Land Management Data Research Articles

Transferability of a Bayesian Belief Network across diverse agricultural catchments using high-frequency hydrochemistry and land management data

Biogeochemical catchment models are often developed for a single catchment and, as a result, often generalize poorly beyond this. Evaluating their transferability is an important step in improving their predictive power and application range. We assess the transferability of a recently developed Bayesian Belief Network (BBN) that simulated monthly stream phosphorus (P) concentrations in a poorly-drained grassland catchment through application to three further catchments with different hydrological regimes and agricultural land uses. In all catchments, flow and turbidity were measured sub-hourly from 2009 to 2016 and supplemented with 400–500 soil P test measurements. In addition to a previously parameterized BBN, five further model structures were implemented to incorporate in a stepwise way: in-stream P removal using expert elicitation, additional groundwater P stores and delivery, and the presence or absence of septic tank treatment, and, in one case, Sewage Treatment Works. Model performance was tested through comparison of predicted and observed total reactive P (TRP) concentrations and percentage bias (PBIAS). The original BBN accurately simulated the absolute values of observed flow and TRP concentrations in the poorly and moderately drained catchments (albeit with poor apparent percentage bias scores; 76 % ≤ PBIAS≤94 %) irrespective of the dominant land use, but performed less well in the groundwater-dominated catchments. However, including groundwater total dissolved P (TDP) and Sewage Treatment Works (STWs) inputs, and in-stream P uptake improved model performance (−5 % ≤ PBIAS≤18 %). A sensitivity analysis identified redundant variables further helping to streamline the model applications. An enhanced BBN model capable for wider application and generalisation resulted.

Comparative Performance Analysis of Türkiye's Land Management System Using SWOT Analysis Method

With sustainability and digitalization, countries are urgently conducting technical studies as well as legal and economicstudies in land management. In this study, land management models developed by 12 countries with different landmanagement systems were analyzed according to the qualitative research method. The data obtained by the selectedcountries have been examined under these headings: land management, registered data, legal side, technicalinstitutions, digitalization studies and technical models. Comparison tables of the countries were created under thedetermined headings. In addition, a comparison table was created by examining the land management data modelsdeveloped by the countries. The performance analysis of the land management studies in Türkiye (In terms of Planning,Cadastre, Land Infrastructure, Real Estate Valuation) has been made by using the SWOT Analysis method of evaluationof these countries. The strengths and weaknesses of Türkiye's land management system were evaluated as a result ofthe analysis.

Evaluation of RothC model for predicting soil organic carbon stock in north-west Ethiopia

Assessing soil organic carbon (SOC) is vital for water retention, soil health, nutrient cycling, greenhouse gas emissions, and pollutant reduction and thereby contributes to sustainable agricultural production and food security. Thus, using long-term climate, soil, and land management inputs, the Rothamsted Carbon (RothC) model was applied to assess the current and future SOC stocks in the Anjeni watershed using long term climate, soil and land management data. RothC was calibrated with long-term SOC, land management, and climatic data from the Anjeni watershed in north-west Ethiopia. The correlation coefficient between simulated and observed SOC in 1997 and 2021 were 0.77 and 0.86, respectively, suggesting that the model could characterize the SOC of the Anjeni watershed. Then, the RothC was used to estimate SOC in the watershed for 30 years, from 2022 to 2052, under three slope gradients and four land use type and carbon storage scenarios (business as usual (BAU), low, medium and high carbon inputs). The result indicated that in the lower slope gradient, the current SOC simulation is less than all future scenarios considered under all land use types. Grass/fallow land showed higher current and projected SOC than cultivated land and plantation forest. Moreover, grass/fallow land with a gentle slope gradient had higher SOC than the watershed's middle and high-elevation parts. Overall, the model projected an increase of SOC under different future scenarios that could be due to climate and land use cover changes, the long-term soil-water conservation camping works and better soil and land managements in the watershed. This future assists for water retention, soil health, nutrient cycling, soil aeration, and greenhouse gas emission reduction, which in turn could enhance agricultural productivity, food security, and sustainable development.

Development of local eco-network of Lutsk territorial community: features and problems

Introduction. Planning of ecological networks at the local level is one of the most difficult stages of geospatial organization of the territory, which requires a detailed and balanced approach, thorough analysis of topographic materials, land management data and the use of geographic information technologies. Local-level eco-networks have a number of features related to the need for a high level of detalization and connectivity of their components. For them, specific model questions are formed about the assignment of certain areas to the structural and functional elements of the ecological network. At the same time, these elements are complementary elements in the structure of ecological networks of regional importance. The purpose of the article. The purpose of the study is to find out the conditions and specific features of the local eco-network of the Lutsk territorial community, to justify the allocation of its structural and functional elements, the current state of development and recommendations to ensure proper functioning. Methods. To study the features of the territorial organization of preserved areas of the urban community, in particular, as part of the nature reserve network and the Emerald network, substantiation of the boundaries of functional components of the local eco-network, elucidation of functional relationships between its elements, construction of cartographic models methods of field research, comparative geographical analysis, cartographic analysis, statistical analysis were used. Results. The natural conditions of the community, sources of economic impact and anthropogenic transformation of the environment, indicators of nature reserves, the level of naturalness of other areas: swamps, wetlands, water protection zones, forests, protective forest belts, reclaimed areas due to their obvious necessity inclusion in the local eco-network to ensure its functional integrity were analyzed. 13 natural nuclei, seven connecting elements, buffer zones potentially suitable for increasing the area of natural nuclei and ecological corridors of the territory of restoration and territory of natural development have been identified. The scientific novelty. The substantiation of structural and functional elements of the first local level eco-network in Volyn Region is made, the map of the local eco-network is developed, the problems of functioning are determined and the prospects of development are analyzed. Practical significance. The development of the local ecological network of the Lutsk town territorial community is a pilot project of the development of local ecological network of the territorial communities of the Volyn region.

Fire exposure index as a tool for guiding prevention and management

Protected Areas (PA) in Brazil have legal instruments for the conservation and protection of fauna and flora. The Sustainable Use Reserves (SURs) category have mechanisms to ensure the security of traditional lifestyles. Despite the existence of mechanisms and information that contribute to the protection of forest areas, threats to its conservation such as deforestation, fires, and climate extremes are increasing. Fires represent a major threat to many sustainable development goals, such as climate, health and food security, especially for people who depend on forest resources. This study covers two SURs, the Tapajós National Forest (FLONA Tapajós) and the Tapajós-Arapiuns Extractive Reserve (RESEX Tapajós-Arapiuns) located in Pará State, Brazilian Amazon, where deforestation, fires and land conflicts have escalated during the last decade. This research aimed to analyze environmental and land management data to construct a Fire Exposure Index (FEI), identify the pressure exerted on SURs and a tool to guide strategic planning since exposure is a component of vulnerability, therefore also of risk. The index is composed of four dimensions: fire, landscape, climate and territorial management. We analyzed the spatio-temporal dynamics between 2003 and 2020 to determine the Fire Exposure Index in 2020. The results indicate where and how interactions occur in priority areas, with regard to fire, landscape, climate and territorial management. High values of FEI (above 0.8) were mainly distributed around the northern and southeastern part of FLONA Tapajós in approximately 1,300 km2, an area occupied by a high density of roads and agricultural expansion, which may affect the interior of the SURs. In the RESEX Tapajós-Arapiuns, the area with high FEI occur along the banks of the Arapiuns and Tapajós rivers, covering an area of about 330 km2, where most of the riverside communities live. The methodology developed in this research is potentially replicable for other protected areas in Brazil and in the world to support understanding and the development of management strategies to deal with fire threats. The additional format of communicating the results of this research to society and decision makers was conceived as a dashboard to facilitate its use.

Evaluating Soil Conservation Effectiveness: An Investigation of Spatial Targeting, Conservation Adoption, and Financial Incentives

ABSTRACTIdentifying and treating erosion‐prone, critical source areas (CSA) presents the opportunity to effectively address erosion at a watershed scale. Social and financial drivers of conservation adoption, however have buffered implementation. An integrated systems understanding is needed to identify internal feedbacks and potential synergistic conservation policies. We simulate the physical, social, and financial incentive interactions with a high‐level system dynamics model to understand the conservation adoption and subsequent erosion behavior of the system. A Bass diffusion model integrated with physical modeling results enables the simulation of CSA, the diffusion of innovations, and payment for conservation practices. Land retirement and tillage reduction best management practices are assessed for the dryland wheat farming region in the Inland Pacific Northwest of the United States. Model utility was confirmed with quantitative land management data and qualitative local expertise. Historical, voluntary‐based efforts to reduce erosion suffer marginal returns. We conclude that: (1) All targeting of CSA reduces long‐term erosion rates; (2) The most effective use of conservation funds, however, occurs when the diffusion of innovation mechanism is reinforced by broad‐scale payments for tillage reduction; and (3) By identifying and utilizing positive feedback, our simulations suggest large gains in erosion reduction and conservation fund efficiency are possible.

Estimating Soil Organic Carbon Density in the Otindag Sandy Land, Inner Mongolia, China, for modelling spatiotemporal variations and evaluating the influences of human activities

Accurate quantitative estimates of Soil Organic Carbon Density (SOCD) can effectively represent regional carbon cycle processes and regulation mechanisms, and can serve as reference data when making land management decisions. Limited research, however, has been carried out in arid or desert zones covered with sparse vegetation, despite the fact that these cover wide areas of the earth and play a significant role in global carbon cycles. In this study, the Otindag Sandy Land and its surroundings (OSLAIS) in the Inner Mongolia Autonomous Region of China was selected as the study area. The study introduces a useful technique for making high spatial coverage SOCD estimates for drylands by utilizing GF-1 WFV optical satellite images and a time series of MODIS satellite remote sensing datasets, and using these to optimize parameters for simulation models in conjunction with other technical procedures that are described. The results showed that the resulting model's accuracy was 77.87%, R2 = 0.8627, and so the SOCD estimates modelled by soil basal respiration (SBR) could be used for SOCD estimation and for analyzing the spatial distribution patterns across the OSLAIS. The average SOCD was 1.22 kgC/m2 for the whole of the OSLAIS, and it had a heterogenous distribution pattern. The SOCD was closely related to the way the land was used in each area, and the average SOCD for the main land use types were: forest land = 2.88 kgC/m2, farmland = 1.63 kgC/m2, shrub land = 1.41 kgC/m2, and grassland = 1.08 kgC/m2. In conclusion, we believe that the proposed method, based on high-resolution GF-1 WFV data and optimized estimation models constructed by integrating climate and vegetation characteristic data, can effectively describe the spatial distribution patterns of SOC and SOCD in the OSLAIS area, in depth and in detail, especially for the areas where the SOCD values are high. We expect this research to provide useful technical support and scientific reference data for land management and for land degradation/desertification assessments, for the study area monitored, as well as across the whole dryland area of China.

Assessment of a Simplified Connectivity Index and Specific Sediment Potential in River Basins by Means of Geomorphometric Tools

Sediment connectivity is a major topic in recent research because of its relevance in the characterization of the morphology of river systems and assessing of sediment transport and deposition. Currently, the connectivity indices found in the literature are generally dimensionless and need to be coupled with quantitative soil-loss data for land management and design purposes. In the present work, a simple methodology is proposed to assess two different indices, namely, the simplified connectivity index (SCI) and the specific sediment potential (SSP), based on geomorphometric tools that are commonly available in commercial and open-source geographic information system (GIS) platforms. The proposed metrics allows us to easily assess both the SCI and the SSP as functions of the estimated soil erosion per unit area of the catchment and of the inverse distance of each unit area from the river outlet, this distance being measured along the network path. The proposed indices have been devised to express, respectively, the potential sediment transfer ability and the sediment mass potentially available at a given section of the drainage network. In addition to other parameters used to describe the catchment characteristics potentially affecting the river sediment delivery capacity, the SCI and SSP indices can help to refine theoretical models in order to assess the sediment yield (SY) in ungauged river basins.

Comparing an Annual and a Daily Time-Step Model for Predicting Field-Scale Phosphorus Loss.

A wide range of mathematical models are available for predicting phosphorus (P) losses from agricultural fields, ranging from simple, empirically based annual time-step models to more complex, process-based daily time-step models. In this study, we compare field-scale P-loss predictions between the Annual P Loss Estimator (APLE), an empirically based annual time-step model, and the Texas Best Management Practice Evaluation Tool (TBET), a process-based daily time-step model based on the Soil and Water Assessment Tool. We first compared predictions of field-scale P loss from both models using field and land management data collected from 11 research sites throughout the southern United States. We then compared predictions of P loss from both models with measured P-loss data from these sites. We observed a strong and statistically significant ( < 0.001) correlation in both dissolved (ρ = 0.92) and particulate (ρ = 0.87) P loss between the two models; however, APLE predicted, on average, 44% greater dissolved P loss, whereas TBET predicted, on average, 105% greater particulate P loss for the conditions simulated in our study. When we compared model predictions with measured P-loss data, neither model consistently outperformed the other, indicating that more complex models do not necessarily produce better predictions of field-scale P loss. Our results also highlight limitations with both models and the need for continued efforts to improve their accuracy.

Woody colonization of road embankments: A large spatial scale survey in central Spain

Planting of woody species is a commonly used method to restore road embankments. Given the importance of road verges as potential corridors and refuge for biodiversity, natural plant regeneration processes may also play an important role in establishing vegetation into these novel landscape elements. Most studies on woody colonization of roadsides have considered only a few sites covering a very limited environmental range. Therefore, it is unclear whether or not there are general patterns that may explain the development of woody vegetation. We analyzed woody vegetation colonization in embankments over a large and heterogeneous territory, using aerial photographs, available repositories of environmental and land management data sets and some embankment features. We addressed the following questions: (1) To what extent does the presence of planted woody plants influence patterns of natural recruitment in road embankments? and (2) What are the key factors underlying natural/passive plant colonization in road embankments? We used Multi-Model Inference (MMI) analysis to model woody vegetation cover. According to our results, woody-planted vegetation does not have a facilitating effect on natural colonization, questioning the efficiency of reforestation measures in the ecological integration of areas affected by road construction. Passive natural plant colonization occurs spontaneously in road verges and shows a highly site-dependent pattern, driven mainly by the age of embankments and the immediate surrounding vegetation. Therefore, we suggest that natural succession may be sufficiently effective as a passive restoration measure on embankments in the long term.

Estimating Sediment Yield from Upland and Channel Erosion at A Watershed Scale Using SWAT

Sediment discharge is one of the main water quality concerns in integrated watershed management. A proper identification of sediment sources is therefore important to the success of watershed conservation programs. Since water quality monitoring data collected at the mouth of the watershed alone are typically not sufficient for identifying key sediment sources distributed in the watershed, hydrologic models can be applied to prioritize Best Management Practices (BMPs) implementation for sediment control in a watershed. In this paper, the Soil and Water Assessment Tool (SWAT) is applied to the South Tobacco Creek (STC) watershed in Canada to identify sediment sources and to estimate the spatial distribution of sediment yield from both upland and channel erosion processes. The model is calibrated and validated against observed flow and sediment data measured at fourteen edge-of-field and mainstream stations based on 20 years of land management data. Modeling results show that approximately 60 and 40 % of the sediment discharge at the mouth of the watershed are originated from channel erosion and upland erosion respectively. A high spatial and temporal variation of sediment yield is found in the watershed depending on climate, topography, land use, and soil conditions. These findings will be helpful for understanding the runoff and erosion processes and evaluating the cost-effectiveness of soil and water conservation programs at a watershed scale.

Effects of groundwater level variations on the nitrate content of groundwater: a case study in Luoyang area, China

Most researchers usually adopt laboratory experimental methods when studying the effects of water level variations on the concentrations of pollutants. In this study, the data from routine monitoring sites in the city of Luoyang, China, are collected and analyzed to verify the results of previous laboratory experiments and to examine whether variations in the water level affect the concentration of pollutants in different locations, particularly that of nitrates. Statistical studies conducted between 2007 and 2011 show a significant variation in the groundwater depth in the Luoyang area. This depth variation clearly affected the groundwater environment in the soil system. This study uses field data to investigate the effects of water table fluctuation on the nitrate content of groundwater. Hydrogeological information and land management data are collected from five monitoring points in Luoyang. The significance of and correlation between the environmental indicators of groundwater depth and soil–water systems are then analyzed using SPSS and Origin software. The results show that the redox potential (Eh) and nitrate nitrogen content are strongly correlated with groundwater depth. Significantly negative correlations were found between nitrate nitrogen and ammonium nitrogen concentration, between Ehand ammonium nitrogen concentration, and between pH and nitrate nitrogen concentration. These results indicate that water table fluctuation affects the soil–water physicochemical properties and further exerts a significant effect on nitrate movement across soil sola.

Relative sea-level rise in the Basque coast (N Spain): Different environmental consequences on the coastal area

Short sediment cores taken from (i) a recently regenerated salt marsh (Plentzia estuary), (ii) an incipient marsh and (iii) a pristine marsh (Urdaibai estuary), have been interpreted for evidence of environmental impacts and sea-level change on the basis of microfaunal and geochemical determinations and historical land management data. Under the current relative sea-level rise scenario, it might be expected that salt marsh ecosystems lose their ability to keep up with tidal flooding and drown following a transgressional pattern where marsh vegetation replaces woody plant species. With more frequent inundation from rising sea level, the change would progress from high marsh through a transition to the low marsh state. Ultimately this would lead to the development of a mud flat when sea level rises beyond low marsh accretion rates, with important coastal management implications.Geological observations from the southeastern Bay of Biscay, however, suggest that this model does not always apply. Evidence indicates that reclaimed areas rapidly gain elevation due to very high sedimentation rates and are colonized by salt marsh vegetation within a few decades, pristine salt marshes in this case have kept up with current sea-level rise, but more importantly, due to high sedimentation rates, even former intertidal mud flats have gained elevation over the last 50 years allowing salt marsh vegetation to colonize new areas. This recent evolution, however, has to be considered in a context of anthropogenic impacts in river catchments wherein sediment supply has been enhanced by human activity.

Economic evaluation of tillage management practices at the watershed scale in southern Manitoba

The costs, risk, and additional management associated with the conversion of agricultural land from conventional tillage to conservation tillage play a significant role in the producers’ likelihood of adoption of such practices. A local watershed organization in the South Tobacco Creek (STC) watershed in southern Manitoba has been collecting land management data for almost 20 years. As part of the national Watershed Evaluation of Beneficial Management Practices (WEBs), a tillage index and model were developed based on field tillage operations and production costs, and net incomes. The index and model quantified economic impacts of land management practices for three crop rotations under three tillage systems at the watershed scale. Based on a tillage index to define tillage levels for zero, minimum, and conventional tillage, a tillage cost function related tillage cost to tillage passes and crop residue management. Net income of crops and typical rotations under three tillage systems has been estimated. For canola, the greatest net income was generated in the conventional tillage (CT) system, which is attributed to the yield response to the tilled seedbed. As tillage frequency decreased, net income for canola declined. In contrast, the income response for cereals, such as wheat, was highest under minimum tillage (MT) due to reduced fuel and depreciation costs relative to conventional tillage. However net income for cereals managed with zero tillage (ZT) was significantly reduced due to increased equipment costs. Using the same tillage index, the model has produced results suggesting that for a wheat–canola rotation there is a significant difference between cropping system costs in areas of labour, oil and fuel, chemical and tillage costs; however, there is no significant difference between the three tillage levels in areas of total costs and net income. Although MT overall performed better compared to ZT or CT, net income of these three different tillage systems was offset between crops of the wheat–canola rotation and generally no statistically significant differences were observed. These results explained why most farmers in the STC watershed prefer conventional or minimum tillage to zero tillage-due to increased machinery investment and lower net returns for zero tillage. If conservation tillage is to be promoted in this region of Manitoba, additional incentives may be required to encourage its further adoption. However, increased net income for conservation tillage of cereals provides a clear incentive to adopt this practice.

Field-Level Targeting Using SWAT: Mapping Output from HRUs to Fields and Assessing Limitations of GIS Input Data

Soil erosion from agricultural fields is a fundamental water quality and quantity concern throughout the U.S. Watershed models can help target general areas where soil conservation measures are needed, but they have been less effective at making field-level recommendations. The objectives of this study were to demonstrate a method of field-scale targeting using ArcSWAT and to assess the impact of topography, soil, land use, and land management source data on field-scale targeting results. The study was implemented in Black Kettle Creek watershed (7,818 ha) in south-central Kansas. An ArcGIS toolbar was developed to post-process SWAT hydrologic response unit (HRU) output to generate sediment yields for individual fields. The relative impact of each input data source on field-level targeting was assessed by comparing ranked lists of fields on the basis of modeled sediment-yield density (Mg ha-1) from each data-source scenario. Baseline data of field-reconnaissance land use and management were compared to NASS and NLCD data, 10 m DEM topography were compared to 30 m, and SSURGO soil data were compared to STATSGO. Misclassification of cropland as pasture by NASS and aggregation of all cropland types to a single category by NLCD led to as much as 75% and 82% disagreement, respectively, in fields identified as having the greatest sediment-yield densities. Neither NASS nor NLCD data include land management data (such as terraces, contour farming, or no-till), but such inclusion changed targeted fields by as much as 71%. Impacts of 10 m versus 30 m DEM topographic data and STATSGO versus SSURGO soil data altered the fields targeted as having the highest sediment-yield densities to a lesser extent (about 10% to 25%). SWAT results post-processed to field boundaries were demonstrated to be useful for field-scale targeting. However, use of incorrect source data directly translated into incorrect field-level sediment-yield ranking, and thus incorrect field targeting. Sensitivity was greatest for land use data source, followed closely by inclusion of land management practices, with less sensitivity to topographic and soil data sources.

Agricultural management explains historic changes in regional soil carbon stocks

Agriculture is considered to be among the economic sectors having the greatest greenhouse gas mitigation potential, largely via soil organic carbon (SOC) sequestration. However, it remains a challenge to accurately quantify SOC stock changes at regional to national scales. SOC stock changes resulting from SOC inventory systems are only available for a few countries and the trends vary widely between studies. Process-based models can provide insight in the drivers of SOC changes, but accurate input data are currently not available at these spatial scales. Here we use measurements from a soil inventory dating from the 1960s and resampled in 2006 covering the major soil types and agricultural regions in Belgium together with region-specific land use and management data and a process-based model. The largest decreases in SOC stocks occurred in poorly drained grassland soils (clays and floodplain soils), consistent with drainage improvements since 1960. Large increases in SOC in well drained grassland soils appear to be a legacy effect of widespread conversion of cropland to grassland before 1960. SOC in cropland increased only in sandy lowland soils, driven by increasing manure additions. Modeled land use and management impacts accounted for more than 70% of the variation in observed SOC changes, and no bias could be demonstrated. There was no significant effect of climate trends since 1960 on observed SOC changes. SOC monitoring networks are being established in many countries. Our results demonstrate that detailed and long-term land management data are crucial to explain the observed SOC changes for such networks.

Changes in land management and nitrogen balance at different scales in the Weiße Elster river basin, Germany

Sound river basin and environmental management depend on accurate data for land use and management. To date, the appropriate sources of agricultural land management data for different planning levels have not been determined. Hence, our study investigated the use of three different information sources of land management: (i) statistical data, (ii) postal surveys, and (iii) interviews. For different aggregation levels, comprising (i) district/community level, (ii and iii) farm level, a detailed analysis was conducted to identify the information about land management and its impact on the nitrogen balance. Land management data are used as the basis for calculation of nutrient balances. Therefore, the analysis included the use of the nutrient balance model REPRO (Reproduction of the soil organic matter) on the small scale for the years 1999–2003. The benefi ts and limitations of the three information sources were assessed using the example of the “Weiße Elster” river basin in Central Germany. Statistical data are suitable for an overview and first classification, but information about fertilizer application is not available. Postal surveys are suitable for the generation of questionnaires that give specific information about the topic. However, although the low rate of return gives information on land management distribution, it does not provide area-wide information. Interviews are appropriate for smaller areas, and there is a higher response than compared to postal surveys, however interviews are very time consuming. We detected remarkable changes in land management due to the structural changes in the agricultural sector since German unifi cation in 1990. The three different information sources all showed that there has been a marked decrease of livestock densities and land management intensity since German unification. The high resolution data for the “Parthe” sub-basin of the “Weiße Elster” river basin showed that nitrogen balances are significantly influenced by the weather conditions: both very dry and wet conditions led to lower crop yields, and consequently to higher nitrogen balances.

A Comprehensive Modeling Approach for Reservoir Water Quality Assessment and Management Due to Point and Nonpoint Source Pollution

A comprehensive modeling approach has been developed for use in formulating a watershed management plan to improve the water quality of Cedar Creek reservoir, one of five large water supply reservoirs in north central Texas operated by Tarrant Regional Water District. Eutrophication, or specifically the increase in concentrations of chlorophyll-a (chl'a') over the last 18 years, is a major concern for the water managers. To develop a watershed management plan, the watershed model SWAT was linked with the lake eutrophication model WASP. Several intensive field campaigns and surveys were conducted to collect extensive water quality and land management data for model setup and calibration. In addition to the streamflow, the SWAT model was well calibrated for sediment (including channel erosion) and nutrients. Further, a simple modification to the SWAT in-stream routine allowed simulation of the nutrient load due to channel erosion. The in-stream water quality parameters for SWAT were based on an independent QUAL-2E model calibration. The calibrated SWAT model showed that more than 85% of the total N and total P loading to the lake are from watershed nonpoint sources. Although cropland occupies only 6% of the watershed area, it contributed more than 43% of the sediment, 23% of total N, and 42% of total P loading from the watershed. The channel erosion contributed about 35% of the total sediment load. The watershed model identified subbasins that contribute considerable amounts of sediment and nutrients. Based on these loads, the calibrated WASP model showed that the watershed nonpoint-source nutrient load (total N and total P) should be reduced by at least 35% to see a significant reduction in chl'a' concentrations when compared to the WASP calibration levels.

An increased understanding of soil organic carbon stocks and changes in non-temperate areas: National and global implications

National and sub-national scale estimates of soil organic carbon (SOC) stocks and changes can provide information land degradation risk, C sequestration possibilities and the potential sustainability of proposed land management plans. Under a GEF co-financed project, ‘The GEFSOC Modelling System’ was used to determine SOC stocks and projected stock change rates for four case study areas; The Brazilian Amazon, The Indo-Gangetic Plains of India, Kenya and Jordan. Each case study represented soil and vegetation types, climates and land management systems that are under represented globally, in terms of an understanding of land use and land management systems and the effects these systems have on SOC stocks. The stocks and stock change rates produced were based on detailed geo-referenced datasets of soils, climate, land use and management information. These datasets are unique as they bring together national and regional scale data on the main variables determining SOC, for four contrasting non-temperate eco-regions. They are also unique, as they include information on land management practices used in subsistence agriculture in tropical and arid areas. Implications of a greater understanding of SOC stocks and stock change rates in non-temperate areas are considered. Relevance to national land use plans are explored for each of the four case studies, in terms of sustainability, land degradation and greenhouse gas mitigation potential. Ways in which such information will aid the case study countries in fulfilling obligations under the United Nations Conventions on Climate Change, Biodiversity and Land Degradation are also considered. The need for more detailed land management data to improve SOC stock estimates in non-temperate areas is discussed.

Canadian agricultural land-use and land management data for Kyoto reporting

The land use and management data requirements for assessing, monitoring and reporting on the impact of agricultural production practices on the environment, especially in a country as large as Canada, are considerable. In view of the fact that environmental assessments are a relatively new phenomenon, data collection activities targeted toward these needs are not widespread. As a result, we find it necessary to acquire and integrate a variety of data sources with differing time lines, spatial scales and sampling frameworks. This paper uses our current activities with respect to Kyoto reporting as a focus to present and discuss the types of data required and the spatial analysis and integration procedures being developed to provide them. The essential data for this activity include the area of crop and land use types, land use changes since 1990, farm and land management practices and biomass production. The spatial framework selected for national analysis is the Soil Landscapes of Canada, and the primary existing data sources are the Census of Agriculture, sample-derived yield estimates and satellite-based land cover products. These are supplemented with detailed, multi-season, multi-year satellite image interpretations conducted at an ecologically and statistically stratified sample of sites across the country. The use of these data in preparing an account of greenhouse gas sources and sinks identified a number of gaps and problems, and a brief outline of future work designed to improve the data inputs is presented. Key words: Kyoto reporting, data integration, land use and management, greenhouse gases, carbon sequestration