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Management of nitrogen and composted biosolids to cycle nutrients and enhance environmental quality during production and after transplanting turfgrass sodSchnell, Ronnie Wayne 15 May 2009 (has links)
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. Research
objectives were developed to evaluate the options for cycling of MB through turfgrass sod
during production and after transplanting. The first objective was to compare the
production of Tifway bermudagrass sod between fields grown with and without MB under
increasing rates of supplemental fertilizer N. The second objective was to compare runoff
losses between soils constructed with and without MB before planting to sprigs or sod
transplanted from turfgrass grown in soil with and without incorporation of MB.
Incorporation of 25% by volume of MB in soil enhanced (p < 0.001) turfgrass
coverage of the soil surface compared to soil without MB. In addition, amending soil with
MB reduced wet and dry sod weights (p < 0.001) and increased soil water content (p <
0.001) at harvest compared to sod 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. In addition, 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. Similarly, runoff loss of NO3-N was greater (P = 0.05) for soil mixed with 25% by
volume of MB than soil alone and variation of NO3-N loss among treatments was directly
related to soil NO3-N concentration within the 0- to 5-cm depth. In contrast, runoff
concentrations of NH4-N were directly related to inputs of N from turf clippings returned
to soil rather than soil NH4-N concentrations. Total Kjeldahl N (TKN) concentration in
runoff was unrelated to soil N concentrations, but was linearly related to mass loss of
sediment in runoff. Transplanted sod reduced sediment loss compared to sprigged soil
during turfgrass establishment and MB-amended soil reduced sediment loss compared to
soil without MB. In addition, the MB imported in sod or incorporated in soil before
sprigging increased soil organic carbon and mean soil water content compared to sod or
soil without MB over a 92 day period. Incorporation of MB within soil prior to planting
fertilizer grown turfgrass sod enhanced water conservation and reduced nutrient loss
compared to planting MB-grown sod on un-amended soils.
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