Influence of coupling irrigation volume and organic nutrient solution formula on yield, quality, and water utilization efficiency of greenhouse tomatoes.

The coupling of irrigation volume and organic nutrient solution plays an important role in improving the quality and yield of substrate-cultivated tomatoes. We used 'Kade Yali' tomatoes as the test material and adopted an organic substrate cultivation in a plastic greenhouse. Based on the irrigation amount (ET) calculated by the advanced decision-making irrigation model, three irrigation levels (I1: 1.2ET+1.4ET, I2: 1.0ET+1.2ET, I3: 0.8ET+1.0ET) were crossed with three organic nutrient solution formulations O1, O2, O3 [(N:P:K content mg·L^-1) were 108:20:157, 103:20:205, 105:20:213 respectively], resulting in nine treatments. We examined the effects of the coupling of volume and organic nutrient solution formulations on growth, photosynthesis, yield, qua-lity, and water use efficiency of tomatoes in spring and autumn. The weights of each indicator were calculated using the analytic hierarchy process, entropy weight method, and a combination of weights based on game theory. The overall evaluation of each treatment was conducted using the TOPSIS method and the GRA method, and the most suitable water and fertilizer scheme was finally selected. The results showed that plant morphology and photosynthetic characteristics varied across treatments. The effect of irrigation volume was greater than that of the formulation of organic nutrient solution. Among them, the I1O2 treatment had the highest dry matter accumulation and yield in both spring and autumn crops, with 261 g and 5177 g in spring and 234 g and 4742 g in autumn, respectively. These values were significantly different from other treatments. The I3O2 treatment had the highest water use efficiency, with 35.66 and 35.42 g·kg^-1 in spring and autumn crops, respectively, an increase of 1.9%-13.8% and 3.8%-26.5% compared to other treatments. The lycopene content of the I3O3 treatment was 0.73 mg·kg^-1. The I1O2 treatment had the highest sugar-acid ratio of 9.65, soluble protein (207.45 mg·g^-1), and Vc content (152.14 mg·kg^-1). The most influential factor in the comprehensive evaluation of the treatments was yield, followed by water use efficiency. The I1O2 treatment had the highest comprehensive evaluation value, representing the optimal combination of tomato yield, quality, and water use efficiency.