Guan'gai paishui xuebao (Feb 2023)
Optimizing Irrigation Scheduling for Greenhouse Crops Using the CRITIC-TOPSIS Framework
Abstract
【Objective】 Greenhouse agriculture relies on irrigation and optimizing irrigation to balance crop yield and quality is critical to maximizing its profitability. Taking cucumber and melon as an example, we propose to optimize the irrigation based on evaporation measured from standard 20 cm evaporation pan (Ep) and other factors. 【Method】 The experiment is carried out in a drip-irrigated greenhouse. It compares four irrigation treatments with the irrigation amount setting at 50 (I5), 70 (I7), 90 (I9) and 110% (I11) of Ep respectively. In each treatment, we analyze the changes in morphological and quality indexes of the fruits, as well as yield and water use efficiency (WUE). The optimal irrigation for each crop is determined using the CRITIC-TOPSIS framework. 【Results】 ①I7 and I9 increase the weight and diameter of the cucumber significantly compared with other treatments, but at the expense of fruit numbers and fruit length. For the melon, I9 is optimal for improving morphological traits of the fruits. ②Increasing irrigation amount reduces the total soluble solids (TSS), vitamin C (Vc), soluble sugars content (SSC) and soluble proteins content (SPC) in the cucumbers. For the melon, its Vc, SSC and SPC peakes in I7, and TSS maximizes in I5. ③The maximum cucumber yield is 96.1 t/hm2, achieved in I9, with its WUE and irrigation water use efficiency (IWUE) being 17.9% and 32.2% respectively less than those in I5. There is no significant difference in melon yield between I9 and I11, but the WUE and IWUE of the former are 9.2% and 16.3% higher than those in the latter. 【Conclusion】 Comprehensive evaluation using 11 indicators for the cucumber and 10 for the melon shows that the optimal irrigation for the greenhouse cucumber and melon is to irrigate 90% and 70% of water evaporated from the 20 cm standard evaporation pan installed in the greenhouse, respectively.
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