Tuesday, November 6, 2007 - 10:00 AM
144-3

Runoff Loss of Nutrients and Carbon During Turfgrass Establishment on Biosolid Amended Urban Soils.

Ronnie Schnell1, Donald Vietor2, Richard H. White2, Tony Provin3, and Clyde H. Munster4. (1) Texas A&M University - Soil & Crop Sciences, Texas A&M University, 1138 Private Road 4482, Giddings, TX 78942, (2) Soil and Crop Sciences, Texas A&M University, 2474 TAMU, 370 Olsen Blvd, College Station, TX 77843-2474, (3) Texas AgriLife Extension Service, Texas A&M University System, 343 Heep Center TAMU 2474, College Station, TX 77843-2474, (4) Texas A&M University, Biological & Agricultural Engineer, College Station, TX 77843-2117

Land application of large, volume-based rates of municipal biosolids (MB) enhances soil physical properties and provides an alternative to disposal in landfills. Yet, topdressing or incorporation of the volume-based rates can increase non-point source losses of sediment and nutrients from excavated soils to surface waters. Three replications of seven turfgrass establishment methods with and without 25% by volume of MB were installed on an 8.5 % slope and runoff was channeled into collection tanks for sampling. The first objective was to compare soil water retention and runoff losses of sediment, P, N and organic C among contrasting establishment methods during seven rain events. The second objective was to relate organic C and extractable P and N concentrations in the amended soil layer of establishment treatments to total and dissolved concentrations and mass losses of N, P and organic C in surface runoff. The MB imported in sod or incorporated in soil before sprigging increased mean soil water content compared to sod or soil without MB. Transplanted sod reduced sediment loss compared to sprigged soil during turfgrass establishment and MB-amended soil reduced sediment loss compared to soil without MB. Runoff concentrations and mass loss of total dissolved P (TDP) were significantly greater (P=0.001) for MB-amended compared to un-amended sod. A linear relationship (R2 = 0.94) was observed between water extractable soil P within the 0- to 2-cm depth and concentrations and mass loss of TDP in runoff. Mass loss of NO3-N in runoff was greater (P = 0.05) for soil mixed with MB than soil alone. Total Kjeldahl N (TKN) concentration in runoff was linearly related to mass loss of sediment in runoff. Incorporation of MB within soil prior to transplanting fertilizer grown turfgrass sod enhanced water conservation and reduced nutrient loss compared to MB-grown sod transplanted on soil without MB.