Fertilizer schedule under limited irrigation with zero-tilled wheat (Triticum aestivum) after rice (Oryza sativa) in north-west Himalayas

Field experiment was conducted for two years during 2005–06 and 2006–07 at CSKHPKV, Rice and Wheat Research Centre, Malan to find out the fertilizer schedule for limited irrigation zero-tilled wheat {Triticum aestivum (L.) emend. Fiori & Paol.}. Five nitrogen levels viz., 0, 60, 90, 120 and 150 kg/ha along with 40 kg P₂O₅ and 40 kg K₂O/ha in main plots and three time-methods of fertilizer application viz. M₁: Placement of ⅓N with full P and K as basal & topdressing ⅔N at first node stage, M₂: Broadcast of ⅓N with full P and K as basal & topdressing ⅔N at first node stage, and M₃: Broadcast of full P and K as basal & full N one month after sowing, in sub-plots were tested using split plot design replicated thrice. Significant response of wheat to nitrogen application was observed up to 150 kg N/ha, which was more profitable too. Grain and straw yield of the crop was significantly higher at 150 kg N/ha compared to lower levels. Increase was 30.6 (0.75 t/ha) and 27.0 (0.59 t/ha) per cent over the 90 kg N/ha in first and second year, respectively. Mean net returns were 33,950/ha and benefit: cost ratio 2.45 were the highest at 150 kg N/ha. N use efficiency was 11.0 & 13.2 kg grain/kg N applied at this level in 2005–06 and 2006–07, respectively. The relationship between grain yield and N was quadratic in nature predicting still higher dose of optimum N. Wheat grain yield was significantly varied by time and method of fertilization application. In 2005–06 which was a drought like year at initial phase, application of full dose of N one month after sowing (M₃) recorded significantly higher grain yield (2.69 t/ha) compared to ⅓N applied at sowing time and ⅔N at first node in M₁ and M₂ treatments. Whereas in 2006–07 rainfall was comparatively well distributed and application of ⅓N with full P and K as basal placement (M₁) recorded significantly higher values of grain yield and straw yield compared to M₂ and M₃ treatments. Similarly M₃ was more economical (net returns 30,307/ha, 2.32 B:C) in drought like year and M₁ in 2006–07. Thus, placement of 50 kg N, 40 kg P₂O₅ and 40 kg K₂O/ha as basal dose followed by topdressing of 100 kg N/ha at first node stage be adopted to realize more productivity of zero-tilled wheat under limited irrigation conditions in north western Himalayas. However, if there is dry spell during the initial crop phase, Broadcast of full P & K as basal and full N one month of sowing is also effective.