Response of Rainfed Bt Cotton to Different Crop Residues Application on Yield, Soil Fertility and Nutrient Uptake under Deep Black Vertisols

Poor soil fertility is a yield limiting factor in cotton production for realizing higher seed cotton yield. Chemical fertilizers are an important input to get higher crop productivity, but over reliance on chemical fertilizers is associated with declines in some soil properties and crop yields over time and causes serious problems, such as soil degradation. Therefore, an integrated use of inorganic fertilizers with organic manures is a sustainable approach for efficient nutrient usage which enhances efficiency of the chemical fertilizers while reducing nutrient losses.

A field experiment was conducted in the Agricultural Research Station, Kovilpatti under dryland situation to evaluate the effect of organic and inorganic nutrients on crop yield, quality and soil fertility status in rainfed Bt cotton. Different crop residues viz., sunflower, pulse haulm, sorghum and cotton residues were collected and composted using TNAU biomineralizer and applied to the experimental trial.

It was observed that the application of recommended dose of fertilizer (RDF) (120:60:60 N:P:K kg/ha) along with vermicompost @ 2.5 t/ha registered the higher seed cotton yield (1600 kg/ha), dry matter production (2444 kg/ha, net income (Rs.11168 ha^-1), B:C ratio (1.40) and rain water use efficiency (2.02 kg ha^-1 mm) and also increased the plant nutrient uptake. Integrated application of organic and inorganic plant nutrients increased the soil available nutrients in the deep clay soil and sustain the productivity of seed cotton yield in semiarid region of southern district.