ISHS Acta Horticulturae 511: XXV International Horticultural Congress, Part 1: Culture Techniques with Special Emphasis on Environmental Implications - Nutrient Management
NITROGEN AND PHOSPHORUS FERTIGATION OF TOMATO AND EGGPLANT |
| Authors: | I. Papadopoulos, Leena M. Ristimäki |
| Keywords: | Drip irrigation, fertilisers, N, P fertigation, Urea phosphate |
| Abstract:
Field studies, on Pellic Vertisol, were designed to investigate the response of drip-irrigated tomato (Lycopersicon esculentum L.), to conventional soil P fertiliser application as Triple Superphosphate (TSP) and fertigation when P is applied in the form of Urea Phosphate (UP), Monoammonium Phosphate (MAP) or Diammonium Phosphate (DAP). The N and P applied in soil were 300 and 94 kg/ha. An equivalent amount of P and an amount of 70 kg P/ha in a combination with 150, 300 and 450 kg N/ha were applied with irrigation water at a total amount of 200 mm of water. The K applied was 450 kg/ha in all treatments. Irrigation was applied when the soil water potential was between 0.03 and 0.04 Mpa and at full growth of plants was equivalent to 0.8 of pan evaporation from a screened USWA Class A pan. Similar treatments were tested with eggplant (Solanum melongena L.) The results indicate that fertigation irrespective of the combination of fertilisers is superior than soil application. With less N by 50% higher yield was obtained with fertigation suggesting that N is more efficient when applied with the irrigation water. UP as a source of P gave the highest yield with both tomato and eggplant even when P supplied was by 25% less. Most probable explanation is the "double acidification effect" of the UP fertiliser. The mechanism is elaborated in the paper. | |
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