Reduced nitrogen proportion during the vegetative growth stage improved fruit yield and nitrogen uptake of cherry tomato plants under sufficient soil water regime

Under the current context of reducing chemical N input in agriculture, it is important to investigate better N allocation to different growth stages of crops. The plants were subjected to sufficient and reduced soil water regimes in interaction with two N application proportions applied at the vegetative and reproductive growth stages of tomato plants, respectively. In terms of the soil water impact, across the N proportion treatments, the reduced water treatments significantly decreased leaf and biomass growth by 33% and meanwhile remarkably reduced stomatal conductance of leaves, which significantly decreased water consumption by 41%. Consequently, plant WUE markedly decreased by 10.4%. The N uptake and fresh yield were considerably reduced by 37.5% and 39.3%, respectively. Regarding the N proportion effect across the soil water treatments, the lower N application of 30% at the vegetative growth stage significantly enhanced photosynthesis products allocated to fruits, which substantially improved the fresh yield by 32.9%. Furthermore, it significantly improved N accumulation by 9.0% compared to the higher N application of 70% at this stage. Conclusively, when given the certain amount of N supply, the N allocation should be reduced at the vegetative growth stage to achieve high yield and N uptake in tomato production .