Effect of different compost on growth, yield and nutrient uptake by Bt cotton in vertisols

A field experiment was conducted during the 2024-25 kharif season at the Research Farm, Department of Soil Science, Dr. Panjabrao Deshmukh Krishi Vidyapeeth, Akola (Maharashtra),with objective was to evaluate the effect of various composts on the growth, yield, and nutrient uptake by Bt cotton in Vertisols. The study included eight treatments: T1 - Absolute Control, T2 - 10 t ha⁻¹ FYM (University recommended dose), T3 - 75% RDN through vermicompost, T4 - 75% RDN through NPS compost, T5 - 75% RDN through phosphocompost, T6 - 100% RDN through vermicompost, T7 - 100% RDN through NPS compost, and T8 - 100% RDN through phosphocompost. The experiment laid out in a Randomized Block Design (RBD) with three replications. The results reveal that the application of 100% RDN through NPS compost was found significantly highest at 60, 90 DAS and at harvest, and was found statistically at par with 100% RDN through vermicompost, 10 t ha⁻¹ FYM, and 100% RDN through phosphocompost. The significantly highest numbers of bolls per plant and boll weight were observed under 100% RDN through NPS compost, comparable with 10 t ha⁻¹ FYM and 100% RDN through vermicompost. The seed cotton and stalk yield of cotton were recorded significantly highest with application of 100% RDN through NPS compost (13.54 and 26.23 q ha⁻¹) and was found at par with 10 t ha⁻¹ FYM, 100% RDN through vermicompost, and 100% RDN through phosphocompost. N, P, and K uptake was significantly enhanced with 100% RDN through NPS compost, with nitrogen and phosphorus uptake at par with 10 t ha⁻¹ FYM and 100% RDN through phosphocompost and in potassium uptake it was found at par with 100% RDN through vermicompost. All parameters were found lowest in the absolute control. It can be concluded that the application of 100% RDN through NPS compost, mutually beneficial with the application of 100% RDN through vermicompost and 100% RDN through phosphocompost increased the growth, yield as well as enhanced the nutrient uptake by cotton.