Residual effect of farmyard manure, fertilizer and biofertilizer on succeeding wheat (Triticum aestivum)

A field experiment was conducted during the rainy and winter seasons in 1997–98 and 1998–99, to evaluate the residual effect of integrated nutrient management in sorghum [Sorghum bicolor (L.) Moench] on succeeding wheat (Triticum aestivum L. emend. Fiori & Paol.) crop. Two farmyard manure (FYM) levels (0 and 10 tonnes FYM/ha), 4 fertility levels (control, 50%, 75% and 100% recommended dose of fertilizer) and 4 biofertilizer treatments (control, Azospirillum, phosphate-solubilizing bacteria (PSB) and co-inoculation of Azospirillum and PSB) were compared. Application of 10 tonnes/ha FYM and nitrogen and phosphorus fertilizer up to 75% of recommended level significantly enhanced grain and fodder yields of sorghum. Azospirillum alone and in combination with phosphate-solubilizing bacteria increased sorghum yield by 6–7%. Both available P and N status in soil after sorghum harvest were improved with FYM application, while fertility levels and PSB inoculation increased only P status of soil after sorghum harvest over the control. Residual effect of FYM, 75% and 100% recommended level of fertilizer (N and P) significantly enhanced growth, yield attributes, yield and nutrient uptake of wheat by 9–12% but biofertilizers did not show any residual effect on wheat. Available P status in soil after wheat harvest was also significantly influenced by residual effect of FYM and fertility levels.