Growth stage sensitivity of wheat to irrigation water salinity

The effects of irrigation water salinity (12 dS m−), imposed at maximum tillering (35−40 days after sowing, DAS) or booting (50−60 DAS) or grain filling (75−85 DAS) stage of wheat, on growth and yield of the crop was demonstrated. The experiment comprised four treatments – I1: irrigation by fresh water (FW) at all three growth stages (control), I2: irrigation by saline water (SW) at maximum tillering stage and by FW at other stages, I3: irrigation by SW at booting stage and by FW at other stages, and I4: irrigation by SW at grain filling stage and by FW at other stages. The experiment was set in a randomized complete block with three replications. Wheat was grown under three irrigations (each of 3 cm) and recommended fertilizer doses (120 kg N, 32 kg P, 62 kg K, 20 kg S, 3 kg Zn and 1 kg B ha−). Salinity of irrigation water imposed, separately, at the three growth stages did not impart significant (p = 0.05) negative influence on plant height, spike density, spike length, spikelets and grains per spike and 1000-grain weight. It, however, significantly hindered leaf area index (LAI), above ground dry matter (ADM), grain and straw yields, grain-straw ratio and water productivity of the crop. The least grain (3.622 t ha−) and straw (5.772 t ha−) yields, LAI (1.24 and 2.18 at 50 and 70 DAS, respectively), ADM (0.80, 4.78 and 7.66 t ha−) and water productivity (186.5 and 297.3 kg ha− cm−) obtained under I3 implied that salinity of irrigation water imposed at booting stage exerted the maximum retarding effects on the growth and yield of wheat. Grain yield decreased by 13.4% in I3 over the control, I1. An increase in grain and biomass yields by 14.3 and 11.9%, respectively under I2 over I1 demonstrated a positive contribution of irrigation water salinity imposed at maximum tillering stage of wheat.