Response of green gram to different levels of phosphorus and rhizobium inoculation

Abstract:

Government policy in KwaZulu-Natal now actively promotes pulse cultivation to address protein malnutrition and soil fertility decline, yet local fertilizer recommendations for green gram remain poorly defined. This research examined the interaction between five phosphorus levels (0, 20, 40, 60, 80 kg P₂O₅ ha⁻¹) and Rhizobium inoculation on growth, nodulation, and grain yield of green gram (cv. Jade-AU) at the KwaZulu-Natal Agricultural College, Pietermaritzburg, South Africa, during 2022-24. A split-plot design with three replications was used. The combination of 60 kg P + Rhizobium produced the highest grain yield (15.8 q ha⁻¹), 36.2% more than P alone and 132.4% more than the control. Nodulation peaked at 60 kg P with Rhizobium (32.4 nodules plant⁻¹). The P × Rhizobium interaction was significant (p< 0.01). These results establish 60 kg P₂O₅ ha⁻¹ with Rhizobium as the recommended practice for green gram in the Pietermaritzburg area.