ISHS Acta Horticulturae 807: International Symposium on Strategies Towards Sustainability of Protected Cultivation in Mild Winter Climate
THE INFLUENCE OF FERTIGATION STRATEGIES ON WATER AND NUTRIENT EFFICIENCY OF TOMATO GROWN IN CLOSED SOILLESS CULTURE WITH SALINE WATER |
| Authors: | A. Pardossi, L. Incrocci, D. Massa, G. Carmassi, R. Maggini |
| Keywords: | hydroponics, runoff, soilless culture, Solanum lycopersicum L., water quality |
| Abstract:
Two experiments were conducted in the spring-summer season of two consecutive years (2005 and 2006) to investigate the possible effect of different fertigation strategies on the water and nitrogen use efficiency of tomato plants grown in closed-loop substrate (rockwool) culture using irrigation water with a NaCl concentration of approx. 9.5 mmol L-1: A) crop water uptake was compensated with fresh nutrient solution (EC = 2.5 dS m-1) and recirculating nutrient solution (RNS) was flushed out whenever EC surpassed 4.5 dS m-1; B) EC was maintained at about 3.0 dS m-1 and RNS was flushed out whenever Na concentration exceeded 20 mmol L-1 and the concentration of nitrogen (N) was lower than 1.0 mmol L-1; C) as strategy A, but when ECRNS reached 4.5 dS m-1, crop water consumption was compensated with fresh water only in order to take out N from RNS before discharge. In 2005, an open system (strategy D) was included in order to verify the possible influence of Na accumulation and/or nutrient depletion on crop performance. In both 2005 and 2006, neither crop water uptake nor fruit yield were affected by the method to manage fertigation; however, strategies B and C were more environment-friendly than the others on account of lower N leaching and water use, at least for strategy C. A third experiment was carried out in the spring of 2007 with tomato plants grown in semi-closed rockwool system using irrigation water of different salinity levels (10 and 20 mmol L-1 NaCl) and following the strategy C previously described with two different degree of oscillation for ECRNS. An EC variation up to 5.0 dS m-1 (with a maximum EC of the recycling water as high as more than 9.0 dS m-1) did not produce important effects on both crop yield and fruit quality, which were more affected by the average salinity level in the root zone. | |
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