Organic matter enrichment through cowpea fodder clipping management for sustainable productivity in degraded savannah soils of Nigeria

Abstract

Cowpea is a vital food crop in the semi-arid tropics where it is reported to be the second most important food legume in tropical Africa. It is grown mainly for the mature seeds and therefore features prominently in the farming systems of the region. However the severe nutrient depletion of the soils of the savannah tropics of the African region over the years has made it difficult to improve the productivity of these varieties using cultural practices only. But, it has been observed that when the cowpea crop plant is cut [clipped] before sensescene, it can regenerate after defoliation [provided there is enough soil moisture]. And when the clipped organic fodder is added and/or ploughed back into the soil, it enriches the content of the soil organic matter [SOM], which in turn enhances crop productivity. In the light of the above, this study was carried out with the objeactive of determining the influence of intra-row spacing, lipping height and time on soil organic matter [SOM] and yield of the dual purpose cowppea. Results showed that total harvested organic fodder yield of about 15t ha^-1 were  obtained; and when this quantum of green organic plant biomass was added back into the soil, it increased the soil organic matter [SOM] content by about 70%. Consequently, cowpea pod and grain yield were highest at the closest [15cm] intra-row spacing. Though higher grain yield was produced with the unclipped [control] plants compared to the clipped plants, the control plots produced  statistically similar pod yields with plots clipped at 25.0cm heights. Significantly, the gain recorded in the amount of SOM added to the soil, compensates for the little grain loss. Generally higher pod and grain yields were recorded when crop plants were clipped at 64 days after planting - DAP than at 74 and 84 DAP respectively. Based on the result of these investigations, it can be concluded that the  adoption of this innovative clipping management technology, holds great potential of increasing the soil organic matter (SOM]  and crop productivity for the source poor farmers in a sustainable manner in the region. Indeed , thid ecologically friendly farming practice promotes the building of improved soils and fertility, safer and healthier livelihoods; which arre at the core of organic agriculture [OA] management principles.