| In protected agricultural production,the temperature,irrigation amount,and fertilization frequency in the greenhouse can be controlled more precisely,and at the same time,there is a complex interaction between the three.Scientific and rational irrigation and fertilization at different temperatures can promote crop growth,yield and quality improvement,and reduce waste of water resources and fertilizers to a certain extent.However,there is still a lack of relevant research on how to adjust the amount of irrigation and fertilization frequency to achieve high quality and high yield under different temperature conditions in the facility.To clarify the irrigation amount and fertilization frequency suitable for the comprehensive growth of facility cucumbers under different temperature conditions,in this study,the cucumber variety ’Bonai 526’ was used as the test material,temperature,irrigation amount,and fertilization frequency were used as experimental factors,and three factors,five levels,two Sub-orthogonal rotation combination design test treatment combination,three season tests were carried out in autumn 2020,spring 2021,and autumn 2021.By measuring the growth,photosynthesis,yield,quality,water use efficiency and other indicators of cucumber,the effects of temperature,irrigation amount,and fertilization frequency on the comprehensive growth of cucumber were explored.The 19 sub-factors included in the four indexes of efficiency were used for comprehensive evaluation,and the TOPSIS comprehensive evaluation value of different treatment combinations was obtained.A temperature-driven multi-factor coupled cucumber comprehensive growth model of irrigation amount and fertilization frequency was established to analyze the regulatory effects of temperature,irrigation amount and fertilization frequency single-factor,two-factor interaction and threefactor coupling on the comprehensive growth of cucumber,and the irrigation effects at different temperatures were obtained.In order to obtain an irrigation and fertilization management scheme that can promote the high quality and high yield of facility cucumbers,and provide scientific and reasonable theoretical basis and water and fertilizer technical guidance scheme for the planting of facility cucumbers at different temperatures.The main findings are as follows:1.The determination of the weight of the comprehensive evaluation index of cucumber based on the combination weighting of game theory and the comprehensive evaluation and analysis of the cucumber based on the TOPSIS method.Determination of subjective weights of four types of indicators and their sub-factors based on AHP.The weights of the four types of indicators for cucumbers are ranked in descending order: Yield,fruit quality,water and fertilizer use efficiency and growth indicators.The subjective weights of each sub-factor of cucumber are ranked as follows: hectare yield >fruit number per plant > VC > single fruit weight > FAA > nitrate > PFP > WUE > total dry matter mass > TSS > RS > N element accumulation > SP > Pn > P element accumulation > K element accumulation > Gs > Tr > Ci.The objective weights of various indicators and subfactors based on the entropy weight method vary by season.In the three seasons planting,the growth indicators with the largest and the smallest weights are Gs and Ci;the yield indicators vary by season,and in the autumn planting,the largest and smallest weights are hectare yield and single fruit quality,respectively.In the autumn of 2020 and the spring of 2021,the quality indicators with the largest weight are FAA.In the autumn of 2021,the quality indicators with the largest weight are VC,and the quality indicators with the smallest weight are also different among the three plantings.The quality indicators with the smallest weights in the spring of2021 and the autumn of 2021 are TSS,nitrate and SP respectively;in the three seasons planting,the water and fertilizer use efficiency indicators with the largest weight are all WUE,and the index with the smallest weight is due to the planting year.There are differences.The water and fertilizer use efficiency indicators with the smallest weights in 2020 and 2021 are the accumulation of K elements accumulation and N elements accumulation,respectively.Based on game theory,each index was combined and weighted to determine the final weight.The index with the largest weight in the three crops was the hectare yield,and the index with the smallest weight was the Ci.The representative factor of growth index is Gs,the representative factor of yield index is hectare yield,the representative factor of quality index is FAA in 2020,VC in 2021,and the representative factor of water and fertilizer use efficiency is WUE.Based on the TOPSIS comprehensive evaluation method,it is determined that the best combination of the three crops is the treatment with the code value of(0,0,0),that is,the air temperature is 27/17 °C(day/night),the irrigation amount is 100% ETc,and the fertilization frequency is6-day treatment;but the sub-optimal combination of spring and autumn planting is different,the treatment with the code value of the sub-optimal combination of spring planting is(0,0,-1.682),that is,the temperature is 27/17 ℃(day/night).),the irrigation amount was 100% ETc,and the fertilization frequency was once every 3 days.The treatment with the suboptimal combination code value of autumn season planting was(0,-1.682,0),that is,the temperature was 27/17 °C(day/night),the irrigation amount was 75% ETc,and the fertilization frequency was once every 6 days.2.Establishment of regression model for comprehensive evaluation of temperaturedriven irrigation amount and fertilization frequency.The three-factor coupling of air temperature,irrigation amount and fertilization frequency has a significant regulatory effect on the comprehensive growth of cucumber.In the single factor analysis,the relationship between the comprehensive growth of cucumber and temperature,irrigation amount and fertilization frequency is a parabolic relationship with an opening downward,that is,the regulatory effects of temperature,irrigation amount and fertilization frequency on the comprehensive growth of cucumber are all positive regulation first.After reaching the most suitable range for comprehensive growth of cucumber,it showed a negative regulation effect.The three fertilization frequencies all have thresholds once every6 days.The three seasons temperature and irrigation thresholds are different.The 2020 autumn,2021 spring,and 2021 autumn temperature thresholds are 27.82/17.82 ℃,26.99/16.99 ℃,25.93 /15.93 ℃,the thresholds of irrigation amount for autumn in 2020,spring in 2021,and autumn in 2021 were 99.52% ETc,100.03% ETc,and 100.68% ETc,respectively.In the twofactor interaction of temperature,irrigation amount and fertilization frequency,there was a positive interaction between irrigation amount and fertilization frequency on the regulation of comprehensive growth of cucumber.In the three-factor interaction model of temperature,irrigation amount,and fertilization frequency,in autumn 2020,the day and night temperature is 27.82/17.82 ℃,the irrigation amount is 99.52% ETc,and the fertilization frequency is once every 6 days;in 2021 spring,the day and night temperature is 26.99/16.99 ℃,irrigation amount of 100.03% ETc,and fertilization frequency of once every 6 days;the autumn crop in2021,the day and night temperature of 25.93/15.93 ℃,irrigation amount of 100.68% ETc,and fertilization frequency of once every 6 days were the most favorable treatment combinations for cucumber growth,increased yield,improved quality and utilization of water and fertilizer,thereby promoting the comprehensive growth of cucumbers.3.The Matlab software was used to simulate and optimize the comprehensive growth model of cucumber,and the optimal combination of irrigation amount and fertilization frequency suitable for the comprehensive growth of cucumber at different temperatures was determined.The optimal combination for autumn planting stubble: When the temperature is 18.00-21.65 °C,the frequency of fertilization is 6-7 d,and the amount of irrigation is 89.87%-101.75%ETc;when the temperature is 21.65-27.00 °C,the frequency of fertilization is 5-7 d once,the amount of irrigation is 95.81%-104.72% ETc;when the temperature is 27.00-32.35 °C,the irrigation volume is 95.81%-107.70% ETc,and the frequency of fertilization is 5-7 d;when the temperature is 32.35-36.00 °C.The frequency of fertilization is 5 d,and the amount of irrigation is 98.78%-113.64% ETc.The optimal combination for spring planting: fertilization frequency is once every 5-7days,but the irrigation amount varies with different temperatures,specifically: when the temperature is 18.00-21.65 ℃,the irrigation amount is 95.81%-113.64% ETc;when the temperature is 21.65-27.00 ℃,the irrigation amount is 98.78%-122.56% ETc;when the temperature is 27.00-32.35 ℃,the irrigation amount is 107.70%-122.56% ETc;when the temperature is 32.35-36.00 ℃,the irrigation amount is 98.78%-116.61% ETc. |
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