EFFECT OF N AVAILABILITY ON GROWTH, N UPTAKE, LIGHT INTERCEPTION AND PHOTOSYNTHETIC ACTIVITY IN PROCESSING TOMATO

Growth, N uptake, light interception and leaf photosynthetic activity were studied in processing tomato grown in the field at different levels of N fertiliser in 1996-97. Nitrogen supply greatly increased crop growth and N uptake.
Plant N concentration declined during the entire crop cycle.
The relationship between total above-ground dry mass of tomato and critical N concentration was % N = 4.3 DW^-0.32 for total-N and % N = 3.82 DW^-0.26 for reduced-N. Relative growth rate (DW > 1 t ha^-1) of N deficient plants increased with reduced-N concentration of the whole above-ground biomass according to a linear relationship (R² = 0.72) but closer relationships were found with the reduced-N of the leaves (R² = 0.85) and with the ratio between the reduced-N accumulated in the leaves and in the whole plant (R² = 0.94). These results support the assumption that the plant growth is directly associated with the leaf area and to some extent to the metabolic component of the plant.
Actually, increasing N availability increased the LAI, light interception, and leaf assimilation rate at saturating irradiance and decreased the fraction of sunlit LAI while radiation use efficiency was slightly affected.

Workshop Towards and Ecologically Sound Fertilisation in Field Vegetable Production

F. Tei, P. Benincasa, M. Guiducci

Lycopersicon esculentum Mill., field crops, critical % N, RGR, RUE

https://doi.org/10.17660/ActaHortic.2002.571.25