Sheet mulching
Encyclopedia
Permaculture
Permaculture is an approach to designing human settlements and agricultural systems that is modeled on the relationships found in nature. It is based on the ecology of how things interrelate rather than on the strictly biological concerns that form the foundation of modern agriculture...
, sheet mulching is an agricultural no-dig gardening
No-dig gardening
No-dig gardening is a non-cultivation method used by some organic gardeners. The origins of no-dig gardening are unclear, and may be based on pre-industrial or nineteenth-century farming techniques. Two pioneers of the method in the twentieth century included F. C...
technique that attempts to mimic natural forests' processes. When deployed properly and in combination with other permacultural principles, it can generate healthy, productive and low maintenance ecosystem
Ecosystem
An ecosystem is a biological environment consisting of all the organisms living in a particular area, as well as all the nonliving , physical components of the environment with which the organisms interact, such as air, soil, water and sunlight....
s.
Technique
1. The area of interest is flattened by trimming down existing plant species such as grass
Grass
Grasses, or more technically graminoids, are monocotyledonous, usually herbaceous plants with narrow leaves growing from the base. They include the "true grasses", of the Poaceae family, as well as the sedges and the rushes . The true grasses include cereals, bamboo and the grasses of lawns ...
es.
2. The soil is analyzed and its pH
Soil pH
The soil pH is a measure of the acidity or basicity in soils. pH is defined as the negative logarithm of the activity of hydrogen ions in solution. It ranges from 0 to 14, with 7 being neutral. A pH below 7 is acidic and above 7 is basic. Soil pH is considered a master variable in soils as it...
is adjusted (if needed).
3. The soil is moisturized (if needed) to facilitate the activity of decomposers.
4. The soil is then covered with a thin layer of slowly-decomposing material (known as the weed barrier), typically cardboard. This suppresses the weeds by blocking sunlight, adds nutrients to the soil as weed matter quickly decays beneath the barrier, and increases the mechanical stability of the growing medium.
5. A layer (around 10 cm thick) of weed-free soil rich in nutrients is added, in an attempt to mimic the A horizon
Soil horizon
A soil horizon is a specific layer in the land area that is parallel to the soil surface and possesses physical characteristics which differ from the layers above and beneath. Horizon formation is a function of a range of geological, chemical, and biological processes and occurs over long time...
.
6. A layer (at most 15 cm thick) of weed-free, woody and leafy matter is added in an attempt to mimic the forest floor
Forest floor
The forest floor, also called detritus, duff and the O horizon, is one of the most distinctive features of a forest ecosystem. It mainly consists of shed vegetative parts, such as leaves, branches, bark, and stems, existing in various stages of decomposition above the soil surface...
or O Horizon. Theoretically, the soil is now ready to receive the desirable plant seeds.
Variations And considerations
- Often the barrier is applied a few months before plantation to ensure the penetration of roots of newly planted seeds.
- Very thick barriers can cause anaerobic conditions.
- Some permaculturists incorporate compostCompostCompost is organic matter that has been decomposed and recycled as a fertilizer and soil amendment. Compost is a key ingredient in organic farming. At its most essential, the process of composting requires simply piling up waste outdoors and waiting for the materials to break down from anywhere...
ing in steps 5 and/or 6. - Sheets of newspaper and clothing can be used instead of cardboard.
- Before step 4, an initial layer (2-3 kg/m2) of matter rich in nutrients (such as compost or manure) may be added to bolster decomposition.
- Some varieties of grasses and weeds may be beneficial in a number of ways. Such plants can be controlled and used rather than eradicated. See also: mulchMulchIn agriculture and gardening, is a protective cover placed over the soil to retain moisture, reduce erosion, provide nutrients, and suppress weed growth and seed germination. Mulching in gardens and landscaping mimics the leaf cover that is found on forest floors....
, list of beneficial weeds. - One variation of sheet mulching, called hugelkultur, involves using buried logs and branches as the first layer of the bed.
Advantages
Sheet mulch has important advantages relative to conventional methods:- Improvement of desirable plants' health and productivity.
- Retention of water and nutrients and stabilization of biochemical cycles.
- Improvement of soil structureSoil structureSoil structure is determined by how individual soil granules clump or bind together and aggregate, and therefore, the arrangement of soil pores between them...
, soil lifeSoil lifeSoil life or soil biota is a collective term for all the organisms living within the soil.-Overview:In balanced soil, plants grow in an active and steady environment. The mineral content of the soil and its heartiful structure are important for their well-being, but it is the life in the earth that...
and prevention of soil erosionErosionErosion is when materials are removed from the surface and changed into something else. It only works by hydraulic actions and transport of solids in the natural environment, and leads to the deposition of these materials elsewhere... - Avoidance of potentially dangerous pesticidePesticidePesticides are substances or mixture of substances intended for preventing, destroying, repelling or mitigating any pest.A pesticide may be a chemical unicycle, biological agent , antimicrobial, disinfectant or device used against any pest...
s, especially herbicideHerbicideHerbicides, also commonly known as weedkillers, are pesticides used to kill unwanted plants. Selective herbicides kill specific targets while leaving the desired crop relatively unharmed. Some of these act by interfering with the growth of the weed and are often synthetic "imitations" of plant...
s. - Reduction of overall maintenance labor and costs.
Disadvantages
- Some weed seeds (such as those of Bermuda grassCynodon dactylonCynodon dactylon , also known as Dūrvā Grass, Bermuda Grass, Dubo, Dog's Tooth Grass, Bahama Grass, Devil's Grass, Couch Grass, Indian Doab, Arugampul, Grama, and Scutch Grass, is a grass native to north and east Africa, Asia and Australia and southern Europe...
and species of bindweedBindweedBindweed may refer to:* Convolvulaceae , a family including about 60 genera and more than 1,650 species** Calystegia , a genus of about 25 species of flowering plants...
) may persist under the barrier and within the soil seed bankSoil Seed BankThe soil seed bank refers to the natural storage of seeds, often dormant, within the soil of most ecosystems. The study of soil seed banks started in 1859 when Charles Darwin observed the emergence of seedlings using soil samples from the bottom of a lake. The first scientific paper on the subject...
. - SlugSlugSlug is a common name that is normally applied to any gastropod mollusc that lacks a shell, has a very reduced shell, or has a small internal shell...
populations may increase during the early stages of decomposition. However they can be kept away or harvested. - The system may need a constant supply of organic material, at least during the early stages.
- Roaming animals may destroy the array.
See also
- AgroecologyAgroecologyAgroecology is the application of ecological principles to the production of food, fuel, fiber, and pharmaceuticals. The term encompasses a broad range of approaches, and is considered "a science, a movement, [and] a practice."...
- EcoagricultureEcoagricultureEcoagriculture describes landscapes that support both agricultural production and biodiversity conservation, working in harmony together to improve the livelihoods of rural communities....
- Ecosystem ApproachEcosystem ApproachThe Ecosystem Approach is considered one of the most important principles of sustainable environmental management.The Fifth Conference of the Parties to the Convention on Biological Diversity defined the Ecosystem Approach in Decision V/6, Annex A, section 1 as ‘a strategy for the integrated...
- Forest gardeningForest gardeningForest gardening is a food production and agroforestry system based on woodland ecosystems, incorporating fruit and nut trees, shrubs, herbs, vines and perennial vegetables which have yields directly useful to humans...
- Ecological designEcological designEcological design was defined by Sim Van der Ryn and Stuart Cowan as "any form of design that minimizes environmentally destructive impacts by integrating itself with living processes." Ecological design is an integrative, ecologically responsible design discipline...