| Tomato is the largest area of vegetable cultivated in greenhouses,and traditional soil cultivation is facing some problems such as continuous crop barrier,low fruit quality,and soil salinization.Substrate cultivation is a simple soilless cultivation method using integrated water and fertilizer integration technology,which is an important cultivation method to effectively avoid continuous crop barriers and improve fruit quality and water and fertilizer utilization.However,the problems of technical difficulty and high cost in substrate cultivation have limited the widespread application of substrate cultivation.In order to promote the widespread use of substrate cultivation and reduce production costs,this study investigated the effects of different root zone volumes,irrigation frequency,and fertilizer application frequency on physiological indicators,yield,quality,and water and fertilizer use efficiency of tomatoes in greenhouse tomato cultivation,using large-fruited tomatoes as test materials.And this study analyzed the coupling differences of different root zone volumes and irrigation and fertilization frequencies using TOPSIS integrated analysis.Additionally,Pearson correlation was used to analysis the correlations between root zone volume,irrigation and fertilizer application frequency and tomato fruit yield and quality.The main findings of the study were showed:1.The coupling effect of root zone volume and irrigation frequency had a significant effect on tomato growth,photosynthesis,yield,and quality.The experiment was conducted by12 treatments,coupled with 4 levels of root zone volume(V1=1L;V2=3L;V3=5L;V4=7L)and 3 levels of irrigation frequency(T1:6 times/d;T2:10 times/d;T3:14 times/d),and the results showed that the treatments of V4T1 had the highest plant height,stem thickness,dry matter mass,root length and root surface area,and reached significant differences with other treatments.The plant height,stem thickness and dry matter mass of tomato increased with increasing irrigation frequency at root zone volumes of 1,3 and 5L.The root zone volume of5 L and irrigation frequency of 10 treatment had the highest yield and water use efficiency among the 12 treatments,which was not significantly different from V2T3 and significantly different from the other treatments,followed by V2T2 which also had higher yield and water and fertilizer use efficiency per plant and V1T1 which was the worst.Stomatal conductance and transpiration rate were significantly higher in the root zone volume of 5 L and irrigation frequency of 10 treatments than in the other treatments,followed by V1T2 treatment,but V1T2 had the highest net photosynthetic rate,significantly higher than the other 11 treatments.The net photosynthetic rate of the treatment with irrigation frequency of 10 was much higher than that of the treatments with irrigation frequency of 6 and 10 for the same root zone volume.The effect of increasing irrigation frequency on net photosynthetic rate was not significant at root zone volumes of 3,5,and 7 L.In terms of overall fruit quality,the treatment with root zone volume of 7 L and irrigation frequency of 10 was significantly better than the other treatments,followed by V3T2 and then V4T1.The fruit quality of V2T2 was the worst.2.The coupling effect of root zone volume and fertilizer application frequency had significant effects on tomato growth,photosynthesis,yield,and quality.The test was conducted by coupling six treatments with 2 levels of root zone volume(V1=3L;V2=5L)and3 levels of fertilizer application frequency(T1: 1 time/d during the whole reproductive period;T2: once before 4 d of fruit expansion and once 2 d after the expansion period;T3: once before6 d of fruit expansion and once 3 d after the expansion period),and the results showed that the highest plant height,stem thickness,and dry matter mass were obtained in V2F2 treatment,which was not significantly different from V2F3,and reached significant differences with other treatments.Under the same root zone volume,plant height,stem thickness and dry matter mass of tomato increased and then decreased with decreasing frequency of fertilizer application.V2F1 had the highest root length and root surface area,which were significantly different from the other five treatments.The highest yield was obtained with a root zone volume of 5 L and fertilizer application frequency of 1d,which was not significantly different from V1F2,but significantly different from the other four treatments.V2F3 had the highest fruit weight per fruit,which was significantly different from the other treatments.V2F1 had the highest net photosynthetic rate and transpiration rate,while the difference in net photosynthetic rate of V1F1 was not significant,but significantly different from the other treatments.In terms of overall fruit quality,the root zone volume of 5L and fertilizer application frequency of once a day had the best quality,which was significantly better than the other treatments,followed by V1F1.V2F1 had the highest sugar to acid ratio and V1F1 had the highest soluble sugar and Vc,and both were significantly different from the other treatments.3.The results of the analysis of organic and inorganic cultivation patterns on tomato fruit yield and quality as well as economic benefits showed that the bag cultivation(A2)treatment with organic nutrient solution had the highest fruit weight,yield per plant,yield per mu,and water use efficiency,while the pot cultivation(B1)treatment with inorganic nutrient solution had the lowest.Application of organic nutrient solution significantly increased the fruit weight of tomatoes per fruit.The potted treatment(A1)with organic nutrient solution application had the best fruit quality with the highest sugar to acid ratio,reducing sugar,soluble sugar,lycopene,and Vc content among the treatments.Both root-limited cultivation and the use of organic nutrient solution improved fruit quality.The highest net gain among the treatments was in the pot treatment with inorganic nutrient solution application.The best fruit quality was obtained with organic nutrient solution in root-limited cultivation,but the net gain was slightly lower than with inorganic nutrient solution.Considering the volume of the substrate,the yield and quality of the tomatoes,it was considered that using 5L cultivation substrate,selecting a frequency of 10 daily irrigation and supplying a daily fertilization frequency was the best management plan. |
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