ISHS Acta Horticulturae 126: Symposium on Substrates in Horticulture other than Soils In Situ
ALTERNATIVE SOURCES OF IRON FOR USE IN RECIRCULATING NUTRIENT SOLUTIONS FOR TOMATOES |
| Authors: | E.W. Johnson, D. Oldfield |
| Abstract:
The Chelate EDTA-Fe is the usual source of iron used in recirculating nutrient solutions. This is an expensive material (subsequently reduced to compete with ligno sulphonate-Fe) so an alternative cheaper source was sought, which would still provide iron in a form available to plants. In this trial single plots containing 8 tomato plants were used to compare EDTA-Fe, a polyphenolic acid-Fe material and ferric chloride (FeCl3) at 3 different pH levels, maintained by using ammonium nitrogen at 5, 10 and 15% of the total solution nitrogen content. The highest yield was obtained with EDTA-Fe (8.4 kg/plant) followed closely by FeCl3 + 15% NH4 - N (7.6 kg/plant); FeCl3 + 10% NH4 - N (7.5 kg/plant) and FeCl43 + 5% NH4 -N (6.5 kg/plant) The control yield was 6.7 kg/plant and polyphenolic-Fe produced only 6.0 kg/plant. The method of Katyal and Sharma (1980) was used to assess the 'active' iron level in the leaf on two occasions and was found to be effective for demonstrating iron deficiency. | |
Download Adobe Acrobat Reader (free software to read PDF files) | |
