Optimizing Fenugreek (Trigonella foenum-graecum L.) Cultivation: Role of Rhizobium Inoculation and Phosphorus Fertilization on Growth, Nodulation, and Yield Attributes

Rhizobium inoculation and phosphorus fertilization play a crucial role in enhancing the growth, nodulation, and yield attributes of fenugreek by improving nitrogen fixation. Aim of the study is to explain co-application of Rhizobium and phosphorus treatment on the agronomic performance of fenugreek under rainfed conditions. Study was conducted in a split-plot randomized complete block design with four replications, where Rhizobium inoculation served as the main factor, and phosphorus doses as subplots. The results showed that Rhizobium inoculation significantly increased seed yield per plant and seed yield by 52.4%, biological yield by 22.3% and seed yield by 20%, respectively, demonstrating the effectiveness of biological nitrogen fixation. 60 kg P₂O₅ ha⁻¹ fertilization caused the highest plant height (22.7 cm), pod formation (15), and seed yield (135 kg da⁻¹ seed yield). Furthermore, nodule formation showed a linear increase with phosphorus application from 3.33 to 9.00. The best agronomic performance was determined in Rhizobium and 60 kg P₂O₅ ha⁻¹ treated plants, therefore, this fertilization strategy optimally supports plant growth and productivity. According to results, it is recommended that fenugreek cultivation incorporate Rhizobium inoculation along with 60 kg P₂O₅ ha⁻¹ to maximize yield potential. Future research should focus on the long-term effects of these treatments on soil fertility and sustainability to further refine fertilization strategies for fenugreek and other leguminous crops.