Impact of Phosphorus and Rhizobium on Mungbean Seed Yield and Nodulation

Mungbean plays a crucial role as a rotational crop, enhancing soil fertility and contributing to sustainable nutrient management. The integration of biofertilizers further supports environmentally friendly and sustainable farming practices. To investigate the combined influence of Rhizobium inoculation and phosphorus fertilization on the yield of mungbean (cv. Binamoog-8), an experiment was conducted at the Agronomy Field Laboratory, Bangladesh Agricultural University, Mymensingh, from October 2023 to February 2024. The study was designed as a split-plot with three replications. Rhizobium inoculation (two levels: without inoculation and with inoculation) was assigned to the main plots, while phosphorus levels (five levels: 0, 10, 15, 20, and 25 kg P ha^-1) were allocated to the subplots. Seeds were pre-treated with molasses and subsequently coated with microbial (Rhizobium) fertilizer before sowing. The findings showed that the application of Rhizobium inoculation and 20 kg of phosphorus ha^-1 enhanced the growth parameters (plant height, number of branches plant^-1 at 60 DAS and number of nodules plant^-1 at 45 DAS) and the yield  parameters of mungbean (number of seeds pod^-1, pod length, 1000 seeds weight, seed yield, stover yield, biological yield, and harvest index). The results of interaction effect revealed that the combined application of Rhizobium inoculation and 20 kg of phosphorus ha^-1 improved the growth parameters (plant height, number of branches plant^-1 at 60 DAS and number of nodules plant^-1 at 45 DAS) and the yield parameters of the crop (pod length, 1000 seeds weight, seed yield). The soil quality was also improved by the combined application of Rhizobium and phosphorus. The result showed an effective improvement of soil pH, organic matter, soil nitrogen, sulfur, potassium, and phosphorus from the combination of Rhizobium inoculation and 20 kg of phosphorus ha^-1 application. Thus, the use of Rhizobium inoculation and 20 kg of phosphorus ha^-1 in mungbean cultivation is recommended in order to obtain the maximum seed output.