Yield and water use efficiency of drip irrigated cotton (Gossypium hirsutum L.) at different irrigation intervals and watering regimes.

摘要

The study observed the effects of different watering regimes on yield and water use efficiency of N-84 cotton (Gossypium hirsutum L.) variety in the Aegean Region of Turkey during 2003 and 2004. Trials comprised two irrigation intervals (4-d and 8- d) within each of which three different watering regimes (100%, 67% and 33% of cumulative Class-A pan evaporation) were applied. The highest irrigation water level was applied to the full irrigation treatment (IR-100) for both irrigation intervals. Seasonal water use values in the treatments varied from 313-650 mm in 2003 and 249-603 mm in 2004. Seed cotton yield was significantly affected by irrigation intervals and irrigation levels. The maximum and minimum seed cotton yields were obtained from the 8-d IR-100 and the 8-d IR-33 treatments and averaged 5508 kg ha-1 and 3419 kg ha-1, respectively. Significant curvilinear relationships between seed cotton yield and crop water use were obtained for 2003 and 2004. Averaged across years, the highest water use efficiency (WUE) (1.21 kg m-3) was obtained in the 8-d IR-33 treatment and the lowest WUE (0.83 kg m-3) in the 4-d IR-100 treatment. The average yield response factor (k_y) was 0.59 for the 4-d irrigation interval and 0.67 for the 8-d irrigation interval, respectively. Overall, the results of this research indicated that the 8-d irrigation interval with the IR-100 irrigation treatment could be used for cotton grown in semi-arid regions under no water shortage. Moreover, results obtained from the 8-d, IR-67 treatment could be used as a good basis for reduced drip irrigation strategy development under water shortage because 33% of water saving was obtained with only a 6.0% yield loss averaged across years.