Effect of soil and water conservation measures on cowpea and maize performance in the Northern and Upper East regions of Ghana.

Agricultural land in Ghana is being degraded, with soil erosion becoming an increasing threat to crop production. Soil and water conservation (SWC) practices are promising intervention especially if developed to suit a given climate, soil type as well as crops. This study was set out to evaluate the impact of four treatments [contour farming (CF), half-moon (HM), contour ridges (CR) and farmer’s practice (FP)] on cowpea and maize growth and yield as well as on soil moisture content. A survey was used to assess farmers’ level of knowledge on soil erosion and erosion control practices as well as factors that cause soil erosion. The study was carried out in the Northern and Upper East Regions of Ghana on-station and on-farm using cowpea and maize as test crops. The on-station experiment consisted of four replicates each of cowpea and maize with the four treatments. The on-farm experiment was carried out in six communities across the Northern and Upper East Region of Ghana with each community as a replicate. Plant height, stem girth, root biomass, number of leaves, leaf area index (LAI) at flowering/tasseling and grain yield were determined. The on-station experiment showed that SWC measures significantly (P < 0.05) retained more moisture compared to the farmers’ practice. In the cowpea trial, there was about 23.4%, 19.2% and 17.8% significant (P < 0.05) retention in soil moisture in the CF, CR and HM treatments respectively over the FP whilst in the maize trial, CF, CR and HM recorded about 24.0%, 20.4% and 19.4% significant (P < 0.05) retention in soil moisture over the FP respectively. Only cowpea stem girth was significantly affected (P < 0.05) by SWC measures. Effect of SWC measures on cowpea in the Upper East was only significant (P < 0.05) for the LAI whilst significant effect (P < 0.05) of SWC measures on cowpea in the Northern Region was observed on stem girth, LAI, root biomass and yield. The SWC measures effect on maize at the on-station trial were significant (P < 0.05) on v maize height, stem girth, root biomass and yield. The Upper East maize trial recorded significant effect (P < 0.05) of SWC measures on maize height, LAI and yield whilst the Northern Region maize trial recorded significant effect (P < 0.05) of SWC measures on yield only. Where there was no significant treatment effect (P < 0.05) on the growth and yield components of the cowpea and maize performed better with the SWC measures (CF, HM and CR) compared to the control (FP). The survey revealed that all the respondents in both regions were aware of what soil erosion is about. All respondents had knowledge of soil erosion whilst 85% of respondents across the two regions had knowledge or were aware of SWC measures as erosion control techniques. The respondents agreed that the causes of soil erosion included cultivation on steep slopes, poor SWC practices, excessive rainfall, population pressure, over cultivation, deforestation and over grazing. All respondents rated erosion as a severe problem and mentioned that the rate of soil erosion has been increasing over time. They were aware that erosion can be controlled. Farmers in the Northern and Upper East Regions of Ghana should adopt soil and water conservation (SWC) measures especially contour farming (CF) for maize and cowpea production.

Source: KNUST