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Introduction to Conservation Agriculture
 

Introduction to Conservation Agriculture

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Pat Wall

Pat Wall

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    Introduction to Conservation Agriculture Introduction to Conservation Agriculture Presentation Transcript

    • Introduction to Conservation Agriculture and Conservation Farming P.C. WallCIMMYT®
    • What is Conservation Agriculture?An array of technologies such asresidue retention, zero- andreduced tillage, crop rotations,green manure cover crops,controlled traffic and raisedbeds. When used in combinationthese, over time, reduce, andoften revert, the degradation ofsoil and water resources.Residue retention distinguishesconservation agriculture fromconventional agriculture, and allconservation systems include atleast a certain level of surfaceresidue cover.
    • Some Characteristics of Conservation Agriculture• Comprises two basic components  Surface crop residue retention  Minimal soil movement
    • Some Characteristics of Conservation AgriculturePlus other components essential to overcome problems that emerge once crop residues are retained:  Crop rotation  (Green manure cover crops)
    • Conservation Agriculture is acomplex technology: it involves a complete change in the agricultural system.
    • Why the term “Conservation Agriculture”?• To distinguish it from Conservation Tillage = 30% ground cover after seeding• Take the emphasis off the word “tillage”
    • Why Soil Tillage?• Weed Control• Prepare a seed-bed• Mineralise nitrogen• Eliminate compacted zones• Incorporate fertilizers and ammendments• Control diseases and pests• Control water run-off• Accumulate water
    • Why Soil Tillage?• Weed Control• Prepare a seed-bed• Mineralise nitrogen• Eliminate compacted zones• Incorporate fertilizers and ammendments• Control diseases and pests• Control water run-off• Accumulate water
    • ConservationAgriculture withPlanting Basins Both the basins and the mulch provide benefits – together they provide the optimum
    • Why Soil Tillage?• Weed Control• Prepare a seed-bed• Mineralise nitrogen• Eliminate compacted zones• Incorporate fertilizers and ammendments• Control diseases and pests• Control water run-off• Accumulate water
    • Nitrogen mineralization implies organic matter breakdown• It is a “quick fix”. It is a dwindling short- term gain that causes long-term harm.• The release of nitrogen after tillage comes in a “flush” and considerable amounts may be lost.• In conservation agriculture organic matter breakdown is reduced, and so a little more nitrogen must be added to the system, at least for the first few years.
    • Effect of Tillage on Soil Rhizobium Populations 60 50 Rhizobium cells 40 30 20 10 0 Zero Tillage Conventional TillageFrom Voss and Sidiras, 1985
    • Why Soil Tillage?• Weed Control• Prepare a seed-bed• Mineralise nitrogen• Eliminate compacted zones• Incorporate fertilizers and ammendments• Control diseases and pests• Control water run-off• Accumulate water
    • Why Soil Tillage?• Weed Control• Prepare a seed-bed• Mineralise nitrogen• Eliminate compacted zones• Incorporate fertilizers and ammendments• Control diseases and pests• Control water run-off• Accumulate water
    • Effect of Tillage on Soil Phosphorus Oxisol Conv Oxisol Zero Alfisol Conv Alfisol Zero 0-10 Soil Depth (cm.) 10-20 20-40 40-60 0 10 20 30 40 50 P (ppm)Adapted from Sidiras and Pavan, 1985
    • Effect of Tillage on Soil pH Oxisol Conv Oxisol Zero Alfisol Conv Alfisol Zero 0-10 Soil Depth (cm.) 10-20 20-40 40-60 0 2 4 6 8 pHAdapted from Sidiras and Pavan, 1985
    • Effect of Tillage on Soil Organic Carbon Oxisol Conv Oxisol Zero Alfisol Conv Alfisol Zero 0-10 Soil Depth (cm.) 10-20 20-40 0 0.5 1 1.5 2 2.5 Organic Carbon %Adapted from Sidiras and Pavan, 1985
    • Effect of Tillage on Earthworm Populations Oxisol Alfisol 30 Earthworms/m 2 25 20 15 10 5 0 Conv. Vert. Zero Source : Derpsch et al., 1991. Oxisol :- 0-30 cm. after 4 years Alfisol :- 0-10 cm. after 1.5 years
    • Why Soil Tillage?• Weed Control• Prepare a seed-bed• Mineralise nitrogen• Eliminate compacted zones• Incorporate fertilizers and ammendments• Control diseases and pests• Control water run-off• Accumulate water
    • Monoculture leads to a build-up of pests and diseases. This is far more marked in zero tillage than in conventional tillageThe key to controlling pests and diseases in zero tillage agriculture is crop rotation. One should avoid seeding a crop into it’s own residues before these are decomposed.
    • Why Soil Tillage?• Weed Control• Prepare a seed-bed• Mineralise nitrogen• Eliminate compacted zones• Incorporate fertilizers and ammendments• Control diseases and pests• Control water run-off• Accumulate water
    • Effect of Tillage on Water Erosion Soil Loss (t/ha/year) Brazil Paraguay (Sidiras) (Venialgo)Conventional Tillage 68.2 22.9Vertical Tillage 55.0Zero Tillage 6.9 0.5
    • Why Soil Tillage?• Weed Control• Prepare a seed-bed• Mineralize nitrogen• Eliminate compacted zones• Incorporate fertilizers and amendments• Control diseases and pests• Control water run-off• Accumulate water
    • Effect of Tillage and Residue Cover on Water Infiltration Treatment % Residue % Water Soil Loss Cover Runoff t/ha Deep plough, disc 0 90 28.5 Rip, disc 10 70 6.7 Chisel plough, 30 34 1.6 cultivate Zero tillage 80 6 1.0 63mm in 1 hour – 4% slope.Cedara Agric. Res. Stn, Kwazulu-Natal, RSA
    • Aesthetics!
    • World wide adoption of Zero-tillage 2002 Millions of hectares Total = 67 million ha. Rest of the World 1.4 Canada 4.1 USA 21.1 China 1.0? IGP 0.2 Brazil 17.3 Ghana: 100.000 small farmers use NT Paraguay 1.3 Argentina 11.7 Australia 9.0Based on Derpsch 2002
    • Farmers Perceptions of the Benefits of Conservation Agriculture Perceived by: Benefit Large Farmers Small FarmersLower labour requirement + +++Simplifies labor management +++ +Reduced drudgery +++Fuel savings +++ +Increased machinery use efficiency +++Can expand planted area with existing resources +++ ++Reduces production costs ++ +++Higher yields, especially in drought years +++ +++Can seed more of the crop at optimum time +++ + (+++) aAvoid re-seeding of crops ++ ++Longer tractor life +++ +Reduces soil erosion ++ +Facilitates weed control + +Facilitates pest control + +Reduced fertilizer requirements + +a Very dependent on region and limiting factors.
    • The principles of conservation agriculture appear to have extremely wide application The actual formulae andtechnologies for applying theseprinciples are very site-specific.