Water-yield relation and water use efficiency of cotton (Gossypium hirsutum L.) and second crop corn (Zea mays L.) in western Turkey

A field study was carried out during the 2003 and 2004 cropping season in the western Turkey. The effect of water deficit or water stress on crop yield, yield response, water use efficiencies, dry matter yield (DM) and leaf area index (LAI) were evaluated. Cotton (named as S letter for cotton) and corn (named as T letter for corn) were grown under five irrigation treatments. Treatments were designated as S-100 and T-100 full irrigation; S-70, T-70; S-50, T-50; S-30, T-30; and S-00, T-00, received 70, 50, 30 and 0% times the soil water depletion in the treatment S-100 and T-100 on the same day. The average seasonal water use values ranged from 174 to 558 mm in corn treatments and 257 to 867 mm in cotton treatment. Water deficit significantly affected both crop yields. The average corn grain yield varied from 2880 to 11,340 kg ha−1 and average seed cotton yield varied from 1780 to 5490 kg ha−1. Highest average corn and cotton yield were obtained from the full irrigation treatments (S-100; T-100). The average water use efficiency (WUE) ranged from 1.65 to 2.15 kg m−3 for corn and 0.61 to 0.72 kg m−3 for cotton, respectively, while average irrigation water use efficiency (IWUE) were between 2.30 and 3.52 kg m−3 for corn and between 0.77 and 1.40 kg m−3 for cotton. Yield response factors (ky), 1.04 for corn and 0.92 for cotton, were determined based on averages of 2 years. Leaf area index (LAI) and dry matter yields (DM) increased with increasing water use for both treatments. This study demonstrated that well irrigated treatments (S-100 and T-100) could be used for the semiarid climatic conditions under no water shortage.