EFFECT OF NITROGEN, PHOSPHORUS TYPE AND INOCULATION ON GRAIN YIELD OF SOYBEAN IN TWO SOIL SERIES

Abstract

An experiment to investigate the effects of nitrogen, phosphorus type and inoculation on grain yield of soybeans in two soil series. Soybean ranks first as an oilseed crop in the world and been a legume, it goes through a biological N-fixation process which is the second most important biological process after photosynthesis. Low soil fertility results in low crop yield which affects the livelihood of farmers and increasing yield of oil seed crops such as soybean has the potential to save Ghana foreign exchange. There are hypothesis that application of phosphate fertilizer blend with rhizobia inoculants will stimulate plant N accumulation to enhanced grain yield of soybean in low N environments. It was conducted at Gbulahigu in the Tolon district of the northern part of Ghana in 2021 farming season. The study was 2 x 9 factorial experiment which were laid down in a randomized complete block design (RCBD) with four replications. The factors include; Soil type at two levels (upland and lowland soils) and Fertilizer amendments at nine levels, which consisted of NK + DAP, NK + PR + Inoculant, NK + DAP + Inoculant, NK + DAP + Inoculant + Foliar (Zn + Fe), NK + DAP + Inoculant + Foliar Zn, NK + (DAP + RP), NK + (DAP + RP) + Inoculant, NK + DAP + Inoculant + Soil Zn and control. Afayak soybean variety was used as planting material. Data was analyzed using ANOVA and separated at 5 % probability level using GENSTAT, 18thedition. Results showed some interaction and soil type were not significant, but was significant (P<0.05) for all parameters for fertilizer treatments, NK + DAP + Inoculant + Foliar (Zn + Fe) did better in terms of growth and yield and was therefore recommended for good growth and yield of soybean. Further studies were also recommended, especially the timing and rates of application of these micro nutrients.