soil tensiometers. We maintain between
20 to 30 kPa for optimum plant growth. We normally irrigate once or
twice per week to maintain the optimum soil water tension. Our soils are
clay and have high water holding capacity.

>9) Do you have rodent damage? If so, how do you tackle the problem?<

We have no rodent problem that damage our irrigation system.

>10) Are you pleased with the uniformity of your system or systems? Were they
designed correctly?<

Uniformity of water pressure is our biggest problem here since we
only depend on municipal water for irrigation. Sometimes there is
tremendous fluctuation in water pressure due to demand and usage.

I hope this will give you an idea where we are as far as microirrigation
is concerned here in the Virgin Islands.

Patricia,

In the nursey where I work, we are located in Deerfield Beach, Florida (just
north of Ft. Lauderdale and south of Palm Beach). We use water drawn from
shallow wells in the Biscane Aquafer (~30M). This water is very hard because
the aquafer imparts high amounts of Ca, Mg , and Fe. Although we do have
surface water available and the chemistery of the water is some what better
we only use this source as a back up becase it contains plant pathogenic
bacteria and fungi. While rusty nails might seem like an quick fix to the
problem of iron deficiency, it doesn't quite do the trick because the iron
is in a form the plant is unable to use just like the ochre residue that our
well water leaves behind on all surfaces that it gets upon (another problem
is exposing the workers and the customers to possible tetanus infection...
what a way to scare customers away from buying premium plant material....).
As for our program of plant nutrition, we use a "base" 7-1-5 fertilizer
formula with a full minors package that is injected in to the water at
anywhere from 100ppm to 200ppm N CLF (continuous liquid feed) depending on
the crop and if we should start developing deficiencys in the minor
nutrients, we have the flexability in the system to run nurse tanks of
different solutions like a MgNO3, Fe EDTA, or any other custom Rx the plants
might call for.

Scott Good
Scottgood@aol.com

On 20 April 1995 Patricia Beddows wrote:

" ...One of the points from the journal articles and books I have is that too
low of an iron content (due to activation of sludge, flocating it out,
whatever the cause...) will
inhibite the nitrification process. The bacteria can't function without
a base level of iron. I don't know what that level is though. I also
understand that iron is not exactly a good thing for drip. If the above
is all true maybe the solution would be to sink a couple of iron nails in
the pots..."

Get some mud on your boots.

Hello Roy,
How about infrared sensors that scan selected areas of plant canopy
regularly? If the difference (canopy temperature - air temperature)
goes above some "normal" level, then the plant transpiration rate has
decreased. Mary Hattendorf, working for WSU at Prosser, Washington,
is pretty knowledgeable about use of infrared sensors. She could
say for sure if something like this is doable.

Tom
Tom Hodges, Cropping Systems Modeler
USDA-ARS email: thodges@beta.tricity.wsu.edu
Rt. 2, Box 2953-A voice: 509-786-9207
Prosser, WA 99350 USA Fax: 509-786-9370
== ## Rent this space ## ==
If this represents anything, it is only my opinion.

On Thu, 20 Apr 1995, Roy Leslie wrote:

> I have been watching the discussion concerning the remote sensing of crops
> for determination of moisture stress.
> I am a farmer from the state of washington and am raising hops.
> Currently we are determining our moisture level by soil monioring. This
> has worked ok for us to give us an idea of what is happening in the soil.
> I feel that it is not addressing the plants condition. I have looked at
> temp readings of the plant and a few other ideas but nothing seems to offer
> everything. The main thing I use now is a visual inspection of the plant
> to determine the presence of stress or lack there of. Hops are like
> cotton where excess growth is not wanted.
> It would great if I could determine stress in the plant at any given
> moment.
>
> Leslie
>
>

As a table grape grower, I too use the "eye" as the final gauge as to
irrigate or not and how much. To me all other devices are tools but nothing
can beat experience..... yet.

As a table grape grower for life, I can offer this; I have used most of the
senors listed in all the discussions and have found that they are but tools
to guage the condition of the vine at any given moment. Weather reports and
experience can then interpert this data, adjust for visual inspection, adjust
for the period of growth the vine is in, adjust for the crop load etc., then
irrigate by gut reaction.

**Freddie Lamm's Question of the Week**

I have hypothesized there may be differences in biological activity
in subsurface driplines related to installation depth. For example,
deep installations may see less fluctuation in temperatures than
lines at or near the soil surface. More constant temperatures might
mean less cycles of biological activity and decay.

Is anyone aware of any citable references related to this hypothesis
or does anyone have any anecdotal experiences??

Yes, this is a researchable question, but alas, there is always more
research to do than can be done?

Freddie
**

I don't believe there is any single device or combination of devices that
can adequately estimate field properties (incl. water stress, pest
pressure/presence, etc.) without a model of the underlying physical
processes. The models may range from simple to complex, depending on the
structure of the canopy (e.g. height, density, gaps). For instance, an
energy budget model for an alfalfa field may be represented by a "big
leaf" approximation without gross error, but an orchard or vineyard is
likely to be poorly represented by such models, as has been my experience.

I think many of the failings of the "rush to technology" in agriculture is
the emphasis on the device rather than the method. The approaches tend to
be largely empirical and thus, often result in innaccuracy and
non-portability. The infrared sensor doesn't measure temperature, of
course, it measures infrared radiation. From a plant canopy, this energy
emanates from plant surfaces at a multitude of "layers" within the canopy
as well as the soil, the latter of which becomes a greater factor in
fields with gaps. Without a decent model of the origin of the sensed
radiation, it can be difficult to sort out the plant stress. Thus, I am
skeptical of approaches that use "surface temp. minus air temp" as their
basis, at least in complex plant canopies.

I have enjoyed this topic. Maybe we can revisit it again. Thanks for
letting me ramble on.

Mark

---
Mark D. Greenspan
mdgreenspan@ucdavis.edu
University of California, Davis
Agricultural Engineering / Viticulture & Enology

>Date: Tue, 18 Apr 95 00:08:19 -0400
>From: dr27@umail.umd.edu (David S. Ross)
>Subject: Bromine over chlorine for disease control
>
>Besides chlorine, there is bromine. A horticulturist here in Maryland is
>recommending bromine to a grower to kill diseases in recycled irrigation
>water. I have not seen much on bromine for awhile but was asked to help the
>grower set up an application system if it is the way to go. There was and
>may still be a product on the market. Anyone have experience or information
>sources on bromine? Anyone using it over chlorine?
>**********************************************************
>David S. Ross dr27@umail.umd.edu Voice 301-405-1188
>Agricultural Engineering Department FAX 301-314-9023
>University of Maryland Dept 301-405-1198
>College Park, MD 20742-5711
>**********************************************************
Hello David, I have been using the product Agribrom from Great Lakes
Chemical Co, as a disinfestant for about 5 years on a greenhouse "ebb and
flow" irrigation system for potted plants. I keep the bromine level around 5
ppm using a coloremetric test kit as a tool. Agribrom comes in Granules and
Tablet form, I have never been able to get the Tablet form to "work". My
system is "homemade" but I use a 30 gal plastic drum, and hang a 0.5 to 0.75
lb. mesh net bag inside the tank. This "stock tank" is kept filled by a
float valve and the solution is kept in a constate of motion by the use of 2
large aquarium air pumps, air stones weighted to the bottom. This stock
solution is a concentrate which is diluted by the use of 2 sytles of venturi
systems. One venturi adds the concentrate to the recirculating flow and the
other set is attached to the makeup water outlet, adding concentrate when
the main tank needs additional water. My main concern has been to prevent
Pythium or other water mold diseases from spreading within my system. I
monitor the algae growth as a good indicator of wether the Agribrom is
working. In reality the actual measured levels vary from 15 ppm to 0 ppm,
but with careful maintaince we get 5 ppm.

Phil Soderman sgrower1@rain.org
Carpinteria, California USA
ZONE 10

On Mon, 6 Mar 1995, Freddie Lamm wrote:

> I wanted to post the availability of a new extension paper on SDI.
>
> Subsurface Drip Irrigation for Field Corn: An Economic Analysis
> by
> K. C. Dhuyvetter
> F. R. Lamm
> D. H. Rogers
> November 1994
> KSU Cooperative Extension, Manahattan Kansas. L-909. 6 pages.
>
> Request free single copies from
> kdhuyvet@oznet.ksu.edu
> Phone 913-532-5823
>
> Multiple free copies may also be available. Not being in extension
> myself, I don't know all the mechanics of multiple copies.
>
> Freddie
>
>
>
> Freddie Lamm
> Research Agricultural Engineer
> KSU Northwest Research-Extension Center
> 105 Experiment Farm Road, Colby, Kansas 67701-1697
> Ph. 913-462-6281
> FAX 913-462-2315
>
Please send me a copy of your report. I am the Water Operations Mgr. for
an irrigation district in the Central Valley of California. Many of our
dairy men would find this interesting.

Thanks Stev

ATTENTION fellow subscribers and Internet friends....

This afternoon, while I was visiting a former colleague at the USDA/ARS
Aquatic Weeds Lab in Ft. Lauderdale, FL, I saw a copy of a notice being
circulated through the University of Florida IFAS Ft. Lauderdale Research and
Education Center. I can not vouch for the authenticity of this notice but I
would take great care in protecting against this threat to what we hold near
and dear.... Our COMPUTERS and thier 'innerds'.... Text of warning follows:

" ...The following information was recieved from the MITRE corporation.

There is a new computer virus that is being sent across the Internet. If you
recieve a message witht the subject line 'GOOD TIMES' , DELETE IT
IMMEDIATELY.

The FCC released a warning last Wednesday concerning a matter of MAJOR
importance to any regular user of the Internet. Apparently, a new computer vir
us has been engineered by a user of America On Line that in UNPARALLELED in
its destructive capability. Other, more well-known viruses such as 'STONED',
'Airwolf', and 'Michaelangelo' pale in comparison to the prospects of this
new creation by a warped mentality. What makes this virus so terrifying,
said the FCC, is the fact that NO PROGRAM NEEDS TO BE EXCHANGED FOR A NEW
COMPUTER TO BE INFECTED. It can be spread through the existing e-mail systems
of the Internet. Once a computer is infected, one of several things can
happen. If the computer contains a hard drive, that will most likey be
DESTROYED. If the program is not stopped, the computer's processor will be
placed in an nth-complexity infinite binary loop, which can severly damage
the processor if it is left running that way too long. Unfortunately, most
novice computer users will not realize what is happening untill it is far too
late.

Luckily, there is one sure means of detecting what is now known as the 'GOOD
TIMES' virus. It always travels to new computers the same way in a test
e-mail message with the subject line reading simply 'GOOD TIMES'.

Avoiding infection is easy once the file has been recieved -- NOT READING IT.
The act of loading the file into the mail server's ASCII buffer causes the
'GOOD TIMES' mainline program to initialize and execute. The program is
HIGHLY INTELLIGENT -- it will send copies of itself to everyone whose e-mail
adress is contained in a recieved-mail file or a sent-mail file, if it can
find one. It will then TRASH the computer it is running on.

The bottom line here is -- if you recieve a file with the subject line 'GOOD
TIMES', DELETE IT IMMEDIATELY!!! DO NOT READ IT!!! Rest assured that
whoever's name was on the 'From:' line was struck by the virus.

Please pass this on... especially to anyone you know who uses America on line
or the Internet regularly..."

End of Warning.

Like I said earlier, I don't know if this threat is authentic, I have not
seen anything from AOL about the virus, but everybody would agree that we are
in a twisted world, we are not in Kansas any more (sorry Freddie), a mg of
'prevention' is worth a Kg of 'cure' and no one's 'good' name is sacred.

Scott M. Good
Scottgood@aol.com

Don't worry. The Good-times virus message is already circulating more
then a year around on the Internet, and soon it will be placed in the
Internet Hall of Fame. A message like this one is always following the
first warning.

It is impossible to get a virus on your computer by simply reading your
mail. Reading mail does not start any binary part of a mail-message, and
viruses can only be transfered to other computers in binary files.

In general, it is always advisable to scan programs that you download
from the internet for viruses, but there is nothing to worry about when
you are just reading mail.

For the newcomers at the Internet: This is called (as I'm not mistaken)
an Urban Legend. There are some other interesting messages going around
on different mailing lists and newsgroups. But that's more for other places
to discuss (If you are interested in more Legends, just send me an E-mail,
and I'll try to find them).

Richard Soppe
USDA/ARS/Water Management Research Laboratory
2021, S.Peach Ave
Fresno, CA 93727-5951

E-mail: RSOPPE@asrr.arsusda.gov
RSOPPE@cati.csufresno.edu

I can't relate to any of this. Are you guys for real?

Hi, I thought this definitive statement would help put to rest the Good
Times hoax.

---
Kevin Wolf
724 N St
Davis, CA 95616
phone and fax: 916-758-4211

Begin forwarded message:

Errors-To: listmanager@cheetah.llnl.gov
Date: Mon, 24 Apr 1995 13:13:49 -0700
Errors-To: listmanager@cheetah.llnl.gov
Reply-To: christen@cheetah.llnl.gov
Originator: ciac-notes@cheetah.llnl.gov
Sender: ciac-notes@cheetah.llnl.gov
Precedence: bulk
From: "Marvin J. Christensen" <christen@cheetah.llnl.gov>
To: stuarts@landau.ucdavis.edu
Subject: CIAC NOTES 09
X-Listprocessor-Version: 6.0b -- ListProcessor by Anastasios Kotsikonas

-----BEGIN PGP SIGNED MESSAGE-----

U.S. DOE's Computer Incident Advisory Capability
___ __ __ _ ___ __ __ __ __ __
/ | /_\ / |\ | / \ | |_ /_
\___ __|__ / \ \___ | \| \__/ | |__ __/

Number 95-09 April 24, 1995

This edition of CIAC NOTES describes the recent rebirth of "Good Times",
and reiterates CIAC's previous position that "Good Times" is a hoax.
Please send your comments and feedback to ciac@llnl.gov.

$-$-$-$-$-$-$-$-$-$-$-$-$-$-$-$-$-$-$-$-$-$-$-$-$-$-$-$-$-$-$-$-$-$-$-$
$ Reference to any specific commercial product does not necessarily $
$ constitute or imply its endorsement, recommendation or favoring by $
$ CIAC, the University of California, or the United States Government.$
$-$-$-$-$-$-$-$-$-$-$-$-$-$-$-$-$-$-$-$-$-$-$-$-$-$-$-$-$-$-$-$-$-$-$-$

There is a rebirth of the "Good Times" urban legend. CIAC and other
response teams, along with the Federal Communications Commission and
America Online, have received numerous queries regarding the validity
of the "Good Times" virus. The current "Good Times" message appears to
be a repeat of the hoax perpetuated last December.

CIAC first released CIAC NOTES 94-04 in December 1994 which is titled
"THE 'Good Times' VIRUS IS AN URBAN LEGEND." The original "Good Times"
message that was posted and circulated contained the following:

---------------------------------------------------------------------------
| Here is some important information. Beware of a file called Goodtimes. |
| |
| Happy Chanukah everyone, and be careful out there. There is a virus on |
| America Online being sent by E-Mail. If you get anything called "Good |
| Times", DON'T read it or download it. It is a virus that will erase your |
| hard drive. Forward this to all your friends. It may help them a lot. |
---------------------------------------------------------------------------

Soon after the release of CIAC NOTES 04, another "Good
Times" message was circulated. This is the same message that is
being circulated during this recent "Good Times" rebirth. This
message includes a claim that the Federal Communications Commission
(FCC) released a warning about the danger of the "Good Times"
virus. This "Good Times" hoax message contains the following:

The FCC released a warning last Wednesday concerning a matter of
major importance to any regular user of the InterNet. Apparently,
a new computer virus has been engineered by a user of America
Online that is unparalleled in its destructive capability. Other,
more well-known viruses such as Stoned, Airwolf, and Michaelangelo
pale in comparison to the prospects of this newest creation by a
warped mentality.
What makes this virus so terrifying, said the FCC, is the fact
that no program needs to be exchanged for a new computer to be
infected.

... { stuff deleted } ...

CIAC contacted the FCC to ensure that this reference was fabricated
and that the "Good Times" is truly a hoax.

ADDITIONAL INFORMATION
======================
Having malicious code (malware) buried in the body of an E-mail
message that would "infect" your computer is not a very likely
possibility because characters in an E-mail message are displayed, not
executed. CIAC still affirms that reading E-mail, using typical mail
agents, will not activate malware delivered in or with the message.

Many people believe "in theory" that malware can be delivered and
activated by some mail agents that have automated services. An
example of such malware is mail delivered to a PC that has embedded,
seemingly invisible escape sequences which affect screen display or
program the keyboard to do some nastiness when some key is
"accidently" pressed. The following is an excerpt from CIAC NOTES
05 which included and update to the "Good Times" urban legend.

CIAC did not claim that E-mail could not be a delivery agent for
malware. A real threat comes from attached files which could
contain viruses or Trojan programs. You should scan any executable
attachment before executing it in the same way that you scan all new
software before using it. It is possible to create a file that
remaps keys when displayed on a PC/MS-DOS machine with the ANSI.SYS
driver loaded. However, this only works on PC/MS-DOS machines with
the text displayed on the screen in text mode. It would not work in
Windows or in most text editors or mailers. A key could be remapped
to produce any command sequence when pressed, for example DEL or
FORMAT. However, the command is not issued until the remapped key
is pressed and the command issued by the remapped key would be
visible on the screen. You could protect yourself by removing
ANSI.SYS from the CONFIG.SYS file, but many DOS programs use the
functionality of ANSI.SYS to control screen functions and colors.
Windows programs are not effected by ANSI.SYS, though a DOS program
running in Windows would be.

- - ------------------------------
Who is CIAC?

CIAC is the U.S. Department of Energy's Computer Incident Advisory
Capability. Established in 1989, shortly after the Internet Worm, CIAC
provides various computer security services free of charge to
employees and contractors of the DOE, such as:

. Incident Handling Consulting
. Computer Security Information
. On-site Workshops
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CIAC is located at Lawrence Livermore National Laboratory in
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Technology Center. Further information can be found at CIAC. CIAC is
also a founding member of FIRST, the Forum of Incident Response and
Security Teams, a global organization established to foster
cooperation and coordination among computer security teams
worldwide. See FIRST for more details.

- - ------------------------------
CIAC, the Computer Incident Advisory Capability, is the computer security
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CIAC is also a founding member of FIRST, the Forum of Incident Response
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CIAC services are available to DOE and DOE contractors, and can be
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Previous CIAC notices, anti-virus software, pgp public key, and other
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Anonymous FTP: ciac.llnl.gov (128.115.19.53)
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CIAC has several self-subscribing mailing lists for electronic publications:
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- - ---------------------------------------------------------------
This document was prepared as an account of work sponsored by an
agency of the United States Government. Neither the United States
Government nor the University of California nor any of their
employees, makes any warranty, express or implied, or assumes any
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End of CIAC Notes Number 95-09 95_4_24

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Quoting ScottGood@aol.com:
>
> ATTENTION fellow subscribers and Internet friends....

[Nonsense deleted]

This is a hoax. Anyone with any knowledge of how system software functions
knows that _reading_ data is an inherently safe operation.

Folks,
I've seen this warning on several other servers about the "Good Times"
virus. This is a hoax started at some university as a prank and should
be treated as such (at least I have received several disclaimers to this
effect).

Hello All - I'm a newbie to the list, and am involved in
the landscape and gardens at a Houston area public building.
Does anyone have referrals for wholesale sources of automated
timers for greenhouses/sprinkler zones? We are a non-profit.
The summer droughts are approaching.... I'll be automating with
timers upstream of drip hose, drip emitters, & rainbird sprinkler
head systems. We used to have a 4 zone rainbird timer, but it
now is kaput. I am looking to replace that, and expand to
other zones as well.

Thanks in Advance for any phone # &/or address references.
Greg in Houston.

A note to all subscribers:

Thanks for the clarification on "GOOD TIMES". As you might guess correctly tha
t I would be deluged by messages. I did get several copies of the CAIC NOTES
and other 'insightful' messages. While I did note twice that I could not
authenticate the 'threat', I thought I would still post it (knowledge is
power....???). I apologize for being new to the Internet system and being
further under the 'knowledge curve' than I thought. I still belive that it
was better to post and look the part of court jester than not say anything
till after a worse case senerio has hit.... (The bug that ate the Internet).

Another day wiser (and older),
Scott Good
Scottgood@aol.com

Gopher strikes have been discussed quite recently and I claimed that gopher
damage in SSD was quite rare and not a serious problem. I now have a grower
with a serious problem!
The drip lines are at 16 inches in sandy soil and drippers are 42 inches
apart. The wetted areas are not joining. Is it reasonable that the gophers
avoid the wetted area around the emitters and are channelled into the dry
mid sections where they strike?
Any experts out there?

Rodney.

The following is a response from a new member in Australia. He answered a few
of the welcome survey questions which are self explanatory.

I am an agriculture graduate willing to do my post graduate studies
in trickle irrigation. I am willing to do my research project on
effluent reuse with trickle irrigation.
2. The crops I am going to use are maize and cotton
3. Average depth I am willing to practice is 30cm.

This is going to be my first trial in trickle irrigation.
I could comunicate with you with the progress of my
experiment particularly with regard to other questions you put
forwarded.

Regards

Joseph Rajeswaran
957321@student.hawkesbury.uws.EDU.AU

My only suggestion is (assuming that the installation is not permanent) to
treat the field and the perimeter with a gopher machine and poisin seed PRIOR
to installation. This is @95% effective in cleaning the field.

Many of us are on a learning curve of how to use SSD well. My particular
interest in SSD in permanent crops. I have prepared the following draft
paper putting together everthing that I have learned about the practical
matter of design, installation and operation of SSD in permanent crops with
respect to how it differs from above ground drip.
I think that this paper could be of use for many Trickle-L members so I
invite your comments and advice before general publication.

DRAFT

=46ACTORS IN THE DESIGN, INSTALLATION AND OPERATION OF A SUBSURFACE DRIP
IRRIGATION SYSTEM IN PERMANENT CROPS

This paper is written for professionals skilled in above ground drip
irrigation who wish to apply their skills to subsurface drip irrigation
(SDI).

The objectives of a SDI system are:

=AE A dry soil surface to minimize weed growth, moisture loss and disease.
=AE Broad lateral spread and minimum deep percolation to maximize the
wetted root volume and minimize percolation water losses and
contamination of the groundwater with agricultural chemicals.

=AE Dry Soil Surface:
To reduce the risk of water erupting to the surface:
1. Pulse the irrigation cycle with set times of one hour if practical. To
enable pulsing the mains and submains should be designed to stay full of
water between irrigations so that the filling time of the system is less
than 10 minutes. The use of non-return valves can assist in this objective.
2. Install the system in a position where equipment will not run over the
buried line, compacting the soil.
3. If the soil is compacted lightly till over the buried drip line.
4. Water penetration problems effect about 20% of California farmlands.
The key elements from a chemical analysis of an irrigation water which
govern the water's infiltration characteristics are the total salinity of
the water (ECw) and the relative sodium content. The relative sodium
content is evaluated through a calculated value called the Sodium
Absorption Ratio (SAR). The SAR is calculated from the elemental levels of
calcium (Ca), magnesium (Mg), and sodium (Na) in the water.
The infiltration rate generally increases when the water is saltier and
decreases with high SAR values. When the salt content of the water source
is very low there can be water penetration problems irrespective of the SAR
(1).
Growers have reported improvement of penetration of water into the soil by
adding gypsum through the drip system. This should be done under the
advice of an expert in this field using special fine grades of gypsum.
5. Disturbing the soil during installation can also cause water to surface.

Time will resolve the problem as the soil settles and the root system of
the crop penetrates the region around the emitter..

=AE Broad Lateral Spread and Minimum Deep Percolation:
1. Pulse the system - see 1 above. Claude Phene has shown that a pulsed SDI
system can have 46% greater wetted volume and 62% greater wetted interface
area than a pulsed surface drip system (2).

Problems to Avoid:

Inadequate fertility at the greater root depth,
Vacuum ingestion of soil into the drip system,
Gophers and
Root intrusion.
=46ortunately we have secure solutions; fertigation, vacuum relief valves an=
d
ROOTGUARD=AE

=AE Inadequate fertility at the greater root depth - Fertigation:
To achieve the best results it is essential to supply fertilizers through
the buried drip system. In particular phosphorus and potassium are often in
deficit of the plant needs at the usual 18" to 24" inch depth of burial.
Every system must have provision for fertilizer injection both for
fertilizers and for injection of chlorine or acids to control bacterial
slimes.

=AE Vacuum ingestion of soil into the drip system - Vacuum Relief Valves:
1) To prevent soil ingestion adequate vacuum relief valves must be
positioned at all high points. Use vacuum relief valves twice the size of
that used for an above ground system. Above ground vacuum relief valves are
sized to prevent collapse of the pipe - we need to keep water and soil from
being drawn in through the emitters.
In particular be careful when using pressure compensating emitters of the
type with a rubber diaphragm pressed against a labyrinth (EQUALINE=81, AGRI+
and RAM etc.). The ingested soil can lodge between the diaphragm and the
labyrinth sealing surface and cause an increase in flow.
2) Use slow closing valves.

=AE Gophers:
Gophers are not usually a significant problem. To reduce gopher strike risk
bury the line more than 18" deep, most gophers do not operate at the deeper
levels. Ensure that the wetted circles from the emitters overlap so that
all the dripline is in wetted soil. Gophers appear to prefer to dig through
dry soil.

=AE Root intrusion.- ROOTGUARD etc.
(My bias on this topic is well known to most Trickle-L members, so I have
not included the text of my paragraph which my company will use
commercially).

The Three Questions Most Commonly Asked

=AE How do I know if the system is working?
=AE How deep do I bury the dripline?
=AE How to I manage the immediate needs of new plantings with the long term
needs of the fully developed tree or vine?

=AE How do I know if the system is working? Monitoring the System:
A flow meter and pressure gauge are essential parts of any SDI system.
When the system is installed a standard flow rate at a standard pressure
should be established for each section.
In the event of any variation of flow of more than 5% remedial action
should be taken:
(a) The usual first step is to clean the system with chlorine or acid or
one of the proprietary products.
(b) If this does not bring the system back to standard then one must
examine the line by digging up a section.
Caution: With pressure compensating emitters with rubber diaphragms even a
small increase in flow may signal a serious problem. With turbulent flow
emitters an increase in flow indicates a broken lateral or leaking
pipeline.

=AE How deep do I bury the dripline?
Like most SDI decisions this is soil dependent. Given deep soil with
neither severe changes in structure with depth nor high water tables then
18" to 24" depth has generally been suitable. The shallower depths for the
sandier soils.
With walnuts we recommend 24" depth to reduce the risk of strangulation by
the very large walnut tree roots.

=AE How to I manage the immediate needs of new plantings with the long term
needs of the fully developed tree or vine?
Vines:
With well rooted benchgrafts the simplest approach is to bury the drip line
at the preferred depth just off to one side and plant the vine in the fall
before the winter rains. Or
do the same as above but over-irrigate and be prepared to waste water for
the first few months. Or,
with less well developed cuttings place the dripline about 1" below ground
next to the row of vines. At the end of the season pick up the dripline and
bury at the preferred depth.
Trees:
Any trees with a row spacing in excess of 15' will usually have two rows of
dripline. There are several reports of jets being better than drip for
established trees. If one compares one row of jets with one row of drippers
this is often correct. Two rows of SDI will outperform jets almost every
time.
Place the first row of dripline just off to one side of the tree as per
vines above. You do not need to connect the second dripline row immediately
at planting. After one or two years connect the second line on the windward
side at the estimated dripline of the fully grown tree.

References:
1. Ron Brase, 1995. Water Penetration Problems. Central Valley Farmer,
=46eb. 1 ,1995.
2. Claude Phene, K. R. Davis, R.B. Hutmacher, B. Bar-Yosef, D.W. Meek 1990.
Effect of high frequency subsurface and surface drip irrigation on root
distribution of sweet corn. Irr. Science, 12:135-140.

=A9 Copyright Rodney Ruskin, April 28, 1995.
Permission is granted to any interested party to reproduce this material in
whole or in part provided that the source is correctly credited.

Rodney: I Enjoyed getting a copy of your draft could you send me the
paragraph on root guard so I have a complete text
You asked about drip lines with drippers at 42 inches not wetting together
in a previous note. Do you have any knowledge of soils becoming hydrophobic
over time.
Since my company works in all areas of specialty agriculture I see problems
within different areas that are not well understood in water management,i.e.
golf course greens have "isolated dry spot", areas of Northern California and
north into Washington have soils that do not wet and dry uniformly due to
magnesium silicate( talcum powder) ,Container growers and greenhouse
sometimes have major problems due to the medias wetting character. Is this a
problem in trickle irrigation?
On a different subject does anyone know if the oxygen status of the soil at
the depth of installation affects the oxidation or reduction status of
elements applied? For instance does sulfur tend to reduce to H2S in the
immediate area of the dripline?

Thanks , Jim

The draft appears very pertainent to our experience with SDI.

>A flow meter and pressure gauge are essential parts of any SDI >system.

I cannot over emphasize the importance of this. I make sure that we have a ge
nerous straight section of appropriatey sized pipe to achieve accurate and
repeatable readings (e.g. 4" for 325 gpm nominal).

Due to 'noisy', or 'bouncing' instant flow readings I find the best way to
accurately read flow is to time how long it takes to advance the totalizer
several hundred gallons, and convert that to GPM. Repeatabilty is within one
percent at same pressure using this method. Instant flow readings are nice
for a quick check, but seem to be too unstable for truly accurate flow
readings. Using the 'timed' method of determining flow, I can detect one
open hose out of 200 if the break is near the mainline, and can detect 4 or
more open hoses if the breach is near the hose ends (+/- 600' runs, 16mm
hose).

Another factor is how dry the soil is around the hose ... flow tends to drop
by as much as a few percent as the runtime progresses and the soil begins to
resist infiltration ... so it is most accurate to take the flow reading at,
say, one hour into the run for each check.

I do high accuracy checks every few weeks, as well as right after the
injection of some fertilizers (e.g. soluablized K2SO4).

By the way ... don't panic if flow drops a little as summer progresses ...
check the pressure again and you might find slightly lower reading as the
ground water table drops ... we get a 10' to 20' (resulting in 3 to 7 psi
variation) annual water table fluctuation depending on rainfall and nearby
pumping. This makes it a very good idea to chart normal flow over a range of
pressures. If you accurately sound your well, this information will also let
you monitor the condition of your pump bowls and adjustment.

Craig Thompson

Enclosed below is data from the Irrigation Journal 1994 survey of land area
dedicated to subsurface and surface drip irrigation, respectively. The
Irrigation Journal had more information on irrigation, but I extrapolated
only drip data. All numbers are in hectares (1 ha = 2.471 acres). Of this
list below, I found two things interesting:
1) The number of states NOT using drip irrigation at all (Nevada, Montana,
Nebraska, New Hampshire, Puerto Rico, Vermont). Three out of those six states
are considered arid to semi-arid.
2) There is a proportionally large ratio of subsurface to surface drip
irrigated land in Hawaii and Texas. I can understand Hawaii having a high
percentage in subsurface due to high land cost, water saving incentives and
the growth of intensive cash crops, but I was really amazed with the Texas
figure. Anyone in Texas willing to explain this phenomena?

For all the non-U.S. countries represented on Trickle-L, it would be great
to see their country's data of subsurface vs surface drip irrigated land
area. Please contribute information to this list if you have any numbers
available.

Please note that subsurface drip is the first number, and surface drip is
second.
(No bias intended)

State (USA) SSD-Ha, SD-Ha
****************************
Alaska 0,10
Arizona 1296, 3563
Arkansas 415 ,1275
California 22317 , 323590
Colorado 40, 486
Connecticut 0 , 810
Delaware 0, 202
Florida 810 ,28340
Georgia 3887 , 22672
Hawaii 28340, 8097
Idaho 61, 142
Illinois 0 , 1417
Indiana 0, 81
Iowa 202 , 2024
Kansas 0, 2024
Kentucky 405 , 2429
Louisiana 40, 729
Maine 0, 81
Maryland 1204, 0
Massachusetts 202, 567
Michigan 0 , 21862
Minnesota 0, 810
Mississippi 283, 1215
Missouri 283 , 1134
Montana 0, 0
Nebraska 0 , 0
Nevada 0 , 0
New Hamsphire 0, 0
New Jersey 0, 2611
New Mexico 0, 1872
New York 202, 1903
North Carolina 405, 2429
North Dakota 14, 26
Ohio 0, 827
Oklahoma 810, 3644
Oregon 0, 3036
Pennsylvania 0, 3644
Puerto Rico 0, 0
Rhode Island 0, 81
South Carolina 0, 3846
South Dakota 40, 81
Tennesee 0, 2429
Texas 16194, 2429
Utah 17, 339
Vermont 0, 0
Washington 1417, 8097
West Virginia 0, 381
Wisconsin 0, 243
Wyoming 0, 202
SSD-HECTARES SD-HECTARES
Total 78886 461676
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