Effect of phosphorus and sulphur application on their dynamics and nodulation in soil under black gram [Vigna mungo (L.) Hepper] crop

Abstract

The experiment comprising of four levels of phosphorus, i.e., 0, 20, 40 and 60 kg ha-1 and three levels of sulphur, i.e., 0, 15 and 30 kg ha-1, was conducted during summer of 2015-16 to investigate the effect of phosphorus and sulphur application on their dynamics in soil under the crop of black gram cv. Uttara. The treatments were laid out in randomized block design (factorial) and replicated three times. The results reveal that the available and organic phosphorus (kg ha-1) significantly increased with each successive application of phosphorus in soil up to highest level (60 kg ha-1) at 20 days after sowing (DAS) of black gram, while it showed decreasing trend with time intervals of 40 DAS and at maturity of black gram. The application of successive doses of sulphur had no significant effect on available and organic phosphorus at each time interval. Similarly, significant increase has also been recorded in available and organic sulphur (kg ha-1) in soil with each successive application of sulphur up to 30 kg ha-1 at 20 DAS of black gram, thereafter, it showed decreasing trend. The application of successive doses of phosphorus had no significant effect on available and organic sulphur at each time interval. Number of nodules plant-1 also increased significantly with increasing levels of phosphorus and sulphur up to highest level and the optimum values were recorded with combined application of phosphorus 60 kg ha-1 and sulphur 30 kg ha-1.