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Appendix SP0538 Climate change and soil function Appendix 1 Specific findings from reviewed research projects 1.1 Specific findings from Defra research projects CC0242 developed a modelling tool for estimating changes in soil carbon stocks due to changes in land use and management for the National Carbon Dioxide Inventory, although the system was also applied to possible climate impacts using UKCIP02 and HadCM3 scenario data. This showed that, assuming constant residue inputs from vegetation, increased temperatures would lead to considerable losses of soil carbon, which were generally more marked in the South and East of England since temperature increases were predicted to be greatest in this region. CC0333 looked at the timescales of potential farm-level responses and adaptation to climate change in England and Wales. The majority of crops investigated showed an increase in yield under climate change, which would potentially mean increased crop residue inputs to agricultural soils. It was generally concluded that radical adaptations to climate change would not be necessary. The main exception was winter oilseed rape which showed yield declines in Southern and Eastern England. Unirrigated root crops showed small yield increases or decreases on light soils or in Southern England. Warmer conditions increased the availability of grass on farms in spring, although grazing yields declined in summer on farms on light land in the South and East. Grain maize generally gave low yields; yields of sunflower were improved under climate change, which became competitive with oilseed rape in East Anglia. On arable farms, there were generally less available work days in spring and autumn, although western locations had increased autumn workdays. Dry summers in the South and East meant it could become more profitable to increase irrigation of root crops, and could lead to reduced livestock production (with a small move from livestock production to arable). Increased irrigation demands could have implications for regional water management policies. Wetter springs and drier summers could lead to an earlier end to autumn field work, and have implications for grassland management and control of herbicide-resistant weeds. The main adaptations needed would include maximising machinery efficiency, increasing the areas of spring barley or setaside where winter root crop establishment could become limiting, and improved shepherding on hill farms to minimize damage to upland pastures. CC0336 assessed drought risks for UK crops under future climate change. Increased soil moisture deficit (because of increased evapotranspiration) for winter wheat was predicted, especially on shallow soils but despite this 15-23% yield increases by the 2050s could be expected due increases in radiation use efficiency because of elevated CO2 concentrations. Similarly for sugar beet, increases of up to 10% in drought stress could be expected especially on sandy and shallow soils, but the CO2 effect still led to increased yields. However, sowing dates could affect achievable yields because of wet springs which could lead to late sowing and large yield reductions. 1 Appendix SP0538 Climate change and soil function CC0337 developed regional climate change impact studies for East Anglia and Northwest England, covering several sectors. The impact of climate change depended upon the region and climate scenario considered. Under the ‘regional enterprise’ scenario in East Anglia, a reduced area of land was available for agriculture due to increased flooding risks and urban area, although there was an increase in crop production from sugar beet and potatoes which needed greater irrigation. There was also increased specialisation in cereal and root crops. Changes in coastal grazing marsh and freshwater habitats could occur depending on management and abandonment. Decreased water resources were predicted as a result of increased domestic and agricultural demands, along with increased winter flooding and changes in spatial nitrate concentrations. Under the ‘global sustainability’ scenario, increasing sugar beet and potato production were also predicted, along with greater irrigation needs, more break crops, decreased water resources and slight improvements in nitrate concentrations. In the Northwest, the ‘regional enterprise’ scenario led to increasing sugar beet and potato production with little need for irrigation, and some conversion of grassland to arable, most marked in the uplands. The ‘global sustainability’ scenario would lead to a reduction in permanent grass and conversion to arable crops, such as peas, beans, rape, sugar beet, and linseed with little need for irrigation. Overall, the project highlighted the importance of socio-economic trends in determining cropping patterns. CC0339 looked at the effects of climate change on agricultural land use in England and Wales. The project predicted that growing seasons would remain insufficient for considerable production of either sunflowers or maize. CC0357 aimed to identify and cost adaptive responses of agriculture under different climate change scenarios. Important yield effects were shown for wheat, which could be offset by introduction of new cultivars, and irrigation was unlikely to be cost effective unless already installed. Substitution of grain maize for wheat was unlikely unless yields changed a lot. Potato yield losses could be offset by new cultivars, although Cornwall, providing the earliest crops, may not be able to adapt to the longer growing season. Cauliflower yields increased in Northern England and might require more spraying for aphids. A general increase in grass yields was expected, with a reduction in N inputs and an increase in legume usage. CC0372 investigated the implications of the wet autumn of 2000 for agriculture. Wet autumns affected root crop harvests, winter vegetables and the establishment of later crops. A smaller area of winter crops were sown, compensated by spring crops, although weed control was difficult and greater than normal spring herbicide use resulted. Poor and damaged soil structure resulted from the need to work in wet conditions, when it was difficult to use minimal cultivation techniques. Increased erosion risks resulted in flood sensitive areas, especially after autumn cultivations, with knock-on impacts on P loss on suspended particles. Phosphorus, nitrogen, sulphur and pesticide leaching losses also resulted from high rainfall, whilst warm and wet soils resulted in greater nitrous oxide losses. CC0378 conducted a scoping study on the potential impacts of climate change on nutrient pollution of water from agriculture. Increases in the crop growing season were most marked in the Southeast of the country, and changing rainfall patterns were predicted to lead to increased nutrient losses in winter. However, there was potential for 2 Appendix SP0538 Climate change and soil function greater N uptake by certain crops, which could reduce the nitrate available for leaching. Changes in vegetation cover could have implications for P losses via changes in runoff and soil detachment by rainsplash. PS2208 assessed the impacts of climate change on the fate and behaviour of pesticides in the environment. The project suggested that climate change could have very variable effects on pesticide fate and transport as a result of uncertainties in climate projections, the complexity of the environment and competing climate-controlled processes which influence fate and transport. Land use change could have more significant effects on pesticide fate and transport than the direct effects of climate change. Increased pests, disease and weed prevalence could lead to wider and more frequent pesticide applications, although climatic changes could possibly lead to more rapid degradation rates. Increased winter rainfall would likely lead to more rapid pesticide movement, more bypass and drain flow, and surface waters receiving more pesticides from surface runoff, erosion and sediment. Changes in soil water content could lead to changes in degradation rates and residues. For instance, higher winter soil water contents could cause increased degradation. Dryer warmer summers might lead to increased cracking of shrink-swell clays and therefore greater bypass flow in winter. However, dryer summer soils might result in lower biodegradation potential and thus longer pesticide persistence. More intense and frequent storms might lead to more flushing of pesticides to groundwater, whilst higher groundwater levels particularly in winter, could result enhanced transfer to groundwater. Further work, including modelling, was recommended. WT01001 revisited the impact of climate change on the demand for water, predicting likely increases in water demands in the agricultural, domestic and commercial sectors. Within agriculture, this was a result of changes in plant physiology, soil water balances, cropping mixes, cropping patterns (making use of longer growing seasons), and changes in food demands. Increased demands for irrigation were notable in Eastern, Southern and Central England, of the order of 20% and 30% by the 2020s and 2050s respectively. SP0511 developed a UK soils database for modelling soil C fluxes due to land use change for the national carbon dioxide inventory, which was further used in CC0242, discussed earlier. SP0306 investigated whether there were critical levels of soil organic matter for maintaining soil functions. Declines of around 5% in cereal yields had been observed if SOC declined to around 1%, and this decline could not be corrected by adding fertilisers. Soil structure (aggregate stability) could deteriorate unacceptably if SOC concentrations fell much below 2%. In the soils databases from England and Wales, SOC explained around 10% in the variability of water holding capacity of topsoils, and made no contribution to the water holding capacity of subsoils. Soil structure was shown to be affected by reduced levels of SOC – there was a marked decrease in the dispersibility of aggregates for soils under arable cultivation where SOC was below around 1.5% SOC. SOC made little contribution to the plastic limit of soils (how readily soils deform) and none to the soil liquid limit (the point above which soils lose their mechanical strength). SOM was shown to be a considerable source of nutrients, especially on sandy, clayey and chalk soils. Use of the RothC soil C model with the UKCIP Medium-high scenario indicated that equilibrium SOC could decline by about 0.5% - and Eastern England could experience considerable declines in SOC. 3 Appendix SP0538 Climate change and soil function SP0519 assessed critical levels of soil organic matter in surface soils in relation to soil stability, function and infiltration. This suggested that there was a critical level of SOC to maintain aggregate stability. Intense rainfall was found to displace, entrain and transport soil containing a greater proportion of SOC and fine particles than bulk soil. Thus the particle and stability conferring parts of soil were bring eroded and transported away. Grassland soils were found to be relatively stable to rainfall. Silt-rich soils, low in SOC, were found to be susceptible to damage, loss of sediment and surface runoff of rain, with conventional tillage having an additional negative impact. In light of this, the project recommended that SOC should be increased and maintained by land management. SP0523 developed economically and environmentally sustainable methods of C sequestration in agricultural soils. In conclusion, the best scenarios of land management for C sequestration involved converting arable land and marginal grassland to woods. Arable land management (set aside, field margins, residue returns, manures and tillage) was also found to be of merit. CC0375 aims to develop a soil properties database for England and Wales for climate impact studies. 1.2 Specific findings from NERC research projects Specific findings are not reported since final/interim research reports were not available from the internet. 1.3 Specific findings from BBSRC research projects Specific findings are not reported since final/interim research reports were not available from the internet. 1.4 Specific findings from Environment Agency research projects Specific findings are not reported since final/interim research reports were not available from the internet. 1.5 Specific findings from EPSRC research projects Specific findings are not reported since final/interim research reports were not available from the internet. 1.6 Specific findings from ESRC research projects The project ‘Environmental and distributional impacts of climate change in Scotland’ included land cover effects, biodiversity and a modelling strategy. This utilised UKCIP climatic scenarios, a crop yield estimator and a farm management decision model. This showed that both elevated CO2 and climate change had positive effects on crop yields with the exception of the site in south east Scotland which suffered from water stress. Land use changes were likely to include a move towards spring crop varieties although some more significant changes were predicted to occur. There were variable effects on biodiversity, depending on the implied changes in land management, although effects were generally not large. Increased fertiliser inputs were needed under climate change in some sites. 4 Appendix SP0538 Climate change and soil function 1.7 Specific findings from NAW research projects NAW conducted a scoping study on the impacts of climate change in Wales to 2080 involving the University of Bangor, CEH, CRU-UEA and ECOTEC. Key biodiversity effects included a northwards migration of sensitive species and possible losses of coastal and lowland zones by increased storms and sea level rise. It was considered possible that bogs would dry out unless artificially managed; upland ecosystems could be particularly vulnerable, especially in artic-alpine systems where soils play a crucial role. Archaeological sites in low-lying regions could suffer from flooding, subsidence and severe storms. In agriculture, increased crop growth from elevated CO2 concentrations might be offset by yield reductions from increased temperatures although grass yields were likely to increase. Agriculture might be able to adapt by changing crops or varieties (e.g. fodder maize), and by conversion of livestock to arable farming, although increased irrigation needs were likely in summer. Difficulties in getting machinery on to land in autumn and winter might be encountered. Land use is likely to be affected by market forces, with small projected impacts on upland systems but significant increases in arable land areas in East Wales. Reduced water supply and increased demands would put pressure on increasing needs for irrigation. Flooding could also lead to some loss of arable land in coastal zones. Forests could be damaged by storms and high winds, and more frequent fires in dry summers. Land use changes were likely to lead to losses in biodiversity and some terrestrial and freshwater habitats. In particular, coastal floodplains and grazing marshes could be lost due to sea level rise and storm damage although this loss could be mitigated by managed retreat elsewhere; montane habitats could suffer from increased summer temperatures and droughts and warmer winters making the environment less suitable for arctic-alpine species; lowland raised bogs could be damaged by warmer summers and droughts; blanket bogs could suffer minor or considerable impacts depending on the severity of climate change – possibly irreversible changes in shallow peats could occur if they dried out and oxidised with knock on impacts on wetlands, aquatic habitats and climate feedbacks from GHG fluxes. The historic environment might suffer from lower or fluctuating water tables and pH changes which could have a significant impact on the preservation of artefacts. Climate change could also impact wetland and waterlogged habitats which are notable areas of archaeological preservation. The projected increase in arable agriculture might increase destruction of archaeological remains and new woodlands could also have a negative impact. However, whilst drier conditions in summer might improve reconnaissance and excavation the benefits of this would probably be outweighed by negative impacts. Increased rainfall patterns could also have an impact on land stability and landslips. 1.8 Specific findings from SEERAD research projects SEERAD commissioned a scoping study on the implications of climate change on Scotland. The project discussed direct impacts (as a result of changes in climatic variables) and indirect impacts (as a result of measures to reduce GHG emissions). This suggested that climate change might be beneficial to forestry due to increased tree growth under higher temperatures, increased afforestation, and biomass fuel usage although excess wind could have a negative impact and moisture stress might be an issue in Southeast Scotland. Subsidy changes were likely to be more important that direct climate impacts on agriculture although more diverse and valuable crops (sugar beet, fodder 5 Appendix SP0538 Climate change and soil function maize, oilseed rape) may be grown in the future. Climate change might result in lower fertiliser usage although water stress could affect cropping in Southeast Scotland and high water demand crops such as potatoes. Water logging could cause problems with fieldwork and harvesting. Increased demands for water from house building and irrigation for horticulture and agriculture (especially in East Lothian and Fife) were likely. The scoping study was one of the few projects reviewed to have a section specifically covering climate impacts on soils. This noted that increased temperatures could increase organic matter decomposition and nutrient release from soils, possibly increasing plant growth, whilst increased rainfall could increase atmospheric N deposition and elevated CO2 concentrations would enhance plant growth. The vegetation of heather moorlands and high-altitude heaths are adapted to nutrient-poor soil conditions and enhanced soil fertility under climate change could result in invasion from competitive species. Predicted changes in climate were unlikely to have large effects on erosion in Scotland although in high altitude soils where freeze-thaw driven solifluction could decrease, this could increase competition between low productivity plant species and more vigorous species. Increases in temperature could increase both the rates of peat formation and decay, and thus changes in rainfall could have important effects on the fate of peatlands under climate change. Lower rainfall would likely lead to peat loss and CO2 release; wetter conditions would result in more peat formation and CH4 emissions. Afforestation could dry peats and offset the benefits of carbon uptake in trees. The transport sector could be affected by increased landslides, and flooding and drainage problems. A further scoping study was developed to identify potential adaptation strategies for climate change in Scotland. This suggested that agricultural crop ranges might spread northwards; high-quality horticultural crops might be susceptible to negative impacts; the potential for soils to support agriculture was strongly depended on changes in soil water; increased soil erosion and leaching could result from greater winter rainfall; problems of vehicular access to agricultural land were likely due to waterlogged soils in autumn and winter; greater crop yields might result from longer growing seasons and reduced frost days although increasing rainfall could limit these benefits and those of increased temperatures and CO2 levels. SEERAD also commissioned a review of the contribution of organic soils under different land uses to climate change. This focussed on GHG fluxes historically rather than likely future impacts, but recommended development of a process-based model for future work. 6 Appendix SP0538 Climate change and soil function Table 1 Effects of climate change on soils for agriculture and forestry Increasing summer temperature Increasing winter temperature More extreme high temperature Less extreme low temperature Higher winter rainfall Less summer rainfall Loss of soil organic matter Decreased moisture retention Increased mineralization Loss of structural stability Reduced tilth mellowing Increased pest and disease persistence in soil Earlier start to growing season More extreme high temperatures Livestock heat stress (Forest fires) Crop failure No significant effect Decreasing tilth mellowing-freeze-thaw Decreased access for forestry More persistent pests and diseases in soil, therefore increase use of pesticides or management Longer growing season leads to higher moisture deficits No significant effect Reduced machinery work days/stocking capacity, leading to soil structural damage. Reduced farm waste disposal opportunities. Surface runoff and erosion – control with catchment sensitive farming and single farm payment. Nutrient leaching, and methane and N2O flux More compaction, smearing, poaching Increased nutrient/chemical leaching Decreased opportunity for farm waste disposal Increased waterlogging – reduced stability Yield reduction and harvest timing. Loss of soil organic matter (mineralization and N2O flux) Potential for loss of rainfall surfeit leading to salinisation Fire risk for woodland and peats Crop failure – increased litter input Reduced yield – reduced litter input Timing issues Abstraction license issues Earlier harvest leading to increased erosion Re-cropping in autumn – problems with germination Lower methane and higher N2O 7 Appendix SP0538 Climate change and soil function More intense downpours Sea level rise and increased coastal flood risk Possibly more winter storms Rainfall runoff lost to crop available water. Increased frequency/severity of large erosion events (rill and gully formation). Direct crop damage and lodging. Difficulty timing machinery. Less infiltration – confound drought Pesticide/herbicide application – ease of application Compaction Smearing Poaching Direct loss of soils on Best and Most Versatile agricultural land. Rising water table and encroachment of salt water Limits scope for woodland thinning and pushes management towards clear felling. Erosion and crop damage Over-turning – soil damage Soil sealing/crusting Reduced forestry rotation height 8 Appendix SP0538 Climate change and soil function Table 2 Effects of climate change impacts on soil, air and water interactions Increasing summer Increased GHG fluxes? temperature Reduced soil moisture, aquifer recharge Increased water demands Reduced OM and CEC Increased autumn flush of pollutants Increased pesticide applications (arable and livestock?) Erosion from upland cultivation? Increasing winter temperature Increased GHG fluxes? Reduced OM and CEC Increased pesticide applications? Nutrient pool exhaustion Farming operations/livestock – soil structure More extreme high temperature Water stress/demands Wind erosion Cracking clays – bypass flow Less extreme low temperature Freeze-thaw / tillage Increased N2O flux Increased pesticide loadings (arable and livestock) Higher winter rainfall Increased runoff, erosion, flooding Diffuse pollution Forest wind-throw Inundation of sewage works Increased N2O fluxes Less summer rainfall Urban first flush pollution events Water demand stress, aquifers Pollutant build up in soils Less N2O, CO2 mineral soils Less CH4, more CO2 organic soils Wind erosion, cracking Fires: erosion risk, GHG More intense downpours Pollutant flushing Extreme erosion, flooding, flash floods Reduced aquifer recharge, surface runoff Sediment loss Capping – gaseous exchange Sea level rise, coastal flood Saline intrusion, irrigation, drinking water risk Nutrient flushing e.g. Norfolk Broads Damage to soil structure (salt) Increased N2O and CH4 fluxes More winter storms As extreme rainfall Soil disturbance plus windthrow in forests 9 Appendix SP0538 Climate change and soil function Table 3 Effects of climate change impacts on soil biodiversity Increasing summer Deeper burrowing by worms, temperature and less summer More flushes in activity as a result of an enhanced rainfall “priming effect” leading to potential increases in ground and surface water eutrophication, Changes in competitive advantage leads to change in species composition – will this still support the existence of conservation target assemblages? Changes in structure will lead to changes in gaseous exchange and physical access Changes in the “workable window”. Increasing winter temperature Increasing anaerobicity, increases in methane, higher winter rainfall and less ammonium and nitrogen emissions extreme low temperature Loss of vernalisation leading to loss of vernal species Increases in survival of pathogens/herbivorous pests More extreme high Potential population crashes temperature Skewed gender profile of offspring? More intense downpours and thunderstorms Sea level rise, coastal flood risk Bursts of “anaerobicity” Increasing erosion leading to soil loss and eutrophication of surface waters Increasing tree strikes and fires Increasing flooding events Loss of water storage for human use Changes in run-off Salinisation Managed realignment vs. conservation of habitats adjacent to sea walls Loss of species Migration inland of habitats 10 Appendix SP0538 Climate change and soil function Table 4 Effects of climate change impacts on soils in the landscape and cultural heritage Increasing summer temperature Increasing winter temperature General effects on landscape and vegetation due to climate change and effects through the soil. More extreme high temperature Significant changes to appearance of landscape due to changing land-use and farming practices, including changes to crop types; more areas affected by fires (forest/brush/scrub) Less extreme low temperature Higher winter rainfall Less summer rainfall More intense downpours Sea level rise, coastal flood risk More winter storms Flooding more common and widespread; greater risk of soil erosion and loss of artefacts Significant changes to appearance of landscape due to changing land-use and farming practices, including changes to crop types; more areas affected by fires (forest/brush/scrub) Greater risk of soil erosion and loss of artefacts Loss of coastal land and landscape; loss of archaeological opportunity Risk of windthrow and disturbance to archaeological evidence under woodland; greater risk of catastrophic landscape change, e.g. after 1987 storm in south-east England 11 Appendix SP0538 Climate change and soil function Table 5 Effects of climate change impacts on soils in mineral extraction, construction and the built environment Increasing summer temperature Increasing winter temperature More extreme high temperature Changes in organic matter in materials added as amendment to soil-forming materials Increase the rates of gas emissions and volatilisation of some organic pollutants and mercury Increase autumn flush of pollutants Changes in the rate of organic matter mineralisation for added materials Soil materials used for construction purposes may change, which may affect the availability of certain construction materials, notably quality hardstones and the location of extraction sites Increased GHG fluxes Higher chance of prolong leaching of pollutants Reduction of the use of de-icing salts, and subsequent salt contamination of roadside soils Possible disturbance to building foundations due to increase likelihood of shrink-swell in soils with shrinkswell clay minerals Vegetation may be discouraged on clay soils in urban areas due to compaction Potential risk of engineered structures based on clay caps Cracking clays – bypass flow Effects of soil compaction are likely to be greater in restored soils Less extreme low temperature Higher winter rainfall Less summer rainfall Potential increase in leachate generation and release in landfill gases Increase release of metals and pollutants into soil and stream water Unpredictability of high rainfall events pose the need to reconsider the risk of geomorphic phenomena (e.g. landslips, slope failure). Better planning and factoring unpredictable rainfall events into surface drainage system on mineral sites Raised water tables with consequent effect on drainage, flooding, cesspit and sewage treatment Increased methane emissions from landfill sites Possible disturbance to building foundations due to increase likelihood of shrink-swell in soils with shrinkswell clay minerals Vegetation may be discouraged on clay soils in urban areas due to compaction Potential risk of engineered structures based on clay caps 12 Appendix SP0538 Climate change and soil function More intense downpours Urban first flush pollution events Pollutants build up Window to establish vegetation on newly placed soil may narrow due to early summer drought and increased soil strength and root penetration resistance The risk of erosion may be greater The provision of irrigation to establish vegetation may become essential in drier south-east Pollutant flushing Elevated risk of soil erosion, with greatest danger on brownfield land where soil materials may be contaminated and soil erosion could lead to pollution of surface waters Increased risk of flooding, flash floods and surface runoff again leading to potential risk of surface and ground water contamination Capping – gaseous exchange Sea level rise, coastal flood risk More winter storms 2 Forest soil functions – research gaps and needs The main issues in the research gaps and needs on climate change impacts on forest soil function are to: Integrate intensive woodland ecosystem monitoring in the UK to monitor climate change impacts and drive model development. Investigate interactions between climate change and pollutant deposition and exposure, particularly critical loads (levels) and critical loads exceedance for woodland in relation to issues of acidification/recovery and eutrophication. Enhance inventories of carbon stocks and stock changes in woodland soils, and in particular focus on vulnerable soils. Promote model development for organic and woodland soils, including the collection of data required for parameterisation and verification. Improve estimates of non-CO2 GHG balance (primarily N2O and CH4) of forest soils, including predictions of the impacts of climate change and the effects of forest management; extension to broadleaf woodland and deforestation activities is important. Investigate the effects of climate change (principally soil moisture content and temperature) on mycorrhizal associations. Assess the effects of climate change on soil erosion and interactions with forest management practices. Collate information on the likely effects of climate change on soil chemical and physical properties and how archaeological remains may be affected. 13 Appendix SP0538 Climate change and soil function The research carried out in the UK on the effects of climate change on forest soil function is limited. However, the growing interest in forests and the potential of forest soils for carbon mitigation necessitates immediate action for further research in this area. The research areas highlighted in this section deal specifically with soil function. However, the response of soil function to climate change is also dependent, both directly and indirectly, on the response of vegetation to climate change. Uncertainty in vegetation responses (as outlined below) should therefore be considered in future assessments of the impacts of climate change on soil function, while future research into these areas of uncertainty should include an assessment of implications for soil function: The response of trees beyond the sapling stage to rising CO2 levels. Interactions between rising CO2 levels, air pollution and a changing climate. The response of woodland to climatic extremes as compared to mean climate. Changes in the incidence of insect pest and pathogen outbreaks. Long-term monitoring is an essential component of research into the effects of climate change on soil function; without monitoring data, models cannot be adequately validated or verified and their predictions must be viewed with caution. Soil inventories may not be able to provide the required level of detail, in isolation, and their ability to identify change may be compromised by changes in other environmental or land use related factors. Only intensive monitoring at the ecosystem level (ie including aboveground components and processes) can provide this level of detail, including signals warning of the early stages of climate change induced changes to soil function. At present, long-term monitoring at this level of detail is primarily undertaken through the Environmental Change Network (ECN) and the EU/UNECE ICP-Forests Intensive Forest Monitoring Network (Level II). Woodland land cover is limited in the former, while the latter is largely restricted to managed forests. Ensuring compatibility across the two networks, with commonality of protocols developed specifically for woodland ecosystems would provide a more robust data-set, while targeted monitoring of natural ecosystems thought to be most at risk to climate change should be considered. There is some uncertainty over the future of both Level II and ECN. In the case of Level II, European Union co-funding is uncertain beyond 2006 while the voluntary basis of the funding of ECN by participating organisations cannot be guaranteed in the long-term. Long-term monitoring at these sites should not be discontinued for financial reasons without due consideration of additional funding streams. Interactions between climate change and the impacts of pollutant deposition are uncertain. When the effects of climate change on critical loads (of pollutants) are considered, sensitivity analyses of key parameters indicate that further research should be focussed on the effects of nitrogen in the forest environment. Changing rainfall patterns and their potential to enhance nitrate leaching, together with the effects of rising temperature on mineralisation rates are areas of particular concern and uncertainty. The role that soils plays in diffuse pollution is an area of particular concern to regulatory agencies and directives. 14 Appendix SP0538 Climate change and soil function The greenhouse gas balance of forest soils is a key area of uncertainty in predictions of future GHG emissions scenarios. While forest inventories can provide detailed information on changes in above-ground carbon stocks, assessment of carbon stocks and stock changes in forest soils is extremely limited, not only in the UK, but across Europe in general. An enhanced inventory of carbon stock changes in forest soils therefore warrants consideration. However, future predictions can only be made on the basis of robust models which, at present, represent forest soils poorly. The collection of appropriate data for parameterising and validating these models, including inputs (eg litter, root exudates), outputs (DOC, gaseous emissions) and the chemical characterisation of soil organic matter, is an essential component of model development. These data should not be restricted to surface horizons, but include the entire soil profile. A key issue is the widespread evidence of rising DOC levels in waters which is directly related to water quality. Another particular area of concern is the effect of forest harvesting and deforestation on soil C storage. To date, research has concentrated on conifer woodland and upland soils; there is a need for these studies to be extended to include native woodland expansion, especially on organic soils. The effects of climate change on the balance of non-CO2 GHGs represents an even greater area of uncertainty than for carbon dioxide. Although for both N2O and CH4, exchange in forest soils is limited relative to other sources (and sinks) at a national scale, it is important that the non-CO2 GHG balance of forest soils is better quantified, particularly in the context of changes in forest and land management including deforestation. Mycorrhizal associations enhance the ability of trees to extract nutrients from soils, while there is also limited evidence that they may confer some protection against soil-borne pathogens. Although research effort into elucidating the effects of both pollutant deposition and atmospheric CO2 levels on mycorrhizae is continuing, knowledge of how mycorrhizal associations vary in response to other environmental factors is more limited. The same considerations apply more generally to the wider soil microflora. There is little or no direct research relating specifically to climate change and the implications for archaeological resources. Although some inferences may be drawn from predictions of changes in soil chemistry that may derive from other studies, there is an urgent need to draw this information together. 15 Appendix SP0538 Climate change and soil function Table 6. Summarised peer-reviewed literature on the effects of climate change on forest soil functions in the UK. Reference Soil type, Objectives and Experimental set up Naden, P.S. and Watts, C.D. (2001). Estimating climate-induced change in soil moisture to five areas of ecological interest in the U.K. Climate change 49, 411-440. Five soil types were identified: 1) clay soils on an impermeable or slowly permeable substrate; 2) well-drained loams on a macroporous substrate (e.g. chalk or limestone) 3) sandy soils on a macroporous substrate 4) soil types developed on hard impermeable rocks (e.g. lithosol); 5) peat. Bridget, A.E., Beier, C., Estiarte, M., Tietema, Modelled climate-induced changes on soil moisture at the landscape level (100-250 km2) are assessed using the UK Hadley Centre Transient (UKTR) model (with 20302040 and 2060-2070 scenarios). This is expressed in terms of distribution of monthly mean soil moisture values on a 50 m grid, which include the lateral movement of water and the effects of typography and soil type. Four soil types were studied under dominant Effects on soil chemistry Effects on soil physics, hydrology The modelling results show: 1) Decrease in modelled PE and relatively small increase in rainfall between nowadays and the two climate change scenarios contributed to the significant increase in soil moisture deficit in northern, middle and southern England in comparison with Scotland where a slight decrease in soil moisture deficit is modelled. 2) There is a seasonal pattern of soil moisture change depending on soil type. The largest amount of modelled changes is for the three more southerly sites in England in the clay soils (type 1). 3) Substantial drying does occur under the above climate change scenario and the moisture levels in April and September suggest that clay soils are more vulnerable in comparison to loams and sandy soils. 4) Critical soil moisture threshold for different plant communities are also discussed and the modelled results suggest that there may a risk of reduction in suitable habitat for wetloving plant communities under the climatic scenario used. The results indicate: 1) Strong seasonal trends 16 Effects on soil biology Uncertainties, questions and research gaps identified Appendix SP0538 Climate change and soil function Kristensen, H.L., Williams, D., Peňuelas, J., Schmidt, I. and Sowerby, A. (2004). The responses of soil processes to climate change: Results from manipulated studies of shrublands across an environmental gradient. Ecosystems 7, 625637. vegetation of ericaceous shrub Calluna vulgaris: 1) 2) 3) 4) Sandy podzol (DK) Peaty podzol (UK) Sandy podzol (NL) and Petrocalcic calcixerepts (ES) The effects of soil warming and drought on soil respiration net nitrogen mineralisation and litter decomposition were assessed in experiments in the UK (North Wales), DK, NL and ES. 2) 3) 4) 5) 6) in soil respiration rates were observed, which closely followed seasonal patterns of soil temperature. There was a trend of reduced soil respiration rates of 3%-29% in response to drought relative to the control and 0%-19% increase in response to warming. A linear model of soil respiration dependence on temperature and soil moisture which explained 73% of the variation is proposed for the soil at 5-10 cm depth. Net N mineralisation rates were significantly related to soil moisture content across the sites, with positive rates generally recorded in soils with moisture content between 2060%. Within the soil moisture range (20%-60%), a significant linear response to temperature was observed. No significant relationship with moisture was observed within this range. In the UK site, net N immobilisation (negative values) was often recorded, possibly as a result as a combination of wetter and colder conditions and the low availability of other 17 Appendix SP0538 Climate change and soil function nutrients. The effect of climate gradient and effect of experimental treatments on litter decomposition were assessed. 8) Across the environmental gradient, mass loss rates were positively related to air temperature (explained 81% of the variance). Rhizosphere respiration increases significantly at elevated temperature. 7) VanHees, P.A.W., Jones, D.L., Finlay, R., Godbold, D.L. and Lundström, U. (2004). The carbon we do not see – the impact of low molecular weight compounds on carbon dynamics and respiration in forest soils: a review. Soil Biology & Biochemistry 37, 1-13. Lukas, M., Calfapietra, C. and Godbold, D.L. 2003. Production, turnover and mycorrhizal colonisation of root systems of three Populus species grown under elevated CO2 (POPFACE). Global Change Biology 9, 838848. Thornley, J.H.M. and Cannel, M.G.R. (2001). Soil carbon storage response to temperature: a hypothesis. Annals of Botany 87, 591-598. CO2 increase and subsequent warming effect on soil carbon dynamics were assessed. Below-ground biomass and fine root turnover increased and thus total C flux to the soil. In this paper, an alternative to the additional hypothesis is proposed to explain the apparent insensitivity of soil carbon stocks to temperature under some circumstances. The Both a simple analytical model and a more complex model demonstrate that if this hypothesis is true, warming may cause little decrease in total soil carbon in the longterm and would cause an increase in soil carbon if 18 Appendix SP0538 Climate change and soil function Norby, R.J., Cotrufo, M.F., Ineson, P., O’Neill,E.G. and Canadell, J.G. (2001). Elevated CO2, litter chemistry, and decomposition: a synthesis. Zerva, A., Ball. T., Smith, K.A. and hypothesis is that warming may increase the rate of physico-chemical processes which transfer organic carbon to “protected”, more stable, soil carbon pools. Indeed, physico-chemical “stabilisation” reactions may respond more to warming than microbial ‘decomposition/respiration’ reactions. If this is true, soil carbon stocks may remain relatively unchanged, or even increase, with increase in temperature, without invoking low temperature sensitivity for microbial respiration in the older mineral pools. It is proposed that soil physicochemical reactions, which stabilise soil carbon and protect it from microbial respiration, may be accelerated by warming. A review on different soil types. The results of published and unpublished experiments investigating the impacts of elevated [CO2] on the chemistry of leaf litter and decomposition of plant tissues are summarised. physico-chemical stabilisation reactions were over 50% more sensitive to temperature than microbial reactions. It should be stressed that shifts between soil carbon pools can be slow and that the hypothesis refers to equilibrium carbon storage which may not be reached for decades or centuries. Research has been shown that soil respiration may be greatly increased with little loss of soil carbon shortly after a step-wise increase in temperature, but after some time, both respiration and soil carbon decrease and at equilibrium, respiration will equal net primary production and total soil carbon may have actually increased. It is clearly not adequate to draw conclusions about real world conditions from short-terms warming experiments. Peaty gley The soil carbon stock of the first rotation stands was 140 t It is concluded that any changes in decomposition rates resulting from exposure of plants to elevated [CO2] are small when compared to other potential impacts of elevated [CO2] on carbon and N cycling. An indication of potential decline in litter N and increase in plant litter lignin which will slow the litter decomposition rate was suggested for CO2 enriched litter. Soil respiration was the highest at the grassland 19 Appendix SP0538 Climate change and soil function Mencuccini, M. (2004). Soil carbon dynaimcs in a Sitka spruce (Picea sitchensis (Bong.) Carr.) chronosequence on a peaty gley. Forest Ecology and Management (in press). Dewar, R.C. and Cannell, M.G.R. (1992) Carbon sequestration in the trees, products and soils of forest plantations: an analysis using UK examples. Tree Physiology 11, 4971. Heath, J., Ayres, E., Rossell, M., Bardgett, R.D., Black, H.I.J., Ineson, P., Stott, A. and Kerstiens, G. (2005) Rising atmospheric CO2 reduces soil carbon sequestration. To be submitted. Karjalainen, T., Pussinen, A., Liski, J., The impact of planting forests on organic grassland soils on the losses of soil carbon due to the site preparation for the planting of trees and other disturbances has been investigated. Soil respiration, soil carbon stocks and annual litterfall were also measured while allometric equations were used for the estimation of the above and belowground biomass. The sites chosen were: 40-year-old first rotation stands, 12, 20 and 30 year-old second rotation stands, one 18-month-old clearfelled site and unplanted natural grassland sites. The soil was a fine montmorillonitic, mesic udertic Paleustoll with texture of silt loam or silty clay loam and a range of clay content from 26 to 34%. The soil was imported from the USA but it is inoculated in the UK. Analysis of the impacts of two forest management C ha-1, far lower than in the surrounding unplanted grasslands with 274 t C ha-1, while clearfelling cause a further decline to 100 t C ha-1. Soil carbon accumulated again as the forest grew during the second rotation. site (14.2 t C ha-1 year-1), after the forest establishment the respiration was 2.3, 2,2, 5,4 and 5.0 t C ha-1 at the age of 12, 20, 30 and 40 years, while in the clearfelled site soil respiration was 5.6. CO2 enrichment, while causing short-term growth stimulation in a range of European tree species, also lead to an increase in microbial respiration, resulting in a marked decline in sequestration of root derived carbon in the soil. Carbon stocks in tree biomass, soil and wood 20 Appendix SP0538 Climate change and soil function Nabuurs, G., Eggers, T., Lapvetelainen, T. and Kaipainen, T. (2003) Scenario analysis of the impact of forest management and climate change on the European forest sector carbon budget. Forest Policy and Economics 5, 141-155. (felling increased 0.5-1% per year until 2020 and forest management paid more attention to current trends towards more nature oriented management) and two climate change scenarios (mean annual temperature increased with 2.5 C and annual precipitation 5-15% between 1990 and 2050) on the European forest sector carbon budget between 1990 and 2050 have been carried out in this study. Sanger, L.J., Anderson, J.M., Little, D. and Bolger, T. (1997) Phenolic and carbohydrate signatures of organic matter in soils developed under grass and forest plantations following changes in land use. European Journal of Soil Science 48, 311-317. Comparisons were made between phenolic and carbohydrate signatures of soil profiles developed under grass, spruce and ash stands. Samples were collected from a brown earth soil which was originally under the same land use, but over the past 43 years has supported different monocultures. Jo M. Anderson, Professor of Ecology, Biological Sciences Department, Exeter University (personal Discussion on the above research (paper N 11) includes the use of lignin signature to track SOM following changes in vegetation cover. They products increased in all applied management and climate scenarios, but slower after 2010-2020 than that before. This was due to ageing of forests and higher carbon densities per unit of forest land. Differences in carbon sequestration were very small between applied management scenarios, implying that forest management should be changed more than in this study if aim is to influence carbon sequestration. Applied climate scenarios increase carbon stocks and net carbon sequestration compared to current climatic conditions. A relatively undecomposed phenolic fraction from the lignin and hydrolysable carbohydrate fractions from plants had accumulated in the soil under spruce and ash which largely reflected the quantity and quality of the litter inputs from the ash and spruce compared to the grass. The phenolic and hydrolisable carbohydrate fractions accounted for as much as 60% of the total organic carbon concentration in the deep soil horizons. The conclusions are that the decay rate of these fractions are function of vegetation type. From his experience, Prof.. Anderson conclude that 21 Appendix SP0538 Climate change and soil function communication). Dewar, R. C. and Cannell, M.G.R. (1992) Carbon sequestration in the trees, products and soils of forest plantations: an analysis using UK examples. have shown that a conifer, even on a fertile soil, has a very shallow signature of SOM compared to the broad leaf species. Whether the deep signature under ash was due to DOC as well as roots they were unable to determine. A carbon-flow model for managed forest plantations was used to estimate carbon storage in UK plantations differing in Yield Class, thinning regime and species characteristics. A sensitive analysis revealed the following processes to be both uncertain and critical: the fraction of total woody biomass in branches and roots; litter and soil organic matter decomposition rates; and rates of fine root turnover. Results showed that: 1) Increasing the Yield Class from 6 to 24 m3 ha-1 year-1 increased the rate of carbon storage in the first rotation from 2.5 to 5.6 Mg C ha-1 year-1 in unthinned plantations. Thinning reduced total carbon storage in P. sitchensis plantations by 15%, and it is likely to reduce the carbon storage in all plantation types. 2) If the objective is to store carbon rapidly in the short term and achieve high carbon storage in the long term, Populus plantations growing on fertile land (2.7 m spacing, 26-year rotation, YC 12) were the best option examined. 3) If the objectives is to achieve carbon storage in the medium term (50 years) without regards to the initial rate of storage, then plantations of conifers of any species with aboveaverage yield class would suffice. In the 22 Appendix SP0538 Climate change and soil function Ineson, P., Benham, D.G., Poskitt, J., Harrison, F., Taylor, K. and Woods, C. (1998) Effects of climate change on nitrogen dynamics in upland soils 2. A soil warming study. Global Change Biology 4, 153-161. A warming technique was developed and demonstrated in this study, together with the consequences for the release of nitrate from lysimeters due to increase soil temperature. Three soil types were under investigation: Brown earth, Micropodzol and peaty gley. Jones, D.L., Hodge, A. and Kuzyakov, Y. (2004) Plant and mycorrhizal regulation of rhizodeposition. New Phytologist, 163: 459480. The paper summarising the C flows in and from the rhizosphere and underlined the importance of the better understanding the complexity of the rhizosphere in order to fully engaged with key scientific ideas such as development of sustainable agricultural systems and the response of ecosystems to climate change. In this study, carried out within the cross- European research project CLIMOOR, the effect of climate change, resulting from imposed manipulations, on carbon dynamics in shrubland Gorissen, A. et al. (2004) Climate change affects carbon allocation to the soil in shrublands. Ecosystems 7, 650661. long term (100 years), broadleaved plantations of oak and beech store as much carbon as conifer plantations. Minirotations (10 years) do not achieve high carbon storage. The response of the soil solution concentration of nitrate to increase of soil T up to 3C more than the control varied markedly between soil types, but showed a significant decrease in the brown earth during the first 5 months of additional heating. This suggests that increased nitrogen release is masked by plant uptake in this soil, but the responses of the other two soils were less marked. Drought clearly reduced carbon flow from the roots to the soil compartments. The fraction of the 14C fixed by plants and allocated into the soluble carbon fraction in the soil and to soil microbial 23 Differences in climate, soil, and plant characteristics resulted in a gradient in the severity of the drought effects on Appendix SP0538 Climate change and soil function ecosystems was examined. The experiments performed were 14C – labelling experiment to probe changes in net carbon uptake and allocation to the roots and soil compartments as affected by a higher temperature during the year and a drought period in the growing season. Lenton, T.M. and Huntingford, C. (2003). Global terrestrial carbon storage and uncertainties in its temperature sensitivity examined with a simple model. Global Change Biology 9, 1333-1352. Chapman, S.J., Thurlow, M. (1996). The influence of climate on CO2 and CH4 emissions from organic soils. Agricultural and Forest Meteorology 79, 205-217. biomass in Denmark and the UK decreased by more than 60%. The effects of warming were not significant, but, as with the drought treatments, a negative effect on carbon allocation to soil microbial biomass was found. The changes in carbon allocation to soil microbial biomass at the northern sites in this study indicate that soil microbial biomass is a sensitive, early indicator of drought or temperature-initiated changes in these shrubland ecosystems. In this paper, key controls on global terrestrial carbon storage are examined using a simple model of vegetation and soil. CO2 and CH4 emissions from two peat sites in Scotland were monitored and related to temperature and moisture. One site is a deep Sphagnum bog and the other is planted with Sitka spruce and Lodgepole pine. CO2 emissions rates at both sites showed a marked seasonal pattern and paralleled the ambient soil temperature. Values ranged from 10 mg C m-2 h-1 in the bog area in March to 190 mg C m-2 h-1 in the adjoining forest area in July. Values in the dry area tended to be about 40% greater than those in the wet area while those in the forest plantation were on average 90% greater than 24 net carbon uptake by plants with the impact being most severe in Spain, followed by Denmark, with the UK showing few negative effects at significance levels of p< or = 0.10. The reduced supply of substrate to the soil and the response of the soil microbial biomass may help to explain the observed acclimation of CO2 exchange in other ecosystems. Land carbon sink is a significant uncertainties in global change projections. Appendix SP0538 Climate change and soil function those in the indigenous bog area. The effect of temperature was modelled by Arrhenius equation (linear regression of the log of the CO2 flux against the reciprocal of the absolute temperature should give a straight line). This model showed that 57-70% of the CO2 variations could be explained by temperatures. Q10 values were estimated as 3.3. and 6.1 respectively, which seemed to be greater than many published values for minerals soils. Significant CH4 emissions were found only for the bog area and only 23 % of their variations were explained by temperatures by the model used. Using the responses to temperature as determined above it was possible to estimate the increase in carbon dioxide emission from these sites for any given rise in annual mean temperature. For delta T = 2.5 C, the increase in CO2 emission was 36% and 59% for the bog and wet areas respectively. For delta T = 4.5 C, a doubling of CO2 emissions was predicted, which extended over the global range of peat and organic soils, could have a significant effect on the contributions of soil carbon to atmospheric CO2. Repeating the above calculations for methane gave an increase 605 for delta T = 4.5C. However, the main effect on 25 Appendix SP0538 Climate change and soil function methane would be due future changes to the moisture content. Land use changes such as drainage and afforestation can have a major effect in reducing methane emissions. Smith, P., Smith, J.U., Powlson, D.S. etc… (1997). A comparison of the performance of nine soil organic matter models using datasets from seven long-term experiments. Geoderma 81, 153225.. Nine organic models were evaluated using twelve datasets from seven longterm experiments. Datasets represent three different land-uses (grassland, arable cropping and woodland) and a range of climatic conditions within the temperature region. Different treatments (inorganic fertilisers , organic manures and different rotations) at the site allowed the effect of different land management to be explored. Model evaluation were evaluated against the measured data and the performance of the models was compared both qualitatively and quantitatively. Hargreaves, K.J., Milne, R. and Cannell, M.G.R. (2003). Carbon Balance of afforested peatland in Scotland. Forestry, 76 (3), 299- The annual net CO2 exchange over undisturbed deep peatland in Scotland was measured continuously for 22 months using eddy covariance. Annual CO2 exchange Not all models were able to simulate all datasets. No one model performed better than all others across all datasets. A comparison of overall performance of models across all datasets reveals that the model errors of one group of model (RothC, CANDY, DNDC, CENTURY, DAISY and NCSOIL) did not differ significantly from each other. Another group (SOMM, ITE and Verberne) did not differ significantly from each other but showed significantly larger model errors than did models in the first group. Assuming that the trees accumulated carbon at rates commensurate with yield class 10 m3 ha-1 a-1, the peat beneath the The undisturbed peat accumulated approx. 2.5 t C ha-1 a-1. Newly drained peatland (2-4 years after ploughing) emitted between 2 and 4 t C ha-1 a –1, but when ground vegetation 26 Appendix SP0538 Climate change and soil function 317. over peatlands that had been drained, ploughed and afforested with conifers 1, 2, 3, 4, 8, 9 and 26 years previously were estimated by extrapolating two to four weekly measurements, using relationships between daytime fluxes and solar radiation and night-time fluxes and air temperatures. Pilling, C. and Jones, J.A.A. (1999). High resolution climate change scenarios: implications for British runoff. Hydrological processes 13, 28772895. Nationwide changes in spatially well-resolved patterns of British runoff were investigated under two climate change scenarios derived from general circulation model (GCM) output. A physical process-based hydrological model (HYSIM) was used to simulate effective runoff across a 10 x 10 km British grid under baseline and future climate conditions. A gridded baseline climatology for precipitation and Penman variables was used to validate HYSIM across Britain using grid cellspecific parameters derived from land use and soil type. The climate change scenarios were constructed from the Hadley Centre’s high recolonised, the peatland became a sink again, adsorbing approx. 3 t C ha-1 a-1, 4-8 years after tree planting. Thereafter, the trees dominated the budget and afforested peatland adsorbed up to 5 t C ha-1 a-1. Annual effective runoff is shown to increase throughout most of Britain under the UKHI scenario for 2050, whilst it decreases over much of England and Wales under the UKTR scenario for 2065. Both scenarios show an increasing gradient in runoff between a wetter northern Britain and a drier south-eastern Britain. This gradient is more pronounced under the UKTR scenario. Changes in effective runoff for winter and summer show an increase in seasonality under both scenarios. Winter runoff is shown to increase most in northern Britain under both scenarios, whilst summer runoff is shown to experience major reductions over much of England and Wales under the UKTR scenario. 27 trees after canopy closure was estimated to be decomposing at only approx. 1 t C ha-1 a –1 or lee. This is slower than previously though and suggested that afforested peatlands in Scotland accumulate more carbon in trees, litter, forest soil and products than is lost from the peat for 90-190 years. If these simulations are realised, Britain may expect an accentuated north to south-east imbalance in available water resources. If this is combined with a temporal imbalance suggested by the increased seasonality, there could be problems of the future management of British water resources. Appendix SP0538 Climate change and soil function Grogan, P. and Matthews, R. (2002). A modelling analysis of the potential for soil carbon sequestration under short rotation coppice willow bioenergy plantations. Soil Use and Management 18, 175183. Falloon, P., Smith, P., Szabo, J. and Pasztor, L. (2002). Comparison of approaches for estimating carbon sequestration at regional scale. Soil Use and Management 18, 164-174. Thornley, J.H.M. and Cannell, M.G.R. (2000) Managing forests for wood yield and carbon storage: a theoretical study. Tree Physiology 20(7), 477-484. resolution equilibrium GCM (UKHI) for 2050 and transient GCM (UKTR) for 2065. Future effective runoff was simulated under both scenarios. The paper describes a process-based model specifically designed to evaluate the potential for soil carbon sequestration in short rotation coppice (SRC) willow plantations in the UK. A mechanistic forest ecosystem simulator, which couples carbon, nitrogen and water (Edinburgh Forest Model), was calibrated to mimic the growth of a pine plantation in a Scottish climate. The model was run to equilibrium 1) as an undisturbed forest, 2) removing 2.5, 10, 20 or 40% of the woody biomass each year, 3) removing According to the model predictions, the conclusions were that the potential for soil carbon sequestration in these plantations is comparable to, or even greater than, that of naturally regenerating woodland. Our preliminary, site –specific model output suggest that soil carbon sequestration may constitute about 5% of the overall carbon mitigation benefit arising from SRC plantations. Their results suggest that carbon sequestration potential is greatest in soils whose carbon content has been depleted to relatively low levels due to agricultural land use practices such as annual deep ploughing of agricultural soils. More carbon was stored in the undisturbed forest (35.2 kg C m-2) than in any regime in which wood was harvested. Plantation management gave moderate carbon storage (14.3 kg C m2 ) and timber yield 915.6 m3 ha-1 year-1). Notably, annual removal of 10 or 20% of woody biomass per year gave both a high timber yield (25 m3 ha-1 year-1) and high carbon storage (20-24 kg C There was no simple inverse relationship between the amount of timber harvested from a forest and the amount of carbon stored. Management regime that maintain a continuous canopy cover and mimic, 28 Appendix SP0538 Climate change and soil function 50% of the woody biomass every 20 years, and 4) clear-felling and replanting every 60 years as in conventional plantations in this climate. m-2). The efficiency of the latter regime could be attributed (in the model) to high light interception and net primary productivity, but less evapotranspiration and summer water stress than in the undisturbed forest, high litter input to the soil giving high soil carbon and N2 fixation, low maintenance respiration and low N leaching owing to soil mineral pool depletion. to some extent, regular natural forest disturbance are likely to achieve the best combination of high wood yield and carbon storage. 29 Appendix SP0538 Climate change and soil function Table 7 Summary of email feedback and web search on the projects associated with the effects of climate change on forest soil functions in the UK. Research Contact Professor Paul Jarvis Department Project Ecology and Resource Management. University of Edinburgh. Centre for Ecology and Hydrology, Edinburgh IMP Forest Focus (EU funded) Grid ENabled Integrated Earth system model (GENIE) Global Atmosphere Division includes modules on: 1. Development of plant biomass components for the RothC soil carbon model (with Pete Smith, Aberdeen University), 2. Incorporating effects of changes in climate, nitrogen deposition and CO2 in projections of forest carbon budgets, 3. Development of soil process modelling for the UK national GHG Inventory (with Rothamsted Research), 4. Demonstration and evaluation of Forest Carbon Monitoring Network (with Mark Broadmeadow, Forest Research). Assessment of the relative importance of N-deposition, climate change and forest management on C-sequestration at intensive monitoring plots in Europe Dr Pete Smith www.ierm.ed.ac.uk/people/academic/jarvis.htm [email protected] www.ceh.ac.uk A modular, distributed and scaleable Earth System Model for long-term and paleo-climate studies (NERC funded) 1. Department of Plant and Soil Science. Aberdeen University Further Information C sequestration and water evaporation in relation to global environmental change in the boreal forest in Saskatchewan, temperate forest in Scotland and Mediterranean oak forest in Portugal. Preparation of annual Greenhouse Gas Inventory for Land Use Change and Forestry in UK - funded by DEFRA Dr Ronnie Milne, Details Intercomparison of Dynamic Global Vegetation Models (CEH funded) Application of Bayesian methods of parameterisation, updating and testing to CEH ecosystem models (CEH funded). CEH 2. Research consortium SEERAD/NAW funded Developing a model to simulate carbon and nitrogen dynamics in organic soils and predict the response of these soils to landuse and climate change. 30 www.abdn.ac.uk/pss/petesmith.hti Appendix SP0538 Climate change and soil function Professor JM Anderson University of Exeter Dept Biological Sciences Dr David Viner Climatic Research Unit, University of East Anglia DEFRA funded Climate Impacts LINK project Professor Richard Bardgett Department of Biological Sciences, University of Lancaster NERC Opinion based on tropical forest research: Roots are the major sources of carbon in mineral soils; Root material is deposited within the mineral matrix and therefore has a high potential for C stabilisation; Root carbon can be deposited deep in the soil profile where it is relatively unaffected by climate change compared to surface pools; Distribution and amount of root carbon vary with species management; With global warming there will be an increase in the active depth of soils leading to greater root deposition in mineral soils and the potential for C stabilisation, particularly if there is a shift from conifer to broadleaf forests. • Soil erosion and the interactions with land-management and climate. Collaboration with Anglia Polytechnic University and local (Norfolk) land managers. • Climate Change Impacts, Options, Strategies and Solutions for Rural Estate and Land-Use Management in the European Union. Collaboration with EU partners, the European Land Owners Organisation and the Country Land and Business Association. Just completed a project looking at C sequestration under various tree species under elevated CO2. The studies showed that C sequestration is actually reduced, due to priming of soil C. 31 Sanger et al. (1997) Haron et al. (1998). http://www.cru.uea.ac.uk/link/dave/dave.html Not specified the links with forestry Publication in press Appendix SP0538 Climate change and soil function Professor Douglas Godbold University of Wales, Bangor Free Air Carbon Enrichment (FACE) experiment Determining the influence of elevated CO2 on forest ecosystem C fluxes (Birch, Alder and Beech). Planted in March 2004, will run for at least 6 years. The design of the BangorFACE site allows for: Investigations of competition between tree species under current and future atmospheres; C and N dynamics of afforestation, in particular whole ecosystem C budgets, Changes in greenhouse gas emissions Investigation ectomycorrhizal succession and of nitrogen fixation under the influence of elevated CO2. [email protected] Reference: D. Godbold “BangorFACE – investigating global climate change” Information Sheet, unpublished. Work is currently concentrating on the influence of elevated atmospheric CO2 on C balance and C sequestration of old field afforestation. Determining whether elevated CO2 increases C sequestration of afforestation and to establishing the fate of old C stored in the soil prior to afforestation. Dr Andreas Heinemeyer University of York Professor John Grace Atmospheric and Environmental Science, University of Edinburgh Carboage project His research areas include: Improving understanding of soil carbon responses to environmental factors (e.g. temperature) and assessing the importance of separating soil microbial from root respiration; a main focus will be on forest soils and northern peatlands. A new approach is the York based mobile continuous-flow mass-spectrometer unit, enabling monitoring and partition of carbon fluxes under labelled and natural abundance levels in connection with treatments such as soil trenching and soil warming (e.g. infra-red light). We will also attempt to use this approach to link soil carbon fluxes to changes in the canopy environment via natural (photosynthetic) discrimination against 13C within the canopy. 1. Measure stocks of carbon at five sites over Europe, including carbon in biomass and soil; 2. Measure CO2 fluxes using eddy covariance in the 'roving tower' approach, over a chronosequence which will include existing EUROFLUX sites; 3. Measure soil respiration over time, also in the chronosequence; 4. Model the age-related changes in net primary production (NPP) and net ecosystem production (NEP), so that these models can be used as a management tool; 5. Develop products for users and stakeholders, so that such people can estimate the likely uptake of carbon by forests. 32 www.shef.ac.uk/ctcd/heinemeyer.html www.ierm.ed.ac.uk/lab101/annex1.doc www.geos.ed.ac.uk/abs/research/carboage Appendix SP0538 Climate change and soil function Dr Tom Nisbet (Forest Research), Professor Ian Reid (Loughborough University) and Professor Ian Calder (University of Newcastle Upon Tyne) Trees and Drought project of Lowland England (TaDPoLE) consortium Objectives of TaDPoLE include: Study soil moisture deficits under a range of landuses (conifer or broadleaf woodland, heath and grass). Understand evaporative moisture losses and groundwater recharge in woodlands overlying sandy soils. To generate quantitative information for input into national modelling http://www.lboro.ac.uk/departments/gy/tadpole/index.html Feedback from Professor Reid: “Our modelling of forest hydrology was very successful and gave us hope that this could be extended to include climate change scenarios”. “TaDPole already has the expertise, a massive database and the ability to resurrect the experimental set-up”. Sanger LJ, Anderson JM, Little D and Bolger T (1997) “Phenolic and carbohydrate signatures of organic matter in soils developed under grass and forest plantations following changes in land use” European Journal of soil science, 48 311-317 Haron K, Brookes PC, Anderson JM and Zakaria ZZ (1998) “Microbial Biomass and Soil Organic Matter Dynamics in Oil Palm Plantations, West Malaysia” Soil Biology and Biochemistry 30(5) 547-552 33 Appendix SP0538 Climate change and soil function Table 8. DEFRA – funded projects in the UK related to the effects of climate change on forest soil functions Research project/project code/time period Review of the potential for soil carbon sequestration under bioenergy crops in the U.K (NF0418), 01/02/0110/04/01 UK Emissions by Source & Removals by Sinks due to Land Use, Land Use Change & Forest Activities (GA01054), 02/06/03 – 31/05/06 Contractor organisation and location Project details Uncertainties, questions and research gaps identified Institute of Water and Environment, Cranfield University at Silsoe, Bedfordshire, MK 45 2PA At present, the experimental data suggested that soil carbon sequestration rates under short rotation coppice plantations can range from 0-1.6 Mg C ha-1 y-1. Of all available models, CENTURY seemed to be the best potential for adaptation to bioenergy crop systems because of its integrated plant-soil approach. A simple model using a carbon mass balance approach to predict soil carbon sequestration was also developed, which is site specific model, calibrated to soil data from natural woodland regeneration site in the U.K. According to the model output, there is a potential for a significant soil carbon sequestration in shortrotation coppice plantations in the U.K. The model identified the following factors of being major controls on rates and amounts of soil carbon sequestration under willow coppices: 1) carbon inputs (net primary production), 2) decomposition rates of the major soil carbon pools, 3) initial soil carbon content, 4) crop/plantation management practice, 5) depth of soil being influenced by the bioenergy crop. Carbon sequestration is most likely on soil whose carbon content has been depleted relatively low levels due to previous management practices. Carbon sequestration in soils is likely to occur until the original climatically-controlled equilibrium point between soil carbon inputs and outputs is reached. Considerable further research would be required to develop a general model that could incorporate climatic and soil-type variation, as well as hydrological interactions associated with the relatively high water demand of bioenergy crops, to accurately predict the potential for soil carbon sequestration in bioenergy plantations across the U.K. Centre for Ecology and Hydrology Projects aims are to provide estimates of greenhouse emissions by sources and removals by sinks associated with land use, land use change, forestry (LULUCF) in the U.K. and Devolved Administrations. The project will: 1. ensure that UK can meet its annual inventory reporting requirements on emissions by sources and removals by sinks associated with LULUCF 2. project UK emissions by sources and removals by sinks associated with LULUCF 3. ensure that UK’s inventory in these areas is significantly defensible, meets international reporting requirements, including IPCC guidelines and any Good Practice Guidance agreed by the UNFCCC COP, and uses the full range of available relevant information. The project is ongoing Department of Plant and Soil Science. Aberdeen University Developing a model to simulate carbon and nitrogen dynamics in organic soils and predict the response of these soils to land-use and climate change. www.abdn.ac.uk/pss/petesmith.hti 34