Selected Growth and Yield Parameters of Green Gram (Vigna radiata) under Rhizobium Inoculation and Phosphate Rock Fertilizer Application

This research was aimed to determine the interactive effects of Rhizobium inoculation and phosphate rock on two different varieties namely KS20 and N26. Green gram is an important source of food security in Tharaka Nithi County. As a result, a low-cost and long-term agricultural production system is required to enhance productivity. In combination with phosphate rock, the legume/Rhizobium symbiosis provides a natural mechanism for enhancing green gram nitrogen fixation. As a result, the goal of this study was to see how Rhizobium and phosphate rock fertilizer affected the growth and yield characteristics of the N26 and KS20 varieties. The study was carried out at Chuka University Horticultural Research Farm for two seasons, November 2019 to January 2020 and February to April 2020. Factorial experiment of 2x2x2 was laid out in a Randomized Complete Block Design (RCBD). There were three factors, variety (N26 and KS20), phosphate rock (0 and 30 kg P ha-1) and Rhizobium MEA 716 (0 and 100 g ha-1). Eight treatments were used in the experiment, each of which was reproduced three times. The data was collected fortnightly on four randomly selected plants on parameters such as plant height, number of leaves, branches, pods, total dry biomass, shoot and root dry weight and grain yield. Statistical Analysis Software(SAS) was used to analyze the data. At a probability level of 5%, significant means are separated using Least Significant Difference (LSD). Results for both seasons indicated that combined application of Rhizobium MEA 716 Rhizobium 100 g ha-1 and phosphate rock 30 Kg ha-1 phosphate under variety in treatment (R1P1V2) showed significantly (P<0.05) higher plant height (76.07 cm), number of branches (14.08 plant-1), shoot dry biomass (52.01 g plant-1), root dry biomass (7.60 g plant-1), total dry biomass (146.4 g plant-1), number of pods (84 plant-1) and yield (2158 kg ha -1) compared to variety N26 in treatment (R1P1V1). As a result, combining Rhizobium MEA 716 100 g ha-1 with phosphate rock 30 Kg ha-1 under the variety KS20 resulted in increased growth qualities and yield components of the KS20 variety over the N26 variety. Based on these findings, 100 g ha-1 Rhizobium MEA716 and 30 Kg ha-1 phosphate rock under variety KS20 were advised for better and long-term green gram production in the research area.