Effect of bio-fertilizer and phosphorus on growth and yield of cowpea

The present investigation entitled “Effect of Bio-Fertilizer and Phosphorus on Growth and Yield of Cowpea” was conducted from November 2024 to April 2025 at the Research Field of the Department of Horticulture, Naini Agricultural Institute, Sam Higginbottom University of Agriculture, Technology, and Sciences, Prayagraj. The experiment was laid out in a randomized block design with ten treatments and three replications to evaluate the effect of various biofertilizers (Rhizobium, VAM, PSB) in combination with graded phosphorus levels (30, 40, and 50 kg/ha) on phenological, yield, and quality traits of cowpea under zaid conditions. Results revealed that biofertilizer treatments delayed flowering and maturity slightly compared to the chemical control. Among treatments, VAM + P 40 kg/ha recorded superior performance in terms of number of pods per plant, seed weight, test weight, total soluble solids (TSS), and green pod yield per plant. Rhizobium + P 40 kg/ha gave the highest pod yield per hectare. On the other hand, the highest phosphorus level (50 kg/ha), especially in combination with PSB, did not enhance performance and showed signs of diminishing returns. Overall, the study suggests that the integration of biofertilizers with moderate phosphorus application (particularly VAM or Rhizobium with 40 kg/ha P) is effective in improving cowpea productivity and quality while reducing reliance on chemical fertilizers.