High electrical conductivity and radiation-based water management improve fruit quality of greenhouse tomatoes grown in rockwool
2000
Chretien, S. | Gosselin, A. | Dorais, M.
In order to improve fruit quality under the Northern climatic growing conditions prevailing in Quebec, Canada (lat. 47 degrees N, long. 71 degrees W), a greenhouse tomato (Lycopersicon esculentum Mill. cv. Blitz) spring production experiment was conducted using several irrigation regime and electrical conductivity (EC) levels. The irrigation regime treatments were a function of the global solar radiation, with three thresholds applied to each EC treatment. The irrigation thresholds (KJ(.)m-2) were 1) 468, 2) 540, and 3) 612. Two EC treatments were used: 1) control EC (2.0 to 3.5 mS(.)cm-1) and 2) 30% higher EC than the control (2.6 to 4.6 mS(.)cm-1), which was raised by adding NaCl to 12 mmol(.)L-1. Plant water potential in summer and in the fall and plant growth after 6 months were not affected by irrigation or EC treatments. Raising the EC increased the Na content of reproductive and vegetative parts and decreased the N concentration of the vegetative parts. The highest EC improved fruit quality by reducing the incidence of fruit cracking. Although marketable yields were not affected by EC (P = 0.09) or irrigation regime (P = 0.08) treatments, higher EC during March to September increased (P less than or equal to 0.01) the proportion of Class 2 fruit by reducing fruit size.
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