and potential for future research -Perspectives from Norway Marianne Bechmann Svein Skøien Bioforsk Jord og miljø

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1 Today s knowledge and potential for future research -Perspectives from Norway Anne Falk Øgaard Marianne Bechmann Svein Skøien Bioforsk Jord og miljø

2 Eutrophic lake in a complex agricultural landscape - How do we reduce P loads to the lake most efficiently?

3 P loss processes Source Transport Sink..... After Sharpley et al. 2001

4 Soil erosion the main focus in Norway

5 Maps of erosion risk -derived from soil maps

6 Soil erosion effect of reduced d soil tillage Results from lysimeter experiments

7 Effect of reduced tillage in autumn on soil loss Middel årlig jordtap for 5 forsøksfelter Høstpløying Ikke pløying Bjørnebekk Askim Hellerud Øsaker Syverud Jordtap kg/daa Clay soils on all sites Slope 10-13% Knowledge gaps: - Effect of reduced tillage on areas with low erosion risk - Effect of reduced tillage on subsurface runoff Helge Lundekvam

8 Tillage winter wheat Plot 2: Harrowing before seeding SS-kons: 1110 mg/l Plot 3: Direct drilling SS-kons: 5 mg/l Plot 4: Ploughing before seeding SS-kons: 5820 mg/l Surface runoff

9 Erosion risk at different tillage Autumn ploughing 1,00 Autumn harrowing 0,50 Spring ploughing (No autumn tillage) 0,14 Grass 0,05

runoff SS S (kg/daa), TP (g/daa) 300 250 200 150 100 50 0 SS TP Avrenning 500 450 400 350 300 250 200 150 100 50 0

10 From plot scale to catchment scale Mørdre catchment (JOVA catchment): Increased area with no autumn tillage from 1990 to 2009 But still increased particle and phosphorus concentration in the stream Climate change increased runoff SS S (kg/daa), TP (g/daa) SS TP Avrenning Avrenning (mm) 91/92 92/93 93/94 94/95 95/96 96/97 97/98 98/99 99/00 00/01 01/02 02/03 03/04 04/05 05/06 06/07 07/08 08/09

11 Connectivity it Sedimentation of eroded soil before it reaches watercourses? Distance to watercourses and landscape shapes

12 Improved soil structure reduced erosion risk Average yearly soil and P loss in surface runoff Askim Slope 13% Clay 29% Syverud Slope 13% Clay 23% Soil Suspended Phosphorus aggregate solids stability kg/ha kg/ha Low ,4 High 131 0,39 H. Lundekvam

13 Erosion in streams Algal availability of P in subsoil?

14 Soil and P losses also through tile drains Kværnø og Bechmann (2010)

15 P fertilization and soil P status P-AL 24 /L) To otal P (µg P-AL Suspended solids (mg/l) Marianne Bechmann

16 Particle bound P not always particle bound Clay soil, Ås Sandy soil, Råde (mg/100g) P AL 3,5 P AL 4,9 P AL 8,7 P AL 13 (mg/100 g) P AL 6,3 P AL 9,2 P AL 24 P AL 38 CaCl2 P 4 2 CaCl2 P solution:soil solution:soil

17 Critical soil test P value for P loss? 20 Silty clay loam P-Ca acl2 (mg P/kg) P-AL (mg/100g) Tore Krogstad

total P in cultivated soil potential available

inorganic P Organic P was not readily available

18 Particle bound P available for algae? Biotests (Krogstad & Løvstad, 1991): % of total P in cultivated soil potential available for blue-green algae; dependent of the part of inorganic P Organic P was not readily available for algae Chemical test (Krogstad & Løvstad, 1991): Total Reactive P (TRP) in soil suspensions otal eact ve ( ) so l suspe s o s P available to blue-green algae

19 Algal available P related to P-AL Algal available P (TRP) as a function of P-AL TRP (mg/kg g) TRP = 1.63 P-AL R 2 = P-AL (mg/kg) Tore Krogstad

20 P distribution on particle-size fractions Particles <20 µm would stay suspended long enough to be a potential ti source of P to algae (Huettl et al. 1979) Increasing P concentration with decreasing particle size Sandy soil Clay soil P AL 23,5 P AL 28 mg P/kg mg P/kg Whole soil < 20 µm < 2 µm Rikard Pedersen 2008 A large part of excess P fertilization is found in the clay fraction (Øgaard 1996)

21 Reduced P fertilization in the catchment of western Vansjø Average for 75 % of the fields kg P/ha ,8 4,4 Effects of reduced P fertilization on P runoff?

22 TP/SS relationship in streams

23 Small constructed wetlands for P retention

24 Effect of constructed wetlands Braskerud (2001): Retention of soil particles: 45-75% Retention of total P: 21 44% Retention of dissolved P: Low Tore Krogstad

25 Maintenance of constructed wetlands important Årlig retensjon n (%) Av renning (m mm) TP SS Avrenning (mm)

26 Filtralite P filter at the end of constructed wetlands Filtraliteli P (0,5-4 mm): Expanded d clay aggregates with lime Cost of Filtralite P: per m 3 Wetland Filter Outlet

27 P retention in the filter - one year after establishment t P/l TP µg Before filter After filter Data from E. Hougsrud 2009 But: Only 0.2 l/s through the filter

28 Required characteristics ti for filters for agricultural runoff High hydraulic conductivity High adsorption capacity and short reaction time Flocculation of clay particles

29 Grassed buffer zones Where are grassed buffer zones efficient? - topography -soil type - soil tillage If the grass is not cut; release of dissolved d P during winter/spring

30 Grassed buffer zones % TP og SS fjern net i veg getasjon nsone TP - 5m Grorud TP - SS - 10m 5m SS - 10m Mørdre SS - TP - 5m 5m Summer Winter N. Syversen

31 Release of P from different plant species after winter frost Ongoing research: 18-42% av total P released last winter, depending on plant species

32 Application of manure Injection techniques for manure application influence on risk for P losses?

33 Identify high-risk areas Calculator for P-index

34 P runoff from forests?

35 Thank you for the attention!

Phosphorus Risk Assessment Index Evaluation Using Runoff Measurements

Volume 8, Number 1 Phosphorus Risk Assessment Index Evaluation Using Runoff Measurements Bahman Eghball and John E. Gilley USDA-ARS, Lincoln, NE Introduction Manure and composted manure are valuable and