Losses of Surface Runoff, Total Solids, and Nitrogen during Bermudagrass Establishment on Levee Embankments
- Robert W. Burwella,
- Jeffrey S. Beasley *a,
- Lewis A. Gastona,
- Steven M. Borsta,
- Ron E. Sheffieldb,
- Ron E. Strahana and
- Gregg C. Munshawc
- a School of Plant, Environmental and Soil Sciences, Louisiana State Univ. Agricultural Center, Baton Rouge, LA 70803
b R.E. Sheffield, Dep. of Biological and Agricultural Engineering, Louisiana State Univ. Agricultural Center, Baton Rouge, LA 70803
c G.C. Munshaw, Dep. of Plant and Soil Sciences, Mississippi State, MS 39762. Assigned to Associate Editor Liwang Ma
Nutrient and sediment runoff from newly constructed levee embankments pose a threat to water quality during soft armor vegetation establishment. Research was initiated in 2008 and 2009 to evaluate the effect of bermudagrass (Cynodon dactylon L.) coverage and N source on nutrient and sediment runoff from levee embankments during establishment. Bermudagrass plots were seeded at 195.3 kg pure live seed ha−1 and fertilized at 50 kg N ha−1 using a water-soluble N source, urea or NH4–NO3, or slow-release N source, S-coated urea (SCU) or urea formaldehyde (UF), with controls unfertilized. Vegetative cover percentage, time until the onset of runoff, runoff volume, and total solids (TS), NO3–N, and NH3–N concentrations were measured from simulated and natural rainfall events for 70 d in 2008 and 56 d in 2009. Bermudagrass at 90% grass cover delayed the onset of runoff an additional 441 to 538 s and reduced runoff volumes 74 to 84% of that exhibited at 10% grass cover. Nitrogen fertilizers did not accelerate bermudagrass growth sufficiently, however, to reduce TS loading compared with unfertilized bermudagrass in either year of the study. The application of urea and SCU resulted in cumulative N losses of 2.45 and 3.13 kg ha−1 compared with 1.59 kg ha−1 from the unfertilized bermudagrass in 2008, and 1.73 kg ha−1 from NH4–NO3 vs. 0.24 kg ha−1 from controls in 2009. Only UF increased bermudagrass establishment without increasing cumulative N losses compared with unfertilized bermudagrass. Therefore, the benefit of greater erosion and runoff resistance expected from N-accelerated vegetative growth did not occur but had the unintended consequence of higher N losses when water-soluble N and SCU fertilizers were applied.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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