The impact of cold climate on physical and biological processes, especially the role of air and soil temperature in recovering photosynthesis and transpiration in boreal forests, was investigated in a series of studies. A process-based ecosystem model (CoupModel) considering atmospheric, soil and plant components was evaluated and developed using Generalized Likelihood Uncertainty Estimation (GLUE) and detailed measurements from three different sites. The model accurately described the variability in measurements within days, within years and between years. The forcing environmental conditions were shown to govern both aboveground and belowground processes and regulating carbon, water and heat fluxes. However, the various feedback mechanisms between vegetation and environmental conditions are still unclear, since simulations with one model assumption could not be rejected when compared with another. The strong interactions between soil temperature and moisture processes were indicated by the few behavioural models obtained when constrained by combined temperature and moisture criteria. Model performance on sensible and latent heat fluxes and net ecosystem exchange (NEE) also indicated the coupled processes within the system. Diurnal and seasonal courses of eddy flux data in boreal conifer ecosystems were reproduced successfully within defined ranges of parameter values. Air temperature was the major limiting factor for photosynthesis in early spring, autumn and winter, but soil temperature was a rather important limiting factor in late spring. Soil moisture and nitrogen showed indications of being more important for regulating photosynthesis in the summer period. The need for systematic monitoring of the entire system, covering both soil and plant components, was identified as a subject for future studies. The results from this modelling work could be applied to suggest improvements in management of forest and agriculture ecosystems in order to reduce greenhouse gas emissions and to find adaptations to future climate conditions. / QC 20110921 / the Nitro-Europe project

A process oriented modeling of an irrigated rice field in a semi arid area of Mali has been done with the help of computational tool CoupModel. The model has been used to simulate two levels of irrigation rates, in an attempt to test and see adequacy of a recommended irrigation rate and its environmental impact over the current management. A simpler simulation to represent less water demanding crops like sorghum or millet has also been done to indicate extent of the excess water and as alternative crop cultivation. Important processes and parameters to represent a rice cropping system have been identified and simulation was run for a 12 year period. Results show an irrigation amount of 916 mm delivers an overall 6 % increased yield. Results from the reduced irrigation also show a better output in surface runoff, nitrogen leaching and uptake, photosynthetic water use efficiency and fertilizer efficiency. Soil nitrogen and carbon storage shows nearly the same trend. Only nitrous oxide (N2O) emission rate increased by 13 % in the case of reduced irrigation. Simulation done for the other crops also shows a reasonable yield of sorghum or millet can be obtained with 46 % of water used for current rice irrigation.

Miscanthus Giganteus is a rapidly growing perennial grass utilizing C4 photosynthesis that is a promising candidate as a raw resource for “second generation” biofuel production. This study seeks to determine the long-term sustainability, from a water balance perspective, of cultivating this plant in different climate zones. CoupModel, a model for the soil-plant-atmosphere system, is utilized to model M. Giganteus and simulate its cultivation over a 30-year period at four sites in Europe, each representing a different climate zone. A future climate scenario building on historical climate data together with projections for monthly changes in temperature and precipitation, as modeled by the HadCM3 global climate model in the A2 emission scenario, is then created and used for another simulation at each site. The growth, yields, and water balances in each simulation are analyzed and compared. The highest yields and water use efficiencies are achieved in the warmest climates, but the most sustainable zones when taking water balance into account are the more humid ones. The humid continental, Dfb, zone and the humid subtropical, Cfa, zone are determined to be sustainable in the long-term for cultivation of M. Giganteus. / Miscanthus Giganteus är ett snabbväxande perennt gräs med C4-fotosyntes samt en lovande kandidat som resurs i tillverkandet av andra generationens biobränslen. Denna studie syftar till att bestämma den långsiktiga hållbarheten av odling av denna växt i olika klimatzoner ur ett vattenbalansperspektiv. CoupModel, en datamodell som simulerar systemet “jord-planta-atmosfär”, används för att simulera M. Giganteus och dess tillväxt över en 30-årsperiod för fyra platser i Europa vilka alla representerar en klimatzon. Ett framtida klimatscenario som bygger på historisk klimatdata tillsammans med projektioner för framtida månatliga förändringar i temperatur och nederbörd, framtaget av HadCM3 för IPCC:s utsläppsscenario A2, tas sedan fram och används för att göra ytterligare en simulering för varje plats. Plantans tillväxt, skörd och vattenbalans för varje simulation analyseras och jämförs. De högsta skördarna och högst vattenanvändningseffektivitet uppnås i de varmaste klimaten, men de mest hållbara zonerna för odling av M. Giganteus när vattenbalansen tas hänsyn till är zonerna med mest nederbörd. Dfb-zonen, med fuktigt inlandsklimat, och Cfa-zonen med fuktigt subtropiskt klimat bedöms vara långsiktigt hållbara för odling av M. Giganteus.

The removal of vegetation and overburden changes the naturalwater purifying processes and thus decreases the groundwaterprotection in gravel pit areas. The sand and gravel depositsusedfor aggregate extraction in Sweden are also often valuablefor extraction of groundwater as a drinking water resource. TheSwedish legislation requires that gravel pits be restored afterthe cessation of extraction, the aim being to reestablishvegetation and to reinstate groundwater purifyingprocesses. The objective of this study was to improve our understandingof the processes governing groundwater protection andvegetation establishment so that these could be applied toimproving restoration methods for reestablishing naturalgroundwater protection. The focus was on the importance of soilphysical properties of the topsoil for vegetation establishmentand groundwater recharge. Actual field methods for restoration were reviewed.Conflicts between aggregate extraction and groundwaterinterests were common. In many cases the actual restorationcarried out differed from pre-planned specifications in permitdocumentation. Commonly available substrates that might be used forrestoration of gravel pits were investigated. The soils weredescribed as regards texture, organic content, porosity, waterretention and hydraulic conductivity. The way in which acombination of the water retention characteristic and theunsaturated conductivity influenced the behaviour of thesoil-plant-atmosphere system was demonstrated using aprocess-orientated simulation model. Plants with well-developedaboveground characteristics and shallow roots in particularexerted the highest requirements on the soil physicalproperties. Key words:groundwater protection, soil physicalproperties, CoupModel, unsaturated conductivity, waterretention, transpiration, soil evaporation

With the use of a process-orientated ecosystem model andmeasurements conducted at different Swedish coniferous forestsites, abiotic and biotic interactions between tree and soilwere identified and related to governing factors. Two differentmodelling approaches to describe soil temperatures at two sitesincluding hydrological transects were tested (I). The approachin which both canopy and soil were considered proved to be amore flexible tool to describe soil temperatures, especiallyduring snow-free winter periods. Five sites along a climatetransect covering Sweden were used to describe soil carbon poolchanges during an 80-year period simulation (II). The dynamicmodelling approach, with a feedback between abiotic and bioticsub-models, was successful in describing simplified patterns offorest stand dynamics and furthermore in differentiatingbetween climate and nitrogen availability factors. The largereffect of nitrogen availability compared to climate on soilcarbon pool changes was clearly shown. Keywords:SPAC; soil surface energy balance; Norwayspruce; canopy; LAI; climate; nitrogen; CoupModel

There is now a general consensus among scientists on occurrences of more and intense climatic disasters, floods and droughts, everywhere in the future. To act sooner and smarter against these negative impacts, we must shift our focus in better understanding of the future climate change and possible implications of that to better manage our water resources. Certainly, there is a link between the future effects of climate change on water resources and trends of climatic variables. In this study, by using Mann-Kendall trend analysis method, it is concluded that from 1961 to 2010 only temperature has an upward trend, in all the seasons and yearly, in all the 16 studied stations from north, middle and south of Sweden. Furthermore, runoff simulated by HBV model shows increasing trend in summer and winter which is in partially agreement with the recorded one that discerns a growth in the mentioned seasons, as well as yearly. What is more, potential evapotranspiration estimated by FAO Penman-Monteith equation and actual one simulated by CoupModel reveal a rise in spring for the former and both spring and winter for the latter. Other meteorological variables do not show any significant trend, while intensive precipitation increased in winter and summer in the majority of the stations. Comparing the runoffs simulated by CoupModel and HBV model shows that HBV works better for three selected stations which can enforce the claim that HBV works better for smaller fields.

The impact of long term management strategies of irrigation with saline water in semi-arid region of Gordonia, South Africa is the highest interest to optimize water consumption, soil conservation, and crop yield for sustainable water allocations to human food production and ecosystem without irreversible damages to soil and water body. An integrated ecosystem assimilation, in shape of soil-water storage model based on physical approach for 30-year simulation run defined in form of digital ecosystem modelling with help of CoupModel tool to assemble together the most important underlying processes of soil hydraulics, irrigation demands, leaching fraction, evapotranspiration, salt transport. Two scenarios of water management strategy; surface as traditional and drip as subsurface irrigation considered to apply water and salt into the ecosystem model. Gaining high food production for human with respect to ecosystem sustainability, in each water management scenario studied by evaluating general and detailed result from water and salt balance for the entire simulation period plus long term nitrogen and carbon turnover as crop yield indicator. Non-productive water losses, salt accumulation in root zone, carbon and nitrogen turnover, salt transport to aquifer via deep percolation observed thoroughly. Decline in crop yield due to water and salt stress, conducted by monitoring biomass production with respect to water consumption and soil osmotic pressure in root zone. Drip scenario had better functionality to perform less water wastage by decreasing soil evaporation as non-productive water loss almost 40 %, however productive water consumption decreased 20 % due to insufficient leaching fraction and also salt accumulation increased in root zone. Precipitation had a significant role to accomplish leaching deficiency and removing salt from root zone. Salt accumulation flushed out from root zone by more leaching, though resulting more water wastage and more possibility of salinization threatening beneath aquifer. Ecosystem in terms of soil-water and plant responding differently facing salinity in different water management practices and salt as source of pollution could either stabilized in soil by accumulating in root zone causing anthropogenic soil desertification or percolate to beneath aquifer resulting aquifer salinization.

Evapotranspiration (ET) is an essential component of water cycle as it is an interlinkage between atmosphere, vegetation and soil surface in terms of energy and water balance. However, whether potential ET has the same tendency to change as actual ET and how ET trend (based on the difference between precipitation and runoff) is directly driven by dominant meteorological factors alone or combined with ecosystem‘s feedbacks to climate change (like land-use change) is still under the discussion. In this report, five ET parameterizations within two rainfall-runoff models [Coupled Heat and Mass Transfer Model (CoupModel) and Hydrologiska Byråns Vattenbalansavdelning (HBV)] have been set up based on six subcatchments of Sweden. The scenario derived from CoupModel shows that the trend of ET is affected by the change of land-use, where soil evaporation tends to shift to transpiration and interception evaporation. However, HBV model produces the other scenario: the trend of ET is merely the consequence of meteorological factors. Increased ET is contributed by increased interception evaporation due to the increased precipitation. After identifying the time split of changing ET trends, a dynamic simulation constructed both from HBV and CoupModel indicate that the increased total ET is primarily from increased ET in winter time. More and more interceptive water loss and transpiration resulted from land-use change due to more vegetation. On the other hand, land-use change is also a feed back to climate change. Transpiration controlled by the mechanism of stomata and water uptake controlled by reduction of soil moisture is highly related to variations of climatic conditions.

There is an extended concern for how to quantify the fluxes of greenhouse gasses (GHG) and how they are related to climate change and land use. Efforts have already been done, mostly regarding carbon (C) compounds, but there is still much to be done especially to understand regulating factors and interactions with the Nitrogen cycle. NitroEurope is a large project for the integrated European research into the N cycle. This study shares its aim, to improve the understanding the physics involved in the fluxes of the reactive N (Nr). More specifically, the patterns of some physical and biological processes related to Nr have been studied for two wetlands, one in the proximity of Edinburgh and the other in the North of Finland.   A common model setup has been used for both of them, since they are both peat soils. The differences applied to achieve appropriate performances give insights of their nature. The presence of snow is a major factor that governs the behavior of the site in Finland. The scaling of existing models for the estimation of heat transfer in the soil of the Scottish site is also critical, such as its groundwater level. The sites represent different climatic conditions, but for CO2 fluxes they showed similar behavior and response to governing meteorological conditions. Using the GLUE method in combination with a process oriented ecosystem model, some further insights have been gained for the regulation and control of greenhouse gas emissions from the two sites.

This study provides a long-term understanding of the impact of climate varia-bility and land use on seasonal water balance conditions for sustainable agricul-ture development, hydropower generation and ecosystem stability in the Lower Rufiji Basin. The severity of soil drought, extreme flooding and salinity intru-sion in the lower Rufiji floodplains are currently increasing smallholder poverty and enhance the sensitivity on the natural wetlands for shifting farming and livestock pastures. The CoupModel and SWAT hydrological model were ap-plied to assess and compare the impact of climate variability on the water bal-ance. The monthly river discharge was used for calibrating and validating the runoff at the Stiegler's Gorge. The simulated results for water balance compo-nents at Stiegler's Gorge showed 55% of accumulated precipitation is lost through evapotranspiration and 42 % is river runoffs for downstream agricul-ture and ecosystem services. The evaluation of the models simulation perfor-mance and posterior distribution of parameter behavioral value indicates the (GLUE) calibration method in the CoupModel agreed satisfactory with the Bayesian calibration (BC). The minimal variance in the Bayesian Calibration posterior parameter distribution was observed in the parameter for regulating water uptake from (CritThresholDry) and soil moisture availability for soil evaporation(PsiRs_ip). The SWAT simulation showed that south of the central floodplains has high risk of soil drought. The overall assessment implies that drought and river runoff dynamics in the LRB is affected by upstream land use activities. The strategies for building smallholder resilience towards climate change and land use impact requires collective and coordinated water manage-ment actions powered by individual, institutional, financial and technological adaptation.