Decision-making Of Irrigation Combined With Potassium And Magnesium Of Cherry Tomato Based On Comprehensive Evaluation

In the production of agricultural crops,the fine management of water and fertilizer factors plays an important role in the yield,quality and resource utilization.The field experiment was conducted to study the comprehensive effects of irrigation and potassium and magnesium on cherry tomato,the optimum conditions of irrigation,potassium and magnesium application were determined,which provided theoretical basis for balanced fertilization and scientific irrigation of Cherry Tomato.Spring（March-july,2021S）,autumn（August-December,2021F）,and spring（March-July,2022S）,with irrigation,K₂O and mgo as the experimental factors,the orthogonal design with three factors and three levels（-1,0,1）was adopted,and 9 treatments were carried out.The indexes measured in the experiment can be divided into four categories:growth photosynthesis index,quality index,yield index and efficiency index.The effects of irrigation combined with potassium and magnesium on yield and quality of cherry tomato were analyzed,and a comprehensive evaluation system of cherry tomato was established based on correlation analysis,using subjective and objective combination to determine the weight of each evaluation index,on the basis of adopting TOPSIS,MFA and GRA three evaluation methods,the effects of irrigation and combined application of potassium and magnesium on the growth of cherry tomato were evaluated by the method of integrated difference combination,and the response model of the comprehensive growth evaluation to irrigation,potassium and magnesium application was established,the regulation effect of experimental factors and their interaction on the comprehensive evaluation value of cherry tomato was analyzed,and the optimal irrigation and potassium-magnesium combination scheme was determined.The specific results are as follows:（1）With the increase of irrigation water,the hectare yield showed an upward trend,while the soluble solids and acidity showed a downward trend,while the number of fruits per plant,soluble total sugar,soluble protein,vitamin C and lycopene performed best under I0.With the increase of K₂O and MgO application,acidity showed a downward trend,and hectare yield,soluble solids,soluble total sugars,soluble protein,vitamin C and lycopene performed best in K0 and M0.The yield of T9 was the highest in the three test seasons and reached 42533.21（2021S）,24461.06（2021F）and 39877.54（2022S）kg/ha,the application of potassium and magnesium at medium level was more beneficial to the formation of yield of cherry tomato,the combination of high-K and low-Mg,high-Mg and low-K was unfavorable to the formation of soluble solid,soluble protein and soluble total sugar,and the three test seasons all have the inhibitory effect to the vitamin C.（2）A comprehensive evaluation system for cherry tomatoes was constructed in four categories:growth,yield,quality and efficiency,and six comprehensive evaluation indicators were determined based on correlation analysis:biomass,stomatal conductance,hectare yield,soluble solids,vitamin C and water use efficiency.Based on game theory,the combined weights of each index were determined,and the maximum weight indicators of the three experimental seasons were hectare yield（0.3734,0.3505,0.3688）,the minimum weight indicators of 2021S and 2022S were stomatal conductance（0.0841,0.0861）,and the biomass（0.0944）was 2021F.The three single evaluation methods of TOPSIS,MFA and GRA were used to comprehensively evaluate the combined application of irrigation and potassium and magnesium,and the standard deviation of the single treatment evaluation results reached 1.73,which was a significant difference;based on the overall difference combination evaluation,T4,T5 and T9 ranked in the top three in the three trial seasons,although the ranking of each trial season was slightly different,the worst treatment in the three trial seasons was T1.（3）Based on comprehensive evaluation,the response model of cherry tomatoes to irrigation and potassium and magnesium application was established,and the model was tested to be effective.In univariate analysis,the effects of irrigation water,K₂O and MgO application rate on the comprehensive score were all parabolic with an open downward opening,too high or too low was not conducive to comprehensive growth,irrigation was0.33（2021S）,0.22（2021F）,0.36（2022S）at the factor level,K₂O was 0（2021S）,0.14（2021F）,0（2022S）at the factor level,and MgO was 0.17（2021S）,0.22（2021F）,0.18（2022S）at the factor level,the evaluation value reached a peak;The peak value of the three stubble tests was different,but the regulation law tended to be consistent.There was an interaction between irrigation,K₂O application amount and MgO application amount.The regulatory effects of the three factors on the comprehensive score of cherry tomatoes were irrigation,MgO,and K2O in descending order.（4）Analyze the model,and determine the application interval of the three factors with an optimal comprehensive score of more than 95%,and the optimal irrigation water,K₂O amount and MgO application amount,respectively:2021S（1917.31～1976.06m3/ha、192.32～202.19kg/ha、23.75～24.88kg/ha）,2021F（1101.70～1136.58m3/ha、146.78～153.82kg/ha、17.35～18.16kg/ha）,2022S（2045.16～2107.28m3/ha 229.98～241.78kg/ha、24.26～25.41kg/ha）.