Effect of sowing time and nitrogen schedules on phenology, yield and thermal-use efficiency of wheat (Triticum aestivum).

摘要

The effect of sowing time and nitrogen schedules on phenology, yield and thermal-use efficiency of wheat was studied during the winter season of 2003-04 and 2004-05 on a sandy loam soil in Hisar, Haryana, India. There were 3 sowing dates, 15 November, 5 December and 25 December; and 7 N treatments, i.e. no N, 75 kg N at sowing+75 kg N at first irrigation, 50 kg N at sowing+50 kg N at first irrigation+50 kg N at anthesis, 37.5 kg N at sowing+75 kg N at first irrigation+37.5 kg N at anthesis, 68 kg N at sowing+75 kg N at first irrigation+7 kg N (3% urea spray) at anthesis, 50 kg N at sowing+50 kg N at first irrigation+43 kg N at anthesis+7 kg N (3% urea spray) at milk stage, 37.5 kg N at sowing+68 kg N at first irrigation+37.5 kg N at anthesis+7 kg N (3% urea spray) at milk stage. Delayed sowing reduced the crop duration by 16-30 days, duration of reproductive phase (12 and 13) and grain growth duration (9 and 13) under late (5 December) and very late (25 December) conditions, respectively. The reduction of 23 and 30 kg ha-1 day-1 in grain yield with delay in sowing by 20 and 40 days, respectively, was recorded. The 40 days delay in sowing also significantly reduced the heat unit consumption and thermal-use efficiency of the crop. The recommended dose of nitrogen (150 kg/ha) significantly increased crop duration over the control. The increase in splits and foliar application of nitrogen increased duration of maturity, reproductive phase and grain growth phase and thus resulted in higher grain and biological yields.