Farmers in the Sudano-Sahelian region rely on a cereal-based cropping systems to produce grain and stover. The stover is an important source of dry season animal fodder. The nutritional quality of the otherwise nutritionally poor stover can be improved by undersowing or intercropping a cereal with a nitrogen fixing legume. The forage legume would also improve soil physical and chemical properties, and if well managed would not reduce cereal yield. Stylosanthes hamata has been shown to be a potentially valuable forage crop for the region, but information on cereal/forage-legume cropping systems in the drier areas of the region is sparse.
N. R. Hulugalle of the International Institute of Tropical Agriculture/SAFGRAD Project at the Kamboinse Research Station in Ouagadougou, conducted a three year study on the effects of tied ridges and undersown S. hamata on soil conditions and crop yields in the West African Sudan savannah. The experimental treatments were tied and open ridges, both of which were planted to either monocropped maize or maize undersown with S. hamata.
Measurements were made on soil water content, water infiltration, soil temperature, particle size distribution, soil organic matter, nitrogen, exchangeable Ca, Mg, K and Na, and cation exchange capacity. Observations were also made of root growth and relative leaf water content (RLWC) of maize.
Profile water content was greater with tied ridging than open ridging. Among tied ridged plots, undersowing with S. hamata resulted in drier soil profile in 1986 and 1987, when compared to moncropped maize. Furrows of tied ridged plots were higher in clay content, soil organic matter, total cation exchange capacity, and exchangeable Ca, Mg, and K. Sand content was lower in the furrows of tied ridged plots than open plots. Among the open ridged plots, those undersown with S.hamata had higher levels of exchangeable bases and CEC. Relative leaf water content of maize was increased only by tied ridging. Subsoil root densities were greater for treatments with tied ridges. Of all the trials, those undersown with S. hamata resulted in the deepest root system.
Tied ridges significantly increased grain and dry matter production of maize,but did not effect that of S. hamata. Grain and dry matter yield of maize in tied ridged plots were reduced by undersowing with S. hamata only when drought occurred during reproductive and late vegetative growth, respectively. In open ridged plots, dry matter and maize yield were not affected by the cropping system. Highest total dry matter production was observed in undersown, tied ridged plots.
For more information:
Dr. N.R. Hulugalle, 117/1 Pieris Avenue