Optimum irrigation scheduling for a cucumber [Cucumis sativus] field in a Chinese style greenhouse

The water balance of a cucumber field during the growing season under an irrigated condition has been analyzed using an empirical water balance model in a Chinese Style Greenhouse (CSG). The study was conducted in Yan'an district in semi arid region on the Loess Plateau. Through the analysis of on-going irrigation scheduling, it became clear that soil water increased in the latter stage of the total growth period. It suggested that water-saving irrigation could be applied to this field. Furthermore, water balance simulations were conducted under six scenarios. In simulations, the growth period of the cucumber was divided into three stages in Case 1 and two stages in Case 2, and each case had three scenarios of irrigation scheduling. According to the simulations, the first irrigation scenario, with 352 mm of total water applied as 45 mm per irrigation at a 38-day interval in stage I, 44 mm per irrigation at a 15-day interval in stage II, and 43 mm per irrigation at a 13-day interval in stage III, was the method that amount of irrigation water and frequency of irrigation were smallest. Moreover, crop was not subjected the moisture stress. As a result, it was cleared that this scenario was optimum for this field and it was demonstrated that the current irrigation scheduling in a CSG can be improved by optimizing irrigation time and amount.