Rhizobium japonicum, nitrogen and phosphorus effects on nodulation, symbiotic nitrogen fixation and yield of soybean (Glycine max (L.) Merrill) in the Southern Savanna of Ghana

Abstract

Abstract An experiment conducted in 1976 on a Nyigbenya-Hatcho soil tested the effects of Rhizobium japonicum inoculation, nitrogen and phosphorus on nodulation, symbiotic nitrogen fixation and yield of soybean (Glycine max (L.) Merrill) in the southern savanna region of Ghana. The treatments significantly increased plant height, node number per plant, pod number per plant, leaf area index, total dry matter per plant, grain yield and seed weight. Low rates of nitrogen and medium to high rates of phosphorus promoted nodule number, dry weight and leghaemoglobin content. Rhizobia inoculation and applied nitrogen increased protein in seed while the application of phosphorus was beneficial to oil formation. The data indicate that inoculation with Rhizobium japonicum could increase soybean yield on the Nyigbenya-Hatcho soil. Contrary to our expectation, rhizobia and nitrogen or phosphorus application did not cause further yield increases.