Impact of nitrogen application on the performance of wheat (Triticum aestivum) and nitrogen use efficiency under different dates of sowing

Field experiments were conducted during rabi seasons of 2003–04 and 2004–05 to find out the effect of sowing time and nitrogen schedules on perofrmance of wheat and N balance in sandy loam soils of Hisar, Haryana.The results showed that 40 days delayed sowing resulted in 24.5% reduction in wheat grain yield. However, there was increase in nitrogen content in grains with the delayed sowing whereas, nitrogen uptake decreased with delayed sowing. Maximum mobilization of nitrogen to grain was recorded on 25 December and minimum on 15 November sown crop. There was decrease in physiological efficiency (PE), agronomic efficiency (AE), nitrogen recovery (NR) and nitrogen use efficiency (NUE) by 8.4, 37, 9 and 8% respectively with delay in sowing from 15 November to 25 December. There was 4.14% increase in grain yield when N was applied as 45.3% of recommended N (150 kg) at sowing (F₄) followed by 50% at first irrigation and 4.7% as foliar application @ 3% concentration over recommended (F₁) schedule (50% at sowing and 50% at first irrigation) and 58.4% increase over no nitrogen application. About 60 kg/ha increase in nitrogen uptake was recorded in different nitrogen schedules over control. The highest nitrogen mobilization was observed in treatment where no nitrogen was applied and minimum in recommended schedule. NR, NUE and AE were 15.7%, 8.0% and 12% more under F₄ when compared with F₁ treatment. However, there was decrease of 6% in PE under F₄ than F₁ treatment. The highest B:C ratio was also recorded in early sowing and in F₄ treatment.