Search

• Water, N and year significantly affect dry matter accumulation, fruit yield, quality, water and N productivity. • The Entropy Weight-TOPSIS method was adopted to achieve the multi-objective optimization of water and N fertilizer. • I80N360 (80% ET 0 - 360 kg N ha−1) is the ideal water and N management strategy for greenhouse cherry tomato. In the context of climate-change and shortage of fresh water resources, improving agricultural productivity has become a major challenge globally, especially in China with large population. In this study, the purpose was to achieve the optimal combination of water and nitrogen (N) rates for greenhouse cherry tomato based on fruit yield, quality, net income and water-N productivity. Herein, during 2019–2021, three irrigation levels (I100: 100% ET 0 ; I80: 80% ET 0 ; I60: 60% ET 0 , where ET 0 was the reference evapotranspiration) and five N rates (450, 360, 270, 180 and 0 kg N ha−1, defined by N450, N360, N270, N180 and N0, respectively) with 15 treatments were set up. The 3-year ANOVA analysis indicated that irrigation, N fertilizer and year had significant effects on dry matter accumulation, fruit yield, quality, water and N productivity of greenhouse cherry tomato. Both the highest fruit yield (56.72 t ha−1, average of 3-year) and net income (60.8 × 104 CNY ha−1) were occurred under I80N360 treatment, though peak N partial factor productivity (PFPN, 294.88 kg−1) was observed under I80N180 treatment. The combined application of water and N fertilizer increased water productivity (WP) by 15.64% (average of 3-year) compared to I60N0 treatment, with I80N360 and I60N270 treatments having the highest WP. N fertilizer addition significantly increased fruit yield and WP irrespective of irrigation level, but the differences between N360 and N450 treatments were not significant in 80% ET 0 and 100% ET 0 irrigation level treatments, and between N270, N360 and N450 treatments in 60% ET 0 irrigation level treatments. Nevertheless, PFPN decreased significantly as the N rate increased. In addition, fruit quality could be improved at some extent under deficit irrigation relative to full irrigation regardless of N rate. More specifically, compared with the full irrigation treatment (I100), the I80 treatment increased the content of total soluble solid (TSS) by an average of 6.68%, soluble sugar (SS) by 11.96%, organic acid (OA) by 4.91%, sugar acid ratio (SAR) by 11.28%, vitamin C (VC) by 14.55%, lycopene by 30.06% and firmness by 7.60%; meanwhile, the I60 treatment increased TSS by an average of 11.17%, SS by 18.60%, OA by 12.04%, SAR by 10.02%, VC by 27.55%, lycopene by -7.93% and firmness by 13.14%, respectively. The increase of N rate largely increased TSS, SS, SAR, VC and lycopene, while these indicators decreased when N rate exceeded a threshold. Nevertheless, OA and firmness increased with increasing N rate, while firmness showed a slight decrease when N rate increased from N360 to N450 treatment. Generally, in a greenhouse cherry tomato production agroecosystem, the optimal amount of N fertilizer applied for each indicator varies with the availability of irrigation water. Furthermore, the Entropy-Weight TOPSIS method was adopted and the results indicated that the optimization of irrigation and N fertilizer supply schedule (I80N360 treatment: 80% ET 0 –360 kg N ha−1) was conducive to increase fruit yield, net income and water-N productivity whilst maintaining fruit quality in greenhouse cherry tomato cultivation. [ABSTRACT FROM AUTHOR]