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

ABSTRACT 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 .