Review of the Annual Phosphorus Loss Estimator tool - a new model for estimating phosphorus losses at the field scale

2014 ◽  
Vol 30 (3) ◽  
pp. 337-341 ◽  
Author(s):  
C. McW. H. Benskin ◽  
W. M. Roberts ◽  
Y. Wang ◽  
P. M. Haygarth
Keyword(s):  
Field Scale ◽  
Phosphorus Loss ◽  
New Model ◽  
Phosphorus Losses ◽  
Loss Estimator

Field‐Scale Nitrogen and Phosphorus Losses from Hayfields Receiving Fresh and Composted Broiler Litter

1998 ◽  
Vol 27 (5) ◽  
pp. 1246-1254 ◽  
Author(s):  
R. W. Vervoort ◽  
D. E. Radcliffe ◽  
M. L. Cabrera ◽  
M. Latimore
Keyword(s):  
Field Scale ◽  
Nitrogen And Phosphorus ◽  
Broiler Litter ◽  
Phosphorus Losses

scholarly journals Effectiveness of Cover Crops for Water Pollutant Reduction from Agricultural Areas

2021 ◽  
Vol 64 (3) ◽  
pp. 1007-1017
Author(s):  
Reid Christianson ◽  
Jordan Fox ◽  
Neely Law ◽  
Carol Wong
Keyword(s):  
Water Quality ◽  
Cover Crops ◽  
Cover Crop ◽  
List Type ◽  
Loss Reduction ◽  
Nutrient Losses ◽  
Phosphorus Loss ◽  
Dissolved Phosphorus ◽  
Freeze Thaw ◽  
Phosphorus Losses

HighlightsNitrogen loss reduction due to a cover crop tends to improve with increased cover crop biomass production.Mixed phosphorus loss reduction results in cold climates where freeze-thaw cycles occur and can increase dissolved phosphorus losses.Cereal rye was the primary cover crop studied and tended to provide the most water quality benefits.Abstract. Mitigating nutrient losses from agricultural fields retains these nutrients for subsequent crop production and reduces the risk to downstream water quality. This study evaluated the impact of cover crops, as part of an annual cropping system, on reducing nutrient losses and enhancing water quality. Cover crop literature focusing on water quality was reviewed to determine important factors regarding cover crop performance and cost. Results show that a grass-based cover crop and mixes with grasses tend to increase nitrate loss reduction (40%) compared to legumes (negligible). Biomass growth was also important, with early seeding or growth of a cover crop in areas with increased growing degree days enhancing performance. For phosphorus loss, benefits did not necessarily increase with increasing biomass. Further, dissolved phosphorus concentrations may increase due to freeze-thaw cycles (23%), although overall dissolved phosphorus losses tend to decrease due to less runoff (34%). Cover crop implementation costs ranged from a savings of $25 to $44 ha-1 year-1 before soybeans and corn, respectively, when implementing a cover crop for five straight years to a cost of $193 ha-1 year-1. Including a cover crop in annual crop rotations with adequate time in the fall for germination and growth can reduce nitrogen and phosphorus losses from production agriculture to help meet water quality goals across the U.S. Keywords: Catch crop, Nitrogen, NRCS, Phosphorus, Practice Code 340, USDA, Water quality.

scholarly journals Soil parameter variability affecting simulated fieldscale water balance, erosion and phosphorus losses

2009 ◽  
Vol 18 (3-4) ◽  
pp. 402-416 ◽  
Author(s):  
I. BÄRLUND ◽  
S. TATTARI ◽  
M. PUUSTINEN
Keyword(s):  
Water Balance ◽  
Management Practices ◽  
Agricultural Land ◽  
Expert Knowledge ◽  
Agricultural Soils ◽  
Data Sets ◽  
Field Scale ◽  
Lack Of Information ◽  
Scale Modelling ◽  
Phosphorus Losses

Field-scale modelling is widely used as a means to look into interdependencies of processes and to assess potential effects of agricultural management practices as well as of climate and socio-economic scenarios. Generalisation from field-scale results to cover all agricultural land in a catchment by using typical soilcrop- slope combinations has been restricted by a lack of information for the systematic parameterisation of soils. Data from single experimental fields are seldom representative for the whole respective catchment. In this study typical soil profiles for mineral agricultural soils in Finland are defined. Key parameters describing e.g. the texture and water holding capacity of soils, were generated from existing soil data using expert knowledge and are aimed to be used for field-scale modelling when the target is not to model a particular field but soils of certain type in general. Estimates for water balance and phosphorus losses, obtained with the ICECREAM model by applying these data sets, were realistic and compatible with experimental results measured in Finland.;

Fertilisers and phosphorus loss from productive grazing systems

Soil Research ◽  
1999 ◽  
Vol 37 (3) ◽  
pp. 403 ◽  
Author(s):  
David M. Nash ◽  
David J. Halliwell
Keyword(s):  
Management Strategies ◽  
Phosphorus Uptake ◽  
Macropore Flow ◽  
Phosphorus Species ◽  
Phosphorus Loss ◽  
Nutrient Sources ◽  
Matrix Flow ◽  
Grazing Systems ◽  
Phosphorus Losses ◽  
Species Being

This paper reviews phosphorus loss from productive high rainfall grazing systems. In particular it describes the processes occurring when phosphatic fertilisers are added to soil, the different pathways through which fertiliser and other nutrient sources may contribute to phosphorus losses, and an evaluation of the management strategies aimed at minimising phosphorus loss. It is now generally accepted that soil is not an endless sink for phosphorus uptake and that at the landscape scale the highest concentrations of phosphorus loss occur in surface runoff, followed by macropore flow and vertical matrix flow. However, loads of phosphorus lost through these pathways are unknown. The development of an understanding of the transport mechanisms and phosphorus species being transported is fundamental to developing management strategies that are effective in decreasing phosphorus losses from grazing systems.

scholarly journals A Permeability Model for Coal and Other Fractured, Sorptive-Elastic Media

SPE Journal ◽  
2008 ◽  
Vol 13 (03) ◽  
pp. 314-324 ◽  
Author(s):  
Eric P. Robertson ◽  
Richard L. Christiansen
Keyword(s):  
Uniaxial Stress ◽  
Elastic Media ◽  
Fracture System ◽  
Field Scale ◽  
Permeability Model ◽  
New Model ◽  
Permeability Changes ◽  
Matrix Blocks ◽  
The Matrix ◽  
Permeability Data

Summary This paper describes the derivation of a new equation that can be used to model the permeability behavior of a fractured, sorptive-elastic medium, such as coal, under variable stress conditions. The equation is applicable to confinement pressure schemes commonly used during the collection of permeability data in the laboratory. The model is derived for cubic geometry under biaxial or hydrostatic confining pressures. The model is designed to handle changes in permeability caused by adsorption and desorption of gases onto and from the matrix blocks in fractured media. The model equations can be used to calculate permeability changes caused by the production of methane (CH4) from coal as well as the injection of gases, such as carbon dioxide, for sequestration in coal. Sensitivity analysis of the model found that each of the input variables can have a significant impact on the outcome of the permeability forecast as a function of changing pore pressure; thus, accurate input data are essential. The permeability model also can be used as a tool to determine input parameters for field simulations by curve fitting laboratory-generated permeability data. The new model is compared to two other widely used coal-permeability models using a hypothetical coal with average properties. Introduction During gas production from a coal seam, as reservoir (pore) pressure is lowered, gas molecules, such as CH4, are desorbed from the matrix and travel by diffusion to the cleat (natural-fracture) system where they are conveyed to producing wells. Fluid movement in coal is controlled by slow diffusion within the coal matrix and is described by Darcy flow within the fracture system, which is much faster than the contribution of diffusion. A coal formation typically is treated as a fractured reservoir with respect to fluid flow, meaning that the sole contributor to the overall permeability of the reservoir is the fracture system, and the contribution of diffusion through the matrix to total flow is neglected. Coalbeds are unlike other nonreactive fractured reservoirs because of their ability to adsorb (or desorb) large amounts of gas, which causes swelling (or shrinkage) of the matrix blocks. Coalbeds have the capacity to adsorb large amounts of gases because of their typically large internal-surface areas, which can range from 30 to 300 m2/g (Berkowitz 1985). Some gases, such as carbon dioxide, have a higher affinity for the coal surfaces than others, such as nitrogen (N2). Knowledge of how the adsorption or desorption of gases affects coal permeability is important not only to operations involving the production of natural gas from coalbeds, but also to the design and operation of projects to sequester greenhouse gases in coalbeds (RECOPOL 2005). Laboratory measurements of permeability using coal samples can be used to gain insight into field-scale permeability changes and to determine key-coal-property values necessary for field-scale simulation. A number of permeability models derived for sorptive-elastic media such as coals have been detailed in the literature and include those proposed by Gray (1987), Sawyer et al. (1990), Seidle and Huitt (1995), Palmer and Mansoori (1998), Pekot and Reeves (2003), and Shi and Durucan (2003). These models were derived to mimic field conditions, and they assume a matrix-block geometry described as a bundle of vertical matchsticks under a uniaxial stress regime (Palmer and Mansoori 1998; Seidle et al. 1992). However, in the laboratory, permeability typically is measured by use of hydrostatic (biaxial) core holders, which apply a single confining pressure to all external points of the core inside the holder. This is obviously different from the stress conditions encountered in the field, which typically are characterized as being under uniaxial stress as noted previously. Moreover, on a laboratory scale, coal matrix blocks may be approximated better by cubic instead of matchstick geometry, as will be discussed later in this paper. A recent study (Robertson and Christiansen 2005c) compared the accuracy of three field-permeability models when applied to laboratory-generated, sorption-affected permeability data and found that none of the three was able to match the data accurately. A model specifically derived for laboratory coreflooding conditions would be expected to provide a more reasonable match of permeability results. This paper describes the derivation of a new model that describes the permeability behavior of a fractured, sorptive-elastic medium, such as coal, under typical laboratory conditions where common radial and axial pressures are applied to a core sample during permeability measurements. The new model can be applied to fractured rock formations where the matrix blocks contribute neither to the porosity nor to the permeability of the overall system, but where adsorption and desorption of gases by the matrix blocks cause measurable swelling and shrinkage, respectively, and thus affect permeability.

scholarly journals Use of Annual Phosphorus Loss Estimator (APLE) Model to Evaluate a Phosphorus Index

2017 ◽  
Vol 46 (6) ◽  
pp. 1380-1387 ◽  
Author(s):  
Nicole M. Fiorellino ◽  
Joshua M. McGrath ◽  
Peter A. Vadas ◽  
Carl H. Bolster ◽  
Frank J. Coale
Keyword(s):  
Phosphorus Loss ◽  
Loss Estimator
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