Nutrient balance of sorghum (Sorghum bicolor) - wheat (Triticum aestivum) cropping sequence under integrated nutrient management system

摘要

A field experiment was conducted during 1997-98 and 1998-99 at Rajasthan College of Agriculture, Udaipur to evaluate the impact of integrated nutrient management on soil fertility under sorghum + wheat sequence. The treatments consisted of two levels of farm yard manure (FYM) (0 and 10 t ha~(-1)) four levels of each of fertilizers (control, 50 percent RDF, 75 percent RDF and 100 percent RDF i.e. 80 kg N and 40 kg P_2O_5) and biofcrtilizers (control, Azospirillum inoculation, phosphate solubilizingbacteria (PSB). Azospirillum + PSB coinoculntion). Results showed that the application of 10 t FYM ha~(-1) increased available N and P in soil after sorghum harvest by 4 and 16 percent over no FYM application while application of fertilizer and biofertilizers increased only available P status of soil after sorghum harvest Available P content in soil after wheat harvest was significantly influenced by FYM and fertility levels. Balance sheet showed in deficit balance for available N and positive balance for available P in soil at the end of sorghum and wheat crop. The magnitude of decrease was less with FYM application and higher with no fertilizer application. However the magnitude of positive balance of P increased with FYM application and increased levels of fertility.