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ARS Home » Southeast Area » Tifton, Georgia » Southeast Watershed Research » Research » Publications at this Location » Publication #270440
Title: Quantifying variable rainfall intensity events on seasonal runoff and sediment losses from strip and conventionally tilled peanuts

Author
item Truman, Clinton
item Potter, Thomas
item Nuti, Russell

Submitted to: Peanut Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/28/2012
Publication Date: 1/28/2012
Citation: Truman, C.C., Potter, T.L., Nuti, R.C. 2012. Quantifying variable rainfall intensity events on seasonal runoff and sediment losses from strip and conventionally tilled peanuts. Peanut Science. 39:62-68.

Interpretive Summary: Over 90% of peanut production in Georgia is in the Coastal Plain region and while the region’s sandy soils and relatively high rainfall provide a favorable environment for the crop, these soils are susceptible to runoff, sediment, and chemical losses from short duration-high intensity, runoff producing storms. We used simulated rainfall technology and measured runoff and sediment losses from single-row peanuts planted on a Tifton loamy sand managed under conventional and strip tillage systems. Simulations were conducted at planting, 30 days after planting, and after peanut harvest using variable intensity (Iv) patterns representative of each time or season (spring=IvSPR, summer=IvSUM, fall=IvFALL). The most runoff was observed from conventional till IvFALL plots; the least from strip till IvSUM plots. The most sediment occurred from conventional till IvSPR plots; the least from strip till IvSUM plots. Conventional till plots averaged 60% more runoff and 3.3-fold more sediment loss than strip till plots. Maximum runoff difference between conventional and strip till plots was for fall events, and the maximum sediment loss difference was for summer events. Results show the pronounced runoff and sediment losses that can occur at critical times (planting, first fungicide application ~30 days after planting, after harvest) during a peanut growing season. Understanding these differences can help define “windows of risk” and provides information on how conservation tillage can reduce those losses and help producers manage natural resources and agrichemical losses from peanut cropping systems.

Technical Abstract: The majority of peanut production in Georgia is in the Coastal Plain region where sandy soils and relatively high rainfall (~1250 mm/yr) provide a favorable environment for the crop. Coastal Plain soils have traditionally been cropped under conventional tillage practices; and are susceptible to runoff, sediment, and chemical losses from short duration-high intensity, runoff producing storms. We quantified runoff and sediment losses from a Tifton loamy sand managed under conventional- (CT) and strip- (ST) tillage systems and planted to peanut at three times during a growing season with simulated rainfall that utilized variable rainfall intensities representative of each time period (spring, summer, fall). In 2008, a field study was established with CT and ST systems each planted to single-row peanut. Simulated rainfall was applied at planting, 30 days after planting, and after peanut harvest with rainfall events comprised of variable intensity (Iv) patterns representative of each time or season (spring=IvSPR, summer=IvSUM, fall=IvFALL). Simulated rainfall was applied to 6-m2 plots (n=3) for each treatment with runoff (R) and sediment (E) yields measured from each plot. Overall, runoff and infiltration from CT and ST plots was 9-22% and 78-91% of the total rainfall applied, respectively. The most runoff occurred from CT-IvFALL plots; the least from ST-IvSUM plots. Sediment yields from CT and ST plots ranged from 105-1419 kg/ha. The most sediment occurred from CT-IvSPR plots; the least from ST-IvSUM plots. The most runoff and sediment per unit of rainfall applied occurred from CT-IvFALL plots. Rainfall intensity and runoff from CT and ST plots for IvSPR, IvSUM, and IvFALL events were correlated (r=0.73-0.95). Runoff and sediment yield from CT and ST plots for IvSPR, IvSUM, and IvFALL events were also correlated (r=0.66-0.99). Values of Rmax for CT and ST plots were 7-20% of the maximum intensity for their respective events. Values of Rmax and Emax for CT and ST plots occurred 3-8 min after the maximum intensity for their respective events. The CT plots averaged 60% more runoff, 86% higher Rmax values, 3.3-fold more sediment, and 3.7-fold higher Emax values than ST plots. Maximum difference between CT and ST plots for runoff (2.4-fold), Rmax (2.7-fold), and sediment (3.8-fold) was for fall events; maximum difference between CT and ST plots for Emax (5.6-fold) was for summer events. Results show the pronounced effect of the three rainfall intensity patterns and tillage on runoff and sediment losses from critical times (planting, first fungicide application ~30 days after planting, after harvest) during a peanut growing season. Understanding the magnitude of runoff and sediment losses help define “windows of risk” and how conservation tillage can reduce those losses and help producers manage natural resources and agrichemical losses from peanut cropping systems.