Antecedent water content effects on runoff and sediment yields from two Coastal Plain Ultisols

• Published in: Agricultural water management 2011-05, Vol.98 (8), p.1189-1196
• Main Authors: Truman, C.C., Potter, T.L., Nuti, R.C., Franklin, D.H., Bosch, D.D.
• Format: Article
• Language: English
• Subjects: Agricultural and forest climatology and meteorology. Irrigation. Drainage; Agronomy. Soil science and plant productions; Biological and medical sciences; coastal plain soils; coastal plains; Detachment; Erosion; Erosion Infiltration Strip-tillage No-tillage Rainfall simulation Soil water; Fundamental and applied biological sciences. Psychology; General agronomy. Plant production; herbicides; Infiltration; irrigation; Moisture content; New technology; No-tillage; pesticide application; Physical properties; Physics, chemistry, biochemistry and biology of agricultural and forest soils; process control; rain; rain intensity; Rainfall; Rainfall simulation; Runoff; sediment yield; Sediments; soil depth; soil quality; Soil science; Soil water; soil water content; Soils; Strip-tillage; Tillage; Ultisols; Water and solute dynamics; water content
• ISSN: 0378-3774; 1873-2283
• DOI: 10.1016/j.agwat.2011.03.001

► Quantified water content effects on runoff and soil loss from 2 soils and 3 tillages. ► Water contents created with post pesticide application irrigations for incorporation. ► Prewetting decreased runoff 8–60% and decreased soil loss at least 59%. ► Compared to conventional till, conservation till decreased runoff and soil loss 2.6-fold. The highly weathered, low-carbon, intensively cropped, drought-prone Coastal Plain soils of Georgia are susceptible to runoff and soil loss, especially at certain times of the year when soil water contents are elevated. We quantified the effects of antecedent water content (AWC) on runoff ( R) and sediment ( E) losses from two loamy sands managed under conventional- (CT), strip- (ST), and/or no-till (NT) systems. Two AWC treatments were evaluated: field moist (FM) and pre-wet (PW), created with and without post pesticide application irrigations (∼12 mm of water added with the rainfall simulated over 30 min) for incorporation. Treatments (5) evaluated were: CT + FM, CT + PW, ST + FM, ST + PW, and NT + PW. Field plots, each 2-m × -3 m, were established on each treatment. Each 6-m 2 field plot received simulated rainfall at a variable rainfall intensity ( I v) pattern for 70 min (site 1) or a constant rainfall intensity ( I c) pattern for 60 min (site 2; I c = 50.8 mm h −1). Adding ∼12 mm of water as herbicide incorporation increased AWCs of the 0–2 (3–9-fold) and 2–15 (23–117%) cm soil depths of PW plots compared to existing field moist soil conditions. Increase in AWC increased R (as much as 60%) and maximum R rates (as much as 62%), and decreased E (at least 59%) and maximum E rates (as much as 2.1-fold) for corresponding tillage treatments. Compared to CT plots, ST and NT plots decreased R (at least 2.6-fold) and maximum R rates (as much as 3-fold), and decreased E (at least 2.7-fold) and maximum E rates (at least 3.2-fold). Runoff curves for pre-wetted CT and ST plots were always higher than corresponding FM curves, whereas E curves for field moist CT and ST plots were always higher than corresponding PW curves. Changes in AWC and tillage affected detachment and transport processes controlling runoff and sediment yields. A more accurate measure of rainfall partitioning and detachment and transport processes affecting R and E losses was obtained when commonly occurring field conditions (increased AWC with irrigation; I v pattern derived from natural rainfall; commonly used tillage systems) were created and evaluated.