OL 333 Assignment Four Discussion
Climate Smart Agriculture
Assignment Four. Survey for Solution-Oriented Techniques for Reducing Soil and Water Loss on Sloping Terrain
These two field guides along with illustrated how-to card and workshop lesson plans are available for downloading from the A4 homework page or from download class documents.
Field Guide: Soil Restoration and Conservation for Smallholder Farmers
Worldwide, challenges for smallholder farmers have increased. Harvest production may be down leading to reduced incomes and reduced crops for family consumption. These challenges can be due to depleted soils, lack of funds for purchasing fertilizer, changes in the beginning and end of the rainy season, unpredictable rain during the rainy season, and increased soil erosion and crop damage during extreme weather events. There are simple, low-cost/no-cost activities that subsistence farmers can adopt that can increase harvest production by restoring soil, reducing the need for chemical fertilizers, buffering the effects of unpredictable rainfall, and protecting valuable topsoil from erosion, thereby increasing family nutrition and agricultural income.
What is soil? Soil is a living, breathing organism of, clay, sand, organic material, earthworms, microorganisms, beneficial flora and fauna, nutrients, minerals, water and plant roots. Plant growth can suffer if soil is too wet, too dry and too sandy, too clayey, too exposed and too steep.
Soil moisture. Moisture in the soil is a chief determinant in crop growth and in agricultural production. Soil moisture improves soil chemical processes and also acts as a transport mechanism for getting nutrients to the plants. Moisture stored in the soil provides a buffer during dry periods or during periods of unpredictable rain. Sufficient organic material in the soil and mulch on the surface of the soil can help rainwater percolate into the soil in order to build up soil moisture.
Organic material. Organic material decomposes in the soil and releases vital nutrients for crops—reducing the need to purchase expensive fertilizer. Increased organic material in the soil also helps to retain soil moisture for longer periods of time—buffering against unpredictable rain or an early end to the rainy season. Organic material in the soil is a benefit for root penetration, drainage, aeration, nutrient availability, soil structure, and can neutralize pH imbalances.
Discussing the Importance of organic material. In the first year, farmers may not have organic material. Let them know that they can begin by spreading whatever chopped-up organic material (OM) they can find on top of their field. This can be leaves, manure, chopped-up corn stalks, vegetable-based kitchen scraps. Explain how many freely available types of OM are available around their village; have participants discuss other materials that they might be able to use. Discuss the importance of re-incorporating maize stalks and other crop residues back into the soil—or using them for mulch—rather than burning them prior to planting.
Incorporating organic material into your soil during soil preparation. Farmers can spread organic material on top of their field as they prepare their fields prior to tilling. The organic material will mix in with their soil during tilling.
Mulching for increased organic material, and reduced erosion and evaporation. The addition of mulch to the top of the soil can reduce soil temperature, keep weeds down, improve drainage, attract earthworms, and reduce both wind and water erosion. It can be an excellent method of adding organic material to the soil as the mulch decomposes during the course of the growing season. It is excellent for water conservation: it reduces evaporation protecting garden plants by retaining soil moisture when water is scarce. Adding mulch to your field is very simple. Use the same materials that you used for making compost: leaves, dry grass, rice stalks, straw, and other agricultural residues. Simply place a thin layer on the soil after planting seeds. As the plants begin to grow add another layer until you have 5 to 10 cm.
Making compost. Compost is the earthy, dark crumbly material that results from the decomposition of plant residue. It is rich in nutrients and organic matter and can be used as a plant fertilizer. To make compost you need the right mix of organisms, air, water and plant wastes such as grass clippings, food scraps, manures, leaf litter and straw.
Compost can be made in a bin or simply as a pile approximately a meter square and meter high. Find a location for the compost pile that is well-drained and sunny. Unless you’re lucky enough to have the materials that you need to make an instant compost pile, begin adding materials as you collect them to the top of the pile. It’s good to alternate layers of dry things like leaves and straw with layers of green grass clippings and kitchen waste. A compost pile should be turned every two or three weeks to allow more air into the compost pile. Show the participants examples of finished compost so they know what it should look like.
Compost can be added to the field’s surface before preparation for planting—in this way it will mix in with the field’s soil during tilling and be accessible to the plant’s roots. It can also be added to the surface of the field after planting and before the application of mulch. Its nutrients can then percolate into the soil with rainwater.
Conclusion. Even highly depleted soils can over the course of several years be restored to a vital condition. The addition of organic material and compost will increase the soil’s ability to retain moisture, increase nutrients stored in the soil, increase beneficial microbes and soil flora and fauna and will improve the structure of heavily compacted soil. Mulching will conserve restored soil by reducing moisture loss through evaporation, will contribute organic material and nutrients to the soil, and will prevent the loss of valuable topsoil by protecting the soil from wind and water erosion.
Field Guide: Agricultural Soil and Water Management for Sloping Land
Subsistence farmers suffer not only from depleted soils but from challenges with water: too little water, too much water, and erosion from water. This field guide looks at different ways of developing barriers on farm fields for stopping the flow of water so that it can percolate into the soil and build up soil moisture. The barriers also conserve soil by reducing loss from erosion. Organize a three-hour workshop with 12 to 15 farmers from your community.
Barriers to water movement. On sloping farm fields, creating barriers reduces the speed of water movement so that it can be absorbed into the soil rather than simply running off the land. These barriers also catch topsoil that the water carries preventing the loss of this valuable resource and offer the added benefit of creating level planting areas behind the barriers as the soil accumulates. Barriers can be terraces, stone and earth walls called bunds, or living barriers such as hedges and grass strips.
Building terraces and stone retaining walls can be very labor intensive. Less formal constructions such as soil bunds, hedgerows or rows of grass can be less labor-intensive and therefore potentially more attractive to farmers.
One thing that all barriers have in common is that they run horizontally along a level contour across the falling slope of a field. An A-frame leveling device is used to determine the level contour lines which are marked with stakes or with stones.
Here are four techniques for farmers to consider. The technique chosen by each individual farmer will be based upon how steeply a farmer’s field slopes, how big their field is, whether they are in a high rainfall or low rainfall region, and how much time they have available for investing in the technique.
Contour ridges. Ridges with furrows on the uphill side are formed approximately 1.5m to 2m apart. This 2m area is the catchment area for rainwater. The ridges are only 15 to 20 cm high—simply high enough to contain the run off—which collects in the furrow. Contour ridges represent the least time investment of these four techniques and can be developed, maintained and improved during preparation for each planting season.
Soil bunds. Soil bunds are a method for both containing water and reducing erosion using on-site materials. After marking the horizontal contour line on the sloping field, a ditch 60 cm deep and 60 cm wide is dug. The soil is placed on the downhill side of the ditch creating the soil wall. The base of the wall is typically twice as wide as the wall is high. Soil bunds are placed from between 5m apart on steep land to 20m apart on more gently sloping land. To determine spacing between the bunds, one rule of thumb is that the top of one bund is level with the base of the adjacent uphill bund. However farmer preferences and the size of the farmer’s field are other determinants.
The soil should be well compacted by hand, then fodder grasses, trees and crops are planted on the bund to stabilize it. Water collects in the ditch during rainstorms and can slowly percolate into the soil increasing soil moisture. As rainwater erodes soil uphill of the bund, the soil will accumulate above the bund and begin creating an increasingly level planting strip. Soil bunds will need annual maintenance—and will need to be checked after heavy rainfall and breaches repaired immediately.
Hedgerows. Hedgerows can also be planted along the contour lines of a hillside—in similar spacing as soil bunds depending on the steepness of the slope of the field. Hedges are usually chosen from nitrogen fixing plants, and from plants that when pruned can be used as fodder for farm animals. Initially, these cuttings can be laid at the base of the hedges on the uphill side to trap eroded topsoil. After two or three years, topsoil will begin to accumulate and form a terrace uphill of the hedgerow. Hedgerows represent substantially less time investment than soil bunds—and use less space—making more land available for planting.
Vetiver grass strips. An inexpensive alternative, vetiver grass can be planted along the contour line of a sloping field to prevent the loss of topsoil, and to reduce the rate at which water runs downhill thereby enhancing infiltration. Topsoil builds up on the uphill side and over time creates level planting areas. Grass strips represent substantially less time investment than soil bunds—and use less space. Grass strips need to be maintained over time to keep them from encroaching into the cropping areas. Grass trimmings can be used as fodder. Vetiver grass is very popular, but check with farmers for local favorites.
Conclusion. Upon completion of this workshop discuss with the farmers which technique would be best suited for them. Then plan a second more specialized training workshop for that specific technique.
Resources which can be linked to from the resource page”Links to Climate Smart Ag 333.”
It appears that Ethiopia is ahead of the curve on soil and water restoration, conservation and management. The first two documents in the list below analyze the effectiveness of some of these technologies—but also importantly the decision-making process that farmers go through to determine which one is best for them. There are three other Ethiopian studies in the section below called Soil and Stone Bunds which also provide additional, valuable information.
It was hard to organize these different documents under specific headings because there’s a lot of overlap. Because the overlapping information is hard to see in unique documents on the computer screen, I have invested in printing these out (over several years!) And refer to them regularly.
Soil and Water Systems; Overview of Soil Moisture and Erosion Control:
IFPRI: Are Soil and Water Conservation Technologies a Buffer against Production Risk in the Face of Climate Change? Insights from Ethiopia’s Nile Basin
Role of collective actions in integrated soil and water conservation: The Case of Gununo Watershed, Southern Ethiopia
This is the best general overview available for this section on LEISA and soil and water. I have used this book extensively:
ILEIA: Learning AgriCultures. Module Two. Soil and Water Systems
World Agroforestry Center: Field methods for managing rainwater
FAO/FARMESA: Soil and Water Conservation with a Focus on Water Harvesting and Soil Moisture Retention
SAI: Rainwater Harvesting and Artificial Recharge to Groundwater
HDRA: Water Harvesting And Conservation
Agrodok: Water harvesting and soil moisture retention
A Research Compendium for Damaged, Critical and Marginal Watershed Areas
OL 333 A4 Agricultural Soil and Water Management for Sloping Land; Field Guide, How To Card and Workshop Lesson Plan
CFU: Conservation Farming & Conservation Agriculture Handbook for Zambia Hoe Farmers
Farming for the Future – A Guide to Conservation Agriculture in Zimbabwe
OL 333 A4 Soil Restoration and Conservation for Smallholder Farmers; Field Guide, How To Card and Workshop Lesson Plan
Farming God’s Way: Trainers Reference Guide
Contour Leveling, Depressions to Catch Water, and Infiltration Ditches on Sloping Land
OL 333 A4 Agricultural Soil and Water Management for Sloping Land; Field Guide How To Card Lesson Plan
HDRA: Water Harvesting And Conservation
Agrodok: Water harvesting and soil moisture retention
Soil and Stone Bunds:
Interdisciplinary on-site evaluation of stone bunds to control soil erosion on cropland in northern Ethiopia
Construction of Soil Conservation Structures for Improvement of Crops in Soil Productivity in Southern Ethiopia
Lessons learnt from 10 years research on soil erosion and soil and water conservation in Tigray
Queensland Government — Natural Resources and Mines: Monto vetiver grass for soil and water conservation
World Bank: The role of Vetiver Grass and Sustaining Agricultural Productivity
The Vetiver System for Agriculture and Related Uses
Good luck—I look forward to hearing about your project —please move on to Assignment Four.