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Overstory....
- To: permaculture <permaculture@franklin.oit.unc.edu>
- Subject: Overstory....
- From: Claude Genest <genest@together.net>
- Date: Wed, 09 Jan 2002 20:57:15 -0500
- In-reply-to: <LISTMANAGER-86479-39633-2002.01.09-17.41.38--genest#together.net@franklin.oit.unc.edu>
- Newsgroups: permaculture
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This is an agroforestry newsletter that a friend sent -
Thought it might be of interest and maybe help provide stats. etc ( re: food
forestry/alley cropping etc.)
Info re: subscribing is at end of email.
Claude
>From: "The Overstory" <overstory@agroforester.com>
>To: "Nicolas Freyre" <fleaunico@hotmail.com>
>Subject: The Overstory #96--Sheet Mulch
>Date: Mon, 7 Jan 2002 19:23:22 -1000
>
>Welcome to The Overstory! This free e-mail journal serves subscribers in
>156 countries. To subscribe (or unsubscribe), please see message at the end
>of this e-mail.
>
>The Overstory Book is now available on CD. The CD contains first three
>years of The Overstory, formatted, indexed and searchable with live web
>links: <http://agroforester.com/overstory/ovbook.html>
>
>
>::::::::::::::
>Overstory #96 - Sheet Mulch: Greater Plant and Soil Health with Less Work
>
>by Craig R. Elevitch and Kim M. Wilkinson
>
>Contents:
>
>: INTRODUCTION
>: BENEFITS OF SHEET MULCH
>: BASIC TECHNIQUES OF SHEET MULCHING
>: STEPS FOR APPLYING SHEET MULCH
>: SHEET MULCH AROUND TREES
>: CAUTIONS/CONSIDERATIONS
>: THE ONGOING PROCESS
>: REFERENCES
>: ORIGINAL SOURCE
>: ABOUT THE AUTHORS
>: WEB LINKS
>: RELATED EDITIONS OF THE OVERSTORY
>: PUBLISHER NOTES
>
>As you have probably noticed, The Overstory covers a wide variety of topics
>related to trees, their cultivation and conservation. This edition presents
>a simple but highly effective technique for protecting and enhancing soil
>called, "sheet mulching." We believe this subject is so valuable for
>practitioners that we are publishing a revised and more detailed account of
>the mulch technique first introduced in The Overstory #1.
>
>
>::::::::::::::
>
>INTRODUCTION
>
>Mulch is a layer of decaying organic matter on the ground. Mulch occurs
>naturally in forests; it is a nutrient rich, moisture absorbent bed of
>decaying forest leaves, twigs and branches, teeming with fungal, microbial
>and insect life. Natural mulch stores the nutrients contained in organic
>matter and slowly makes these nutrients available to plants. Mulch also
>protects soil from desiccation by the sun and wind, as well as from the
>erosive effects of rain and run-off.
>
>Mulch forms a necessary link in nutrient cycling vital for our soils. When
>mulch is absent for whatever reason, the living soil is robbed of its
>natural nutrient stores, becomes leached and often desiccates. Natural
>terrestrial environments without a litter layer are usually deserts.
>Non-desert plants grown in bare soil require constant fertilization,
>nutrient additions, and water, not to mention the work required to keep the
>soil bare.
>
>"Sheet mulch" is a four-layered mulch system for use around crops. The four
>layers (or "sheets") mimic the litter layer of a forest floor, and optimize
>the weed control and fertility benefits of mulch. The sheet mulch technique
>described here is for use with trees or in gardens. The techniques can also
>be adapted for landscaping and other agricultural uses. Sheet mulch is a
>simple and underutilized technique protecting soil, reducing weed
>competition, and restoring fertility.
>
>
>BENEFITS OF SHEET MULCH
>
>* Improves nutrient and water retention in the soil
>* Encourages favorable soil microbial activity and worms
>* Suppresses weed growth and competition around crops
>* Reduces labor and maintenance costs as compared to bare soil culture
>* Provides crops with organic matter and nutrients
>* Improves plants vigor and health, often leading to improved resistance to
>pests and diseases
>* Enhances soil structure
>
>
>BASIC TECHNIQUES OF SHEET MULCHING
>
>Once you get the hang of it, sheet mulching can be used almost anywhere. It
>may be used either in establishing a new garden or tree planting, or to
>enrich existing plantings. Below is described sheet mulching to cover an
>area such as a garden on a small scale, then, how to sheet mulch around a
>tree. In both cases, mulch is applied to bare soil or on top of cut weeds.
>New plantings are planted through the mulch, or a small area is left open
>to accommodate established plants and trees.
>
>The benefits of mulching justify putting the energy into doing the job
>right, using ample materials. Collect all of the materials (as outlined
>below), and complete the mulching process in one session. A reduction in
>maintenance and increase in plant vigor will more than pay off the initial
>effort.
>
>Sheet mulch is put down in four layers to mimic natural forest mulch: well
>decayed compost, weed barrier, partly decayed compost and raw organic
>matter, as described below.
>
>
>STEPS FOR APPLYING SHEET MULCH
>
>Step 1: Prepare site
>
>To prepare the site, knock down tall weeds and woody plants with a scythe,
>brush cutter, or by trampling the existing vegetation so that it lies flat.
>A poultry or pig tractor system (Overstory #50, see link below) is an
>excellent method of site preparation. There is no need to remove
>vegetation, unless it is woody or bulky. It fact the organic matter left
>now will decay and add nutrients to the soil. Once vegetation in the area
>is flattened proceed to lay down the sheet mulch.
>
>Step 2: Add concentrated compost and mineral amendments (Layer #1)
>
>Whether you are mulching bare soil or weeds, "jump start" microbial
>activity by adding high nutrient material which stimulates soil life. This
>material also accelerates the decay of weeds and grass under the mulch.
>Suitable materials are enriched compost, poultry or stock manure, worm
>castings, feather meal or similar at the rate of about 2.2 kg/m2 (50
>lbs/100 ft2). If the soil is overly acid, which is common in disturbed
>soils or those treated with conventional fertilizers, add lime. A soil
>analysis will indicate the need for adjustment of pH or mineral amendments.
>This is the appropriate time to add the recommended doses of minerals such
>as phosphorous and potassium.
>
>Step 3: Water well
>
>Now, soak the area well with water. This is essential as it starts the
>natural process of decomposition. Also it is much easier to soak the ground
>now, before the remaining layers of mulch are applied.
>
>Step 4: Apply a weed barrier (Layer #2)
>
>Most cultivated areas harbor untold numbers of weed seeds. There are also
>weed seeds blown by wind, animals and people. Soil borne seeds are lying
>dormant and waiting for sunlight, moisture and space to sprout. Simply
>pulling or killing growing weeds will not erase the weed problem: more
>seeds will sprout almost as soon as the soil is exposed to moisture and
>light. Therefore the next step in mulching is to put down an organic weed
>barrier. This barrier prevents the germination and eventual emergence of
>weeds through your mulch.
>
>Underneath this weed barrier grasses and weeds die and quickly become food
>for earthworms. The worms turn and aerate the soil.
>
>Of the four sheet mulch layers, the weed barrier has no natural counterpart
>on the forest floor. In the forest, weeds do not sprout because there is
>"no room for them," which simply means a lack of space above and below the
>ground, and a lack of light. By planting an area properly, there will
>eventually be no room for weeds. The weed barrier is needed only for
>establishment of the mulch, and disappears with time. If your area is
>planted appropriately, weeds will not emerge after the decomposition of the
>weed barrier.
>
>Materials for the weed barrier that work well are: cardboard, 4-6 sheets of
>newspaper, burlap bags, old carpets of natural fiber, worn-out clothing,
>gypsum board, or any other similar biodegradable materials. Banana or other
>large leaves also work if laid down in several layers. Overlap the pieces
>of the material so as to completely cover the ground without any breaks,
>except where there are plants you want to save. Around these leave a
>generous opening for air circulation around the root crown. Care in laying
>down the weed barrier without gaps will save you the headache of emerging
>weeds later on.
>
>Both water and good air circulation are necessary for healthy soil.
>Although the weed barrier forms a physical and light barrier, it is
>essential that is be permeable to water and air. Overlapped pieces of
>organic material as recommended above let water and air slowly permeate
>between and through them. If the weed barrier is applied too thickly, the
>soil can become anaerobic. Also, for the same reasons plastic mulches are
>not recommended for most situations.
>
>Step 5: The Compost Layer (Layer #3)
>
>This layer is on top of the weed barrier‹it must be weed seed free. Well
>conditioned compost, grass clippings, seaweed or leaves are ideal materials
>to spread over the weed barrier. Any weed-free material mixture at the
>right moisture level for a good compost will do. This should form a fairly
>dense layer about 8 cm (3 inches) thick.
>
>Step 6: The Top Layer (Layer #4)
>
>The top dressing mimics the newly fallen organic matter of the forest. It
>also must be weed-seed free. Good materials for this layer include leaves,
>twigs and small branches, hay, straw, fern or palm fronds, coffee chaff,
>macadamia nut shells, chipped tree prunings, sawdust, bark, coir, bagasse,
>etc. The top layer will slowly decompose into lower layers, and therefore
>must be replaced periodically; it represents reserves of compost. This
>layer should be about 8-13 cm (3-5 inches) deep. Many materials suitable
>for the top layer often have a pleasant cosmetic appearance. For this
>reason, there should be no hesitation in using sheet mulch in all
>cultivation from landscaping to gardening to permanent orchard crops. In
>fact, as you use mulch, bare soil will begin to seem ugly and undesirable.
>
>When the soil is amended and sheet mulch applied properly, there will never
>be a need to turn the soil. Earthworms do the tilling. The only task left
>is to keep the soil covered by replenishing the mulch.
>
>
>SHEET MULCH AROUND TREES
>
>Planting trees with mulch assures optimal conditions for survival and early
>growth. The method is a specialized version of the steps above. Use locally
>available materials, and adapt this method to your situation. If you are
>unsure about the benefits of mulch, apply mulch to some trees and not to
>others planted at the same time. Usually the difference in growth and vigor
>is amazing.
>
>1. Prepare the planting area and plant the tree the way you usually do.
>
>2. Amend soil around tree out to a radius of 0.5 - 1 meter (1.5 - 3 feet)
>with a light layer of nitrogen fertilizer, such as chicken manure, and
>other mineral amendments if necessary. Water well. (If you are mulching an
>established tree, be sure to amend out to the edge of the crown of the
>tree, also called, "the drip line.")
>
>3. Spread a permeable weed barrier around the tree in a ring shape, leaving
>a gap of 15 cm (6 inches) diameter around the trunk of the tree for air
>circulation. Make certain there are no gaps in the barrier through which
>weeds can emerge. If you are using loose materials such as paper that might
>blow away, water the weed barrier layer now.
>
>4. Spread compost and/or mulch about 15 cm (6 inches) thick over the weed
>barrier, again making sure it is several centimeters away from the stem of
>the plant for good air circulation.
>
>5. Leave a generous gap in the mulch around plants to allow for air
>circulation. Otherwise, the mulch can lead to rot on the plant stem.
>
>
>CAUTIONS/CONSIDERATIONS
>
>In most cases (with exception of the last point below), the benefits of
>sheet mulching outweigh the costs. However, be sure to watch out for these
>potential problems and be prepared to handle them if they arise.
>
>* Slugs and snails are particularly fond of mulch. Especially during the
>dry season, slugs will be attracted to mulch. This can be a threat to
>certain small tree seedlings and many garden plants.
>
>* Poultry such as chickens, turkeys, Guinea fowl and more love to scratch
>in mulch. This may be a problem in certain situations, although usually not
>much more of a problem than without mulch.
>
>* Rodents can find a cozy home in mulch. Certain rodents such as rats and
>voles can readily debark certain trees.
>
>* Pigs love good, moist soils which harbor worms, and will grub out sheet
>mulch if they have access to it. Do not use sheet mulch if pigs have access
>to the area; they will be attracted to it and will destroy both your work
>and your plantings.
>
>
>THE ONGOING PROCESS
>
>Once a mulch is established, the soil is covered and weed-free. With time,
>the mulch materials will decay and begin disappearing into the soil from
>the bottom up. The rate decay will be fast during the hot and wet season,
>and slow during dry or cool periods. As in a natural forest, the mulch must
>be replaced or soon the mulch will disappear and the soil will once again
>see the sun and the weeds will take over. As long as organic materials are
>added to the surface of the mulch, there is no need to lay down the weed
>barrier layer after the first time. From time to time mineral amendments of
>phosphorous and calcium can be added to the mulch. However, for the most
>part maintaining sheet mulch requires only replenishing the top layer
>(Layer #4) with materials such as leaves, trimmings, husks, etc.
>
>It is best to design a garden or orchard mulch system to produce its own
>top layer mulch in sufficient amounts. To make mulching as efficient and
>easy as possible, use mulch materials which are readily available. With
>good planning, mulching of gardens and orchards can become a regular part
>of maintenance‹just mulch with handy materials such as grass clippings,
>plant prunings (roughly chopped), animal bedding, etc. Eventually, other
>tasks such as watering, fertilization and weeding will be reduced. The
>overall maintenance burden in mulched conditions, when efficiently using
>materials on hand, can be less than in conventional systems (which may use
>frequent tillage or applications of herbicide).
>
>There are many ways to produce sufficient mulch at your site. Grass
>clippings, for example, represent nutrient rich mulch material. Deep
>rooted, vigorous growing plants that readily regrow after hard pruning can
>be cut 3-6 times per year to provide mulch. For example, several nitrogen
>fixing trees will produce copious amounts of green matter. Each should be
>evaluated for its appropriateness for a specific site before planting. Many
>other plants produce large amounts of organic matter including various
>trees and bunch grasses (e.g. vetiver or lemon grass). Also, many water
>plants such as water hyacinth and kelp are good mulch materials. Because
>fast growing, vigorous plants are desirable for mulch production, when
>selecting plants for this purpose extreme caution should be taken to avoid
>introducing weedy species.
>
>Sheet mulching as described here seeks to recreate the organic mulch layer
>of the forest with a minimum of effort from people. Properly planned, a
>garden or orchard system will produce its own raw mulch in sufficient
>amounts and people are involved only in putting this material back onto the
>ground where it belongs.
>
>
>::::::::::::::
>REFERENCES
>
>Curry, M. 1996. Sheet Mulch Now! In: The Permaculture Activist, issue No.
>34-A, August 1996.
>
>Hemenway, T. 2001. Gaia's Garden: a guide to home-scale permaculture.
>Chelsea Green Publishing Company, White River Junction, Vermont, USA.
>
>Mollison, B. 1990. Permaculture: A Practical Guide for a Sustainable
>Future, Island Press, Washington, DC.
>
>Stout, R. 1998. Gardening without Work: For the Aging, the Busy, and the
>Indolent. Lyons Press.
>
>
>::::::::::::::
>ORIGINAL SOURCE
>
>Elevitch, C.R. and K.M. Wilkinson. 1998. Sheet Mulching: Greater Plant and
>Soil Health for Less Work. Permanent Agriculture Resources, Holualoa, HI.
>Web site: http://www.agroforester.com/articles/Sheet_Mulching.html.
>
>
>::::::::::::::
>ABOUT THE AUTHORS
>
>Craig R. Elevitch is an Agroforestry Specialist with both public and
>private sector experience in tropical agroforest and forest management. He
>has a Master's degree in Electrical Engineering (Dynamical Systems) from
>Cornell University. He has conducted numerous agroforestry research
>projects and species trials in cooperation with organizations including the
>USDA Sustainable Agriculture Research and Extension, Cornell University,
>and the University of Hawaii. Craig is founding editor of The Overstory and
>co-author of Agroforestry Guides for Pacific Islands. Contact him at: P.O.
>Box 428, Holualoa, Hawaii 96725 USA; E-mail: craig@agroforestry.net.
>
>Kim M. Wilkinson is a reforestation professional and a freelance writer.
>She has B.A. degrees in Anthropology and Ecology from Emory University, and
>is a Certified Permaculture Consultant and Master Gardener. She lives on
>and manages an organic agroforestry project on the Island of Hawaii.
>Through her nursery, Future Forests, she grows many thousands of tree
>seedlings annually for people planting agroforests and reforestation
>projects. She is co-author of Agroforestry Guides for Pacific Islands, as
>well as editor for The Overstory. Contact her at: P.O. Box 575, Holualoa,
>Hawaii 96725 USA; E-mail: kim@agroforestry.net.
>
>
>::::::::::::::
>WEB LINKS
>
>Educational Concerns for Hunger Organization's (ECHO's), "Thick Mulch for
>No-till Gardens": http://echonet.org/tropicalag/aztext/azch5dry.htm#Thic
>
>How to Sheet mulch - a very good introduction particularly for temperate
>areas: http://www.wildwords.com/Bombus/page22.html
>
>US Department of Agriculture Natural Resource Conservation Service's
>Backyard Mulching: http://www.nhq.nrcs.usda.gov/CCS/Mulching.html
>
>Frequently Asked Questions about Mulch:
>http://www.deatech.com/globalance/forestg2.htm#MulchGarden
>
>
>::::::::::::::
>RELATED EDITIONS OF THE OVERSTORY
>
>The Overstory #78--Reforestation of Degraded Lands
><http://www.agroforester.com/overstory/overstory78.html>
>The Overstory #70--Rhizosphere
><http://www.agroforester.com/overstory/overstory70.html>
>The Overstory #66--Carbon Sequestration: Storing Carbon in Soils and
>Vegetation
><http://www.agroforester.com/overstory/overstory66.html>
>The Overstory #50--Animal Tractors
><http://www.agroforester.com/overstory/overstory50.html>
>The Overstory #29--Tropical Green Manures/Cover Crops
><http://www.agroforester.com/overstory/overstory29.html>
>The Overstory #28--Microlife
><http://www.agroforester.com/overstory/overstory28.html>
>The Overstory #22--Pioneering Difficult Sites
><http://www.agroforester.com/overstory/overstory22.html>
>The Overstory #20--Five Fertility Principles
><http://www.agroforester.com/overstory/overstory20.html>
>
>
>::::::::::::::
>PUBLISHER NOTES
>
>Publisher: Permanent Agriculture Resources, P.O. Box 428, Holualoa, HI
>96725 USA; Tel: 808-324-4427; Fax: 808-324-4129; E-mail:
><par@agroforestry.net>; Web site: <http://www.agroforestry.net>
>
>Editors: Craig R. Elevitch and Kim M. Wilkinson
>
>Past editions of The Overstory: <http://www.overstory.org>
>
>This publication is Copyright 2002 Permanent Agriculture Resources. All
>rights reserved worldwide. For conditions of use please send an e-mail to
><par@agroforestry.net> or write to Permanent Agriculture Resources at the
>address above.
>
>This newsletter is designed to provide agricultural information, but is
>sent with the understanding that the editors and publishers are not engaged
>in rendering consultation. If expert assistance is required, the services
>of a professional should be sought.
>
>::::::::::::::
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>
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>
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>
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>
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>
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>
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