Optimizing irrigation and fertilization frequency for greenhouse cucumber grown at different air temperatures using a comprehensive evaluation model

Abstract

The strategy for irrigation and application of fertilizer is essential for the intensive production of greenhouse cucumber. In order to determine the optimal irrigation amount (IA) and fertilization frequency (FF) to promote the integrated growth of cucumber under global climate change in the future, we explored the comprehensive effects of air temperature (AT), IA, and FF on the growth, yield, fruit quality, water and fertilizer use efficiency of cucumber. A five-level quadratic orthogonal rotation combination design with three experimental factors (AT, IA, and FF) was applied for 23 coupling treatments over three growing seasons during spring (2020S) and fall (2020F and 2021F). The technique for order preference by similarity to ideal solution of combining weights based on game theory was applied to construct cucumber comprehensive growth evaluation model. Single and two experimental factors analysis showed that single factor and the coupling of AT−IA, AT−FF and IA−FF both had significant effects on the integrated growth of cucumber for three seasons. For the AT−IA−FF combination in 2020 S, levels of − 0.09 for AT (26.5/16.5, day/night, °C), − 0.21 for IA {97 % crop evapotranspiration (ETc)}, and − 0.13 for FF (time/6 days) were the optimal parameters for comprehensive cucumber growth. The corresponding combinations for 2020F and 2021F were determined as 0.15 and − 0.21 for AT (27.8/17.8 and 25.9/15.9, day/night, °C), − 0.09 and 0.05 for IA (99 % and 101 % ETc), and − 0.08 and − 0.07 for FF (both time/6 days). Furthermore, when the AT ranges were 18/8 − 21.7/11.7, 21.7/11.7 − 27/17, 27/17 − 32.4/22.4, and 32.4/22.4 − 36/26 (day/night, °C), the corresponding to IA and FF intervals that maximized cucumber integrated growth were: 87 %− 91 % ETc and time/6 − 7 days, 94 %99 % ETc and time/5 − 6 days, 99 %− 104 % ETc and time/4 − 5 days, 107 %− 114 % ETc and time/3 − 4 days, respectively. These results suggest for the future global climate change, comprehensively understanding the growth of cucumber could save resources and potentially enhance cucumber production.