ISHS Acta Horticulturae 396: Hydroponics and Transplant Production
SUPPLEMENTARY LIGHT AND PRETRANSPLANT NITROGEN EFFECTS ON TOMATO SEEDLING GROWTH AND YIELD |
| Authors: | L. Basoccu, S. Nicola |
| Keywords: | Fertilization, High-pressure sodium lamp, Supplementary light, Transplants |
| Abstract:
In northern Italy the intensity and duration of sunlight during the winter months can be inadequate for many vegetable transplant production. Besides, the N fertilization may interact with supplementary lighting and influence the yield. The objective of this work was to examine the effects of different levels of supplementary light (natural PAR, id. plus 4 or 8 hours of supplementary light at 150 μmol m-2s-1) and of different N supply in the nursery nutrient solution (4,8,15,30,60 mmol l-1) on tomato (Lycopersicon esculentum Mill.) seedling growth and yield. The supplementary lighting started at sunset. Each plant received 200 ml of N solution in 4 times during nursery growth. The seeds were sown in plastic pots on February 25 and the young plants were transferred in plastic house at the density of 4,1 plants m-2 on April 5 1992. Fruit harvesting began on June 8 and ended on July 31. All the data recorded in nursery and the Growth Rate values calculated were significant. They showed a different role played by N level supply depending on daylight lenght. Increasing the supplementary lighting (from 0 to 8hrs/day) at the seedling stage the early production increased only. It showed the maximum value at 15 mmol l-1 N level, the minimum at 4 and 60 mmol l-1. As regards the early production no interaction between N supply and light was found. | |
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