Rice productivity and soil hydrodynamic properties under lowland Elaeis guineensis and Borassus aethiopum: An asset rice agroforestry system

Lowlands are facing significant destruction of their natural habitats breaking the interrelationships between soil hydro-physical and installed crops yield parameters. This study investigates the response of rice grain and biomass yields, and soil hydrodynamic properties to Elaeis guineensis and Borassus aethiopum rice cropping systems in lowlands of the commune of Parakou, Northern Benin. We considered four lowlands with 18 trees, viz. nine Elaeis guineensis and nine Borassus aethiopum. The results show that trees crown area, DBH and distance from waterbed were 24.2% higher, and 38.6 and 27.6% lower under Borassus aethiopum compared to Elaeis guineensis, respectively. Soil Ks was lower under Borassus aethiopum than Elaeis guineensis; while soil water content, capillary water holding capacity and capillary porosity were higher. Rice grain and biomass yields were 113.1 and 110.8% higher under Borassus aethiopum compared to Elaeis guineensis. However, no difference in grain and biomass yields occurred between outside and under crowns. Positive correlations were obtained between rice grain yield and harvest index, and between rice biomass yield and trees distance from waterbed. Nonetheless, rice grain yield and trees DBH were negatively correlated. Soil depth and crown indirectly influenced rice biomass yield through a direct effect on root biomass, and the two species also indirectly influenced rice biomass and grain yield through direct positive effect on crown area. The findings show that the presence of Elaeis guineensis and Borassus aethiopum trees in rice cropping agroforestry systems can help for their protection and improve the ecosystems and yield of rice cropping agroforestry systems.