Restoring the Soil - Canadian Foodgrains Bank

Existing Green Manure/Cover Cropping Systems Around The World913. Honduras. Gm/ccs that can effectively controlweeds, such as the mucuna in this photo, will begreatly appreciated by farmers.and organic matter from gm/ccs canincrease soil fertility tremendously. As aresult, programs from India to Brazil andthroughout Central America now speaknot just of “soil conservation,” but of “soilrestoration” and “soil recuperation.”3. Zero transportation costs. Unlike mostother materials that improve the soil, theseadditions of organic matter and nitrogenhave no associated transportation costs.They are produced right in the field wherethey will be used, and are already welldistributedacross the field.4. Very low cost. Gm/ccs cost the farmerno money whatsoever once the farmer haspurchased his or her first handful of seed.5. Weed control. Gm/ccs can also be animportant factor in reducing the cost andthe labor required for controlling weeds(Photo 13). Especially in Africa, this often means that women’s total workloads can bereduced by 20% or more.In Africa, a particularly noxious weed is striga (Striga hermonthica). Striga can significantlyreduce yields of maize, sorghum and millet, and is a major concern for farmersin areas with low soil fertility. The solution, however, is quite simple. Striga dies out ifenough organic matter is added to the soil. Thus almost any gm/cc that produces adecent amount of biomass will gradually rid the fields of this weed. 5 In areas wherestriga is a serious problem, this fact in itself will often convince farmers that theyshould use gm/ccs.Imperata grass (Imperata cylindrica) is another serious weed that grows best in poorsoils and therefore becomes less and less problematic as soils recuperate.6. Reduction in the use of agrochemicals. If farmers are using chemical fertilizer,gm/ccs can usually reduce the amount used by 60% to 80% without lowering yields.Herbicide use is either reduced or eliminated, since many gm/cc species are able tosmother weeds. Some species of gm/cc can be used in place of other chemicals. Forexample, mucuna and lablab beans kill nematodes, while sunnhemp (Crotalariaochroleuca) can be used to control pests that eat stored grain.7. Soil cover. The soil cover provided by many gm/ccs can be very important for soilconservation (Photo 13). In general, the value of soil cover (especially in the humid5Dyck, E., et al., Legumes in Every Farm, Strategies for Adoption of Soil-Improving Legumes by Smallholders in Kenya, 1996.