List of options for reducing phosphorus loss from agriculture

This list will be extended in an interactive process with persons interested in the subject. Any contributions are thus highly appreciated. Please mail to: wim.chardon@wur.nl
The list is based on inventories made for the UK (Haygarth, Betson, Withers, Hodgkinson, Harris, and ApSimon), Sweden (Ulén), and The Netherlands.
References of publications (if provided by authors or others), in which these experiences are described, will be collected: click on references.



Note for commercial use within The Netherlands:
Copyright Alterra, Wageningen UR; use of data from this compilation only with permission from the author, W.J. Chardon.



Last update (dd-mm-yr): 22-8-05. List of updates
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The options are grouped under different headings, namely options for:

» »A. reducing agricultural phosphorus input or increasing output
» »B. reducing soluble forms of P ('leaching')
» »C. reducing mobilisation of particulate forms ('erosion')
» »D. reducing phosphorus transport on field scale
» »E. reducing phosphorus transport in surface water
» »F. abating ecological consequences of eutrophication in surface water



Note: some options under 'soluble forms' are also applicable to 'particulate forms', and vice versa.





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A. Options for reducing agricultural phosphorus input or increasing output

Reduction of input
*A1* Nutrient balance below 100% for plots with (very) high P status (depletion) [ref]
*A2* Other plots: make input equal to offtake of P with crops
*A3* Reduce fertiliser inputs to:
a -- arable land [ref]
b -- grassland [ref]
c -- horticulture

Increasing output
*A4* Choose crops with higher P-uptake
*A5* Remove crop residues after harvest

Livestock management
*A6* Reduce feed P input to dairy [ref]
*A7* Use phytase to reduce feed P input [ref]
*A8* Use low phytate feed [ref]

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B. Options for reducing (conversion to) soluble forms of P

Soil residual P management
*B1* Immobilising amendments to soil [ref]
*B2* Ploughing soil for reducing stratification [ref]

Fertiliser management
*B3* Slowly available P fertilisers
*B4* Incorporation of inorganic or organic fertilisers [ref]
*B5* Placement
*B6* Timing windows for application
*B7* Precision farming
*B8* Composting of crop residues

Manure management
*B09* Change from liquid to solid manure [ref]
*B10* Injection of liquid manure [ref]
*B11* Incorporation
*B12* Timing windows for application
*B13* Immobilising amendments to manure [ref]
*B14* Reduce rate of application and redistribution of manure [ref]
*B15* Separate solid and liquid manure fractions (makes transport cheaper)
*B16* Recycle P from animal manure [ref]

Livestock management
*B17* Reduce stocking density
*B18* Stop animal production (locally)
*B19* Restrict livestock access in marginal places/times
*B20* Use plastic for grass silage (decreases risk of P in silage effluent)

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C. Options for reducing mobilisation of particulate forms of P

Changes in cropping
*C1* Choose crops that are less sensitive for surface runoff
*C2* Arable to grassland (margins of arable land e.g. flood areas, uplands)
*C3* Arable to willow coppice (use crop in power station)
*C4* Cover cropping during winter (note: risk of soluble P loss from frozen plant residues) [ref]
*C5* Avoid late sowing in high risk areas

Cultivation management
*C6* Minimum, ridge or no-tillage (especially in autumn) [ref]
*C7* Contour cultivation
*C8* Mulching
*C9* Change tramline management (omit tramlines in the winter)
*C10* Cultivate across slope
*C11* Increase surface roughness
*C12* Subsoiling across slope (decrease surface runoff)
*C13* Level out field
*C14* Improve infiltration capacity of the soil by: [ref]
a - improve organic matter content of the soil
b - avoid tilling of wet soil which deteriorates aggregates and soil structure
c - reduce soil compaction (avoids compact plough pan)
d - deep ploughing for destroying a plough pan (and deep macropores)

Miscellaneous
*C15* Use of soil stabilisers (sand/silt/chalk soils on arable land)
*C16* Increase soil level along ditches
*C17* Restrict livestock access to (borders of) surface water
*C18* Improve subsurface drainage (install artificial drains) [ref]
*C19* Mix the backfill with CaO after digging for drain tiles
*C20* Use controlled drainage for reducing the amount of water leaving a field

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D. Options for reducing phosphorus transport on field scale

*D1* Grass buffers (within field, e.g. half way up field)
*D2* Farm track sediment traps
*D3* Move gateways away from points of drainage i.e. from down to up slope
*D4* Install hedges and make fields smaller
*D5* Stop fertilising ditch borders
*D6* Buffer / riparian zones (on field boundaries) [ref]
*D7* Environmentally sustainable embankment of ditches or streams
*D8* Immobilising amendments to buffer zones (e.g. iron or CaO)
*D9* Disconnect farm infrastructure from sewerage or surface water
*D10* Install surface runoff water inlet (tank without bottom connected to tile drain)
*D11* Increase retention time of (drain) water within field by:
a - removing trenches or ditches
b - removing artificial drains
c - increasing depth of artificial drains

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E. Options for reducing phosphorus transport in surface water

*E1* Purify water, e.g. in infiltration beds
*E2* Sedimentation ponds
*E3* Barrier ditches (linear sedimentation ponds)
*E4* Increase retention time in ditches (stimulates deposition of particulate P)
*E5* Constructed wetlands [ref]
*E6* Immobilising amendments to constructed wetlands [ref]
*E7* Remove sediments from streams (dredging)
*E8* Place removed sediments within field (not on ditch border)
*E9* Immobilising amendments to sediments [ref]
*E10* Prevent that eutrofied surface water enters P-sensitive water (re-routing) [ref]

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F. Options for abating consequences of eutrophication in surface water

*F1* Stimulate growth of submerged water plants
*F2* Remove biomass from ditches and streams (e.g. reed, duck-weed)
*F3* Place removed biomass within field (not on ditch border)
*F4* Biomanipulation (e.g. remove sediment resuspending fish) [ref]
*F5* Increase lake depth (reduces resuspension of sediment by wind) [ref]
*F6* Flushing lake water with 'clean' surface water

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List of publications in which experiences with options to reduce P loss from agriculture are described.
(examples, further references can be added by authors or others)


References are grouped under different headings, namely dealing with options for:

» » reducing agricultural phosphorus input or increasing output
» » reducing soluble forms of P ('leaching')
» » reducing mobilisation of particulate forms ('erosion')
» » reducing phosphorus transport within field
» » reducing phosphorus transport in surface water
» » abating ecological consequences of eutrophication in surface water


By clicking on the year of a reference the specific reference can be seen. Click on "Back" to return to previous position.


*

A. Options for reducing agricultural phosphorus input or increasing output

*A1* Nutrient balance below 100% for plots with (very) high P status (depletion)
Barber, 1979; Brown & Gibson, 2002; Delgado & Torrent, 1997; Delorme et al., 2000; Eghball et al., 2002; Guo et al., 2000; Halvorson & Black, 1985; Hedley et al., 1994; Hooker et al., 1983; Koopmans et al. 2004a, 2004b; Marrs, 1985; McCollum, 1991; Oehl et al., 2002; Pierson et al., 2001; Pothuluri et al., 1991; Schärer, 2003; Sharma et al., 2002, 2003, 2004; Sharpley, 1999; Sims et al., 2002; Sistani et al. 2002; Snow & Marrs, 1996; Wagar et al., 1986; Yli-Halla, 1989,1991; Yli-Halla et al., 2002;

*A3a* Reducing inputs to arable land
-- Bechmann & Stĺlnacke, 2003
*A3b* Reducing inputs to grassland
-- Bechmann & Stĺlnacke, 2003; Environment and Heritage Service, 1999; Smith et al., 2004;
*A6* Reduce feed P input to dairy
-- Dou et al., 2002;

*A7* Use phytase to reduce feed P input
Applegate et al., 2003; Baxter et al., 2003; Cromwell et al., 1993, 1995; Harper et al., 1997; Jongbloed et al., 1992; Keshavarz & Austic, 2004; Lei et al., 1993a, 1993b; Maguire et al., 2003a, b; McGrath et al., 2003a, b; Miles et al., 2003; Moore et al., 2000; Pierce & Cromwell, 1999; Pointillart, 1993; Sands et al., 2001; Smith et al., 2004; Valk et al., 2000

*A8* Use low phytate feed
Applegate et al., 2003; Baxter et al., 2003; Cromwell et al., 1998; Ertl et al., 1998; Keshavarz & Austic, 2004; Miles et al., 2003; Moore et al., 2000; Novak & Watts, 2004; Pierce & Cromwell, 1999; Raboy et al., 1990; Sands et al., 2001; Spencer et al., 2000; Valk et al., 2000; Veum et al., 2001; Wienhold & Miller, 2004; Wilcox et al., 2000;

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B. Options for reducing (conversion to) soluble forms of P

*B1* Immobilising amendments to soil
Alvisyahrin et al., 1998; Anderson et al., 1995; Basta, 2000; Basta & Storm, 1997; Basta et al., 1998, 1999, 2001, 2003 Callahan et al., 2002; Chardon & Koopmans, 1999; Codling et al., 2002; Daniels et al., 1999; Dayton, 1999; Dayton & Basta, 2003; Dayton et al., 2000, 2001, 2003a, 2003b; DeWolfe & Basta, 2003; Elliott et al., 2002; Friend et al., 2003; Gallimore, 1999; Gallimore et al., 1999; Hendriks & Huijsmans, 1995; Jonasson, 1996; Lane, 2002; Novak & Watts, 2004; O’Connor et al., 2002; Peters, 1996; Peters & Basta, 1996; Ritchey, 1998; Schärer, 2003; Scheffer et al., 1985; Schoumans & Köhlenberg, 1995; Schweigert 2004; Shober et al., 2003; Stout et al., 1998, 2000; Zupancic, 1999;

*B2* Ploughing soil for reducing stratification
Morrison et al., 1994; Peltovuori, 2002; Pezzarossa et al., 1995; Rehm et al., 1995; Schärer, 2003; Sharpley, 2003; Weil et al., 1988; Weill et al., 1990;

*B4* Incorporation of inorganic or organic fertilisers
-- Djodjic et al., 2002; Ulén & Mattsson, 2003
*B9* Change from liquid to solid manure
-- Ginting et al., 1998a,b
*B10* Injection of liquid manure
-- Nichols et al., 1994; Pote et al., 2002; Ross et al., 1998

*B13* Immobilising amendments to manure
Dao, 1999; Dao & Daniel, 2002; Dao et al., 2001; Dou et al., 2003; Elrashidi et al., 1999; Gilmour et al., 2004; Miles et al., 2003; Moore & Miller, 1994; Moore et al., 1995; 1999; 2000; Schweigert 2004; Shreve et al., 1995; 1996; Sims & Luka-McCafferty, 2002; Smith et al., 2001; 2004;

*B14* Reduce rate of application and redistribution of manure
Sharpley et al., 1994; Sims, 1997; Ulén et al., 2004

*B16* Recycle P from animal manure
Much information (reports, hundreds of references) on this topic can be found on the web site:
www.nhm.ac.uk/mineralogy/P-recovery/

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C. Options for reducing mobilisation of particulate forms of P

*C4* Cover cropping during winter :
-- Ulén et al., 2002; Ulén, 2004;
*C6* Minimum, ridge or no-tillage (especially in autumn)
-- Ginting et al., 1998a,b; Johnson et al., 1979; Seta et al., 1993; Zhao et al., 2001;
*C14* Improve infiltration capacity of the soil :
-- Ulén et al., 2002; Ulén, 2004;
*C18* Improve subsurface drainage (install artificial drains)
-- Bengtson et al., 1988; Turtola & Paajanen, 1995

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D. Options for reducing phosphorus transport on field scale

*D6* Buffer / riparian zones (on field boundaries)
-- Blanco-Canquia et al., 2004

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E. Options for reducing phosphorus transport in surface water

*E5* Constructed wetlands
Ann et al., 2000a,b; Braskerud, 2000, 2001, 2002; Dosskey, 2001; Dunne et al., 2005; Gray et al., 2000; Kadlec, 1999; Lantzke et al., 1999; Liikanen et al., 2004; Marti et al., 2004;Reddy et al., 1999; Richardson,1985, 1999;

*E6* Immobilising amendments to constructed wetlands
-- Ann et al., 2000a,b; Gray et al., 2000;
*E9* Immobilising amendments to sediments
-- Rydin et al., 2000;
*E10* Prevent that eutrofied surface water enters P-sensitive water (re-routing)
-- Meissner et al., 2003;

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F. Options for abating consequences of eutrophication in surface water

*F4* Biomanipulation (e.g. remove sediment resuspending fish)
-- Hosper, 1997
*F5* Increase lake depth (reduces resuspension of sediment by wind)
-- Hosper, 1997

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A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

Alvisyahrin, T., D.M. Miller, T.C. Daniel, and P.A. Moore. 1998. Bioavailable phosphorus in WTR-amended, excessively manured soils. In Annual Meeting Abstracts ASA, CSSA, SSSA, Madison, WI USA. p. 1998, p. 203.

Anderson, D.L., O.H. Tuovinen, A. Faber, and I. Ostrokowski. 1995. Use of soil amendments to reduce soluble phosphorus in dairy soils. Ecol. Eng. 5:229-246.

Ann, Y., K.R. Reddy, and J.J. Delfino. 2000a. Influence of chemical amendments on phosphorus immobilization in soils from a constructed wetland. Ecol. Eng. 14:157-167.

Ann, Y., K.R. Reddy, and J.J. Delfino. 2000b. Influence of redox potential on phosphorus solubility in chemically amended wetland organic soils. Ecol. Eng. 14:169-180.

Applegate, T.J., B.C. Joern, D.L. Nussbaum-Wagler, and R. Angel. 2003. Water soluble phosphorus in fresh boiler litter is dependent on phosphorus concentration fed but not on fungal phytase supplementation. Poultry Sci. 82:1024-1029.

Barber, S.A. 1979. Soil phosphorus after 25 years of cropping with five rates of phosphorus application. Commun. Soil Sci. Plant Anal. 10:1459-1468.

Basta, N.T. 2000. Examples and case studies of beneficial reuse of municipal by-products. p. 481-504. In J.F. Power (ed.) Land Application of Agricultural, Industrial, and Municipal By-products. Book Series No. 6, Soil Science Society of America, Madison, WI.

Basta, N.T., E.A. Dayton, and L.E. Gallimore. 1998. Nutrient adsorption capacity of drinking water residuals. Agron. Abstr. p. 346.

Basta, N.T., E.A. Dayton, and L.E. Gallimore. 1999. Nutrient adsorption capacity of water treatment residuals. Joint Residuals and Biosolids Management Conference (CD-ROM), Water Environment Federation, Charlotte, NC, Jan. 27-30.

Basta, N.T., E.A. Dayton, D.E. Storm, and J.R. DeWolfe. 2003. Advances in WTR research to manage P, in soil, runoff, manure, and biosolids. Joint Residuals and Biosolids Management Conference (CD-ROM), Water Environment Federation, Baltimore, MD, Feb. 19-22.

Basta, N.T., E.A. Dayton, and R.J. Zupancic. 2001. Beneficial land application of drinking water treatment residual based on chemical and physical characterization. Joint Residuals and Biosolids Management Conference (CD-ROM), Water Environment Federation, San Diego, CA, Feb. 22-24.

Basta, N.T., and D.E. Storm. 1997. Use of alum residuals to reduce nutrient runoff from agricultural land treated with animal manure to protect surface water quality. Proc. 1997 WEF/AWWA Joint Residuals and Biosolids Specialty Conf., Philadelphia, PA.

Baxter, C.A., B.C. Joern, D. Ragland, J.S. Sands, and O. Adeola. 2003. Phytase, high-available-phosphorus corn, and storage effects on phosphorus levels in pig excreta. J. Environ. Qual. 32:1481-1489.

Bechmann, M., and P. Stĺlnacke. 2003. Effect of policy induced measures on suspended sediments and total phosphorus concentrations from three Norwegian agricultural catchments. Sci. Total Environ. (submitted)

Bengtson, R.L., C.E. Carter, H.F. Morris, and S.A. Bartkiewicz. 1988. The influence of subsurface drainage practices on nitrogen and phosphorus losses in a warm, humid climate. Trans. ASAE 31:729-733.

Blanco-Canquia, H., C.J. Gantzer, S.H. Anderson, E.E. Alberts, and A.L. Thompson. 2004. Grass barrier and vegetative filter strip effectiveness in reducing runoff, sediment, nitrogen, and phosphorus loss. Soil Sci. Soc. Am. J. 68:1670-1678

Braskerud, B.C. 2000. Measurement and modeling of phosphorus retention in small constructed wetlands treating agricultural non-point source pollution. p. 75-85. In IWAs 7th Int. Conf. on Wetland Systems for Water Pollution Control, Lake Buena Vista, FL. 11-16 Nov. 2000. Int. Water Assoc., London.

Braskerud, B.C. 2001. The influence of vegetation on sedimentation and resuspension of soil particles in small constructed wetlands. J. Environ. Qual. 30:1447-1457.

Braskerud, B.C. 2002. Factors affecting nitrogen retention in small constructed wetlands treating agricultural non-point source pollution. Ecol. Eng. 18:351-370.

Brown, B.D., and R.G. Gibson. 2002. Double cropped forages for maximizing phosphorus removal in southwestern Idao. In Annual Meeting Abstracts [CD-ROM] ASA, CSSA, SSSA, Madison, WI USA.

Callahan, M.P., P.J.A. Kleinman, A.N. Sharpley, and W.L. Stout. 2002. Assessing the efficacy of alternative phosphorus sorbing soil amendments. Soil Sci. 167:539-547.

Chardon, W.J., and G.F. Koopmans. 1999. Immobilization of phosphorus in excessively fertilized soils. In Annual Meeting Abstracts ASA, CSSA, SSSA, Madison, WI USA. p. 337.

Codling, E.E., C.L. Mulchi, and R.L. Chaney. 2002. Biomass yield and phosphorus availability to wheat grown on high phosphorus soils amended with phosphate inactivating residue: II. Iron Rich Residue. Commun. Soil Sci. Plant Anal. 33:1063-1084.

Cromwell, G.L., R.D. Coffey, G.R. Parker, H.J. Monegue, and J.H. Randolph. 1995. Efficacy of a recombinant-derived phytase in improving the bioavailability of phosphorus in corn-soybean meal diets for pigs. J. Anim. Sci. 73:2000-2008.

Cromwell, G.L., J.P. Pierce, T.E. Sauber, D.W. Rice, D.S. Ertl, and V. Raboy. 1998. Bioavailability of phosphorus in low phytic acid corn for growing pigs. J. Anim. Sci. 76(Supplement 2):54.

Cromwell, G.L., T.S. Stahly, R.D. Coffey, H.J. Monegue, and J.H. Randolph. 1993. Efficacy of phytase in improving the bioavailability of phosphorus in soybean meal and corn-soybean meal diets for pigs. J. Anim. Sci. 71:1831-1840.

Daniels, T.C., G. Hausten, P.A. Moore, and D. Nichols. 1999. Effect of land-applied alum residuals and HCA on runoff phosphorus concentrations from high P-soils. In WEF/AWWA Joint Residuals and Biosolids Management Conference Abstracts, San Diego, CA.

Dao, T.H. 1999. Coamendments to modify phosphorus extractability and nitrogen:phosphorus ratio in feedlot manure and composted manure. J. Environ. Qual. 28:1114-1121.

Dao, T.H., and T.C. Daniel. 2002. Particulate and dissolved phosphorus chemical separation and phosphorus release from treated dairy manure. J. Environ. Qual. 31:1388-1398.

Dao, T.H., L.J. Sikora, A. Hamasaki, and R.L. Chaney. 2001. Manure phosphorus extractability as affected by aluminum- and iron by-products and aerobic composting. J. Environ. Qual. 30:1693-1698.

Dayton, E.A. 1999. Beneficial use of drinking water treatment residuals. M.S. Thesis, Oklahoma State University, Stillwater, OK.

Dayton, E.A., and N.T. Basta. 2003. Combating excess P in manure with alum sludge. Great Lakes By-Products Management Association 4th Annual Conference, East Lansing, MI, Dec. 2-3, 2003.

Dayton, E.A., N.T. Basta, L. Dehass. 2003a. All drinking water residuals are not created equal. Joint Residuals and Biosolids Management Conference (CD-ROM), Water Environment Federation, Baltimore, MD, Feb. 19-22.

Dayton, E.A., N.T. Basta, C.A. Jakober, and J.A. Hattey. 2003b. Using treatment residuals to reduce phosphorus in agricultural runoff. J. Am. Water Works Assoc. 95 (4):151-158.

Dayton, E.A., N.T. Basta, and C.A. Jakober. 2001. Phosphorus sorption capacity of drinking water treatment residuals and potential for use to protect surface water quality. Joint Residuals and Biosolids Management Conference (CD-ROM), Water Environment Federation, San Diego, CA, Feb. 22-24.

Dayton, E.A., N.T. Basta, C.A. Jakober, and D.E. Storm. 2000. Phosphorus sorption capacity of drinking water treatment residuals for potential use as a phosphorus sorbent to protect water quality. Agron. Abstr. p. 403.

Delgado, A., and J. Torrent. 1997. Phosphate-rich soils in the European union: Estimating total plant-available phosphorus. Eur. J. Agron. 6:205-214.

Delorme, T.A., J.S. Angle, F.J. Coale, and R.L. Chaney. 2000. Phytoremediation of phosphorus-enriched soils. Int. J. Phytoremediation 2:173-181.

DeWolfe, J.R., and N.T. Basta. 2003. Use of water treatment residuals to reduce soil P loss and protect surface water quality: An interregional study. Joint Residuals and Biosolids Management Conference (CD-ROM), Water Environment Federation, Baltimore, MD, Feb. 19-22, 2003.

Djodjic, F., L. Bergström, and B. Ulén. 2002. Phosphorus losses from a structured clay soil in relation to tillage practices. Soil Use Manage. 18:79-83.

Dosskey, M.G. 2001. Toward quantifying water pollution abatement in response to installing buffers on crop land. Environ. Manage. 28:577-598.

Dou, Z., D.T. Galligan, C.F. Ramberg, C. Meadows, and J.D. Ferguson. 2001. A survey of dairy farming in Pennsylvania: Nutrient management practices and implications. J. Dairy Sci. 84:966-973.

Dou, Z., K.K. Knowlton, R.A. Kohn, Z. Wu, L.D. Satter, G. Zhang, J.D. Toth, and J.D. Ferguson 2002. Phosphorus characteristics of dairy feces affected by diets. J. Environ. Qual. 31:2058-2065.

Dou, Z., G.Y. Zhang, W.L. Stout, J.D. Toth, and J.D. Ferguson. 2003. Efficacy of alum and coal combustion by-products in stabilizing manure phosphorus. J. Environ. Qual. 32:1490-1497.

Dunne, E.J., K.R. Reddy, and O.T. Carton (ed.). 2005. Nutrient management in agricultural watersheds: A wetlands solution. Proc. Intern. Symp., Wexford Ireland, May 2005. Wageningen Academic Publishers, Wageningen The Netherlands. 288 pp. ISBN 9076998612. Click here for the table of contents and ordering information.

Eghball, B., J.F. Shanahan, G.E. Varvel, and J.E. Gilley. 2002. Reduction of high soil test phosphorus by crop removal. In Annual Meeting Abstracts [CD-ROM] ASA, CSSA, SSSA, Madison, WI USA.

Elliott, H.A., G.A. O’Connor, P. Lu, and S. Brinton. 2002. Influence of water treatment residuals on phosphorus solubility and leaching. J. Environ. Qual. 31:1362-1369.

Elrashidi, M.A., V.C. Baligar, R.F. Korcak, N. Persaud, and K.D. Ritchey. 1999. Chemical composition of leachate of dairy manure mixed with fluidized bed combustion residue. J. Environ. Qual. 28:1243-1251

Environment and Heritage Service. 1999. Eutrophication in Northern Ireland's waters - Proposals for a strategy to control nutrient enrichment. EHS Press, Belfast, UK.

Ertl, D.S., K.A. Young, and V. Raboy. 1998. Plant genetic approaches to phosphorus management in agricultural production. J. Environ. Qual. 27:299-304.

Friend, M.S., N.T. Basta, and E.A. Dayton. 2003. Using water treatment residuals to reduce runoff P entering urban waters. 2003. Joint Residuals and Biosolids Management Conference (CD-ROM), Water Environment Federation, Baltimore, MD, Feb. 19-22.

Gallimore, L.E. 1999. Use of water treatment residuals to reduce nutrient runoff and as an alternate growth media. M.S. Thesis, Oklahoma State University, Stillwater, OK.

Gallimore, L.E., N.T. Basta, D.E. Storm, M.E. Payton, R.H. Huhnke, and M.D. Smolen. 1999. Use of water treatment residuals to reduce nutrients in surface runoff from agricultural land. J. Environ. Qual. 28:1474-1478.

Gilmour,J.T., M.A. Koehler, M.L. Cabrera, L. Szajdak, and P.A. Moore, Jr. 2004. Alum treatment of poultry litter: Decomposition and nitrogen dynamics. J. Environ. Qual. 33:402-405.

Ginting, D., J.F. Moncrief, S.C. Gupta, and S.D. Evans. 1998a. Corn yield, runoff, and sediment losses from manure and tillage systems. J. Environ. Qual. 27:1396-1402.

Ginting, D., J.F. Moncrief, S.C. Gupta, and S.D. Evans. 1998b. Interaction between manure and tillage system on phosphorus uptake and runoff losses. J. Environ. Qual. 27:1403-1410.

Gray, S., J. Kinross, P. Read, and A. Marland. 2000. The nutrient assimilative capacity of maerl as a substrate in constructed wetland systems for waste treatment. Water Res. 34:2183-2190.

Guo, F., R.S. Yost, N.V. Hue, C.I. Evensen, and J.A. Silva. 2000. Changes in phosphorus fractions in soils under intensive plant growth. Soil Sci. Soc. Am. J. 64:1681-1689.

Halvorson, A.D., and A.L. Black. 1985. Fertilizer phosphorus recovery after seventeen years of dryland cropping. Soil Sci. Soc. Am. J. 49:933-937.

Harper, A.F., E.T. Kornegay, and T.C. Schell. 1997. Phytase supplementation of low-phosphorus growing-finishing pig diets improves performance, phosphorus digestibility, and bone mineralization and reduces phosphorus excretion. J. Anim. Sci. 75:3174-3186.

Hedley, M.J., G.J.D. Kirk, and M.B. Santos. 1994. Phosphorus efficiency and the forms of soil phosphorus utilized by upland rice cultivars. Plant Soil 158:53-62.

Hendriks, J.G.L., and J.F.M. Huijsmans. 1995. Research on measures for reducing phosphate leaching from agricultural soils. Application methods for iron hydroxide on phosphate saturated sandy soils (In Dutch). Staring Centrum Wageningen, Report no. 374.3.

Hooker, M.L., R.E. Gwin, G.M. Herron, and P. Gallagher. 1983. Effects of long-term annual applications of N and P on corn grain yields and soil chemical properties. Agron. J. 75:94-99.

Hosper, S.H. 1997. Clearing lakes: an ecosystem approach to the restoration and management of shallow lakes in the Netherlands. PhD thesis Agric. Univ. Wageningen, the Netherlands, 168 p. [*F4*,*F5*]

Johnson, H.P., J.L. Baker, W.D. Schrader, and J.M. Laflen. 1979. Tillage systems effects on sediment and nutrients in runoff from small watersheds. Trans. ASAE 22:1110-1114.

Jonasson, B. 1996. Phosphorus transformations in alum sludge amended soils. Swed. J. Agric. Res. 26:69-79.

Jongbloed, A.W., Z. Mroz, and P.A. Kemme. 1992. The effect of supplementary aspergillus-niger phytase in diets for pigs on concentration and apparent digestibility of dry- matter, total phosphorus, and phytic acid in different sections of the alimentary-tract. J. Anim. Sci. 70:1159-1168.

Kadlec, R.H. 1999. The limits of phosphorus removal in wetlands. Wetlands Ecol. Manage. 7:165-175.

Keshavarz, K., and R.E. Austic. 2004. The use of low-protein, low-phosphorus, amino acid- and phytase-supplemented diets on laying hen performance and nitrogen and phosphorus excretion. Poultry Sci. 83:75-83

Koopmans, G.F., W.J. Chardon, P.A.I. Ehlert, J. Dolfing, R.A.A. Suurs, O. Oenema, and W.H. van Riemsdijk. 2004a. Phosphorus availability for plant uptake in a phosphorus-enriched noncalcareous sandy soil. J. Environ. Qual. 33:965-975

Koopmans, G.F., W.J. Chardon, P. de Willigen, and W.H. van Riemsdijk. 2004b. Phosphorus desorption dynamics in soil and the link to a dynamic concept of bioavailability. J. Environ. Qual. 33:1393-1402.

Lane, C.T. 2002. Water treatment residuals effects on phosphorus in soils amended with dairy manure. M.S. Thesis, Univ. FL., Gainesville, FL 32611-0510.

Lantzke, I.R., D.S. Mitchell, A.D. Heritage, and K.P. Sharma. 1999. A model of factors controlling orthophosphate removal in planted vertical flow wetlands. Ecol. Eng. 12:93-105.

Lei, X.G., P.K. Ku, E.R. Miller, M.T. Yokoyama, and D.E. Ullrey. 1993a. Supplementing corn-soybean meal diets with microbial phytase linearly improves phytate phosphorus utilization in weanling pigs. J. Anim. Sci. 71:3359-3367.

Lei, X.G., P.K. Ku, E.R. Miller, M.T. Yokoyama, and D.E. Ullrey. 1993b. Supplementing corn-soybean meal diets with microbial phytase maximizes phytate phosphorus utilization in weanling pigs. J. Anim. Sci. 71:3368-3375.

Liikanen, A., M. Puustinen, J. Koskiaho, T. Väsänen, P. Martikainen, and H. Hartikainen. 2004. Phosphorus removal in a wetland constructed on former arable land. J. Environ. Qual. 33:1124-1132.

Maguire, R.O., J.T. Sims, J.M. McGrath, and C.R. Angel. 2003a. Effect of phytase and vitamin D metabolite (250H-D3) in turkey diets on phosphorus solubility in manure-amended soils. Soil Sci. 168:421-433.

Maguire, R.O., J.T. Sims, W.W. Saylor, T.J. Applegate, C.R. Angel, W.J. Powers, 2003b. Influence of phytase additon to poultry and swine diets on phosphorus forms and solubility in manures and manured soils. In Annual Meeting Abstracts [CD-ROM] ASA, CSSA, SSSA, Madison, WI USA.

Marrs, R.H. 1985. Techniques for reducing soil fertility for nature conservation purposes: a review in relation to research at Roper's Heath, Suffolk, England. Biol. Conserv. 34:307-332.

Marti, E., J. Aumatell, L. Godé, M. Poch, and F. Sabater. 2004. Nutrient retention efficiency in streams receiving inputs from wastewater treatment plants. J. Environ. Qual. 33:285-293.

McCollum, R.E. 1991. Buildup and decline in soil phosphorus: 30-year trends on a Typic Umprabuult. Agron. J. 83:77-85.

McGrath, J.M., J.T. Sims, R.O. Maguire, W.W. Saylor, and C.R. Angel. 2003a. Effect of phytase and vitamin D metabolite in poultry diets on phosphorus in broiler litter, litter amended soils, and runoff. In Annual Meeting Abstracts [CD-ROM] ASA, CSSA, SSSA, Madison, WI USA.

McGrath, J.M., J.T. Sims, R.O. Maguire, W.W. Saylor, and C.R. Angel. 2003b. Effect of dietary phytase on the forms of phosphorus in stored broiler litter. In Annual Meeting Abstracts [CD-ROM] ASA, CSSA, SSSA, Madison, WI USA.

Meissner, R., H. Rupp, and P. Leinweber. 2003. Re-wetting of fen soils and changes in water quality - experimental results and further research needs. In J. Water Land Development 2003 (7):75-91. (ISSN 1429-7426).

Miles, D.M., P.A. Moore, Jr., D.R. Smith, D.R. Rice, H.L. Stilborn, D.R. Rowe, B.D. Lott, S.L. Branton, and J.D. Simmons. 2003. Total and water-soluble phosphorus in broiler litter over three flocks with alum litter treatment and dietary inclusion of high available phosphorus corn and phytase supplementation. Poultry Sci. 82:1544-1549.

Moore, P.A., T.C. Daniel, and D.R. Edwards. 1999. Reducing phosphorus runoff and improving poultry production with alum. Poultry Sci. 78:692-698.

Moore, P.A., T.C. Daniel, and D.R. Edwards. 2000. Reducing phosphorus runoff and inhibiting ammonia loss from poultry manure with aluminum sulfate. J. Environ. Qual. 29:37-49.

Moore, P.A., Jr., T.C. Daniel, D.R. Edwards, and D.M. Miller. 1995. Effect of chemical amendments on ammonia volatilization from poultry litter. J. Environ. Qual. 24:293-300.

Moore, P.A., and D.M. Miller. 1994. Decreasing phosphorus solubility in poultry litter with aluminum, calcium, and iron amendments. J. Environ. Qual. 23:325-330.

Morrison, J.E., and F.W. Chichester. 1994. Tillage system effects on soil and plant nutrient distributions in Vertisols. J. Prod. Agric. 7:364-373.

Nichols, D.J., T.C. Daniel, and D.R. Edwards. 1994. Nutrient runoff from pasture after incorporation of poultry litter or inorganic fertilizer. Soil Sci. Soc. Am. J. 58:1224-1228.

Novak, J.M., and D.W. Watts. 2004. Increasing the phosphorus sorption capacity of southeastern coastal plain soils using water treatment residuals. Soil Sci. 169:206-214

O’Connor, G.A., H.A. Elliott, and P. Lu. 2002. Characterizing water treatment residuals phosphorus retention. Soil Crop Sci. Soc. Florida Proc. 61:67-73.

Oehl, F., A. Oberson, H.U. Tagmann, J.M. Besson, D. Dubois, P. Mader, H.R. Roth, and E. Frossard. 2002. Phosphorus budget and phosphorus availability in soils under organic and conventional farming. Nutr. Cycl. Agroecosyst. 62:25-35.

Peltovuori, T. 2002. Phosphorus extractability in surface soil samples as affected by mixing with subsoil. Agric. Food Sci. Finland 11:371-379.

Peters, J.M. 1996. Use of municipal and industrial waste amendments to reduce bioavailable phosphorus from agricultural land treated with animal manures. M.S. Thesis, Oklahoma State University, Stillwater, OK.

Peters, J.M., and N.T. Basta. 1996. Reduction of excessive bioavailable phosphorus in soils using municipal and industrial wastes. J. Environ. Qual. 25:1236-1241.

Pezzarossa, B., M. Barbafieri, A. Benetti, G. Petruzzelli, M. Mazzoncini, E. Bonari, and M. Pagliai. 1995. Effects of conventional and alternative management systems on soil phosphorus content, soil structure, and corn yield. Commun. Soil Sci. Plant Anal. 261:2869-2885.

Pierce, J.L., and G.L. Cromwell. 1999. Phytase addition to normal corn- and low phytic acid corn-soybean meal diets for chicks and pigs. J. Anim. Sci. 77(Supplement 1):175.

Pierson, S.T., M.L. Cabrera, G.K. Evanylo, H.A. Kuykendall, C.S. Hoveland, M.A. McCann, and L.T. West. 2001. Phosphorus and ammonium concentrations in surface runoff from grasslands fertilized with broiler litter. J. Environ. Qual. 30:1784-1789.

Pointillart, A. 1993. Importance of phytastes and cereal phytases in the feeding of pigs. p. 192-198. In C. Wenk and M. Boessinger (ed.) Enzymes and animal nutrition. Proc. 1st Symp., Kartause Ittingen, Switzerland. 13-16 Oct. 1993.

Pote, D.H., W.L.Kingery, G.E. Aiken, F.X. Han, P.A. Moore, Jr., and K. Buddington. 2003. Water-quality effects of incorporating poultry litter into perennial grassland soils. J. Environ. Qual. 32:2392-2398.

Pothuluri, J.V., D.A. Whitney, and D.E. Kissel. 1991. Residual value of fertilizer phosphorus in selected Kensas soils. Soil Sci. Soc. Am. J. 55:399-404.

Preedy, N., K. McTiernan, R. Matthews, L. Heathwaite, and P. Haygarth. 2001. Rapid incidental phosphorus transfers from grassland. J. Environ. Qual. 30:2105-2112.

Raboy, V., D.B. Dickinson, and M.G. Nuefer. 1990. A survey of maize kernel mutations for variation in phytic acid. Maydica 35:383-390.

Reddy, K.R., R.H. Kadlec, E. Flaig, and P.M. Gale. 1999. Phosphorus retention in streams and wetlands: A review. Crit. Rev. Environ. Sci. Technol. 29:83-146.

Rehm, G.W., G.W. Randall, A.J. Scobbie, and J.A. Vetsch. 1995. Impact of fertilizer placement and tillage system on phosphorus distribution in soil. Soil Sci. Soc. Am. J. 59:1661-1665.

Richardson, C.J. 1985. Mechanisms controlling phosphorus retention capacity in freshwater wetlands. Science (Washington, DC) 228:1424-1427.

Richardson, C.J. 1999. The role of wetlands in storage, release, and cycling of phosphorus on the landscape. p. 47-68. In K.R. Reddy et al. (ed.) Phosphorus biogeochemistry in subtropical ecosystems. Lewis Publ., New York.

Ritchey, K.D., R.B. Clark, M.A. Elrashidi, and V.C. Baligar. 1998? Examples and case studies of beneficial reuse of gypsum-like by-products. Preliminary draft, Nov. 1997 35 pp.

Ross, I.J., S. Sizemore, J.P. Bowden, and C.T. Haan. 1979. Quality of runoff from land receiving surface application and injection of liquid dairy manure. Trans. ASAE 22:1058-1062

Rydin, E., B. Huser, and E.B. Welch. 2000. Amount of phosphorus inactivated by alum treatments in Washington lakes. Limnol. Oceanogr. 45:226-230.

Sands, J.S., D. Ragland, C. Baxter, B.C. Joern, T.E. Sauber, and O. Adeola. 2001b. Phosphorus bioavailability, growth performance, and nutrient balance in pigs fed high available phosphorus corn and phytase. J. Anim. Sci. 79:2134-2142.

Schärer, M. 2003. The influence of processes controlling phosphorus availability on phosphorus losses in grassland soils. PhD thesis ETH no 15312, Zürich Switzerland, 140 p. For pdf-version click on thesis

Scheffer, B., R. Bartels, and J. Blankenburg. 1985. Possibilities of application of red mud and melanterite on peat soils (In German.) Z. Pflanzenernaehr. Bodenkd. 148:527-535.

Schoumans, O.F., and H. Köhlenberg. 1995. Research on measures for reducing phosphorus leaching from agricultural soils. Possibilities of application of aluminum and iron compounds to soils. (In Dutch.) Staring Centre Wageningen, Report no. 374.2.

Schweigert, P. 2004. Reducing emissions from intensive animal production by using aluminum compounds. (In German.) Berichte über Landwirtschaft 82:351-361.

Seta, A.K., R.L. Blevins, W.W. Frye, and B.J. Barfield. 1993. Reducing soil erosion and agricultural chemical losses with conservation tillage. J. Environ. Qual. 22:661-665.

Sharma, N.C., S. Cheepala, and S.V. Sahi. 2003. Evaluation of crops for phosphate accumulation potential. In Annual Meeting Abstracts [CD-ROM] ASA, CSSA, SSSA, Madison, WI USA.

Sharma, N.C., J.C. Jain, and S.V. Sahi. 2002. Ryegrass - Hyperaccumulator of phosphates. In Annual Meeting Abstracts [CD-ROM] ASA, CSSA, SSSA, Madison, WI USA.

Sharma, N.C., S.V. Sahi, J.C. Jain, and K.G. Raghothama. 2004. Enhanced accumulation of phosphate by Lolium multiflorum cultivars grown in phosphate-enriched medium. Environ. Sci. Technol. 38:2443-2448.

Sharpley, A.N. 1999. Agricultural phosphorus, water quality, and poultry production: Are they compatible? Poultry Sci. 78:660-673.

Sharpley, A.N. 2003. Soil mixing to decrease surface stratification of phosphorus in manured soils. J. Environ. Qual. 32:1375-1384.

Sharpley, A.N., S.C. Chapra, R. Wedepohl, J.T. Sims, T.C. Daniel, and K.R. Reddy. 1994. Managing agricultural phosphorus for protection of surface waters: Issues and options. J. Environ. Qual. 23:437-451.

Shober, A.L., J.T. Sims, F. Coale, J. White. 2003. Temporal changes in P fractionation in biosolids-amended soils: Relationships to P losses in runoff. In Annual Meeting Abstracts [CD-ROM] ASA, CSSA, SSSA, Madison, WI USA.

Shreve, B.R., P.A. Moore, Jr., T.C. Daniel, D.R. Edwards, and D.M. Miller. 1995. Reduction of phosphorus in runoff from field-applied poultry litter using chemical amendments. J. Environ. Qual. 24:106-111.

Shreve, B.R., P.A. Moore, D.M. Miller, T.C. Daniel, and D.R. Edwards. 1996. Long-term phosphorus solubility in soils receiving poultry litter treated with aluminum, calcium, and iron amendments. Commun. Soil Sci. Plant Anal. 27:2493-2510.

Sims, A.L., K.R. Hoff, and J.A. Lamb. 2002. Soil phosphorus fate after 20 years of build up and draw down in a calcareous soil. In Annual Meeting Abstracts [CD-ROM] ASA, CSSA, SSSA, Madison, WI USA.

Sims, J.T. 1997. Agricultural and environmental issues in the management of poultry wastes: recent innovations and long-term challenges. p. 72-90. In J.E. Rechcigl and H.C. MacKinnon (eds.) Agricultural Uses of by-products and wastes. American Chemical Society Symposium Series 668. American Chemical Society, Washington, D.C. 13

Sims, J.T. 2000. The role of soil testing in environmental risk assessment for phosphorus. p. 57-81. In A.N. Sharpley (ed.) Agriculture and phosphorus management. Lewis Publ., Boca Raton, FL.

Sims, J.T., and N.J. Luka-McCafferty. 2002. On-farm evaluation of aluminum sulfate (alum) as a poultry litter amendment. J. Environ. Qual. 31:2066-2073.

Sistani, K.R., G.A. Pederson, and G.E. Brink. 2002. Nutrients uptake by ryegrass cultivars and crabbgrass from a highly phosphorus enriched soil. In Annual Meeting Abstracts [CD-ROM] ASA, CSSA, SSSA, Madison, WI USA.

Smith, D.R., P.A. Moore, Jr., C.L. Griffis, T.C. Daniel, D.R. Edwards, and D.L. Boothe. 2001. Effects of alum and aluminum chloride on phosphorus runoff from swine manure. J. Environ. Qual. 30:992-998.

Smith, D.R., P.A. Moore, Jr., C.V. Maxwell, B.E. Haggard and T.C. Daniel. 2004. Reducing phosphorus runoff from swine manure with dietary phytase and aluminum chloride. J. Environ. Qual. 33:1048-1054

Smith, R.V., S.D. Lennox, and J.S. Bailey. 2003. Halting the upward trend in soluble phosphorus transported from a grassland catchment. J. Environ. Qual. 32:2334-2340.

Snow, C.S.R., and R.H. Marrs. 1996. The effect of harvesting four crops under varying fertiliser regimes on nutrient offtake and selected soil properties. Aspects of Applied Biology 44: 413-418.

Spencer, J.D., G.L. Allee, and T.E. Sauber. 2000. Phosphorus bioavailability and digestibility of normal and genetically modified low-phytate corn for pigs. J. Anim. Sci. 78:675-681.

Stout, W.L., A.N. Sharpley, and J. Landa. 2000. Effectiveness of coal combustion by-products in controlling phosphorus export from soils. J. Environ. Qual. 29:1239-1244.

Stout, W.L., A.N. Sharpley, and H.B. Pionke. 1998. Reducing soil phosphorus solubility with coal combustion by-products. J. Environ. Qual. 27:111-118.

Turtola, E., and A. Paajanen. 1995. Influence of improved subsurface drainage on phosphorus losses and nitrogen leaching from a heavy clay soil. Agric. Water Manage. 28:295-310.

Ulén, B. 2004. Soil erosion in Sweden. Book chapter in “Soil erosion in Europe”. J. Boardman and J. Poesen (ed.). Wiley & Sons Ltd, London.

Ulén, B., C. Calsson, and B. Lidberg. 2004. Recent trends and patterns of nutrient concentrations in small agricultural streams in Sweden. Environ. Mon. Assess. 98:307-322.

Ulén, B., S. Löfgren, and T. Kalisky. 2002. Constraints on successful implementation of the EU water framework directive: a case study - lake Brunnsjön in Central Sweden. Vatten 58:15-23.

Ulén, B., and L. Mattsson. 2003. Losses of different forms of phosphorus and of nitrate from a clay soil under grass and cereal production. Nutr. Cycl. Agroecosyst. 65:129-140.

Valk, H., J.A. Metcalf, and P.J.A. Withers. 1998. Prospects for minimizing phosphorus excretion in ruminants by dietary manipulation. J. Environ. Qual. 29:28-36

Veum, T.L., D.R. Ledoux, V. Raboy, and D.S. Ertl. 2001. Low-phytic acid corn improves nutrient utilization for growing pigs. J. Anim. Sci. 79:2873-2880.

Wagar, B.I., J.W.B. Stewart, and J.O. Moir. 1986. Changes with time in the form and availability of residual fertilizer phosphorus on chernozemic soils. Can. J. Soil Sci. 66:105-119.

Weil, R.R., P.W. Benedetto, L.J. Sikora, and V.A. Bandel. 1988. Influence of tillage practices on phosphorus distribution and forms in three Ultisols. Agron. J. 80:503-509.

Weill, A.N., G.R. Mehuys, and E. McKyes. 1990. Effect of tillage reduction and fertilizer type on soil properties during corn (Zea mays L.) production. Soil Tillage Res. 17:63-76.

Wienhold, B.J. and P.S. Miller. 2004. Phosphorus fractionation in manure from swine fed traditional and low-phytate corn diets. J. Environ. Qual. 33: 389-393.

Wilcox, J.R., G.S. Premachandra, K.A. Young, and V. Raboy. 2000. Isolation of high seed inorganic P, low phytate soybean mutants. Crop Sci. 40:1601-1605.

Yli-Halla, M. 1989. Effect of different rates of P fertilization on the yield and P status of the soil in two long-term field experiments. J. Agric. Sci. Finland 61:361-370.

Yli-Halla, M. 1991. Phosphorus supplying capacities of soils previously fertilized with different rates of P. J. Agric. Sci. Finland 63:75-83.

Yli-Halla, M., H. Hartikainen, and P. Väätäinen. 2002. Depletion of soil phosphorus as assessed by different indices of phosphorus supplying power. Eur. J. Soil Sci. 53:431-438.

Zhao, S.L., S.C. Gupta, D.R. Huggins, and J.F. Moncrief. 2001. Tillage and nutrient source effects on surface and subsurface water quality at corn planting. J. Environ. Qual. 30:998-1008

Zupancic, R.J. 1999. Beneficial utilization of drinking water treatment residuals as a soil substitute in land reclamation. M.S. Thesis, Oklahoma State University, Stillwater, OK.

















*

List of updates of list of options with references (dd-mm-yr).

22-08-05: ref. added to: *E5* Constructed wetlands : Dunne et al., 2005
21-09-04: refs. added to: *B1* Immobilising amendments to soil :
Scheffer et al., 1985; Schweigert 2004
21-09-04: ref. added to: *B13* Immobilising amendments to manure : Schweigert 2004
02-09-04: ref. added to *D6* Buffer / riparian zones (on field boundaries) : Blanco-Canquia et al., 2004
06-08-04: refs. added to: *E5* Constructed wetlands :
Braskerud, 2000, 2001, 2002; Kadlec, 1999; Liikanen et al., 2004
06-08-04: refs. added to: *B4* Incorporation of inorganic or organic fertilisers :
Djodjic et al., 2002; Ulén & Mattsson, 2003
06-08-04: refs. added to: *B14* Reduce rate of application and redistribution of manure :
Ulén et al., 2004
06-08-04: refs. added to: *C4* Cover cropping during winter :
Ulén et al., 2002; Ulén, 2004
06-08-04: refs. added to: *C14* Improve infiltration capacity of the soil :
Ulén et al., 2002; Ulén, 2004
24-06-04: refs. added to: *B1* Immobilising amendments to soil :
Basta, 2000; Basta et al., 1998, 1999, 2001, 2003; Dayton, 1999; Dayton & Basta, 2003; Dayton et al., 2000, 2001, 2003; DeWolfe & Basta, 2003; Friend et al., 2003; Gallimore, 1999; Peters, 1996; Zupancic, 1999
14-04-04: refs. added to: *1* Nutrient balance below 100%: Sharma et al., 2003, 2004;
10-03-04: new option added: *B16* Recycling P from manure, with link to web site
10-03-04: new option added: *B14* Reduce rate of application and redistribution of manure with refs
09-03-04: refs. added to: *A7* Use phytase to reduce feed P input: Keshavarz & Austic, 2004
09-03-04: refs. added to: *A8* Use low phytate feed: Keshavarz & Austic, 2004
08-03-04: refs. added to: *A7* Use phytase to reduce feed P input
Miles et al., 2003; Smith et al., 2003;
08-03-04: refs. added to: *A8* Use low phytate feed
Miles et al., 2003;
08-03-04: refs. added to: *B1* Immobilising amendments to soil :
Anderson et al., 1995; Basta & Storm, 1997; Codling et al., 2002; Daniels et al., 1999; Dayton et al., 2003; Elliott et al., 2002; Gallimore et al., 1999; Lane, 2002; Novak & Watts, 2004; O’Connor et al., 2002; Peters & Basta, 1996; Stout et al., 2000;
08-03-04: refs. added to: *B13* Immobilising amendments to manure :
Miles et al., 2003; Smith et al., 2001; Smith et al., 2003;