WATER BALANCE IN A CECIL SOIL UNDER CONTROLLED IRRIGATION IN LARGE NO-TILL AND CONVENTIONAL TILLAGE PLOTS.

Authors: Endale, Dinku; Schomberg, Harry; Jenkins, Michael

Submitted to: Southern Conservation Tillage Systems Conference
Publication Type: Proceedings
Publication Acceptance Date: 5/20/2006
Publication Date: 6/26/2006
Citation: Endale, D.M., Schomberg, H.H., Jenkins, M. 2006. Water balance in a cecil soil under controlled irrigation in large no-till and conventional tillage plots. In: Proceedings of the Southern Conservation Tillage Systems Conference, June 26-28, 2996, Amarillo, Texas. p. 125-131.

Interpretive Summary: The Southeastern US suffers short-term droughts during critical crop growth periods and periodic multi-year droughts with sometimes devastating consequences on crop productivity. No-till-based crop production is one possible method to mitigate this problem. However, due to variability in weather, soils and topography, site-specific research is needed to produce quantified data to help growers and water resource planners make informed decisions. In a controlled irrigation study conducted from June 4 to 7, 2002, at the USDA-ARS, J. Phil Campbell Sr. Natural Resource Conservation Center in Watkinsville, GA, we compared runoff, drainage and soil water storage differences between long-term (11 Y)conventionally tilled (CT) and no-till (NT) plots in a Cecil soil. The twelve plots were each 33 x 100-ft in size and were instrumented for measurement of runoff and drainage. Following 2.2 in. of irrigation and 0.5 in. of rainfall on June 4, there was about 38% more drainage from the NT plots. There was no runoff on this date. About 1.7 in. of the water input was retained in the soil profile. There was much runoff and drainage on June 5 following 2.6 in. of irrigation and 0.5 in. of rainfall. Runoff from CT was about 4 times that from NT, while drainage from NT was about double that from CT. The soil did not retain any significant amount of the added water as it was close to saturation. For the combined irrigation and rainfall event over the two days, there was 89% more drainage from NT while runoff was again about 4 times more from CT. The research confirms that no-till enhances infiltration in Cecil soils and is an important finding for growers and water resource planners seeking to improve water use and mitigate drought. The finding has great regional importance since Cecil soils occupy over 50% of the 41 million acre Southern Piedmont.

Technical Abstract: There is continuing need for systematic research under site-specific conditions to quantify soil water availability in different soils and tillage practices to help growers make informed decisions. We conducted an irrigation study from June 4 to 7, 2002, on twelve 33 x 100-ft plots on Cecil soil at the USDA-ARS, J. Phil Campbell Sr. Natural Resource Conservation Center in Watkinsville, GA, to quantify differences in the soil hydrologic balance between no-till (NT) and conventional tillage (CT). The plots had been in either CT or NT for eleven years. We found significant differences in hydrology between CT and NT. Following 2.2 in. of irrigation and 0.5 in. of rainfall on June 4, there was about 38% more drainage from NT. No runoff was recorded. The soil profile retained about 1.7 in. of the water input. Runoff and drainage occurred following 2.6 in. of irrigation and 0.5 in. of rainfall on June 5. Runoff from CT was about 4 times that from NT, while drainage from NT was about double that from CT. Soil water content did not rise much as the soil was close to saturation. For the two days, there was 89% more drainage from NT while runoff was again about 4 times more from CT. In an area plagued with common short-term drought during critical crop growth periods and periodic multi-year droughts, this is an important result for growers and water resource planners seeking to improve water use and mitigate drought. The finding has great regional importance since Cecil soils occupy over 50% of the 41 million acre Southern Piedmont.