B.G. Sims, C. Thierfelder, J. Kienzle, T. Friedrich and A. Kassam
Smallholder farm mechanization in sub-Saharan Africa (SSA) relies heavily on manual labour and the hand hoe is the main implement used for crop production on up to 80% of the arable area. Draught animal power (DAP) represents a major advance in terms of available power and is especially important where human resources are being depleted by age, migration and pandemics. However the use of DAP is restricted by the presence of the tsetse fly and by tick-borne diseases such as east-coast fever. Where DAP is possible it is often used to pull the mouldboard plough, although chisel-tined rippers are increasingly used. Less than 10% of the land area in SSA is cultivated by tractor powered systems, mainly on commercial farms; those systems will therefore not be considered in this paper. Farmers perceive advantages with mechanized tillage operations (e.g.: improved weed control; mobilization of nutrients from the organic matter; preparation of a smooth seed bed; elimination of compacted zones; incorporation of amendments; control of pests and diseases; control of water run-off and accumulation of water). However, the damaging effects of the use of hoes and ploughs soon become apparent. They reduce soil organic matter through oxidation, cause various forms of physical, chemical and biological degradation (especially hard pans, soil crusting and erosion) and produce lower yields, which result in increased poverty and hunger, reduced food security and, eventually, abandonment of degraded farm land.
Conservation agriculture (CA), based on minimum soil disturbance, crop residue retention and rotations has been proposed to reverse this degradation in an effort to move towards sustainable cropping systems; however to date there is little information on the challenges to developing a viable CA machinery sector in SSA. Seed drills and planters developed for tilled soil present difficulties when planting through organic cover (in terms of seed placement and covering whilst penetrating the residues); another challenge is the precise application of herbicides for the control of weeds and management of cover crops.
Trackback from your site.