Simulation Water Consumption of Hydroponic-cultured Lettuce: The Effects of Nitrogen Concentration

Abstract

【Objective】 The objective of this paper is to investigate the influence of nitrogen concentration in nutrient solution on physiological traits of lettuce grown in hydroponic culture. 【Method】 The experiment was conducted in a greenhouse, with the Flandria cultivar used as the model plant. We compared five nitrogen concentrations: 12.25, 24.5, 49, 98 and 196 mg/L, each having two replicates. In the experiment, we measured the leaf area index (LAI), accumulated water consumption and the change in meteorologic factors in the greenhouse, from which we derived the relationship between water consumption of the crop and nitrogen concentrations in the solution. 【Result】 The accumulated water consumption and LAI both increased first followed by a decline as the nitrogen concentration increased. The relationships between LAI and the nitrogen concentration can be fitted to a quadratic function, and comparison with measured data showed fitting of the model was accurate. The model describing the change in water consumption with nitrogen concentrations also agreed well with experimental data. 【Conclusion】 Accumulative water consumption and LAI of the hydroponic-cultured lettuce both increased with nitrogen concentration in the nutrient solution, and the models describing their relationships agreed well with experimental data.

Keywords

• hydroponic culture
• water consumption
• leaf area index
• nitrogen concentration
• lettuce