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This study aims at discussing the effects of planting row spacing and irrigation amount on the plant growth, chlorophyll fluorescence parameters and yield of tomato, the purpose is to obtain the suitable arrangement of irrigation amount and planting row spacing for greenhouse tomato in Northwest China. The experiment was conducted in a solar greenhouse at the Green Lily fruit and vegetable cooperatives in Yangling Agricultural Hi-tech Industries Demonstration Zone in Shaanxi province from January to June in 2016. The cultivated variety of tomato in the experiment was HL2109. The treatments comprised three planting row spacing (L1(60 cm), L2(45 cm), L3 (30 cm))with 80 cm ridge distance and 35 cm plant spacing. Based on the cumulative evaporation from a 20 cm diameter pan between two irrigations (E), 0.6 E, 0.8 E, 1.0 E, 1.2 E were set as four different levels of irrigation amount, when the cumulative evaporation reached (20±3) mm, irrigation will be conduct. Twelve treatments were experimented totally and every treatment was replicated three times in randomized complete block designs. Based on the growth indexes, chlorophyll fluorescence parameters in different growth stages and the leaf area index, net photosynthetic rate of tomato plants during the critical period of yield formation, the effects of different row spacing and irrigation amount on tomato growth, photosynthetic physiological activities and yield were analyzed, and the relationship between different growth and physiological indexes with yield were studied. The results showed that tomato growth index: chlorophyll fluorescence parameters, net photosynthetic rate, yield and irrigation water use efficiency were all affected by both planting row spacing and irrigation amount in varying degrees, but there is no significant interaction between the two factors. Low planting row spacing treatment(L3) resulted in redundant plant growth and excessive LAI, thereby photosynthetic physiological activities of crop population were inhibited, finally causing lower yield and irrigation water use efficiency. Excessively low irrigation amount inhibited photosynthetic physiological activities and showed a cumulative effect of water stress with the growth period of tomato plants. By path analysis, LAI and Pn have the most direct impact on yield among the indicators, improving the Pn is an important way to increase crop yield. Plant height and stem diameter have a good regression relationship with leaf area index(P=0.004 6), plant with large stem diameter and low height has suitable leaf area index, which is beneficial to yield formation. The yield of tomato followed a downward quadratic parabola shape with the increase of irrigation amount and planting row spacing, however, when planting row spacing and irrigation amount reached 45 cm and 0.8E respectively, continuing to increase planting row spacing and irrigation amount would not significantly increase yield. Considering the irrigation water use efficiency and yield, L1-0.8E and L2-0.8E treatment were better than others. Compared with the highest yield treatment (L1-1.2E), L1-0.8E and L2-0.8E treatments can increase irrigation water use efficiency by 36.00% and 29.29% when yield reduced by only 4.28% and 9.00%. So, when the ridge distance is 80 cm and the plant spacing is 35 cm, the planting row distance selected 45-60 cm, the irrigation quantity is set to 0.8E would be the appropriate combination of irrigation amount and planting row spacing of greenhouse tomato in Northwest China. [ABSTRACT FROM AUTHOR]

In recent years, the nutritional quality of vegetables has been increasingly concerned by people and investigated by researchers. However, the decline in vegetable internal quality is common due to excessive irrigation and irrational fertilization. Although tomatoes have been grown successfully for many years, there is no accurate formula or recipe on amount of irrigation or fertilizer levels to get tomato fruit with high quality. For tomato fruits, the nutritional quality largely depends on the content of soluble solids, soluble sugar, titratible acid, Vitamine C and lycopene, some of which are correlated with each other. Therefore, tomato nutritional quality could not be assessed according to any one of these attributes. But the comprehensive evaluation of vegetable nutritional quality has not been well studied yet. To construct a comprehensive nutritional quality index of tomato fruits and investigate its response to irrigation amount and fertilizer rates of nitrogen, phosphorus and potassium, a composite quadratic orthogonal regressive rotation design of four factors and five levels was used in a pot experiment. The contents of soluble solids, soluble sugar, titratable acid, lycopene, Vitamin C and sugar-acid ratio were determined for tomato fruits. By using entropy weighting method, the objective weights of six single quality attributes were calculated based on measurements of these attributes. The subjective weights of these six attributes were calculated based on the analytic hierarchy process (AHP) from survey data from both consumers and horticulture experts. Based on these, the comprehensive weighting method of game theory was used to determine the balanced weight of single tomato quality attributes. Results indicated that the attributes were ranked based on their importance by lycopene>sugar-acid ratio>Vitamin C>soluble sugar>soluble solid>titratable acid. The comprehensive nutritional quality index was constructed according to the technique for order preference by similarity to ideal solution (TOPSIS). Moreover, a regression model on the amount of irrigation water and fertilizers and tomato comprehensive nutritional quality index was established. Based on the regression equation, the single, interactive and coupling effects of these four experimental factors on the comprehensive nutritional quality index were analyzed. The results showed that the main effects of four experimental factors on the comprehensive nutritional quality were ordered by P rate>N rate>irrigation amount>K rate. If codes of other three factors were zero, the comprehensive nutritional quality showed a downward quadratic parabola in response to the increase of irrigation amount, as it did in the case of N rate. It is interesting that an upward quadratic parabola occurred with the increase of K rate. The comprehensive nutritional quality increased linearly with P rate. Interaction between amount of irrigation and N, P and K fertilizers significantly affected comprehensive quality of tomato fruits. It indicated that comprehensive tomato nutritional quality decreased with excess input of irrigation amount and N fertilizer, and could be improved by appropriate supply of P and K fertilizers. The findings from this study also allowed us to optimize comprehensive evaluation of vegetable quality that could be used to study the management of water and fertilizers in the future. [ABSTRACT FROM AUTHOR]