Modelling soil phosphorus decline: Expectations of Water Framework Directive policies

Depletion of plant-available soil phosphorus (P) from excessive to agronomically optimum levels is a measure being implemented in Ireland to reduce the risk of diffuse P transfer from land to water. Within the Nitrates and Water Framework Directive regulations the policy tool is designed to help achieve good status by 2015 in water bodies at risk from eutrophication. To guide expectation, this study used soil plot data from eight common soil associations to develop a model of Soil Test P (STP) (Morgan's extract) decline following periods of zero P amendment. This was used to predict the time required to move from excessive (Index 4) to the upper boundary of the optimum (Index 3) soil P concentration range. The relative P balance (P balance : Total soil P) best described an exponential decline (R-2 = 63%) of STP according to a backwards step-wise regression of a range of soil parameters. Using annual field P balance scenarios (-30 kg P ha(-1), -15 kg P ha(-1), -7 kg P ha(-1)), average time to the optimum soil P boundary condition was estimated from a range of realistic Total P and STP starting points. For worst case scenarios of high Total P and STP starting points, average time to the boundary was estimated at 7-15 years depending on the field P balance. However, uncertainty analysis of the regression parameter showed that variation can be from 3 to >20 years. Combined with variation in how soil P source changes translate to resulting P delivery to water bodies, water policy regulators are advised to note this inherent uncertainty from P source to receptor with regard to expectations of Water Framework Directive water quality targets and deadlines. (C) 2010 Elsevier Ltd. All rights reserved.

[1]  R. Bryant,et al.  Dynamics of phosphorus transfers from heavily manured Coastal Plain soils to drainage ditches , 2007 .

[2]  L. Bergström,et al.  Evaluating the success of phosphorus management from field to watershed. , 2009, Journal of environmental quality.

[3]  N. Flynn,et al.  The effect of soil phosphorus on particulate phosphorus in land runoff , 2009 .

[4]  H. Tunney,et al.  The phosphorus requirements for silage production on high fertility soils , 2005 .

[5]  K. Richards,et al.  Evaluation of cover crop and reduced cultivation for reducing nitrate leaching in Ireland. , 2008, Journal of environmental quality.

[6]  O. Fenton,et al.  Variations in travel time for N loading to groundwaters in four case studies in Ireland: implications for policy makers and regulators. , 2009 .

[7]  D. Mcgrath,et al.  Phosphorus fractions and adsorption characteristics in grassland soils of varied soil phosphorus status , 2007, Nutrient Cycling in Agroecosystems.

[8]  M. Herlihy,et al.  Association of soil-test phosphorus with phosphorus fractions and adsorption characteristics , 2006, Nutrient Cycling in Agroecosystems.

[9]  David W. Schindler,et al.  Recent advances in the understanding and management of eutrophication , 2006 .

[10]  S. Grunwald,et al.  Long-term water quality trends after implementing best management practices in South Florida. , 2009, Journal of environmental quality.

[11]  D. A. Clark,et al.  Long term effects of withholding phosphate application on North Island hill country: Ballantrae , 1990 .

[12]  C. Watson,et al.  Increase in phosphorus losses from grassland in response to Olsen-P accumulation. , 2007, Journal of environmental quality.

[13]  H. Tunney A Note on a Balance Sheet Approach to Estimating the Phosphorus Fertiliser Needs of Agriculture , 1990 .

[14]  Philip Jordan,et al.  Characterising phosphorus transfers in rural catchments using a continuous bank-side analyser , 2007 .

[15]  John N. Quinton,et al.  Diffuse Pollution Swapping in Arable Agricultural Systems , 2009 .

[16]  R. Schulte,et al.  Quantifying responses to phosphorus in Irish grasslands: Interactions of soil and fertiliser with yield and P concentration , 2007 .

[17]  Roger Mead,et al.  Statistical methods in agriculture and experimental biology , 1983 .

[18]  H. Tunney,et al.  Phosphorus needs of grassland soils and loss to water. , 2002 .

[19]  M. Herlihy,et al.  Divergent Relationships of Phosphorus Soil Tests in Temperate Grassland Soils , 2006 .

[20]  Rogier P.O. Schulte,et al.  MAJOR AND MICRO NUTRIENT ADVICE FOR PRODUCTIVE AGRICULTURAL CROPS , 2008 .

[21]  P. Sale,et al.  Changes in bicarbonate-extractable phosphorus over time when P fertiliser was withheld or reapplied to pasture soils , 2002 .

[22]  Yibing Ma,et al.  Phosphorus accumulation and depletion in soils in wheat-maize cropping systems: modeling and validation. , 2009 .

[23]  B L Turner,et al.  The phosphorus transfer continuum: linking source to impact with an interdisciplinary and multi-scaled approach. , 2005, The Science of the total environment.

[24]  G. Rayment,et al.  Phosphorus Fertility Assessment of Intensively Farmed Areas of Catchments Draining to the Great Barrier Reef World Heritage Area; 1: Soil Phosphorus Status , 2006 .

[25]  Rogier P.O. Schulte,et al.  AGRICULTURE, METEOROLOGY AND WATER QUALITY IN IRELAND: A REGIONAL EVALUATION OF PRESSURES AND PATHWAYS OF NUTRIENT LOSS TO WATER , 2022, Biology and Environment: Proceedings of the Royal Irish Academy.

[26]  B. Ulén,et al.  Recent trends in nutrient concentrations in Swedish agricultural rivers. , 2007, The Science of the total environment.

[27]  A. Sharpley,et al.  A Comparison of Fluvial Sediment Phosphorus (P) Chemistry in Relation to Location and Potential to Influence Stream P Concentrations , 2001 .

[28]  Karen Daly,et al.  The effect of soil type on phosphorus sorption capacity and desorption dynamics in Irish grassland soils , 2001 .

[29]  G. Rayment Water quality in sugar catchments of Queensland. , 2003, Water science and technology : a journal of the International Association on Water Pollution Research.

[30]  P. Johnes,et al.  Land use scenarios for England and Wales: evaluation of management options to support ‘good ecological status’ in surface freshwaters , 2007 .

[31]  G. Rayment,et al.  Phosphorus Fertility Assessment of Intensively Farmed Areas of Catchments Draining to the Great Barrier Reef World Heritage Area; 2: Potential of Soils to Release Soluble Phosphorus , 2006 .

[32]  Richard J. Williams,et al.  Role of river bed sediments as sources and sinks of phosphorus across two major eutrophic UK river basins: the Hampshire Avon and Herefordshire Wye , 2005 .

[33]  G. Kiely,et al.  Patterns and processes of phosphorus transfer from Irish grassland soils to rivers—integration of laboratory and catchment studies , 2005 .

[34]  R. Foy Variation in the reactive phosphorus concentrations in rivers of northwest Europe with respect to their potential to cause eutrophication , 2007 .

[35]  K. Daly,et al.  Environmental aspects of soil phosphorus testing , 2005 .

[36]  F. Claessen,et al.  Agricultural Effects on Ground and Surface Waters: Research at the Edge of Science and Society , 2002 .

[37]  Charles R. Goldman,et al.  Phosphorus and nitrogen limitation of phytoplankton growth in the freshwaters of North America : a review and critique of experimental enrichments , 1990 .

[38]  Philip Jordan,et al.  Phosphorus and sediment transfers in a grassland river catchment , 2007, Nutrient Cycling in Agroecosystems.

[39]  William A. House,et al.  Geochemical cycling of phosphorus in rivers , 2003 .

[40]  H. ApSimon,et al.  Mitigating diffuse phosphorus transfer from agriculture according to cost and efficiency. , 2009, Journal of environmental quality.

[41]  W. House,et al.  Phosphorus dynamics along a river continuum. , 2003, The Science of the total environment.

[42]  R. Moles,et al.  Good water status: the integration of sustainable grassland production and water resources in Ireland. , 2009 .

[43]  R. Moles,et al.  Effects over time of fertiliser P and soil series on P balance, soil-test P and herbage production , 2004 .

[44]  H. Tunney,et al.  Agriculture as a phosphorus source for eutrophication in the north‐west European countries, Norway, Sweden, United Kingdom and Ireland: a review , 2007 .

[45]  H. Tunney,et al.  The impact of agricultural management practices on nutrient losses to water: data on the effects of soil drainage characteristics. , 2005, Water science and technology : a journal of the International Association on Water Pollution Research.

[46]  H. Tunney,et al.  Long‐term phosphorus grassland experiment for beef production – impacts on soil phosphorus levels and liveweight gains , 2010 .