ISHS Acta Horticulturae 98: Symposium on Research on Recirculating Water Culture
SOME RESPONSES OF TOMATOES TO NITROGEN IN RECIRCULATING SOLUTIONS |
| Authors: | D. Massey, G.W. Winsor |
| Abstract:
Tomato plants grown in shallow, recirculating solution culture at nitrogen concentrations of 10, 20, 40, 80, 160 and 320 mg NO3-N/1 showed no significant differences in yield. The appearance of the plants gave no indication of differences in nitrogen supply, even at the lowest concentration tested. Further examination of the data showed that the apparent lack of yield response to nitrogen concentration was due to two opposing trends. The number of fruit per plant increased somewhat with nitrogen concentration whereas the fruit size (g/fruit) tended to decrease. The percentage of unevenly ripened fruit was particularly low (0.7 – 1.2% by weight), with no significant effect of nitrogen concentration. The uptake of nitrogen increased progressively from 10.9 g to 16.2 g/ plant with increasing nitrogen concentration, the regression being significant at P < 0.001. Uptake of phosphorus and potassium also increased with nitrogen concentration (P< 0.01). Averaged over three sampling dates (March to May), the nitrogen content of the leaves increased from 3.7% at 10 mg N/1 to 4.0% at 320 mg N/1. Inclusion of a proportion of ammonium-N in the nutrient solution decreased the amount of acid required to maintain the pH but increased the incidence of blossom-end rot. | |
Download Adobe Acrobat Reader (free software to read PDF files) | |
