NO-TILL ON CECIL SOIL: HYDROLOGIC AND WATER QUALITY IMPACTS

Authors: Endale, Dinku; Schomberg, Harry; RADCLIFFE, D - UNIVERSITY OF GEORGIA; Jenkins, Michael; CABRERA, M - UNIVERSITY OF GEORGIA

Submitted to: American Society of Agronomy Meetings
Publication Type: Abstract Only
Publication Acceptance Date: 10/15/2004
Publication Date: 11/2/2004
Citation: Endale, D.M., Schomberg, H.H., Radcliffe, D.E., Jenkins, M., Cabrera, M.L. 2004. No-till on cecil soil: hydrologic and water quality impacts [abstract]. American Society of Agronomy Meetings. Paper No. 3949. CDROM.

Interpretive Summary: The Southern Piedmont, a 41 million acre region in the southeastern US, is one of the most severely eroded parts of the nation, partly as a result of generations of intensive single-crop-a-year agriculture based on disturbing the top soil by plowing, disking or harrowing - a practice referred to as conventional tillage. Reversing this man-made degradation of a natural resource so that future generations can make indefinite and beneficial use of a precious resource has been a priority for researchers and government action agencies for decades. Scientists at the USDA-ARS J. Phil Campbell Sr. Natural Resource Conservation center in Watkinsville, GA, and the Crop and Soil Sciences Department, University of Georgia, in Athens, GA, studied an alternative to conventionally tilling the soil referred to as no-till, as it influences off-site soil loss and water quality. In no-till the soil is generally not disturbed at all except for rows of slots less than an inch wide made to plant seeds. In addition, a cover crop is grown in winter to keep the soil under residue cover for the whole year. We found that, in cotton production, no-till reduced runoff and sediment loss in runoff and increased drainage compared to conventional tillage. In addition to improving water quality with respect to sediment load, this enhances soil water availability which can lead to increased crop productivity. The quality of the water running off or draining from the land with respect to the nutrients ammonium, nitrate and dissolved phosphorus, appeared comparable between the two tillage systems or actually improved under no-till. However, nitrate and dissolved phosphorus concentrations in runoff, and the total mass of these nutrients leaving in drainage were slightly increased in no-till. Adoption of no-till in cotton production appears to be a viable alternative in the Southeast both from enhanced environmental quality and production aspect, and would be beneficial to the thousands of growers who plant millions of acres of cotton in the region every year.

Technical Abstract: Cecil and closely related soils occupy more than 50% of soils mapped in the Southern Piedmont, a 16.7 million ha region in southeastern U.S. This region is one of the most severely eroded parts of the U.S. as a result of intense summer storms, the erodible nature of the soils, and generations of conventionally-tilled single-crop agriculture. Progress in equipment for reside management, weed control, and management techniques for cover crops has led to dramatic increases and adoption of no-till as conservation practice in recent decades in the U.S. However, regional environmental and management variables can lead to variations in hydrologic and water quality impacts of no-till. In Cecil soil near Watkinsville, GA, we found that no-till reduced runoff and sediment load in runoff, and increased drainage compared to conventional tillage. While concentrations (mg/L) of NO3-N, and PO4-P were slightly elevated in runoff, load (Kg/ha), however, was reduced as it was for NH4-N. Concentrations of these nutrients were generally comparable in drainage but load was somewhat elevated in no-till. Factors of variation were generally within 1.5-3 range. These data partially demonstrate the potential of no-till for combating environmental degradation in the Southeast arising from cropping based on conventional tillage.