UMD Theses and Dissertations

Permanent URI for this collectionhttp://hdl.handle.net/1903/3

New submissions to the thesis/dissertation collections are added automatically as they are received from the Graduate School. Currently, the Graduate School deposits all theses and dissertations from a given semester after the official graduation date. This means that there may be up to a 4 month delay in the appearance of a given thesis/dissertation in DRUM.

More information is available at Theses and Dissertations at University of Maryland Libraries.

Browse

Filters

2014 - 20172

Settings

Subject: search.filters.subject.manure

Search Results

Now showing 1 - 2 of 2
  • Thumbnail Image
    Item
    Evaluating Soil Phosphorus Dynamics over Time
    (2017) Lucas, Emileigh Rosso; Coale, Frank J; Environmental Science and Technology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    Agricultural nutrient management became mandatory in Maryland (MD) due to water quality concerns. Phosphorus (P) management is complex due to the stability of P in the soil, nutrient mass imbalance, and “legacy” P. To explore how potential P application bans impact historically manured fields, agronomic and environmental soil tests were conducted on plots treated with five manure-P rates, then no P applications, spanning 15 years. Mehlich-3 extractable P (M3P) declined slowly and then generally did not change during the last six years. Phosphorus saturation declined slowly or not significantly. Excessive P soils had sufficient P for crop growth in solution. Phosphorus saturation and M3P were compared in fifty sites across MD pre- and post- nutrient management planning. Results showed an increase in P concentration of Maryland agricultural fields. This response was logical, as better management would increase below-optimum P concentrations, and the regulations were not designed to draw down P.
  • Thumbnail Image
    Item
    Nitrogen dynamics in cover crop-based no-till corn
    (2014) Poffenbarger, Hanna Jane; Weil, Ray R; Environmental Science and Technology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    Legume/grass cover crop mixtures and sidedress subsurface band manure application are two approaches to improving nitrogen (N) use efficiency in a cover crop-based no-till corn (Zea mays L.) system. The objectives of this study were to: 1) quantify cover crop biomass and N content in response to different hairy vetch (Vicia villosa Roth)/cereal rye (Secale cereale L.) sown proportions, 2) evaluate the effects of cover crop species proportions and pelletized poultry litter (PPL) application method on residue decomposition, and 3) model the spatio-temporal dynamics of soil inorganic N as influenced by different cover crop residues and subsurface band-applied PPL. Results suggest that cover crop mixtures can accumulate as much biomass as a cereal rye monoculture and as much N as a hairy vetch monoculture, and have decomposition patterns intermediate between those of monocultures. Subsurface band PPL application provided a localized N source that did not influence decomposition of surface mulches.