The P losses from agriculture are controlled by natural characteristics, agricultural practices and national and international agricultural as well as agri-environmental policies. To reduce the P losses the measures should be targeted at the areas and activities that are responsible for the highest actual losses of bioavailable P. The response of an aquatic ecosystem to agricultural activities is a result of complex interactions between physical, chemical and biological processes

Ekholm, Petri

English

Management of phosphorus: management actions have to be environmentally sustainable, economically viable, technologically feasible, socially desirable (or at least tolerable), legally permissible, administratively achievable and politically expedient (Ducrotoy & Elliott, 2008)

Organic Eprints

Agricultural phosphorus losses and eutrophication in Nordic-Baltic countriesPetri EkholmFinnish Environment Institute(SYKE)NJF 401: Phosphorus management in Nordic-Baltic agriculture - reconciling productivity and environmental protectionPhotos: Petri Ekholm, Seppo Knuuttila, Jouni Lehtoranta/SYKEEcological status of surface waterin Finlandwww.environment.fiHas P a role in aquatic eutrophication? P controls the growth of phytoplankton in many lakes and estuaries P triggers the blooms of blue-green algae Both oligotrophic and eutrophic lakes may show N limitation of phytoplankton growth There are differences among phytoplankton species (e.g. Si limitation of diatoms) Aquatic rooted vegetation may be N-limited Complex ecosystem effectsPhillips G, Pietiläinen OP, Carvalho L, Solimini A, Lyche Solheim A, Cardoso AC. 2008. Chlorophyll–nutrient relationships of different lake types using a large European dataset. Aquat Ecol 42:213−226.Graph: Kiirikki (2002)Phosphate in the surface water in winterAnthropogenic P load to the Baltic Sea in 2000 (t yr–1)Map: Seppo Knuuttila, SYKE, HELCOM≈ 50% of the P flux (incl. natural background) originates from diffuses sourcesIn Nordic-Baltic countries there are differences inAgriculture P use• Baltic countries Animal density• Large P surpluses associated with livestock production Set-aside Special features• 90% watercourses widened or canalized in Denmark• Land levelling in Norway Regulation/incent-ves/advice…Nature Climate• Temperature• Crop yield• Rain/snow• Frost• Precipitation Hydrology/transport pathway• Runoff: 100–1300 mm• Denmark: subsurface losses important• Finland: surface runoff and erosion important• Streambank erosion• Ground water flow Soil typeIES, EU/JRC, Land Management & Natural Hazards UnitChange in use of agricultural land in the catchment of the Gulf of Finland in 1989–2004RUSSIAFINLANDLATVIAESTONIALITHUANIA BELORUSSIAabandoned landother landrecultivated landPiirimäe K, Ekholm P, Porvari M. 2007. Application of a catchment model in predicting changes in agricultural nutrient load. Pitkänen H, Tallberg P. (eds.). Searching efficient protection strategies for the eutrophied Gulf of Finland: the integrated use of experimental and modelling tools (SEGUE). Finnish Environment 15/2007.FAOSTATAgricultural land in Nordic-Baltic countriesProportion in total land area010203040506070DenmarkFinlandNorwaySwedenEstoniaLatviaLithuania% Area010,00020,00030,00040,000DenmarkFinlandNorwaySwedenEstoniaLatviaLithuaniakm2The proportion of arable land in total area in the Nordic countries 18.8% (USA 18%)Use of P in fertilizersFAOSTAT, Nordic Statistical Yearbook, Heckrath et al. (2007)051015202530DenmarkFinlandNorwaySwedenEstoniaLatviaLithuaniakg ha–1Accumulation of P in soil kg ha–1Denmark 1400Finland 1000Sweden 600−700FAOSTAT, Nordic Statistical Yearbook 2007Cattle0.00.51.01.52.0DenmarkFinlandNorwaySwedenEstoniaLatviaLithuania106 Pigs051015DenmarkFinlandNorwaySwedenEstoniaLatviaLithuania106Chicken051015DenmarkFinlandNorwaySwedenEstoniaLatviaLithuania106Estimation of agricultural P loss to waters Monitoring of water flow and P concentration in agricultural catchments Manual sampling -> automatic sampling -> on-line sensors• (Especially older) estimates are more or less uncertain  Source apportionment methods vary• Natural background loss? Extrapolation to a regional and national scale?00.511.522.50 2 4 6 8 10 12 14 16P loss kg ha–1 yr–1Loss of P from arable land in Nordic countriesSvendsen LM, Kronvang B (1991), Rekolainen et al. (1997), Vagstad et al. (2000, 2001), Ulén et al. (2007), Heckrath et al. (2008)DenmarkFinlandNorway SwedenBaltic countries:0.1–5.4 kg ha–1 yr–1Phosphorus losses in Nordic-Baltic countries 35 catchments (<30 km2) in• Denmark, Estonia, Finland, Latvia, Lithuania, Norway, Sweden • Proportion of agricultural land usually >50%• Years 1993−1997 P losses ranged from 0.1 to 4.7 kg ha–1 yr–1• The highest loss in Norway• A catchment with organic soils, relatively high animal density and high runoff• Generally high in Norway and Finland• Hilly erosion-prone areas in Norway• Clayey soils in Finland• Lowest in Estonia and Sweden• Variation within a countryVagstad et al. (2001). Nutrient losses from agriculture in the Nordic and Baltic countries. Tema Nord  591, Kronvang et al. (2007)Concentrations of P and suspended solids in runoff from the 35 catchmentsData from: Vagstad et al. (2001). Nutrient losses from agriculture in the Nordic and Baltic countries. Tema Nord 59100.20.40.60.810 200 400 600 800 1000Suspended solids, mg l–1Total phosphorus, mg l–1NorwayDenmarkSwedenFinland00.20.40.60.810 0.2 0.4 0.6 0.8 1Total P, mg l–1Dissolved reactive P, mg l–1NorwayDenmarkSwedenFinlandLithuaniaTrend in P balance and soil test P in Finland1961-19651966-19701971-19751976-19801981-19851986-19901991-19951996-2000 0246810121416Maan P-luku, mg/lUusitalo R, Turtola E, Grönroos J, Kivistö J, Mäntylahti V, Turtola A, Lemola R, Salo T. 2007. Finnish trends in phosphorus balances and soil test phosphorus. Agricultural and food science 16:301-316.198519881990199319951998200020032005051015202530354045Fosforin lisäysSadon mukana korjattuLisätty fosfori ja sadon mukanapellosta korjattu fosfori, kg/haP inputP outputSoil test Pkg ha–1 mg l–1• Soil test P is often at a level at which annual P fertilization no more gives clear yield responses• Farms specialized in non-cereal plant production and animal production have highest soil test P• An imbalance in P cycling between plant (feed) and animal productionDissolved reactive P in runoff correlates with soil test P1 10 100 10000.0010.010.1110Maan helppoliukoinen fosfori, mg/l maataValumaveteen liuennutfosfori, mg/lDissolvedreactive PSoil-test P, mg l–1 mg l–1 Uusitalo R, Turtola E, Grönroos J, Kivistö J., Mäntylahti V, Turtola A., Lemola R, Salo T. 2007. Finnish trends in phosphorus balances and soil test phosphorus. Agricultural and food science 16:301-316.Soil test P is lowered most on reducing P surpluses in plots that have a high soil test P Phosphorus balances in OECD countries around the Baltic Sea0510152025DenmarkFinlandIcelandNorwaySwedenPolandGermanyP surplus kg ha–11990-19922002-2004OECD1. There is a decreasing trend in the use of P in all Nordic-Baltic countries2. There has been a tendency to stricter regulation-> The P load from agriculture should go down Valtiontalouden tarkastusvirastontoiminnantarkastuskertomus 175/2008Proportion of fields under agri-environmental programmeFinlandSwedenDenmarkTotal PDissolved PSuspended solidsRunoffNo clear decrease in agricultural P losses in FinlandEkholm P, Granlund K, Kauppila P, Mitikka S, Niemi J, Rankinen K, Räike A, Räsänen J. 2007. Influence of EU policy on agricultural nutrient losses and the state of receiving waters in Finland. Agricultural and Food Science 16: 282–300.National Audit Office of FinlandReleased a report in September 2008 on the inefficiency of the Finnish agri-environmental programmeManagement of PManagement actions have to be environmentally sustainable, economically viable, technologically feasible, socially desirable (or at least tolerable), legally permissible, administratively achievable and politically expedient (Ducrotoy & Elliott, 2008)Ducrotoy JP & Elliott M. 2008. The science and management of the North Sea and the Baltic Sea. Natural history, present threats and future challenges. Marine Pollution Bulletin 57:8–21.Complex interactions among farmers, administrators, economics, natural characteristics …P loss from different agricultural activities P that enters a body of waterRetentionP that is in a form that it can be potentially utilized by aquatic primary producers”Burial”Complex interactions(P, N, Si, Fe, SO4, C…)

Agricultural phosphorus losses and eutrophication in Nordic-Baltic countries

www.njf.nuNJF seminar 401 Phosphorus managementin Nordic-Baltic agriculture –reconciling productivityand environmental protectionUppsala, Sweden - 22-23 September 2008NJF Report Volume 4, No 4 • 2008pp _ pNJF Report • Vol 4 • Nr 4 • Year 2008 Agricultural phosphorus losses and eutrophication in Nordic- Baltic countries  Petri Ekholm Finnish Environment Institute, P.O. Box 140, FIN-00251 Helsinki petri.ekholm@environment.fi   Introduction Although nutrient losses from point sources, such as municipalities, to surface waters have been strongly reduced in most Nordic-Baltic countries, there are still severe eutrophication problems in the area (http://www.eea.europa.eu/). Presently, agriculture is the major anthropogenic P source in Denmark, Finland, Norway and Sweden (Heckrath et al., 2007). In Estonia and Latvia, most of the P losses also originate from diffuse sources; only in Lithuania do point sources still form the largest P input to waters (HELCOM, 2005; S. Knuuttila, pers. comm.). Below agricultural P losses in the Nordic-Baltic countries are briefly examined.   Agriculture in the Nordic-Baltic countries There is a wide variation in temperature, precipitation and soil types in the Nordic-Baltic countries (Rekolainen et al., 1997). Such differences in natural characteristics regulate average yields and agricultural production as well as P losses and their transport pathways in this region (Heckrath et al., 2007).  The area of agricultural land totals 145,150 km2 in the Nordic-Baltic countries (excl. Iceland, http://faostat.fao.org). The proportion of arable land is lowest (3%) in Norway and highest (60%) in Denmark. Denmark also has by far the highest stocks of pigs and poultry (in absolute numbers and per hectare of agricultural land).   The use of P in fertilizers has declined in all the countries and the P balances have been reduced by up to 60% between 1990–1992 and 2002–2004 (http://www.oecd.org). The present-day use of P ranges from about 4 kg ha–1 yr–1 in some Baltic countries to about 13 kg ha–1 yr–1 in Norway. Note that the use of P fertilizers, along with the entire agricultural sector, declined drastically in the Baltic countries after the collapse of the Soviet Union. 20 An array of national voluntary or compulsory programmes aim to control agricultural P losses in the area (e.g. Heckrath et al., 2007). In addition, the countries have to adhere to several international agreements and pieces of legislation focusing directly or indirectly on agricultural nutrient loading (EEC 1991, 1992; EC 2000, 2008; HELCOM, 2008).  Phosphorus losses from agriculture in the Nordic-Baltic countries Estimation of agricultural P losses is based on the monitoring of runoff quantity and quality in representative catchments. There is a tendency towards the use of automatic sampling devices and on-line sensors over traditional, more or less infrequent, manual sampling. Especially older estimates of P losses tend to be uncertain as flow peaks may have been missed. In addition, the quantification of the natural background leaching levels and the contribution of different sources in general is problematic; currently there are no harmonized principles for quantifying diffuse losses at catchment scale. Finally, extrapolation of results obtained at a scale of a few square kilometres of the experimental catchments to a national scale is challenging; usually there are not enough data on all typical combinations of soil type, slope, agricultural practices, etc. (see Rekolainen & Leek, 1996).  Compilations of P losses suggest that the losses are highest in Finland and Norway and lowest in Denmark and Sweden (Svendsen & Kronvang, 1991; Rekolainen et al., 1997; Ulén et al., 2007; Heckrath et al., 2007). Vagstad et al. (2001) found that the P losses in 35 Nordic-Baltic agricultural catchments (<30 km2) ranged from 0.1 to 4.7 kg ha–1 yr–1 in 1993−1997. High P losses were often associated with soil erosion, in which case the bulk of P was present in a particulate form. Thus, the P losses were highest in hilly, erosion-prone areas in Norway and on clayey soils in Finland. In turn, the losses were lowest in Estonia and Sweden. Yet, there was also a lot of variation within countries.  In Denmark subsurface losses and stream bank erosion appear to be important, whereas in Finland P is detached in a particulate form from soil surface and transported largely via surface runoff (Heckrath et al., 2007). There is no uniform information on the availability of particulate P in the Nordic-Baltic countries (Rekolainen et al., 1997), which makes it difficult to estimate the effect of erosion control measures on eutrophication.     21As the use of P has generally decreased and farmers have adopted more environmentally friendly cultivation practices in the Nordic-Baltic region (Heckrath et al., 2007), one might anticipate that the agricultural P losses would decline in these countries. Although some decreasing trends have been found, the large nutrient reserves accumulated in the soil appear to slow down the desired development. In addition, fluctuating weather/hydrology easily hide the effect of agri-enviromental measures (Vagstad et al., 2004; Kronvang et al., 2005; Bechmann & Stålnacke, 2005; Kyllmar et al., 2006; Ulén & Fölster, 2007). Finally, a reversal of eutrophication has only rarely been documented (Bechmann et al., 2005; Kronvang et al., 2005).  Finnish trends in P losses Of the EU member states, Finland has the highest share (> 90%) of farms under the agri-environmental programme. Although farmers have been subsidized from 1995 for performing environmentally friendly practices, no clear decrease in nutrient losses, or eutrophication, has been detected (Ekholm et al., 2007).  The failure to reduce nutrient losses has been a topic of political discussions in the country (Anon., 2008). There are several reasons for the low response (Turtola, 2007). For example, the measures have not been targeted at high-risk areas, the area of actively cultivated land has increased and the recent climate may have promoted e.g. erosion. Moreover, although the use of fertilizer P has been strongly reduced, the soil test P values have begun to decrease only recently (Uusitalo et al., 2007). Currently, soil test P is often at a level at which annual P fertilization no more gives clear yield responses. Farms specialized in non-cereal plant production and in animal production tend to have the highest soil test P. In Finland, as in many other counties, there is an exacerbating imbalance in P cycling between plant (feed) and animal production (Uusitalo et al., 2007). The soil test P values correlate with the concentration of dissolved reactive P in runoff (Uusitalo et al., 2007). The superfluous use of P should thus be minimized to reduce the losses of plant available dissolved P.    Conclusions The P losses from agriculture are controlled by natural characteristics, agricultural practices and national and international agricultural as well as agri-environmental policies. To reduce the P losses the measures should be targeted at the areas and activities that are responsible for the highest actual losses of bioavailable P. The   22response of an aquatic ecosystem to agricultural activities is a result of complex interactions between physical, chemical and biological processes. The P losses and their mitigation have traditionally been examined in the context of terrestrial and agricultural sciences; there appears to be little interdisciplinary research between terrestrial and aquatic sciences. Perhaps the lower than anticipated response found in many water bodies is partly due to the fact that we still do not understand all the relevant processes related to eutrophication caused by agriculture.      References Anon., 2008. Maatalouden ravinnepäästöjen vähentäminen. Valtiontalouden tarkastusviraston toiminnantarkastuskertomus 175/2008. Bechmann, M., Stålnacke, P., 2005. Effect of policy-induced measures on suspended sediments and total phosphorus concentrations from three Norwegian agricultural catchments. Sci. Total Environ. 344, 129-142. Bechmann, M., Berge, D., Eggestad, H.O., Vandsemb, S., 2005. Phosphorus transfer from agricultural areas and its impact on the eutrophication of lakes - two long-term integrated studies from Norway. J. Hydrol. 304, 238–250. EC, 2000. Directive 2000/60/EC of the European Parliament and of the Council of 23 October 2000 establishing a framework for Community action in the field of water policy. Off. J. Eur. Commun. L 327, 1–73. EC, 2008. Directive 2008/56/EC of the European Parliament and of the Council of 17 June 2008 establishing a framework for community action in the field of marine environmental policy (Marine Strategy Framework Directive). Off. J. Eur. Commun. L 164, 19–40. EEC, 1991. Council Directive 91/676/EEC of 12 December 1991 concerning the protection of waters against pollution caused by nitrates from agricultural sources. Off. J. Eur. Commun. L 375, 1–8. EEC, 1992. Council Regulation (EEC) No 2078/92 of 30 June 1992 on agricultural production methods compatible with the requirements of the protection of the environment and the maintenance of the countryside. Off. J. Eur. Commun. L 215, 85-90. Ekholm, P., Granlund, K., Kauppila, P., Mitikka, S., Niemi, J., Rankinen, K., Räike, A., Räsänen J., 2007. Influence of EU policy on agricultural nutrient losses and the state of receiving waters in Finland. Agric. Food Sci. 16, 282–300. Heckrath, G., Bechmann, M., Ekholm, P., Ulén, B., Djodjic, F., Andersen, H.E., 2007. Review of indexing tools for identifying high risk areas of phosphorus loss in Nordic catchments. J. Hydrol. 349, 68–87.   23HELCOM, 2005. Nutrient Pollution to the Baltic Sea in 2000. Baltic Sea Environment Proceedings 100. http://www.helcom.fi/stc/files/Publications/Proceedings/bsep100.pdf HELCOM, 2008. HELCOM Baltic Sea Action Plan. http://www.helcom.fi/BSAP/en_GB/intro/ Kronvang, B., Jeppesen, E., Conley, D.J., Søndergaard, M., Larsen, S.E., Ovesen, N.B., Carstensen, J., 2005. Nutrient pressures and ecological responses to nutrient loading reductions in Danish streams, lakes and coastal waters. J. Hydrol. 304, 274-288. Kyllmar, K., Carlsson, C., Gustafson, A., Ulén, B., Johnsson, H., 2006. Nutrient discharge from small agricultural catchments in Sweden – characterisation and trends. Agr. Ecosyst. Environ. 115, 15-26. Rekolainen, S., Leek, R., 1996. Regionalisation of erosion and nitrate losses from agricultural land in Nordic countries. TemaNord 1996:615. Rekolainen, S., Ekholm, P., Ulén, B., Gustafson, A., 1997. Phosphorus losses from agriculture to surface waters in the Nordic countries. In: Tunney, H., Carton, O.T., Brookes, P.C., Johnston, A.E. (Eds.), Phosphorus loss from soil to water. CAB International, pp. 77–93. Svendsen, L.M., Kronvagn, B., (Eds.), 1991. Fosfor i Norden - metoder, biotilgængelighed, effekter og tiltag. Nord 1991:47.* Turtola, E., 2007. Preface. Agric. Food Sci. 16, 279–281. Ulén, B., Fölster, J., 2007. Recent trends in nutrient concentrations in Swedish agricultural rivers. Sci. Total Environ. 373: 473-487. Ulén, B., Bechmann, M., Fölster, J., Jarvie, H.P., Tunney, H., 2007. Agriculture as a phosphorus source for eutrophication in the north-west European countries, Norway, Sweden, United Kingdom and Ireland: a review. Soil Use Manage. 23 (Suppl. 1), 5–15. Uusitalo, R., Turtola, E., Grönroos, J., Kivistö, J., Mäntylahti, V., Turtola, A., Lemola, R., Salo, T., 2007. Finnish trends in phosphorus balances and soil test phosphorus. Agric. Food Sci. 16, 301-316. Vagstad, N., Stålnacke, P., Andersen, H.E., Deelstra, J., Gustavson, A., Iital, A., Jansons, V., Kyllmar, K., Loigu, E., Rekolainen, S., Vuorenmaa, J., 2001. Nutrient losses from agriculture in the Nordic and Baltic region. Tema Nord 2001:591. Vagstad, N., Stålnacke, P., Andersen, H.E., Deelstra, J., Jansons, V., Kyllmar, K., Loigu, E., Rekolainen, S., Tumas, R., 2004. Regional variations in diffuse nitrogen losses from agriculture in the Nordic and Baltic regions. Hydrol. Earth Syst. Sc. 8, 651-662.   24

Agricultural phosphorus losses and eutrophication in Nordic-Baltic countries

Abstract

Similar works

Full text

Available Versions

Organic Eprints

Organic Eprints