DEFINITIONS

Conservation agriculture
No-till (NT)/ Zero tillage (ZT)
Conservation tillage/ Minimum tillage/ Reduced tillage
Direct planting/ Direct seeding
Organic farming

• Conservation agriculture (CA)
  CA is a set of soil management practices that minimize the disruption of the soil's structure, composition and natural biodiversity. Despite high variability in the types of crops grown and specific management regimes, all forms of conservation agriculture share a number of core principles. These include:
  • maintenance of permanent or semi-permanent soil cover;
  • minimum soil disturbance;
  • regular crop rotations;
  • utilization of green manures/cover crops (GMCC's);
  • no burning of crop residues;
  • integrated disease and pest management;
  • reduction in fossil fuel use and greenhouse gas (GHG) emissions; and
  • controlled/limited human and mechanical traffic over agricultural soils.

• Other important definitions
  Conservation agriculture is largely the product of the collective efforts of a number of previous agricultural movements, including no-till agriculture, agroforestry, green manures/cover crops, direct planting/seeding and integrated pest management, among many others. Yet CA is distinct from each of these so-called agricultural packages, even as it draws upon many of their core principles. This is because CA uses many of the available technologies in unison, resulting in something many believe to be much greater than the "sum of its parts."

The following terms are often confused with conservation agriculture:

• No-till (NT)/ Zero till (ZT)
  NT and ZT are technical components used in conservation agriculture that simply involve the absence of tillage operations on the soil. Crops are planted directly into a seedbed not tilled since harvesting the previous crop. Not everyone utilizing no-till technologies adopts other important components of CA.

• Conservation tillage/ Minimum tillage/ Reduced tillage
  These are tillage operations that leave at least 30% of the soil surface covered by plant residues in order to increase water infiltration and cut down on soil erosion and runoff. NT is one form of conservation tillage since one of its goal is to keep the soil permanently covered.

• Direct planting/ Direct seeding
  This a technique whereby special equipment (e.g. NT drill) is used in order to plant seeds directly into crop residues left on the soil surface without needing to prepare a seedbed beforehand. Direct planting is required in NT agriculture, though it may also be used following primary and/or secondary tillage operations.

• Organic farming
  Organic agriculture does not permit the use of synthetic chemicals to produce plant and animal products, relying instead on the management of soil organic matter (SOM) and biological processes. In some parts of the world, farms must be inspected before their food products are certified organic, indicating that no synthetic chemicals were used in producing them.
  
  Unlike organic farming, CA does allow farmers to apply synthetic chemical fertilizers, fungicides, pesticides and herbicides. Many farmers rely on using these to control weed and pest problems, particularly during the early transition years. As soil physical, chemical and biological health is improved over time, the use of agrichemicals can be significantly reduced or, in some cases, phased out entirely.

References

1. Baker, C.J., K.E. Saxton & W.R. Ritchie. 1996. No-Tillage Seeding: Science and Practice. CAB International: Wallingford, Oxon, UK.
2. Brady, N.C. & R.R. Weil. 1999. The Nature and Properties of Soils. 12th ed. Macmillan Publishing Co.: New York, NY.
3. Food and Agriculture Organization (FAO) Conservation Agriculture web site -- http://www.fao.org/waicent/faoinfo/agricult/ags/AGSE/Main.htm
4. Food and Agriculture Organization Crop and Grassland Service (FAO-AGCP) web site -- http://www.fao.org/ag/AGP/AGPC/doc/themes/5e.html
5. Hobbs, Peter, Raj Gupta & Craig Meisner. 2005. Conservation Agriculture in South Asia. (Submitted for publication)
6. Magdoff, Fred & Harold van Es. 2000. Building Soils for Better Crops. 2nd ed. Sustainable Agriculture Publications: Burlington, VT.

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