Yield of Flue-Cured Tobacco and Levels of Soil Oxygen in Lysimeters with Different Water Table Depths
1972
Campbell, R. B. | Seaborn, G. T.
Flue-cured tobacco (Nicotiana tabacum L.) was grown in lysimeters with static water- table levels at $0, 45, 60, and 90 cm below the soil surface to more clearly define the level at which a favorable balance between soil aeration and water supply is attained. The oxygen and CO₂ content of the soil air was determined periodically at various depths. Water-table treatment effects were evaluated in terms of root and shoot growth, yield, and quality of tobacco. Dry leaf yields for the 90-, 60-, and 45-cm water-table treatments were all significantly (P≥0.05) greater than that for the 30-cm treatment. Yields for the 60- and 90- cm water-table levels were larger, but not significantly (P≥0.05) larger than the 45-cm treatment. The yield difference between the 60- and 90-cm treatments was not significant (P≥0.05). Roots of tobacco recovered from soil above the 60- and 90-cm water tables weighed only 10% more than roots recovered from soil above the 30- cm water table. Average CO₂ and O₂ gradients in the soil above the water table were nearly equal but of opposite sign. Soil environmental conditions imposed by the 60-cm water-table treatment of this study provided the most favorable balance between aeration and water supply for tobacco.
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