REDDEPPA REDDY, MREDDI RAMU, YAMMELA2020-11-242020-11-242001https://krishikosh.egranth.ac.in/handle/1/5810155673D1155 - YAMMELA REDDI RAMUA fieId experiment was conducted during rabi, 1999, on sandy loam soils at Tirupaci campus of Acharya N.G. Ranga Agricultural university, to study the effect of nitrogen and phosphorus in combination with bio-fertilizers on growth and yield of soybean. The treatments comprised of combinations of individual as well as dual inocu l at ion of Bradyrhizobium japonicum and Phosphobacterium either alone or in corn binat ion with 50% ,75 % and 100% level of recommended dose of nitrogen, phosphorus or both, recommended dose of nitrogen and phosphorus and uninoculated control. These were rested in a randomized block design and replicated thrice. Brdyrhizobium japonicum (500 g ha-') was seed inoculated and Phosphobacterium (2 kg ha- I) was mixed with well decomposed farm yard manure along with sand (1 :5:5) and applied in seed rows at the time of sowing. Different nitrogen and phosphorus management practices have significantly influenced the growth characters, (Viz., plant height, leaf area index, total dry matter production and number as well as dry weight of nodules), yield attributes, (pod length, number of pods per plant, number of seeds per pod and 100 seed weight), yield, (seed and stalk), nutrient uptake and post harvest soil fertility status. .'.V. Application of bio-fertilizers along with recommended dose of nitrogen and phosphorus resulted in higher stature of growth pameters than with application of recomrnended dose of nitrogen and phosphorus. Dual inoculation in combination with recommended dose of nitrogen and phosphorus has resulted in production of the tallest plants, the largest leaf area index and the highest total dry matter production, but it was on par. with Phosphobacteriurn inoculation along with recommended dose of phosphorus, at all the stages of crop growth, except 25 DAS in case of leaf area index and total dry mattes production. Plant height, leaf area index and total dry matter production of soybean were found to be the lowest with control at all the states of crop growth. Number of nodules and nodule dry weight plant were found to be the highest with dual inoculation coupled with recommended dose of nitrogen and phosphorus which was however, on par with Rhizobiurn inoculation in combination with recommended dose of nitrogen, at all the stages of crop growth except at 50 DAS in case of nodule dry weight plant -I. The least number and dry weight of nodules plant -I were observed with control. Dual inoculation coupled with recommended dose of nitrogen and phosphorus has resulted in the longest pods, more number of pods per plant and number of seeds per pod, which were however, on par with Phusphobacterium inoculation along with recommended dose of phosphoms. The length of pods, number of pods per plant and number of seeds per pod were at the lowest with control. The highest 100 seed weight was observed with dual inoculation in combination with recommended dose of nitrogen and phosphorus, while the lowest 100 seed weight was noticed with control. Dual inoculation in combination with recommended dose of nitrogen and .phosphorus has resulted in the highest seed yield, which was however in parity with Phosphobacrerium inoculation along with recommended dose of phosphorus. Rhizobium inoculation in combination with recomrnended dose of nitrogen was comparable with recornmended dose of nitrogen and phosphorus and these were the next best treatments. The lowest seed yield was recorded in control, Stalk yield of dual inoculation coupled with recommended dose of nitrogen and phosphorus and Phosphobacterium inoculation in combination with recommended dose of phospl-iorus were comparable, which were significantly superior to rest of the treatments. The lowest stalk yield was observed with control. Maximum and minimum values of harvest index were noticed with dual inoculation along with recommended dose of nitrogen and phosphorus and control, respectively. uptake of nitrogen and phosphorus were found to be the highest with dual inoculation coupled with recommended dose of nitrogen and phosphorus, which was comparable with to Phosphobacterium inocuIa tion along w i ti1 recommended dose of phosphorus, at 50 DAS and harvest. The lowest uptake of nitrogen and phosphorus was observed with contro t. Post harvest soil available nitrogen and phosphorus were found to be significantly improved with dual inoculation as well as Phosphobacteriurn inoculation along with recommended dose of nitrogen and phosphorus. Maximum gross returns, net returns and benefit-cost ratio were obtained with dual inoculation along with recommended dose of nitrogen and phosphorus, followed by Phosphobacterium inoculation in combination with recommended dose of phosphorus. In conclusion, the investigation revealed that the highest yield as well as net profit could be obtained with application of both the bio-fertilizers along with recommended dose of nirrogen and phosphorus in soybean on sandy loam soils of Tirupati. Recommended dose of nitrogen and phosphorus could be reduced upto 25 per cent with out any significant reduction in seed yield as well as net returns, when applied in combination with both rhe bio-fertilizers.EnglishThesis