Regulation Effect Of Different Irrigation Amount And Irrigation Frequency On The Plant Growth,Yield And Quality Of Processing Tomato

At present,the growing area of processing tomato cultivation in northwest China and t the shortage of water resources are becoming more serious.This study was based on reference crop evapotranspiration,researching effects of different irrigation amount（high irrigation,W1,100%ET₀;medium irrigation,W2,75%ET₀;low irrigation,W3,50%ET₀）on the fruit yield,quality of different varieties processing tomato（V1:PT-501Q,V2:H1015,V3:Nongfan 3）,and influence of different irrigation amount and irrigation frequency（high frequency,F1,three times a week;conventional irrigation,F2,once a week）on the plant growth,quality and yield of processing tomato respectively in 2016 and 2017.This paper aims to explore the reasonable irrigation system of processing tomato and water demand regulation under mulch drip irrigation,and provide references for further improving yield and optimizing irrigation schedule.The test results show that:（1）With increasing irrigation amount,the soil volumetric moisture content,leaf area,dry matter quality and yield index of V1,V2 and V3 increased,and the quality index decreased;the irrigation amount was reduced,the volumetric moisture content,leaf area,dry matter quality and yield index of V1,V2 and V3reduced,but the quality index was increased.（2）The V1 varieties,the average yield of W1 treatment was highest(114.4 t·hm^-2),the average water use efficiency under W2 26.22%higher than W1,the yield is 7.57%lower than W1,but the difference was not significant（P>0.05）,and titratable acid,soluble solids,soluble sugar was significantly improved（P<0.05）,Therefore,75%of irrigation treatment can be implemented to reduce moisture for the improvement of irrigation system;The V2 varieties,the average yield of W1 treatment was highest(109.6 t·hm^-2),the average water use efficiency under W1 10.18%higher than W1,the yield is 13.36%lower than W1,but the difference was not significant（P>0.05）,and titratable acid,soluble sugar was significantly improved（P<0.05）,Therefore,75%of irrigation treatment can be implemented to reduce moisture for the improvement of irrigation system;The V3 varieties,the average yield of W1 treatment was highest(138.4t·hm^-2),the average water use efficiency under W2 10.50%higher than W1,the yield is 23.62%lower than W1,and the difference was significant（P<0.05）,and soluble solids was not significantly improved（P>0.05）,Therefore,100%of irrigation treatment can be implemented to reduce moisture for the improvement of irrigation system.（3）The soil nitrate content increased gradually with the development of growth period.With the decrease of irrigation amount,the soil nitrate content in the surface layer of 0-40cm showed an increasing trend,expressed as follows:W3>W2>W1.The soil content of nitrate nitrogen in the layer of 40-80cm showed a decreasing trend,showing:W1>W2>W3.From the seedling stage to the young fruit stage,under the treatments of W1,W2 and W3,the soil nitrate content of V3 plants was greater than V1 and V2.From the young fruit stage to the late maturity stage,under the treatment of W1,W2 and W3,V1 plant soil nitrate content is greater than V2,V3.The content of soil nitrate in 0⁴0cm soil layer treated with F2 conventional irrigation was higher than that in F1.The content of soil nitrate in F1 high-frequency treated 40⁸0cm soil layer was higher than that in F2 conventional irrigation.（4）Three times a week in high frequency irrigation treatment of 0⁴0cm,40⁸0cm depth range of average soil volumetric moisture content is smaller,and it can be kept in a stable range.The plant height Leaf area,dry matter accumulation,and yield also increased correspondingly,compared to once a week irrigation treatment.（5）Compared to the irrigation treatment of 50%ET₀,the irrigation treatment of 100%ET₀ and 75%ET₀can significantly increase the single fruit weight and yield（P<0.05）,and the yield difference between 100%ET₀ and 75%ET₀ irrigation treatment is not significant（P>0.05）.From the aspect of saving water resources,it is recommended to use W2 treated irrigation treatmentv in the arid and semi-arid regions.（6）The irrigation with 75%ET₀ of once a week was applied at the seedling stage,and the high frequency irrigation treatment of three times a week was conducted from the fruiting period to the pull period,and through frequency conversion treatment,the content of MDA can be reduced,and the root growth of the root layer can be significantly accelerated and the root activity can be significantly increased（P<0.05）.