Customized Complex Fertilizers for Transgenic Bt-Cotton Hybrids Grown on Rainfed Vertisols

Response of transgenic Bt-cotton hybrids to customized complex fertilizer (CCF) grades was evaluated on rainfed Vertisols. In 2017-18, six treatments, namely, recommended dose of fertilizers (RDF), 1.2 times the RDF (1.2 RDF), physical mix of single nutrient fertilizers (PMF), CCF containing NPKS, farmers practice (FP), and the zero fertilizer control (CON) were evaluated. In 2018-19, 11 treatments, muriate of potash (MOP) and sulfate of potash (SOP) based CCFs equivalent to RDF, RDF+10% more K and RDF-10% less K, RDF, 1.2 RDF, soil test based PMF, FP, and CON were evaluated. Seedcotton yield (SCY) with CCF did not differ with the RDF and PMF in 2017. In 2018, the average yield of the RDF treatments (1902 kg ha(-1)) was significantly lower than the average of the CCF treatments (2407 kg ha(-1)). Among the CCF treatments, the MOP-based CCF (2553 kg ha(-1)) did not differ with the SOP-based CCF (2387 kg ha(-1)). Fiber quality was unchanged with the fertilizer treatments. However, compared to the present FP, the benefit to cost and the marginal cost-benefit ratio (MCBR) was greater with the CCF than the FP. MCBR was greater with the MOP-based CCF than the SOP based. Our results highlight the benefit of CCF for rainfed cotton production.