Scaling up the phosphorus signal from soil hillslopes to headwater catchments

Abstract

1. Phosphorus (P) transfer from agricultural land to freshwater systems has been studied across many scales and environmental compartments that range from understanding biogeochemical processes in soils and fields, to assessment of localised in-stream biotic and ecological impacts. 2. This study tackles the challenges of scale when moving from soil hillslope to headwater catchment scale. The focus is on 'process rules' derived from reductionist approaches at the relatively fine scale, and exploring the signal and evidence thereof at the headwater catchment scale. 3. The methodology uses new data of P dynamics in agricultural grassland headwater catchments in south-west England. 4. We found the following: (i) it was not possible to disaggregate an influence of soil (Olsen) P concentration on P export at the larger scale; (ii) there was no clear temporally dynamic relationship between P additions of fertiliser and recycled manure and the resulting P transferred to the headwater scale; however, (iii) ploughing, digging of stream channel and leakage from farm storage all affected the temporal concentration dynamics; and (iv) overall P loss was influenced by higher long-term history of P inputs, livestock and the domination of hydrologic processes. 5. It is concluded that process rules derived at the finer soil or plot scale cannot always produce a clearly discernable signal when studied at the larger headwater catchment scale.

Changing climate and nutrient transfers: Evidence from high temporal resolution concentration-flow dynamics in headwater catchments

“…Deasy et al, 2008;Haygarth et al, 2006;Haygarth et al, 2012;Heathwaite and Dils, 2000;Preedy et al, 2001;Sharpley et al, 2001), with the phytobenthic community suggesting a direct impact on water quality (Snell et al, 2014). However, for many water bodies, the only available water quality data are the standard condition assessments and the Environment Agency national level programme of routine monitoring at main river (large catchment scale) locations, at fortnightly or monthly resolution.…”

Distinct export dynamics for dissolved and particulate phosphorus reveal independent transport mechanisms in an arable headwater catchment

“…This coupling suggests that the transport mechanisms for both P forms are linked in space and time. However, examples of temporal decoupling between particulate and dissolved P forms also exist as documented in the Mercube, France (Jordan‐Meille and Dorioz, ), the Kleine Aa, Switzerland (Pacini and Gachter, ; Lazzarotto et al ., ), the Corbeira, Spain (Rodriguez‐Blanco et al ., ), two headwater catchments in Devon, England (Haygarth et al ., ) and one sub‐catchment of the Eden River, England (Outram et al ., ). In these six catchments, particulate P (PP) is exported towards the beginning of floods, whilst soluble reactive phosphorus (SRP) exportations are delayed towards the end of floods, when PP and suspended sediment (SS) concentrations have dropped.…”

Dominant mechanisms for the delivery of fine sediment and phosphorus to fluvial networks draining grassland dominated headwater catchments

“…Specifically, this framework enables an assessment of the complicating factors and influences on SS and P transfer at multiple scales (e.g. Haygarth et al, 2012); and, the interaction between catchment structure, connectivity, and pathway dominance under varying environmental conditions (Bilotta et al, 2007;Bilotta et al, 2010;Bracken et al, 2014) .…”