Effect of Corn or Soybean Row Position on Soil Water

Crop plants can funnel water to the soil and increase water content more in the row relative to the interrow. Because the row intercepts more soil water after rains and higher root density, the soil may also dry out more between rains than does soil in the interrow. The objectives of this study were to determine if there is a row position difference in soil wetting after rain and drying between rains, and to determine the seasonal nature of these differences. The first experiment examined soil water content 0 to 0.06 m in row, interrow, and quarter corn row positions for eight sites at specific times during a corn (Zea mays L.)-growing season. During the growing season, the second experiment examined automated soil water measurements at one site for two corn years and one soybean (Glycine max [L.] Merr.) year at row and interrow positions to 0.15-m depth. Soil water content changes were significantly greater in the row than the interrow for some mid-season dates. Temporal soil water changes showed that row wetting and drying dominated over interrow soil water changes for mid season. The mean ratio of row/(row + interrow) soil water changes for wetting was 0.76 and 0.77 for corn and 0.64 for soybean and for drying was 0.58 and 0.84 for corn and 0.60 for soybean. Soybean showed the row effect for a shorter time of the season (up to 71 days) compared with corn (up to 159 days).