Effect of fertilizer levels on nutrient availability and yield of cotton on Vertisol at Rahuri, District Ahemadnagar, India

The field experiment on effect of fertilizer levels on nutrient availability and yield of cotton on Vertisol was conducted at Mahatma Phule Krishi Vidyapeeth, Rahuri during May to September, 2008. The experiment was laid out in factorial randomized block design with three replications and two main treatments i.e. hybrid Bt RCH-2 and Non-Bt RCH-2 and nine sub treatments with different fertilizer doses i.e. F1 - No recommended doses of fertilizer (RDF), F2 -50 % RDF, F3 - 75 % RDF, F4 - 100 % RDF, F5 -125 % RDF, F6 - 150 % RDF, F7 - 100 % RDF + 2% DAP spray, F8 -100 % RDF + 1 % MgSO4 and F9 -100 % RDF + 1% KNO3. The results revealed that the non-Bt hybrid recorded maximum nitrogen (435.67 kg ha-1) and potassium (565.45 kg ha-1) content in 100 % RDF + 1% KNO3 treatment at boll development stage as compared to Bt hybrid. However, magnesium (0.09 kg ha-1) and iron (3.66 ppm) were maximum in 100 % RDF + 1 % MgSO4 treatment in non-Bt as compared to Bt hybrid and phosphorus content (17.58 kg ha-1) was maximum in 100 % RDF + 2 % DAP treatment in Bt as compared to non-Bt hybrid at boll development stage. The application of 100 % RDF + 1 % MgSO4 sprays were recorded highest yield of Bt (33.53 q ha-1) and non-Bt cotton hybrids (31.27 q ha-1)