Effect of Forage Legume Incorporation on Selected Soil Chemical Properties in the Northern Guinea Savanna of Nigeria

Abstract

ABSTRACT The Nigerian savanna soils are low in fertility, organic matter and cation exchange capacity. The traditional method of improving the fertility and productivity of soils of the savanna is through natural fallowing which typically takes three to five years. The method is no longer suitable for most farmers because of the rapid growth of population in developing countries and the resulting intensive cultivation of agricultural land. In this study, a short fallow technique was adopted using forage legumes. Selected soil chemical properties were also evaluated. Incorporation of most of the legume residues significantly (P < 0.05) increased soil organic carbon more than control treatment especially when 5.0t ha−1 of organic matter is incorporated. The application rate of 5.0 t ha−1 gave higher soil organic carbon content than the 2.5 t ha−1 rates. However, the incorporation of maize stover and legume residue resulted in significantly higher soil organic carbon than the initial rate of 5.65 g kg−1. Exchangeable cations were increased by the legume incorporation more than in the control. The impacts created by legume incorporation were mostly felt at the topsoil (0-15 cm). Adoption of the technology might be hindered by the fact that these legumes do not have immediate food grain benefit like the grain legumes (i.e., cowpea and lablab). The fallow legumes and food crops could be intercropped either simultaneously or in a relay pattern with cereal (maize or sorghum) to improve productivity of the land for sustainable food crop production.