The Effects of Rhizobium, Mycorrhizal Inoculations and Diammonium Phosphate (DAP) on Nodulation, Growth, and Yield of Soybean

Abstract

A field trial was conducted for two consecutive winter seasons (2010/11 and (2011/12),), at Demonstration Farm of Collage of Agricultural Studies, Sudan University of Science and Technology at Shambat, to study the effect of rhizobium, mycorrhiza inoculation and diammonium phosphate (DAP) on growth, nodulation and yield of soybean Glycine max (L.) Merrill introduced genotype (E01). The treatments consisted of control (without any fertilizer and inoculation), inoculation with Bradyrihzobium alone, and combinations of inoculation with Bradyrihzobium + mycorrhiza (VAM), Bradyrihzobium + mycorrhiza (VAM) + 100 kg /ha diammonium phosphate (DAP), and Bradyrihzobium + vesicular arbuscular mycorrhiza (VAM) + 150 kg /ha diammonium phosphate (DAP). A completely randomized block design with four replicates was used. The results showed that the combination of Bradyrihzobium and mycorrhiza (VAM) produced significantly higher nodulation number/plant. Relative growth rate was significantly highest in combined of Bradyrihzobium, mycorrhiza (VAM) and 100 kg /ha (DAP). Maximum grain yield was significantly obtained at par with combinations of Bradyrihzobium, mycorrhiza (VAM) and 150 kg /ha (DAP) and Bradyrihzobium, mycorrhiza (VAM) and 100 kg /ha (DAP). In general the effect and interaction of rhizobium, mycorrhiza and diammonium phosphate rhizobium significantly increased nodulation number/plant, relative growth rate and yield of soybean over control. It can be concluded that genotype (E01) of irrigated soybean produced significantly highest growth and yield when combination of rhizobium with mycorrhiza and diammonium phosphate (DAP) was used during winter season under Khartoum conditions.