The oxygen content of flowing nutrient solutions used for cucumber and tomato culture

Abstract

The oxygen (O 2) content of flowing nutrient solutions was monitored periodically at various points along and across the gullies of a nutrient-film culture system (NFT). The O 2 content of solution in which mature cucumber plants were growing was more depleted than that of those in which tomatoes were growing. In good weather there was a marked depletion of O 2 in the nutrient solution as it flowed from the inlet to the lower end of gullies containing cucumber plants, which was not found in gullies with tomato plants. On sunny days, the O 2 content of the solutions in which cucumbers were growing varied through the day at all points in the gullies and was lowest in the afternoons. A cucumber crop was grown from the seedling stage to maturity in 3 NFT gullies containing nutrient solutions with O 2 contents controlled at different levels. Day-to-day variations in O 2 content of the nutrient solutions were recorded throughout the duration of the experiment and the effects of these on the growth, development and yield of the plants was measured. Growth rates, root mass, root appearance, leaf area, water consumption and yield were reduced by low O 2 levels in the nutrient solutions.