Influence of phosphorus and biofertilizers on symbiotic parameters, productivity and profitability of soybean (Glycine max)

A field study was carried out during the rainy (kharif) season of 2019 at the Regional Research Station, Punjab Agricultural University, Ludhiana and Faridkot, Punjab, to study the effect of phosphorus levels and biofertilizers on the symbiotic parameters, productivity, and profitability of soybean [Glycine max (L.) Merr.]. The experiment comprised 4 phosphorus levels (0, 17, 26 and 35 kg P/ha) and 4 biofertilizer treatments [uninoculated control, Bradyrhizobium, Phosphate-solubilizing bacteria (PSB) and Bradyrhizobium + PSB]. Total 16 treatment combinations were laid out in a factorial randomized complete-block design, replicated 3 times. Application of 35 kg P/ha recorded the highest symbiotic parameters, growth and yield attributes and seed yield of 2 and 1.84 t/ha at Ludhiana and Faridkot, respectively, which were significantly higher than the control and 17 kg P/ha but statistically at par with 26 kg P/ha at both the locations. However, the highest production efficiency (14.62 and 13.50 kg/ ha/day at Ludhiana and Faridkot, respectively) was recorded with application of 35 kg P/ha, being statistically at par with 26 kg P/ha. The highest monetary efficiency (302 and 277 `/ha/day at Ludhiana and Faridkot, respectively) was obtained with the application of 35 kg P/ha which were at par with 26 and 17 kg P/ha at Ludhiana, while with 26 kg P/ha at Faridkot. Inoculation with Bradyrhizobium + PSB and sole inoculation of PSB were at par with each other and both proved superior to uninoculated control for growth and yield attributes, seed yield and monetary efficiency.