A comparison of calcium and magnesium ratios in soilless media for optimum vegetable production irrigated with alkaline pH water
Master of Science (MS)
Plant, Environmental Management and Soil Sciences
Home gardeners in areas with alkaline water sources do not have means of acidifying water for vegetable production. A solution to achieving optimal yields with alkaline irrigation water is to use specialized media; however, current media available does not meet these needs. New media recipes with varied levels (0 to 8 lbs/yd3) and sources of Ca (dolomitic lime, calcium sulfate) and Mg (dolomitic lime, magnesium sulfate) were tested using alkaline irrigation on lettuce, cabbage, and cauliflower crops under high tunnel and on nursery yard sites. Media treatments with an 80:20 bark:peat and 7.1 kg/m3 slow release 15-9-11 base mix and the following fertilizer levels: 2.4 kg/yd3 calcium sulfate and 2.4 kg/yd3 magnesium sulfate (Ca/Mg); 2.4 kg/yd3 dolomitic lime (4L); 2.4 kg/yd3 dolomitic lime, 2.4 kg/yd3 calcium sulfate, and 2.4 kg/yd3 magnesium sulfate (4L+Ca/Mg); 4.7 kg/yd3 dolomitic lime (8L), outperformed a commercially available (IS) and control (C) (no Ca or Mg fertilizer) media in nearly all crops. All crops grown on the nursery yard and cabbage grown under the high tunnel had significantly greater yields when grown in medium 4L+Ca/Mg, compared to the IS and C media (p≤0.05). Media treatment 4L produced significantly greater yields and plant growth of all tested crops on the nursery yard compared to the IS and C media (p≤0.05). Media longevity was tested by planting cucumber, tomato, and bell pepper into the same pots, at the same sites, during the spring with no additional pre-plant amendments added to the media. All crops grown on the nursery yard, and cucumber and bell pepper grown under the high tunnel, had significantly greater yields when grown in media 4L+Ca/Mg and 8L, compared to the IS (p≤0.05). Tomatoes and bell peppers grown on the nursery yard and under the high tunnel had significantly greater growth and yield when grown in 4L+Ca/Mg and 8L, compared to the C medium (p≤0.05).
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Bertrand, Sarah E., "A comparison of calcium and magnesium ratios in soilless media for optimum vegetable production irrigated with alkaline pH water" (2014). LSU Master's Theses. 758.