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The phosphorus cycle in northwest European agricultural soils Nutrihort September 17, 2013 Fien Amery Bart Vandecasteele Institute for Agricultural and.

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Presentation on theme: "The phosphorus cycle in northwest European agricultural soils Nutrihort September 17, 2013 Fien Amery Bart Vandecasteele Institute for Agricultural and."— Presentation transcript:

1 The phosphorus cycle in northwest European agricultural soils Nutrihort September 17, 2013 Fien Amery Bart Vandecasteele Institute for Agricultural and Fisheries Research Plant Sciences Unit Agriculture and Fisheries Policy Area

2 Phosphorus in water and soil 2 Phosphorus (P): negative effects on water ecology (eutrophication) → Water Framework Directive → Nitrate Directive Target: agricultural P application Good, but… –Impact on soil and crops? –Efficient tool? –Differences among Member States? Literature study

3 Phosphorus in surface waters 3 Water Framework Directive Goal: good ecological status/potential of water bodies Each member state: –Define ecological reference condition and classifications for each surface water type –Relate ecology to chemical/physical conditions (P concentration) –P concentration standard for each surface water type

4 Phosphorus in surface waters 4 Water Framework Directive Intercalibration exercise between member states Guidance document (not legally binding) Rivers (Claussen et al., 2012) Flanders: 0.14 mg P/l mg ortho-P/l

5 Phosphorus in surface waters 5 Water Framework Directive Lakes (Claussen et al., 2012) Flanders: mg P/l

6 Phosphorus in surface waters 6 Difficult to compare: –Type of concentration –Statistics –Water type –Time of measurement –Monitoring network Groundwater (points/1000 km²) Surface water (points/1000 km²) Belgium 9938 Germany 31 Denmark 345 France 53 Ireland 13 The Netherlands 3313 United Kingdom 1333 Finland average Source: van Grinsven et al., 2012 Thresholds are exceeded in Europe: –60% of NiD measuring points in Flanders –57% of NiD measuring points in the Netherlands → P application in agriculture is targeted

7 Phosphorus in agricultural soils 7 Phosphorus losses from soil –In general: losses increase with increasing soil P concentration –Often: exponential increase above a threshold P concentration –Important: transport and hydrological factors → Keep soil P concentration under threshold Soil P concentration yield target zone P loss

8 Phosphorus in agricultural soils 8 BUT what about crop yields? –Farmers fear smaller crop yields –However: none/small yield reductions expected at P-input < P- export given the large soil P reserves in NW Europe Soil P concentration yield target zone P loss

9 Phosphorus in agricultural soils 9 Target zone: –optimum crop yields (agro-economical) –Minimal soil P losses (ecological) –Left of target zone: P input > P export –In target zone: P input = P export (equilibrium fertilisation) –Right of target zone: P input < P export Soil P concentration yield target zone P loss

10 How to reach the target zone? Sound fertilisation advice Target zone of fertilisation advice –often > economic/ecological target zone –Wide variation in Europe Soil P concentration yield target zone P loss Source: Jordan-Meille et al., 2012

11 How to reach the target zone? Sound fertilisation advice Flanders: highest target zone for fertilisation advice + fertilisation advice for target zone soils > P export Soil P concentration yield target zone P loss CropAdvise (kg P 2 O 5 /ha/yr) a P-export (kg P 2 O 5 /ha/yr) b Chicory8143 Broccoli13012 Celeriac11067 Leek11334 Salsify10327 Spinach13116 Brussels sprouts13233 Carrots13262 Strawberry14611 a Average for the target zone according to the Bodemkundige Dienst België (Maes, 2012) b Average in the Netherlands (Ehlert et al., 2009)

12 How to reach the target zone? Sound fertilisation advice A need for updated fertilisation advice –New knowledge and methods –Advice often based on trials from 40 years ago and limited tested crops Significant effort! Example: the Netherlands (see presentation 23) In addition: farmers often apply more than the recommended dose

13 How to reach the target zone? Application standards Phosphorus application standards to limit soil P concentrations –Most countries: no P limits a First numbers: for Numbers between brackets: proposed standards from 2017 on. Standard for phosphate saturated soils: 40 kg P 2 O 5 /ha/yr; b Agricultural system: grassland or arable crops; c Standards only for organic P fertilisation Country (region)DifferentiationP fertilisation standard (kg P 2 O 5 /ha/yr) Belgium (Flanders)Crop65-95 (55-90) a The NetherlandsSoil and agricultural system b IrelandSoil and crop0-286 Sweden-50 c Slovenia-120 c France (Brittany)Type of farm

14 How to reach the target zone? Application standards Differentiation of the P application standards? –Crop differentiation (Flanders, Belgium): P limit ≈ P-export –Soil P differentiation (the Netherlands): P limit according to P soil –Soil P and crop differentiation (Ireland) Soil P concentration yield target zone P loss Soil P concentration yield target zone P loss Soil P concentration yield target zone P loss Soil P concentration yield target zone P loss Soil P concentration yield target zone P loss Soil P concentration yield target zone P loss

15 How to reach the target zone? Application standards Flanders: no crop differentiation within the vegetable group: 65 kg P 2 O 5 /ha/yr = 28 kg P/ha/yr (2017: 55 kg P 2 O 5 /ha/yr = 24 kg P/ha/yr) Ireland: standards in kg P/ha/yr

16 How to reach the target zone? Application standards Flexibility in application standards? –The Netherlands: 20 kg P 2 O 5 /ha/yr transferrable to next year –The Netherlands and Flanders: P application by compost accounts for only 50% –Not present in legislation: higher application standards when more than one crop per year is grown

17 Remarks 17 Despite attemps to reduce P fertilisation, P concentrations in water bodies remain high –Low mobility of P –Legacy P –Contribution of point sources? –Even if P concentration decreases, ecology not ameliorated Alternatives –Targeting point sources –Targeting transport, edge-of-field measures (e.g. chemical soil amendments, capturing P in wetlands or filters, etc.)

18 Conclusion 18 Large differences in Europe –P concentration standards in water bodies –Monitoring –P fertilisation advice –P application standards When targeting agricultural P application: P gift should be adapted to soil P concentration and crop demand –Sound fertilisation advice –Differentiated application standards Soil P concentration yield target zone P loss

19 Thanks for your attention! Institute for Agricultural and Fisheries Research Plant Sciences Unit Agriculture and Fisheries Policy Area Fien Amery Bart Vandecasteele Nutrihort September P P P P P P P


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