77011 Influence of Fertilization On Nitrogen and Phosphorus Runoff Losses During Roadside Establishment.

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See more from this Session: Graduate Student Oral Soils
Monday, February 4, 2013: 2:30 PM
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Kyle R. Briscoe and Jac J. Varco, Mississippi State University, Mississippi State, MS

               Mississippi Department of Transportation (MDOT) roadside establishment practices specify 13-13-13 fertilizer be applied at rates from 561 to 1122 kg ha-1. Thus, there are concerns over the impact of nitrogen (N) and phosphorus (P) runoff losses on surface water quality. A study was designed to evaluate the influence of N and P sources, rates, and application timings on nutrient loss and vegetative establishment. In July 2011 and June 2012, stainless steel runoff frames (0.75 x 2.0 m) were installed on a roadside near Starkville, MS. A bahiagrass (Paspalum notatum Flugge), tall fescue (Festuca arundinacea Shreb), sericea lespedeza [Lespedeza cuneata (Dum. Cours.) G. Don] and common bermudagrass [Cynodon dactylon (L.) Pers.] mixture was seeded within each frame. Eight fertilizer treatments consisting of 73.5 or 147 kg N and P2O5 ha-1 as 13-13-13, poultry litter, ammonium nitrate, stabilized urea, polymer coated urea, or diammonium phosphate were applied immediately after seeding. Treatments were arranged as a randomized complete block with four replications. Runoff from natural and simulated (30 minute duration, 66 mm hr-1 intensity) rainfall was collected and analyzed for PO43--P, total P, NO3--N, and NO2--N. Preliminary results indicate differences in PO43--P loss during natural and simulated rainfall occurred between P sources in both years. Total P, NO3--N, NO2--N, and PO43--P losses were correlated with runoff volume from natural rainfall. Therefore, rainfall intensity rather than fertilizer source may have the largest influence on nutrient loss. However, NH4+-N, total N, and sediment data are needed to better quantify total nutrient loss as a result of each fertilizer program.

See more from this Division: Submissions
See more from this Session: Graduate Student Oral Soils