Submitted to: Southern Conservation Tillage for Sustainable Agriculture Proceedings
Publication Type: Proceedings
Publication Acceptance Date: June 27, 2005
Publication Date: June 27, 2005
Citation: Busscher, W.J., Bauer, P.J., Sadler, E.J. 2005. Infiltration and evapotranspiration for cotton grown with reduced tillage on goldsboro loamy sand. Proceedings of the Southern Conservation Tillage Systems Conference, June 27-29, Florence, SC. p. 217-221. Technical Abstract: Despite abundant rainfall, southeastern sandy Coastal Plain soils can be droughty because of their low water holding capacity. A frequency domain reflectometry sensor was used to measure amount of rainfall that infiltrated into the soil and was taken up by roots of cotton grown in reduced tillage. Sensors measured volumetric soil water content at 30-min time steps and 4-inch depth intervals to 40 inches. Changes of soil water content were separated into infiltration, evapotranspiration, deep percolation, and runoff using rain gauge measurements and software designed specifically for this experiment. At mid-season, cumulative infiltration was 75 to 85% of the rainfall with spikes up to 90% during storm peaks when water would have ponded on the soil surface. Later in the season, during a wet period, cumulative infiltration dropped to 60% because the lower part of the profile was full, unable to accept infiltration. Evapotranspiration, measured as reduction of soil water content that did not drain deep into the profile, was highest in the top foot and decreased exponentially below that depth. Even though the soil dried out easily and even though it was disrupted deeply under the row to disrupt a hard layer and promote root growth below it, most water for plant growth came from the top foot, the zone that had been tilled.