Abstract:

To explore the water consumption regularity and crop coefficient of open-field lettuce in summer and autumn in central Yunnan, and provide irrigation guarantee for lettuce production in this region, water consumption tests of lettuce in summer and autumn were carried out in the field at the Irrigation Experimental Center Station of Yunnan Province in 2019. The water consumption law and crop coefficient of lettuce in summer and autumn were calculated by using water balance and Penman-Monteith formula, and the influencing factors of water consumption were analyzed by path analysis. The results showed that the water consumption during the whole growth period of lettuce in summer and autumn was 76.47 and 44.54 mm respectively, the daily water consumption intensity at the seedling stage, lotus seat stage, balling stage and mature picking stage of summer lettuce was 0.74, 1.23, 2.26 and 2.52 mm respectively, and those of autumn lettuce was 0.40, 0.73, 0.86 and 1.15 mm respectively. The crop coefficient of summer lettuce in each growth period was 0.17, 0.31, 0.74 and 0.75 respectively, while that of autumn lettuce in each growth period was 0.18, 0.25, 0.37 and 0.81 respectively. The main influencing factors of water consumption of lettuce in summer were the average soil temperature of 0-40 cm and rainfall, while the main influencing factors of water consumption of lettuce in autumn were the average soil moisture content of 0-40 cm and sunshine hours. The coefficient of lettuce crop in summer and autumn was obtained, which could provide a basis for the formulation of irrigation quota and irrigation schedule of lettuce in central Yunnan.

Key words: micro-sprinkling irrigation, open-field lettuce, lettuce, modulus of water consumption, intensity of water consumption, crop coefficient, central Yunnan