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ARS Home » Southeast Area » Tifton, Georgia » Southeast Watershed Research » Research » Publications at this Location » Publication #246139

Title: Furrow Diking in Conservation Tillage

Author
item Truman, Clinton
item Nuti, Russell

Submitted to: Agricultural Water Management
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/5/2010
Publication Date: 2/9/2010
Citation: Truman, C.C., Nuti, R.C. 2010. Furrow Diking in Conservation Tillage. Agricultural Water Management. 97:835-840.

Interpretive Summary: Crop production in the Southeastern U.S. can be limited by water; thus, supplemental irrigation is needed to sustain crop production. Any practice that increased water capture would reduce supplemental irrigation amounts/costs and improve producers’ profit margins. We quantified infiltration (INF), runoff (R), and sediment (E) losses from furrow diked (+DT) and non-furrow diked (-DT) tilled conventional (CT) and strip tillage (ST) systems on a Tifton loamy sand near Tifton, GA and on a Faceville loamy sand near Dawson, GA. Treatments (6) included: CT-DT, CT+DT, ST1 (1-yr old)-DT, ST1+DT, ST10 (10-yr old)-DT, and ST10+DT. Simulated rainfall (50 mm/h for 1 h) was applied at planting to all plots, and runoff and erosion were measured. Runoff, erosion, and estimated plant available water (PAW) values for the two soils yielded trends that decreased in order of CT-DT, CT+DT, ST1-DT, ST1+DT, ST10-DT, and ST10+DT treatments. The combined CT-DT and ST10+DT treatments resulted in 5.9 (worst-case) and 8.1 (best-case) days of water for crop use. Compared to the CT-DT treatment, an agricultural field converted to CT+DT, ST1-DT, ST1+DT, ST10-DT, and ST10+DT would result in a savings of $5.30, $9.42, $13.55, $14.14, and $14.14/ha, respectively, on the cost of pumping the amount of water lost to runoff (and not saved as infiltration) back onto the field. The most water/cost savings occurred for the CT and ST1 treatments as a result of DT. Compared to CT alone, savings from CT+DT, ST1-DT, and ST1+DT treatments during a single 50 mm rainfall event represent 27%, 47%, and 68% of the cost of DT ($20/ha), making the break-even point after 185, 106, and 74 mm of subsequent rainfall or irrigation events of 50 mm/h intensity. These savings also represent 37%, 67%, and 96% of the savings estimated to come from a field that has been in ST for 10 years without DT. For row-crop producers in the Southeastern U.S. with frequent runoff producing rainfall events during the crop growing season, DT is a management practice that can provide considerable cost savings to those producers continuing the use of CT systems and to those who are transitioning to ST systems.

Technical Abstract: Crop production in the Southeastern U.S. can be limited by water; thus, supplemental irrigation is needed to sustain profitable crop production. Increased water capture would efficiently improve water use and reduce supplemental irrigation amounts/costs, thus improving producer’s profit margin. We quantified infiltration (INF), runoff (R), and sediment (E) losses from furrow diked (+DT) and non-furrow diked (-DT) tilled conventional (CT) and strip tillage (ST) systems. In 2008, a field study (Tifton loamy sand, Typic Kandiudult), was established near Tifton, GA with DT, ST, and CT systems. In 2009, a field study (Faceville loamy sand, Typic Kandiudult), was established near Dawson, GA with DT and ST systems. Treatments (6) included: CT-DT, CT+DT, ST1 (1-yr old)-DT, ST1+DT, ST10 (10-yr old)-DT, and ST10+DT. Simulated rainfall (50 mm/h for 1 h) was applied at planting to all plots (2x3 m) (n=3). Runoff and E were measured from each flat, level sloping 6-m2 plot. ST1+DT plots had 80-88% less R than ST1-DT plots. Any disturbance associated with using DT in ST1 systems did not negatively impact E values. For both soils, CT-DT plots represented the worst-case scenario in terms of measured R and E; ST+DT plots represented the best-case scenario. Combining R and E data for CT-DT and CT+DT plots from the two soils yields trends for R, E, and estimated plant available water (PAW) values that decreased in order of CT-DT, CT+DT, ST1-DT, ST1+DT, ST10-DT, and ST10+DT treatments. From a hydrology standpoint, ST1-DT plots behaved more similarly to CT plots than to other ST plots; from a sediment standpoint, ST1-DT plots behaved more similarly to other ST plots than to CT plots. DT had no effect on ST10 plots. The combined CT-DT and ST10+DT plots resulted in 5.9 (worst-case) and 8.1 (best-case) days of water for crop use, a difference of 2.2 days of water for crop use or 37%. Compared to the CT-DT treatment, an agricultural field managed to CT+DT, ST1-DT, ST1+DT, ST10-DT, and ST10+DT would save a producer farming the CT-DT field $5.30, $9.42, $13.55, $14.14, and $14.14/ha, respectively, to pump the amount of water lost to R and not saved as INF back onto the field. No savings occurred for the ST10 treatment as a result of DT. The most water/cost savings occurred for the CT and ST1 treatments as a result of DT. Savings for CT+DT, ST1-DT, and ST1+DT treatments represent 27%, 47%, and 68% of the cost of DT ($20/ha) and 37%, 67%, and 96% of the savings a producer would have if managing the field to ST for 10 years without DT (ST10-DT) in a single 50-mm rainfall event. For row-crop producers in the Southeastern U.S. with runoff producing rainfall events during the crop growing season, DT is a management practice that is cost-effective from a natural resource and financial standpoint for those producers that continue to use CT systems and especially those that have recently adopted ST systems into their farming operations.