Research output: Contribution in Book/Report/Proceedings - With ISBN/ISSN › Other chapter contribution
Research output: Contribution in Book/Report/Proceedings - With ISBN/ISSN › Other chapter contribution
}
TY - CHAP
T1 - Sources of eutrophication
T2 - hydrological pathways of catchment nutrient export
AU - Heathwaite, A. Louise
N1 - Sources of eutrophication: hydrological pathways of catchment nutrient export 9 cites: http://scholar.google.com/scholar?num=100&hl=en&lr=&cites=13643993918474188197
PY - 1995
Y1 - 1995
N2 - The relative importance of different hydrological pathways (surface runoff, subsurface flow, preferential flow) for nitrogen (N) and phosphorus (P) delivery in agricultural catchments is evaluated. The assessment takes account of the different nutrient loads from agricultural land and the role of land use distribution and zonation (e.g. buffer zones) in modifying diffuse nutrient loads before they reach the drainage network. The paper draws on a number of research studies on nutrient transport and transformation in hydrological pathways in southwest England. The geographical scale of these process studies ranges from experimental plot (0.5 m2) scale to hillslope scale. The focus is on grassland systems, in particular the impact of livestock grazing and different forms of organic fertilizers (manure, slurry, directly voided) in modifying the magnitude of nutrient export from the land and in controlling the form that N and P are transported in. The latter was evaluated by chemical fractionation of the total nutrient load. Results suggest that most of the phosphorus load is transported in the unreactive (particulate and organic) fraction via surface runoff. The speciation of the nitrogen load varies with land use and grazing intensity. Ammonium-nitrogen is the main form of nitrogen export in surface runoff from heavily grazed land. Its mobilization appears to be linked with sediment transport.
AB - The relative importance of different hydrological pathways (surface runoff, subsurface flow, preferential flow) for nitrogen (N) and phosphorus (P) delivery in agricultural catchments is evaluated. The assessment takes account of the different nutrient loads from agricultural land and the role of land use distribution and zonation (e.g. buffer zones) in modifying diffuse nutrient loads before they reach the drainage network. The paper draws on a number of research studies on nutrient transport and transformation in hydrological pathways in southwest England. The geographical scale of these process studies ranges from experimental plot (0.5 m2) scale to hillslope scale. The focus is on grassland systems, in particular the impact of livestock grazing and different forms of organic fertilizers (manure, slurry, directly voided) in modifying the magnitude of nutrient export from the land and in controlling the form that N and P are transported in. The latter was evaluated by chemical fractionation of the total nutrient load. Results suggest that most of the phosphorus load is transported in the unreactive (particulate and organic) fraction via surface runoff. The speciation of the nitrogen load varies with land use and grazing intensity. Ammonium-nitrogen is the main form of nitrogen export in surface runoff from heavily grazed land. Its mobilization appears to be linked with sediment transport.
M3 - Other chapter contribution
SN - 1-901502-54-X
T3 - IAHS Publications
SP - 161
EP - 175
BT - Man's influence on freshwater ecosystems
A2 - Petts, Geoffrey
PB - IAHS Publications
CY - Wallingford
ER -