1. You have learnt from the lessons in the earlier Modules that soil properties influence soil health. These soil properties in turn are affected by the agricultural practices followed by a farmer. Good agricultural practices not only help in managing the soil but also improve soil health. What are these good agricultural practices? Virtual Academy for the Semi Arid Tropics Course on Soil and Soil Health Module III: Soil Health Management

2. The good agricultural practices that help in improving and managing soil health focus on: Improving and maintaining organic matter in the soil; Avoiding tillage practices that harm the soil structure; Conserving the soil from erosion and other soil degrading effects; Adopting integrated nutrient and pest management practices, Rectifying soil problems like acidity and alkalinity. Virtual Academy for the Semi Arid Tropics Course on Soil and Soil Health Module III: Soil Health Management

3. Virtual Academy for the Semi Arid Tropics Lesson 3: Conserving the soil from degrading effects Course on Soil and Soil Health Module III: Soil Health Management After successful completion of this Lesson, you will be able to answer: 1.What is soil degradation? 2.What are the causes for soil degradation? 3.What is soil erosion? 4.How soil erosion occurs? 5.List out the various practices that help in preventing soil erosion? 6.Explain the practices that help in preventing soil erosion on soils with different slopes?

4. Virtual Academy for the Semi Arid Tropics Lesson 3: Conserving the soil from degrading effects Course on Soil and Soil Health Module III: Soil Health Management Soil degradation refers to changes in a soil from its original nature. Soil degradation results due to many agricultural activities. The visible soil degradation is due to soil erosion. The invisible soil degradation happens due to the loss of plant nutrients and many useful microorganisms (chemical degradation), damage due to water logging and soil compactness etc (physical degradation).

5. Virtual Academy for the Semi Arid Tropics Lesson 3: Conserving the soil from degrading effects Course on Soil and Soil Health Module III: Soil Health Management World-wide soil Degradation Source of Data: Oldeman, L.R., R.T.A. Hakkeling, and W.G. Sombroek. 1990. World Map of the Status of Human-Induced Soil Degradation. An Explanatory Note, rev. 2nd edition. International Soil Reference and Information Center, Wageningen, the Netherlands.

6. Virtual Academy for the Semi Arid Tropics Lesson 3: Conserving the soil from degrading effects Course on Soil and Soil Health Module III: Soil Health Management Soil erosion results due to washing-off of the rich top soil from a field due to gravity of water from heavy rainfall or wind. Soil erosion

7. Virtual Academy for the Semi Arid Tropics Lesson 3: Conserving the soil from degrading effects Course on Soil and Soil Health Module III: Soil Health Management Fortunately, there are many ways to reduce soil erosion through certain practices: For areas with mild slopes: Reduced tillage: Tilling only the areas that matter while minimally disturbing the soil. Ex.: Tilling between furrows.

8. Virtual Academy for the Semi Arid Tropics Lesson 3: Conserving the soil from degrading effects Course on Soil and Soil Health Module III: Soil Health Management Fortunately, there are many ways to reduce soil erosion through certain practices: For areas with mild slopes: Stubble-mulching: Leaving crop stubble on the field as long as possible to keep the soil covered, reduce evaporation, reduce weed growth and allow the soil organisms to decompose the plant residues.

9. Virtual Academy for the Semi Arid Tropics Lesson 3: Conserving the soil from degrading effects Course on Soil and Soil Health Module III: Soil Health Management For areas with gentle slopes: Contour bunding consist of building earthen embankments across the slope of the land, following the contour as closely as possible. Contour bund

10. Virtual Academy for the Semi Arid Tropics Lesson 3: Conserving the soil from degrading effects Course on Soil and Soil Health Module III: Soil Health Management For areas with gentle slopes: Contour bunding A series of such bunds divide the area into strips and act as barriers to the flow of water, thus reducing the amount and velocity of the runoff allowing better infiltration of water into the soil. Contour bunds

11. Virtual Academy for the Semi Arid Tropics Lesson 3: Conserving the soil from degrading effects Course on Soil and Soil Health Module III: Soil Health Management For areas with gentle slopes: Vegetative bunds: Permanent contour strips of grass or shrubs are useful on gentle slopes. Dense and continuous vegetative cover will slow down the runoff and cause deposition of silt which over time act as a bench terrace. Economically important and unpalatable grasses like Vetiver (Vetiveria zizanoides) and Cymbopogon citratus are useful.

12. Virtual Academy for the Semi Arid Tropics Lesson 3: Conserving the soil from degrading effects Course on Soil and Soil Health Module III: Soil Health Management For areas with gentle slopes: Contour cultivation is a practice of conducting field operations, such as ploughing, planting, and cultivating land, across the slope rather than up and downhill (Fig.).

13. Virtual Academy for the Semi Arid Tropics Lesson 3: Conserving the soil from degrading effects Course on Soil and Soil Health Module III: Soil Health Management For areas with gentle slopes: Contour cultivation: The ridges or broad-bed furrows (BBF) and the crop cover on the contoured rows hold water and thus prevent runoff and soil erosion.

14. Virtual Academy for the Semi Arid Tropics Lesson 3: Conserving the soil from degrading effects Course on Soil and Soil Health Module III: Soil Health Management For areas with gentle slopes: Strip cropping: Growing of crops in strips of few rows of each crop. A strip of tall growing cereal crop can be altered with a strip of short legume crop. This reduces the down slope length of the field considerably, reducing the chance of erosion. Neighboring strips uses leached nutrients.

15. Virtual Academy for the Semi Arid Tropics Lesson 3: Conserving the soil from degrading effects Course on Soil and Soil Health Module III: Soil Health Management For areas with gentle slopes: Strip cropping: Maize strip Soybean strip

16. Virtual Academy for the Semi Arid Tropics Lesson 3: Conserving the soil from degrading effects Course on Soil and Soil Health Module III: Soil Health Management For areas with steeper slopes: Terracing: The ultimate in soil conservation on steeper hills. It is extensively practiced in plantation crops and paddy cultivation in hills where water is also harvested at the same time. Terracing can reduce erosion many-fold.

17. Virtual Academy for the Semi Arid Tropics Lesson 3: Conserving the soil from degrading effects Course on Soil and Soil Health Module III: Soil Health Management For more information on soil and water conservation, please visit the following Internet sites. http://www.krishiworld.com/html/soil_ water_con2.html http://www.krishiworld.com/html/soil_ water_con2.html http://megsoil.nic.in/why_cons.htm

18. This concludes the Lesson 3: Conserving the soil from degrading effects - in this Module. Next, Lesson 4 in this Module, practices for integrated nutrient and pest management are explained briefly. Problem soils and their reclamation procedures are discussed in the last Lesson in this Module. Select Lesson 4 from Module III contents Virtual Academy for the Semi Arid Tropics Course on Soil and Soil Health Module III: Soil Health Management