ISHS Acta Horticulturae 571: Workshop Towards and Ecologically Sound Fertilisation in Field Vegetable Production
EFFECT OF N AVAILABILITY ON GROWTH, N UPTAKE, LIGHT INTERCEPTION AND PHOTOSYNTHETIC ACTIVITY IN PROCESSING TOMATO |
| Authors: | F. Tei, P. Benincasa, M. Guiducci |
| Keywords: | Lycopersicon esculentum Mill., field crops, critical % N, RGR, RUE |
| Abstract:
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. | |
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