Effect of moisture stress level and stage on evapotranspiration and yield of grape under protected and delayed cultivation

Abstract: In order to study the effect of soil moisture stress on water consumption and yield of grape, 3-year of field experiment was carried out from 2012 to 2014 in Zhangye Water Bureau Irrigation Test Center in Zhangye City of Gansu Province (38°56?N, longitude 100°26?E, altitude 1 482.7 m). The grape growth was divided into 5 stages, namely, germination, shoot growth, flowering, fruit enlargement and coloring maturity. There were 2 different stress types: a moderate water stress level that the lower limit for soil moisture content was 55% of field water holding capacity (FC) and a mild stress level that the lower limit for soil moisture content was 65%FC. In addition, the lowest limit of 75%FC was considered as control (CK, full irrigation). The moderate water stress was conducted in each of the 5 stages of grape in 2012. Except for the stage with stress treatment, the other stages were with full irrigation. Similar with 2012, the moderate stress treatments were conducted in 2013 and 2014. In addition, the mild stress was carried out in each of the 5 stages. The grape under protected and delayed cultivation was planted in greenhouse. The greenhouse film was uncovered at the end of May for grape germination and was covered at the beginning of October. The grape was harvested in the middle and late December. During the experiment, water consumption, daily water consumption intensity, grape yield, water use efficiency and others were determined. The results showed: 1) The daily water consumption intensity reached a maximum value (3-year average was 3.2 mm/d) in the fruit enlargement stage, indicating that the fruit enlargement period was a critical period of water requirement for the grape under protected and delayed cultivation; 2) Water stress had obvious effect on the water consumption intensity of each growth period of grape. The moderate water stress in germination period could reduce the intensity of grape water consumption, and water compensation effect appeared after the return of full water supply in the subsequent growth period. The moderate water stress had an obvious effect on the new shoots growing period. Due to the short flowering period, the effect of moderate water stress in this period on water consumption manifested in the subsequent growth period (the fruit enlargement stage). The moderate water stress in the coloring maturity period also significantly reduced water consumption intensity. The mild water stress in the germination stage could also significantly affect the daily water consumption intensity; 3) The moderate water stress in the germination stage could improve grape yield and water use efficiency in 2012 but not in 2013 and 2014. The yield of moderate water stress in the germination stage was 23 542 kg/hm2, 40.7% higher than CK(P<0.05). It probably indicated that the grape had a strong resistance capacity against water stress in 2013 and 2014. The yield and water use efficiency of grape was not significantly different with CK for the other stress treatments, suggesting that either of them was good for grape production. The study would be helpful in understanding water consumption of grape and formulating water-saving plan of grape in greenhouse.