Search

Abstract: Crop production in Georgia and the Southeastern U.S. can be limited by water. Highly-weathered, drought-prone soils are susceptible to runoff and erosion. Rainfall patterns generate runoff producing storms followed by extended periods of drought during the crop growing season. Thus, supplemental irrigation is often needed to sustain profitable crop production. Increased water retention and soil conservation would efficiently improve water use and reduce irrigation amounts/costs and sedimentation, and sustain productive farm land, thus improving producer''s profit margin. Soil amendments, such as flue gas desulfurization (FGD) gypsum, have been shown to retain rainfall and/or irrigation water through increased infiltration while decreasing runoff (R) and sediment (E). Objectives were to quantify rainfall partitioning and sediment delivery improvements with surface applied FGD gypsum from an Ultisol managed to conventional till (CT) and to assess the feasibility of using FGD gypsum on agricultural land in southern Georgia. A field study (Faceville loamy sand, Typic Kandiudult) was established (2006, 2007) near Dawson, GA managed to CT, irrigated cotton (Gossypium hirsutum L.). FGD gypsum application rates evaluated were 0, 1.1, 2.2, 4.5, and 9Mgha−1. Gypsum treatments and simulated rainfall (50mmh−1 for 1h) were applied to 2-m wide×3-m long field plots (n =3). Runoff and E were measured from each 6-m2 plot (slope=1%). FGD gypsum plots averaged 26% more infiltration (INF), 40% less R, 58% less E, 27% lower maximum R rates (R max), and 2 times lower maximum E rates (E max) than control plots. Values of INF and water for crop use increased, and R, E, R max, and E max decreased as FGD gypsum application rate increased. Values of INF, R, E, R max, and E max for 9Mgha−1 plots were as much as 17% greater, 35% less, 1.9 times less, 35% less, and 1.9 times less than those from other FGD gypsum plots, respectively; and 40% greater, 40% less, 2.2 times less, 52% less, and 2.9 times less than those from control plots, respectively. Applying FGD gypsum to agricultural lands is a cost-effective management practice for producers in Georgia that beneficially impacts natural resource conservation, producer profit margins, and environmental quality. Agriculture in the Southeast provides a viable market for the electric power industry to convert disposal costs of FGD gypsum into a profitable commodity. [Copyright &y& Elsevier]

The article discusses a study which evaluates the impact of nonionic surfactant on cotton production on a loamy sand in the coastal plain region of Georgia. The experiment was composed of on-site rainfall simulation and agronomic cotton field trials. Rainfall simulation discovered that the addition of surfactant increased runoff and decreased infiltration. It also found that agronomic field trials showed that crop yields were not different between surfactant-treated and untreated plots.

Abstract: Crop production in Georgia and the Southeastern U.S. can be limited by water; thus, supplemental irrigation is often needed to sustain profitable crop production. Increased water capture would efficiently improve water use and reduce irrigation amounts and other input costs, thus improving producer''s profit margin. We quantified water capturing and erosional characteristics of furrow diking by comparing runoff (R) and soil loss (E) from furrow diked (DT) and non-furrow diked tilled (CT) systems. A field study (Faceville loamy sand, Typic Kandiudult) was established (2006 and 2007) near Dawson, GA with DT and CT systems managed to irrigated cotton (Gossypium hirsutum L.). Treatments included: DT vs. CT; DT with and without shank (+/− S); and rainfall simulation performed (0, 60 days after tillage, DAT). Simulated rainfall (50mmh−1 for 1h) was applied to all 2m×3m plots (n =3). All runoff and E were measured from each flat, level sloping 6-m2 plot (slope=1%). Compared to CT, DT decreased R and E by 14–28% and 2.0–2.8 times, respectively. Compared to DT−S, DT+S decreased R and E by 17–56% and 26% to 2.1 times, respectively. Compared to sealed/crusted soil conditions at 60 DAT, simulating rainfall on a freshly tilled seedbed condition (DAT=0) decreased R by 69% to 3.4 times and increased E by 27%. DT0+S+RF0 plots (best-case scenario) had 2.8 times less R, and 2.6 times less E than CT−S+RF60 plots (worst-case). Based on $1.17ha-mm−1 to pump irrigation water and $18.50ha−1 for DT, a producer in the Coastal Plain region of Georgia would recover cost of DT by saving the first 16ha-mm of water. The DT+S system is a cost-effective management practice for producers in Georgia and the Southeastern U.S. that positively impacts natural resource conservation, producer profit margins, and environmental quality. [Copyright &y& Elsevier]

Abstract: 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 (∼12mm of water added with the rainfall simulated over 30min) for incorporation. Treatments (5) evaluated were: CT+FM, CT+PW, ST+FM, ST+PW, and NT+PW. Field plots, each 2-m×-3m, were established on each treatment. Each 6-m2 field plot received simulated rainfall at a variable rainfall intensity (I v) pattern for 70min (site 1) or a constant rainfall intensity (I c) pattern for 60min (site 2; I c =50.8mmh−1). Adding ∼12mm 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. [Copyright &y& Elsevier]