Investigating relationship between different soil chemical properties and the biomass and grain yield of Sorghum bicolor(L.) Moench (Sorghum) in agroforestry parklands systems along an increasing rainfall gradient in Burkina Faso (West Africa)

Abstract

Cereal crops biomass and grain yield generally reduced under trees canopy, are also improved depending on trees species and structure  in agroforestry parklands suggesting complex interactions in these systems. This research investigated the relationship between soil  chemical properties and sorghum biomass and grain yield in agroforestry parklands for recommendations to maintain or improve  sorghum productivity under climate change. Studied parklands consisted of Vitellaria paradoxa C. F Gaertn and Parkia biglobosa (Jacq.)  Benth in association with sorghum in three climatic zones. Soil chemical parameters were measured using the spectrophotometry infrared method and sorghum biomass and grain yield were calculated by dividing their weight with the area of production. Cation  exchange capacity (CEC) and potassium (K) had a positive effect on sorghum biomass and grain yield when rainfall decreased suggesting  the application of management options improving soil carbon and moisture to increase sorghum productivity with reduced rainfall due  to climate change. CEC had a negative effect on sorghum biomass and in association with P. biglobosa when rainfall increased  suggesting the optimisation of mineral fertilisers use and tree pruning to increase sorghum productivity when rainfall increased due to  climate change. Further research is required to assess the effects of these recommended management options.