Effect of combined use of potassic fertilizer and gliricidia green leaves on soil fertility, nutrient balance and yield of rainfed cotton in Vertisols

A field experiment was conducted at research farm of AICRP for Dryland Agriculture, Dr. Panjabrao Deshmukh Krishi Vidyapeeth, Akola (Maharashtra), to assess the effect of potash management through gliricidia green leaves on soil fertility, nutrient balance and yield of rainfed cotton (Gossypium spp.) in Vertisols during kharif season of 2020. The results revealed that there was significant increase in hydraulic conductivity, organic carbon and available N, P, K of soil and decrease in soil pH, EC and bulk density in the gliricidia incorporated treatments as compared to control. The highest available N (211.1 kg ha-1), P (16.7 kg ha-1) and K (361.5 kg ha-1) was observed with the application of 100 % NP + 10 kg K (inorganic) + 20 kg K through gliricidia which increased by 16, 31.7 and 13.7% respectively over control. Similarly, the nutrient balance after six years of experiment was also higher with the application of 100 % NP + 10 kg K (inorganic) + 20 kg K through gliricidia being 25.4 kg ha-1 for available N, 2.15 kg ha-1 for available P and 39.6 kg ha-1 for available K. There was significant reduction in the bulk density of soil, being lowest (1.40 Mg m-3) in the treatment 100 % NP + 10 kg K (inorganic) + 20 kg K through gliricidia as compared to control. Significant improvement in the seed and stalk yield of cotton was recorded with the application of 100 % NP + 10 kg K (inorganic) + 20 kg K through gliricidia, with increment of 60, 18% and 64, 22% over control and 100% RDF, respectively.