Transport of nitrogen, phosphorus and microorganisms from manure into surface- and groundwater

Citation
Mj. Goss et al., Transport of nitrogen, phosphorus and microorganisms from manure into surface- and groundwater, BIOLOGICAL RESOURCE MANAGEMENT: CONNECTING SCIENCE AND POLICY, 2000, pp. 31-55
Citations number
136
Categorie Soggetti
Current Book Contents
Year of publication
2000
Pages
31 - 55
Database
ISI
SICI code
Abstract
The quality of water resources is an important factor that must be consider ed in any analysis of sustainable agriculture or resource management. Most contaminants affecting water quality in rural areas can be grouped into one of three classes: simple inorganic ions, more complex organic molecules, a nd particulates. Contaminants of all three classes can result from animal m anure. In particular, it potentially provides the source of nitrate, phosph ate, toxic metals, and bacteria as well as materials that generate high bio logical oxygen demand. The concentration of contaminants entering water can be different for each class of contaminant, as they are affected by different processes. Organic molecules are affected by vapour pressure, and solubility in water and soil organic matter, simple inorganic compounds are influenced by exchange and adsorption, whereas the transport of microorganisms are affected by surface charge and population dynamics. The organic matter in manure also alters the physicochemical properties of the soil, thereby increasing the mobility of contaminants and resulting in losses from soil under conditions that might suggest that the materials wou ld be less available to leaching and runoff. Preferential flow paths can develop due to structures present in the surfac e soil or in the subsurface due to soil horizon boundaries. Preferential fl ow can carry water and contaminants to depth very rapidly. This reduces pot ential interactions occurring between the soil and contaminants in solution , and, again, can result in greater impact on water quality than might be e xpected.