Studies on the effect of residual and applied phosphorus on the yield and quality of fodder sorghum (Sorghum bicolor L. Moench) in wheat (Triticum aestivum L.) based cropping system and relative economics of the system

The experiment was carried out with the objective of studying the effect of phosphorus application timings and its sources in wheat-sorghum cropping system during rabi 2004 and kharief 2005, at the main campus Chatha of Sher-e-Kashmir University of Agricultural Sciences and Technology of Jammu, India. The soil was loamy in texture, neutral in reaction with low available nitrogen (N), phosphorus (P) and organic carbon (OC) and medium in available potassium (K). The treatments comprises of two factors viz. four P application timings to preceding wheat crop while the second factor which comprises of four sources of P applied to the succeeding sorghum fodder crop were laid out in split plot design. Studies indicated that wheat crop performed better with basal application of P than its delayed application through improvement in P up-take. However, in subsequent sorghum fodder crop, delayed application of P in preceding wheat crop proved instrumental in production of higher fodder yield. Among the sources used farmyard manure (FYM) as a source of P in sorghum, caused phenomenal increase in growth parameters. Delayed application of P in wheat and application of P in sorghum through different sources favoured crude protein content. However, effect on crude fibre content of the fodder sorghum was not significant. Delayed application of P in wheat followed by recommended P through FYM in sorghum proved beneficial with a benefit cost ratio ranging from 2.07 to 2.08.   Key words: Yield, quality, economics, phosphorus sources, residual effect, wheat-sorghum.