Impact of potash management through gliricidia green leaf manuring on carbon pools and yield of rainfed cotton in vertisols

Abstract

A field study entitled, “Effect of potash management through gliricidia green leaf manuring on carbon pools and yield of rainfed cotton in Vertisols” was conducted during kharif 2019-20 at Research field of AICRP for Dryland Agriculture, Dr. Panjabrao Deshmukh Krishi Vidyapeeth, Akola, Maharashtra. The soil of the experimental site was Vertisol which was moderately alkaline in reaction, low in available nitrogen, Medium in available phosphorus and high in available potassium. The nine treatments replicated three times in randomized block design comprised of control, 100% RDF (60:30:30 NPK kg ha-1), 100%, 75% and 50% N and 100% P through chemical fertilizers and the combinations of 15, 20 and 30 kg K ha-1 through gliricidia green leaf manure at 30 DAS and remaining recommended dose of potassium as basal dose through inorganic fertilizers. The results indicated that application of 100% NP + 10 kg K (inorganic) + 20 kg K ha-1 through gliricidia green leaf manure at 30 DAS recorded significantly higher cotton yield with improvement in various carbon pools, and it was found to be on par with application of 100% NP + 15 kg K (inorganic) + 15 kg K ha-1 through gliricidia green leaf manure. Among the various carbon pools, the very labile and labile carbon pool was highly correlated with yield of cotton. Hence, it is concluded that conjunctive application of 100% NP + 10 kg K (inorganic) + 20 kg K ha-1 through gliricidia green leaf manuring at 30 DAS resulted in higher organic carbon pools and yield of cotton grown in Vertisols under rainfed conditions.