Abstract
Field experiments were conducted on a sandy loam soil in 2002-03 and 2003-04 growing seasons to determine
the effect of nitrogen nutrition on growth, yield and water use efficiency of wheat under adequate and limited
water supply conditions. The treatments comprised of four levels of irrigation (I" one irrigation at tillering stage; 12,
two irrigations, each at tillering and anthesis stages; 13, three irrigations, each at tillering, anthesis and grain
development stages and 14
, four irrigations, each at tillering, stem elongation, anthesis and grain development
stages) in main plots and four N levels (0, 50,100 and 150 kg N ha") in sub-plots of a split plot design and were
replicated three times. Increase in number of irrigations from 1 to 4 and nitrogen levels from 0 to 150 kg N ha',
significantly (p s 0.05) increased the average leaf area index (LAI), crop growth rate (CGR), yield attributes, and
grain yield over the control (10
and No), in both the seasons. The maximum LAI and CGR were commensurate with
highest levels of irrigation as well as nitrogen observed on an average during the 73-88 days after sowing (DAS)
period of growth. The regression analysis revealed that LAI estimates with biological yield were 92% and 38%
during the year 2002-03 and 2003-04, respectively. Mean grain yield in four, three and two irrigation treatments
compared with that in one irrigation treatment increased by 47,23 and 9 % during 2002-03 and by 91,84 and 23
% in 2003-04, respectively. Water deficit reduced spikes m·
2
. In both years, the average reduction in spikes m·
2
at
maximum irrigation deficit (one irrigation) at all N levels was 24%. Similar reduction occurred in grains spike"
where water deficit decreased this component on an average of 36 %. Mean water use efficiency (WUE) at all
nitrogen levels was 41% higher in one irrigation treatment compared with four irrigations treatment. Significantly
higher WUE was observed with 150 kg N ha' at all irrigation treatments. The water use efficiency (WUE).
decreased with increasing number of irrigations, whereas nitrogen application significantly improved WUE
