Abstract:In order to explore the effects of different water and nitrogen application amounts on tomato growth and nutrient uptake, pot experiment was carried out in greenhouse, where treated tomatoes were taken as research object. The irrigation was resumed when soil moisture was reduced to 50%, 65% and 80% of field capacity, and three irrigation levels were therefore designed named as I1, I2 and I3, respectively. Each irrigation level was associated with four nitrogen application rates (Ratio of N to soil quality was 0g/kg, 0.13g/kg, 0.27g/kg and 0.40g/kg named as N0, N1, N2 and N3, respectively). The tomatoes growth, biomass, tissue water content and nutrient accumulation were measured in each treatment. The results showed that the leaf area per plant, stem diameter and plant height were significantly increased with the increase of irrigation amount, and increased first and then decreased with the increase of nitrogen application amount. The optimal growth index was obtained in N1 treatment for each irrigation level. There was no obvious regularity of stem and leaf water content among all treatments. However, increasing irrigation amount significantly improved fruit water content, while increasing nitrogen application amount significantly reduced it. The dry matter content of stems, leaves and fruits were increased firstly and then decreased with the increase of nitrogen application amount, and increased significantly with the increase of irrigation amount. Especially, N1 was the most conducive to dry matter formation. The plant tissues could absorb more total nitrogen(N), phosphorus(P) and potassium (K)when increasing nitrogen application amount under water stress (I1) condition, which benefitted plant reproductive growth. The optimal nitrogen application amount for nutrient uptake by tissues was 0.13g/kg (N1). The accumulated N, P and K of above ground tissues was positively correlated with dry matter and negatively with corresponding nutrient concentrations (except N and K), but not with tissues’ water content. The accumulated N was positively related to accumulated P and K, thus, increasing nitrogen application amount could promote nutrient uptake of tomatoes, especially K uptake. In comparison with N1I3 treatment, the fruit dry matter,nitrogen accumulation and potassium accumulation of N1I2 treatment was decreased by 3.04%, 10.67% and 12.08%, respectively, but the irrigation amount was saved by 25%. The results revealed that the irrigation resumed at 65% of field capacity (I2) associated with 0.13g/kg (N1) was the optimal water-nitrogen combination treatment, which can save water and fertilizer, as well as regulate plant type, and lay the foundation for improving yield and quality.