Legume Nitrogen Fixation and Symbioses in Low-Inputs Rainfed Rice Rotations

Cropping systems with legumes play key roles in farming sub-Saharan Africa. However, how commonly legume associations perform low input-systems is not well-known. Here, we studied four species used three rotation upland rice, i.e., groundnut monocropping, sorghum–cowpea intercropping, and velvet bean–crotalaria two fertilization managements on the previous manure alone or complemented mineral fertilization. Legume suitability was assessed using rhizobial mycorrhizal colonization rates, plant biomass production, shoot N P content, biological N2 fixation based their δ15N natural abundance. Shoot root biomasses varied significantly between were positively correlated nodule number (r = 0.49 0.74, p-value < 0.05 <0.001, respectively) amount of fixed 0.73 0.50, 0.001 <0.05, respectively). The proportion derived from also species, a higher percentage for bean (66%), compared to other (50 60%). roots weakly colonized by AM fungi, similar levels species. Overall, management did impact biomass, symbioses, fixation, yet organo-mineral increased content. lack effect could be due nutrient deficiencies (Ca, Mg, micronutrients), which can hamper symbioses rhizobia mycorrhizae.