Runoff and leaching of crop nutrients from soil in tilted beds as influenced by three rates of dairy lagoon effluent
Titel:
Runoff and leaching of crop nutrients from soil in tilted beds as influenced by three rates of dairy lagoon effluent
Auteur:
Davis, J. G. Burgoa, B.
Verschenen in:
Journal of environmental science and health. Part B, Pesticides, food contaminants, and agricultural wastes
Paginering:
Jaargang 30 (1995) nr. 2 pagina's 243-264
Jaar:
1995
Inhoud:
The objective of this study was to determine the effect of lagoon effluent application on losses of crop nutrients in runoff and leaching solutions. Tilted beds, packed with Fuquay sand and equipped with runoff and leachate collection funnels, were utilized. Lagoon effluent was applied at three rates. Simulated rainfall (5 cm h-1) was applied for two hours, and runoff and leachate were collected. Increasing effluent application rate led to increased NO3-N leaching, decreased PO4-P runoff, and increased Mg leaching. The highest application rate resulted in buildup of ? and ? in soil, but ? losses exceeded applied amounts at all application rates. We propose that as effluent application rate increased, the large ? concentration in the effluent exchanged with soil Ca and Mg on exchange sites, leading to increased Ca and Mg concentrations in soil solution. Increased Mg concentration in soil solution led to increased Mg leaching. However, the Ca2+ ion probably formed the ion pair CaHPO4° with phosphate from the effluent, and readsorbed to soil colloids as an ion pair, thus diminishing ? runoff.
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