Conservation Farming Unit CFU Zambia established in 1996 A reference for researchers, agronomists and extension staff on the definitions of Minimum Tillage (MT), Conservation Tillage (CT), Conservation Farming (CF) and Conservation Agriculture (CA) as applied in Zambia by the CFU. Purists may have alternative definitions but farmers will adopt the practices that suit them best. Are my labour inputs and costs reduced, do I achieve better yields, make better use of seed and other inputs, is there a market for the crop and what are the prices being offered?
Definitions in Zambia: MT CT CF CA Minimum Tillage (MT) Inadequate residues. Either grazed off by communal livestock or burnt off intentionally or unintentionally as a result of uncontrolled bush fires. Insufficient or no rotations with legumes. Correctly spaced MT permanent planting basins/holes or permanent ox/mechanised rip lines established across the slope before the planting rains. Early planting of all crops. Surface soil disturbance 10% maximum. HOE MT as Basins or Holes ADP MT as Ripping ADP MT as Zero Tillage MECH MT as Ripping MECH MT as Zero Tillage For the sake of simplicity ADP and Mechanised Zero Tillage are also categorised as MT practices
Conservation Tillage (CT) Insufficient or no crop rotations, residues retained with more or less 30% cover on non legume plots. Correctly spaced permanent planting basins or ADP or mechanised rip lines established across the slope before the planting rains. Early planting of all crops. Surface Soil disturbance 10% maximum HOE CT as basins ADP CT as ripping ADP CT as zero tillage MECH CT as ripping MECH CT as zero tillage
CT and Residues In Mono-modal rainfall domains grain Legume residues disintegrate with no cover left. Maize and Cotton stalks can produce sufficient residue cover to last the dry season if yields are over 3.5t/ha and 1.5t/ha respectively. Incorporation of Maize and Cotton residues by termites can be significant also uncontrolled communal grazing of Maize residues is commonplace. Groundnuts were here Communal Grazing Termite Action A pragmatic approach is necessary when considering whether a farmer qualifies as a CT adopter. If no burning has occurred which is the primary objective, the farmer qualifies.
Conservation Farming (CF) CT with addition of minimum 20% of cropped land occupied by legumes. Rotation Intercrop MT/CT CF Intercropping as above - or strip cropping where several rows of legumes are alternated with other crops. Farmers will shift between the above definitions depending on prices, market opportunities, exchange rates, input subsidies, NGO handouts and other factors that influence the proportion of crops they grow.
Some Other CF Options with Non Edible Legumes CT with addition of 20% minimum of cropped land occupied by legumes. 1 2 3 1: Tephrosia undersown to Maize with 1 year fallow in following season + firewood benefit 2: Velvet Bean Fallow in Rotation. Edible spreading Cowpeas are a good alternative 3. Sunnhemp Fallow in Rotation
Conservation Agriculture (CA) CF + the establishment and survival of a minimum of 50 Faidherbia albida trees per hectare. Faidherbia is only suited to domains with mono-modal rainfall When Faidherbia approaches maturity after 14 seasons from establishment CF farmers who mono-crop Maize under the trees qualify as it is a legume.
Weed control by cultivation Weeding with Plough Adjustable Ox Ridger MT/CT or CF farmers who revert to using ploughs or ridgers to cultivate weeds do not qualify as soil disturbance is excessive. Damage to young crops is also common.
Weed control after tillage and planting by cultivation Weeding with hoes - notice who is doing it Weeding with ox cultivators MT/CT and CF farmers who weed with hoes or ox cultivators qualify although soil disturbance with cultivators is considerable and the use of herbicides is preferable Ox cultivator
Weed control after tillage and planting with herbicides Eradication of Couch grass with glyphosate using a VLV sprayer 1 day maximum. Hand weeding 20 to 30 days followed by rapid re-emergence! Weed control with herbicides reduces soil disturbance to zero and provides a temporary in situ mulch Alternative Common Definition MT is MT, CT is CT, CF is CA, and CA is CAWT i.e. Conservation Agriculture with Trees.