Presentation on theme: "Benefits and risks of applying compost to European soils"— Presentation transcript:
1Benefits and risks of applying compost to European soils Luca Montanarella
2Status of Soil Organic Carbon in European soils: Spatial data layer of estimated OC contents in the surface horizon of soils in Europe (30cm), 1km grid size.
3Soil Organic Carbon dynamics Hypothetical carbon stock build-up by LULUCF measuresActual terrestrial carbon stockMax. potential carbon stock achievable through LULUCF measuresMax. potential carbon stock at climaxTerrestrial organic carbon poolTerrestrial carbon stock depletion by historical human induced LULUCF activitiestimeCa. 60,000 B.C. to A.D Last “green” revolution present future
4Monitoring SOM on Broadbalk, Rothamsted %OCFYMFYM since 1885FYM since1968NPKNo fertilisers or manuresFYM applied at 35 t ha-1 yr-1Goulding
5Soil specific carbon sequestration potential tCMax tCPotential Carbon Sequestration, PCSCarbon Sequestration Rate, CSRMax & Min tC are soil specificActual tCPotential Carbon loss, PCL (Risk assessment)Carbon Loss Rate, CLRMin tCYears
6Change in organic carbon content of topsoils in England and Wales SOC content is depending on humidity, temperature, soil type and land useExample:Change in organic carbon content of topsoils in England and Wales[after Loveland, NSRI, Cranfield University, Silsoe]
7Carbon losses from all soils across England and Wales 1978-2003 (Bellamy et al., Nature Sep 2005, based on ca samples, 0-15cm)Bellamy et al. estimate annual losses of 13 million tonnes of carbon. This is equivalent to 8% of the UK emissions of carbon dioxide in 1990, and is as much as the entire UK reduction in CO2 emissions achieved between 1990 and 2002 (12.7 million tonnes of carbon per year).
8Total biowaste and green waste arising in the European Union (1,000 t/y) CountryMunicipal solid waste productionBiowaste actually collectedGreenwaste actually collectedBiowaste potentially collectableGreenwaste potentially collectableAustria4 110880(*) 5808501 2201 020Belgium-Flanders(***) 4 781330390900Belgium-Wallonia120160Germany48 71512 00014 000Denmark2 78728049050550France21 10074.7860.69 0065 900Finland2 100100600Spain14 296(**) 60/6 600Greece4 2001 800Italy27 000(****) 1 1009 000Ireland1 848440Luxembourg2993060Netherlands8 4801 5008002 5001 000Portugal3 600101 300Sweden3 998130150970530United Kingdom28 989398603 200European Union54 806J. Barth, An estimation of European compost production, sources, quantities and use, EU Compost Workshop “Steps towards a European Compost Directive”, Vienna, 2-3 November 1999.Modified for France by I. Feix. Data from Germany are from the report Bundesgütegemeinschaft Kompost: Verzeichnis der Kompostierungs- und Vergärungsanlagen in Deutschland, 2003.(*) Biowaste of industrial origin; (**) Catalonia; (***) Belgium total; (****) Italy: CIC and Italian Environmental Agency data for 2002.
9Soil organic matter Origin Turnover Complexity Corg CO2 Decomposing fresh OM(Particulate organic matter)MicroorganismsColloidal OMPolysaccharides and biomoleculesHumic substancessoluble OM-OHCO2Corg
11Potential measures for cropland Freibauer et al. 2003
12Potential soil C sequestration rate MeasurePotential soil C sequestration rate(t CO2.ha-1.y-1)Estimated uncertainty (%)Ref. / notesLimiting factorSoil sequestration potential (106 CO2.y-1) given limitationAnimal manure1.38> 50%1Manure available = t dm.y-186.834Crop residues2.54Surplus straw = t dm.y-190.465Sewage sludge0.951, 2Sewage sludge available in the mid-time (2005) = t dm.y-16.306Composting1.38 or higher>> 50%3, 2Potential production of composted materials present in MSW = 13 to t dm.y-1. Figures include processing of biowaste from agro-industrial by-products, but neither manure, nor crop residues.117-1. Smith et al. (2000); per hectare values calculated using the average C content of arable top soils (to 30 cm) of 53 t C.ha-1; Vleeshouwers and Verhageb (2002), cf. table 5.-2. The sequestration values are based on a load rate of 1 t ha-1.y-1, which was the lowest safe limit in place (in Sweden) at the time of analysis for this figure (1997). A higher loading rate would give a higher sequestration rate per area. As the limiting factor for the application of compost is the amount of producible compost, a higher loading rate on a certain area would imply that a more limited area could be treated.-3. Assumed to be the same as animal manure figure of Smith et al. (2000).-4. Total figure for EU15 calculated from figures in Smith et al. (2000). Total amount of manure available from Smith et al. (1997).-5. Total figure for EU15 calculated from figures in Smith et al. (2000). Total amount of surplus cereal straw available from Smith et al. (1997).
13European Climate Change Programme ECCP 2000-2001 Total carbon sequestration potential of measures for increasing soil carbon stocks in agricultural soils for Europe (EU15) and limiting factors.
14Comparative rates and loads of Cu inputs into French soils Land surface (%UAA)Mean level of Cu (mg.kg-1 dm)Cu rates(kg.ha-1.y-1)Cu annual loads (t.y-1) over FranceUrban sewage sludge1 to 4%3340.668165MSW compost0.1%164.40.82247Biodegradable wastesGreenwaste compost0.2%50.80.25414Households biowaste compost0.02%87.80.4391Animal effluents20-25%Ex.: 52 cattle; 730 pigs0.7 cattle; 2.3 pigs4 460 (all an. effl.)Agricultural practicesP fertilisers80-90%/0.004102Cu fungicides~3% (vineyards & arboriculture)0.8 to 14752 toAtmospheric depositions100%0.006 to 0.015185 to 462TWG Organic Matter
17ConclusionsSoil Organic carbon levels in Europe are low and are constantly declining.There is the urgent need to reverse this negative trendCompost and bio-waste could provide a valuable source of organic matter for European soils.Long-term fate of the exogenous organic material in soils needs to be taken into account, depending on the pedo-climatic local conditions.Potential contamination of bulk organic materials, like compost, sludges and other bio-wastes is a potential threat to human healthCareful application of QA/QC and of the precautionary principle is a pre-requisite for increased acceptance of these materials as soil improvers.