Robert J. A. Jones

Vulnerability of subsoils in Europe to compaction: a preliminary analysis.

Abstract Identifying the vulnerability of subsoils to compaction damage is an increasingly important issue both in the planning and execution of farming operations and in planning environmental protection measures. Ideally, subsoil vulnerability to compaction should be assessed by direct measurement of soil bearing capacity but currently no direct practical tests are available. Similarly, soil mechanics principles are not suitably far enough advanced to allow extrapolation of likely compaction damage from experimental sites to situations in general. This paper, therefore, proposes a simple classification system for subsoil vulnerability to compaction based for field use on local soil and wetness data at the time of critical trafficking, and, at European level, on related soil and climatic information. Soil data are readily available ‘in Country’ or from the European Soil Database and climatic data are stored in the agrometeorological database of the MARS Project. The vulnerability to compaction is assessed using a two-stage process. First, the inherent susceptibility of the soil to compaction is estimated on the basis of the relatively stable soil properties of texture and packing density. Second, the susceptibility class is then converted into a vulnerability class through consideration of the likely soil moisture status at the time of critical loadings. For use at local level, adjustments are suggested to take account of possible differences in the support strength of the topsoil and specific subsoil structural conditions. The vulnerability classes proposed are based on profile pit observations, on a wide range of soils examined mainly in intensively farmed areas where large-scale field equipment is employed. A map of soil susceptibility to compaction in Europe has been produced, as the first stage in developing a more rigorous quantitative approach to assessing overall vulnerability than has been possible hitherto.

Projected changes in mineral soil carbon of European forests, 1990-2100

Forests are a major land use in Europe, and European forest soils contain about the same amount of carbon as is found in tree biomass. Changes in the size of the forest soil carbon pool could have significant impacts on the European carbon budget. We present the first assessment of future changes in European forest soil organic carbon (SOC) stocks using a dedicated process-based SOC model and state-of-the-art databases of driving variables. Soil carbon change was calculated for Europe using the Rothamsted Carbon model using climate data from four climate models, forced by four Intergovernmental Panel on Climate Change (IPCC) emissions scenarios (SRES). Changes in litter input to the soil due to forest management, projected changes in net primary production (NPP), forest age-class structure, and changes in forest area were taken into account. Results are presented for mineral soil only. Under some climate scenarios carbon in forest soils will increase slightly (0.1 to 4.6 Pg) in Europe over the 21st Century, whilst for one scenario, forest SOC stocks are predicted to decrease by 0.3 Pg. Different trends are seen in different regions. Climate change will tend to speed decomposition, whereas increases in litter input due to increasing NPP and changing age-class structure will slow the loss of SOC. Increases in forest area could further enhance the total soil carbon stock of European forests. Whilst climate change will be a key driver of change in forest soil carbon, changes in age-class structure and land-use change are estimated to have greater effects.

Soil Atlas of Africa

of water, nutrients and as a medium for growing. Soil stores, filters, buffers and transforms substances that are introduced into the environment. This capability is crucial in producing and protecting water supplies and for regulating greenhouse gases. Soil is a provider of raw materials. Soil is also an incredible habitat and gene pool. Soil is a fundamental component of our landscape and cultural heritage. The properties of soil vary tremendously from region to region. Soils under tropical rainforests are vulnerable to erosion and nutrient depletion if the vegetation cover is removed. Oasis regions in deserts and the Sahel show how seemingly infertile soils can be cultivated in the presence of water. The wetlands of Congo and other major African systems are stores of soil organic carbon and important wildlife habitats. The black, clay-rich soils of the Nile Valley in Sudan are rich in nutrients but difficult to cultivate when very wet or very dry. Soils with high salt levels are not suitable for the cultivation of crops but may support a unique plant community. AFRICA SOIL ATLAS OF

The effect of soil erosion on Europe's crop yields

A bstractSoil erosion negatively affects crop yields and may have contributed to the collapse of ancient civilizations. Whether erosion may have such an impact on modern societies as well, is subject to debate. In this paper we quantify the relationship between crop yields and soil water available to plants, the most important yield-determining factor affected by erosion, at the European scale. Using information on the spatial distribution of erosion rates we calculate the potential threat of erosion-induced productivity losses. We show that future reductions in productivity in Europe as a whole are relatively small and do not pose a substantial threat to crop production within the coming century. However, within Europe there is considerable variability, and although productivity in northern Europe is not likely to be significantly reduced by soil erosion, for the southern countries the threat of erosion-induced productivity declines is stronger.

A soil and agroclimatic model for estimating machinery work-days: the basic model and climatic sensitivity

Abstract A model is outlined which estimates the number of days when different soils are workable (for ploughing or seed-bed preparation) at different locations during the spring or autumn tillage periods. The procedure integrates soil properties with an agroclimatic parameter, meteorological field capacity. Field capacity, estimated from a simple water balance model, defines the period in days each year when the maximum water holding capacity of the soil is reached and drainage occurs. This period of field capacity is used as a first approximation for soil conditions unsuited to workability. The soil factors considered are wetness class, which quantifies the depth and duration of waterlogging in the soil profile, and retained water capacity, which is a function of texture, organic matter content and bulk density. These are used to assign a workability rating to soils, which reflects their relative suitability for field work. This rating is converted into a number of days that are added to, or subtracted from, the initial climatic estimate of the workable period to derive a final estimate of good machinery work-days (Wd). The spatial distribution of work-days is illustrated for England and Wales. Workability assessments are derived for the dominant soil series within 5 km × 5 km grid squares and this information is integrated with the corresponding, altitude adjusted, climatic data. Upper and lower quartile start and end dates for field capacity were used in the model to indicate the sensitivity of machinery work-days to potential variations in climate. During wet years most of the country is shown to have no spring work-days, but the situation improves dramatically in a dry year. This indicates why spring-sown crops have been less favoured under the climatic conditions of the past 50 years. Conversely, most of the country experiences at least a few autumn work-days even during a wet year. However, soil tillage in the north and west of England and Wales would benefit greatly if the climate was comparable with that during a dry quartile year.

Climate change and land suitability for potato production in England and Wales: impacts and adaptation

The viability of commercial potato production is influenced by spatial and temporal variability in soils and agroclimate, and the availability of water resources where supplementary irrigation is required. Soil characteristics and agroclimatic conditions greatly influence the cultivar choice, agronomic husbandry practices and the economics of production. Using the latest (UKCP09) scenarios of climate change for the UK, the present paper describes a methodology using pedo-climatic functions and a geographical information system (GIS) to model and map current and future land suitability for potato production in England and Wales. The outputs identify regions where rainfed production is likely to become limiting and where future irrigated production would be constrained due to shortages in water availability. The results suggest that by the 2050s, the area of land that is currently well or moderately suited for rainfed production would decline by 88 and 74%, respectively, under the ‘most likely’ climate projections for the low emissions scenario and by 95 and 86%, respectively, for the high emissions scenario, owing to increased likelihood of dry conditions. In many areas, rainfed production would become increasingly risky. However, with supplementary irrigation, c . 0·85 of the total arable land in central and eastern England would remain suitable for production, although most of this is in catchments where water resources are already over-licensed and/or over-abstracted; the expansion of irrigated cropping is thus likely to be constrained by water availability. The increase in the volume of water required due to the switch from rainfed- to irrigated-potato cropping is likely to be much greater than the incremental increase in water demand solely on irrigated potatoes. The implications of climate change on the potato industry, the adaptation options and responses available, and the uncertainty associated with the land suitability projections, are discussed.

Soil Profile Analytical Database for the European Union

Danish Journal of Geography 95: 49–58, 1995. In 1985 the European Communities now the European Union published a soil map covering all the Community countries. This map has been digitized, but for modelling purposes it was necessary to compile a Soil Profile Analytical Database connected to the European Communities Soil Map. This compilation commenced in 1992 following a decade of expert group meetings concerning European soil and land data. This account describes the events that led to the decision to develop this database, and how it was compiled.

Soil Profile Analytical Database for Europe (SPADE): Reconstruction and Validation of the Measured Data (SPADE/M)

Abstract Geografisk Tidsskrift, Danish Journal of Geography 106(1):71–85, 2006 The Soil Profile Analytical Database of Europe of Measured profiles (SPADE/M) was created to provide a common structure for storing harmonized information on typical soil profile properties of European soils. The main difficulty encountered in constructing the database was the transfer of the source data from individual electronic spreadsheet pages to the more rigid structure of a relational database. The data in spreadsheet format had been collected more than 12 years earlier but pressure was mounting for the capability to link these data to the Soil Map of Europe. A semi-automatic process was implemented to transfer data from nominal positions on the spreadsheet page to an intermediate structure highlighting any deviations from expected values. Conflicting situations were solved by manual intervention and expert judgement. Data in the intermediate structure were subjected to a validation procedure with the aim of storing uniform data in the database. The validation checks cover format authentication, restricting entries to permissible values and those passing plausibility tests. In cases where a horizon property could not be represented consistently following the field specifications, the database structure was adapted to accommodate those conditions. The database model was extended to allow data from multiple samples taken at the same plot and from the analysis of samples from different laboratories to be stored.

A review of the impacts of degradation threats on soil properties in the UK

Abstract National governments are becoming increasingly aware of the importance of their soil resources and are shaping strategies accordingly. Implicit in any such strategy is that degradation threats and their potential effect on important soil properties and functions are defined and understood. In this paper, we aimed to review the principal degradation threats on important soil properties in the UK, seeking quantitative data where possible. Soil erosion results in the removal of important topsoil and, with it, nutrients, C and porosity. A decline in soil organic matter principally affects soil biological and microbiological properties, but also impacts on soil physical properties because of the link with soil structure. Soil contamination affects soil chemical properties, affecting nutrient availability and degrading microbial properties, whilst soil compaction degrades the soil pore network. Soil sealing removes the link between the soil and most of the ‘spheres’, significantly affecting hydrological and microbial functions, and soils on re‐developed brownfield sites are typically degraded in most soil properties. Having synthesized the literature on the impact on soil properties, we discuss potential subsequent impacts on the important soil functions, including food and fibre production, storage of water and C, support for biodiversity, and protection of cultural and archaeological heritage. Looking forward, we suggest a twin approach of field‐based monitoring supported by controlled laboratory experimentation to improve our mechanistic understanding of soils. This would enable us to better predict future impacts of degradation processes, including climate change, on soil properties and functions so that we may manage soil resources sustainably.

Software, Data and Modelling News: Soil organic carbon content indicators and web mapping applications

Distributing geographic information via the Internet allows interoperability with similar information and real-time integration of data from around the world. The software developed allows the users to exchange, integrate, and analyze data in new ways. Users can combine various environmental indicators (organic carbon content) and information accessed via the Internet with their local data for display, query, and analysis. In order to guarantee interoperability, the developed services are based on international standards, as promoted by the INSPIRE initiative.