Soil compaction and water table effects on soil aeration and corn growth in a greenhouse study

Abstract

A greenhouse experiment was conducted to study the effects of aeration on growth of corn seedlings. Variable aeration regimes were created by a combination of 3 levels of soil compaction (1.20, 1.37 and 1.56 Mg m −3) and 3 water table depths (10-cm, 20-cm and 30-cm). Soil aeration was assessed by measuring the oxygen diffusion rate (ODR) and the gaseous composition of soil air. Samples of soil air were analyzed for concentrations of oxygen, carbon dioxide, ethylene and nitrous oxide. The ODR decreased with increasing soil compaction. The average ODR for the 30 cm water table was 193.5, 89.2 and 15.4 μg O 2 m −2 s −1 for the three compaction treatments of 1.2, 1.37 and 1.56 Mg m −3, respectively. At 40 days after planting, concentration of carbon dioxide in soil air was as high as 0.5% by volume. High concentrations of ethylene and nitrous oxide were also measured in those samples that contained high levels of carbon dioxide. The range of concentration was 2–19 ppm for ethylene and 2–20 ppm for nitrous oxide. The vegetative growth of corn seedlings, as measured by root and shoot weights and plant height, was not significantly affected by the treatments imposed. However, stomatal conductance and photosynthesis significantly differed among treatments.