Bioresources are generated in a variety of environments and each presents unique
risks and benefits associated with land application. Bioresources from livestock, urban and
bioenergy systems were selected and evaluated through field, greenhouse and laboratory
studies of potential risk and benefits of recycling to agricultural and urban landscapes.
The waste stream, including feedstock sources and treatment processes, affects
composition and properties of bioresources and effects on biogeochemical cycles of
amended soils. Variation of decomposition and nutrient mineralization rates among
bioresources used to amend soil for turfgrass and forage reflected variation among
contrasting feedstock sources and treatments prior to application. During turfgrass
establishment, plant available nitrogen and nitrogen mineralized from a bioresource from
livestock waste streams, (Geotube! residual solids, supplied N in excess of crop uptake
potential and contributed to leaching loss of N. In contrast, N mineralization rates from
bioresources generated during methane production from dairy manure (manure solids)
were not sufficient to maximize crop production, necessitating N fertilizer application.
In addition to variation of composition, bioresource effects on crop productivity
and environmental quality vary among management practices and between forage and
turfgrass cropping systems. Large application rates of bioresources increase soil nutrient
concentration and potential crop productivity, but contribute to increased nutrient loss in
drainage and surface runoff. Yet, incorporation or Alum treatment of bioresources will
reduce runoff loss of dissolved P and protect water quality without sacrificing crop
productivity. Alum treatment of bioresources prior to land application effectively reduced
runoff loss of dissolved P to levels observed for control soil.
For situations in which large, volume-based bioresource rates are top-dressed or
incorporated, export of applied nutrients environmental impacts were compared between
forage and turfgrass systems. Starting during the initial year of production, annual export
of applied N and P in Tifway bermudagrass sod was greater than export through forage
harvests of Tifton 85. Low forage yield limited N and P export from Tifton 85 during the
year of establishment, but increased forage yield during the second year increased export
of manure N and P to levels more comparable to sod. As variation between compost
sources, turfgrass and forage production systems, and application methods indicated,
effective management of bioresources is necessary to balance benefits and risk in cropping
systems. Integrated assessment of bioresource composition and crop-specific management
of application method and rate will enable sustainable bioresource cycling and crop
productivity.
| Identifer | oai:union.ndltd.org:tamu.edu/oai:repository.tamu.edu:1969.1/ETD-TAMU-2010-08-8462 |
| Date | 2010 August 1900 |
| Creators | Schnell, Ronnie Wayne |
| Contributors | Vietor, Donald M., Munster, Clyde L. |
| Source Sets | Texas A and M University |
| Language | en_US |
| Detected Language | English |
| Type | thesis, text |
| Format | application/pdf |
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