Managing soils for a warming earth in a food‐insecure and energy‐starved world

World energy consumption increased from 11.5 EJ in 1860 to 463 EJ in 2005, and is projected to be 691 EJ in 2030 and 850 EJ in 2050. The principal driver of such a drastic surge in energy demand is the increase in world population which was merely 1 billion in 1800, 1.6 billion in 1900, 6.0 billion in 2000, and is projected to be 7.5 billion in 2030 and 9.2 billion in 2050 before stabilizing at ≈10 billion by 2100. Heavy reliance on fossil‐fuel consumption has increased atmospheric CO₂ abundance from 280 ppm in 1750 to 383 ppm in 2008 and is increasing at ≈2 ppm (4.2 Pg) per year along with the attendant threat of climate disruption. Similar to the close link between energy use and atmospheric chemistry, there also exists a close link between food insecurity and climate change through degradation of soils and desertification of the ecosystems. Global annual per capita cereal consumption increased from 267 kg in 1950, peaked at 339 kg in 1985, and decreased to 303 kg by 2000. In the quest for identifying alternate sources of energy, world production of bioethanol (mostly from corn grains in USA and sugarcane in Brazil) was 65 billion L, and that of biodiesel was 13 million Mg (t) (55% in EU countries) in 2008. Conversion of lignocellulosic biomass, using crop residues or establishing energy plantations, has severe constraints of the additional requirements for land area, water, and plant nutrients. Removal of crop residues for energy and other uses has severe adverse impacts on soil quality and agronomic productivity. Yet, globally average crop yields must be increased by 60% to 120% between 2000 and 2050 for meeting the needs of increase in population and change in dietary habits. Meeting demands of the growing world population and rising aspirations necessitate serious and objective considerations of change in food habits (to a more vegan diet), improvement in energy‐use efficiency, increase in crop yield per unit area and input, restoration of degraded soils and ecosystems, widespread adoption of recommended soil and crop practices, and identification of non‐C fuel sources.     

Extent and characterisation of salt‐affected soils in Iran and strategies for their amelioration and management

Salinisation of land resources is a major impediment to their optimal utilisation in many arid and semi‐arid regions of the world including Iran. Estimates suggest that about 34 million ha, including 4·1 million ha of the irrigated land, are salt‐affected in Iran as the consequence of naturally occurring phenomena and anthropogenic activities. The annual economic losses due to salinisation in the country are more than US$ 1 billion. With variable levels of success, different approaches—salt leaching and drainage interventions, crop‐based management, chemical amendments and fertilisers and integrated application of these approaches—have been used to enhance the productivity of salt‐affected soils in the Country. From sustainable management perspective, it is revealed from the past research that integrated salinity management and mitigation approaches have the potential to successfully address the complex problems of salt‐induced land degradation in Iran. As the growing need to produce more food and fibre for the expanding Iranian population necessitates the increased use of salt‐affected land resources in the foreseeable future, there is an urgent need to develop and implement a pertinent National Strategic Plan. In addition to establishing networks for monitoring spatial and temporal changes in soil salinity and water quality, this plan should integrate the management of salt‐affected environments into the overall management of land and water resources in the country. It should also address different management aspects of salt‐affected land resources in a holistic manner by considering the biophysical and environmental conditions of the target areas as well as livelihoods of the affected communities. The involvement of the communities will facilitate in developing a greater understanding about the potential uses and markets of the agricultural products produced from salt‐affected areas. Copyright © 2007 John Wiley & Sons, Ltd.     

Harvesting European knowledge on soil functions and land management using multi‐criteria decision analysis

Soil and its ecosystem functions play a societal role in securing sustainable food production while safeguarding natural resources. A functional land management framework has been proposed to optimize the agro‐environmental outputs from the land and specifically the supply and demand of soil functions such as (a) primary productivity, (b) carbon sequestration, (c) water purification and regulation, (d) biodiversity and (e) nutrient cycling, for which soil knowledge is essential. From the outset, the LANDMARK multi‐actor research project integrates harvested knowledge from local, national and European stakeholders to develop such guidelines, creating a sense of ownership, trust and reciprocity of the outcomes. About 470 stakeholders from five European countries participated in 32 structured workshops covering multiple land uses in six climatic zones. The harmonized results include stakeholders’ priorities and concerns, perceptions on soil quality and functions, implementation of tools, management techniques, indicators and monitoring, activities and policies, knowledge gaps and ideas. Multi‐criteria decision analysis was used for data analysis. Two qualitative models were developed using Decision EXpert methodology to evaluate “knowledge” and “needs”. Soil quality perceptions differed across workshops, depending on the stakeholder level and regionally established terminologies. Stakeholders had good inherent knowledge about soil functioning, but several gaps were identified. In terms of critical requirements, stakeholders defined high technical, activity and policy needs in (a) financial incentives, (b) credible information on improving more sustainable management practices, (c) locally relevant advice, (d) farmers’ discussion groups, (e) training programmes, (f) funding for applied research and monitoring, and (g) strengthening soil science in education.     

Soil conservation and ecosystem services

Accelerated soil erosion, driven by anthropogenic activities such as conversion of natural ecosystems to agroecosystems and mechanical tillage, has numerous adverse impacts on ecosystem services. In addition to degrading soil quality and reducing agronomic/biomass productivity on-site through a decrease in use-efficiency of inputs, off-site impacts of accelerated erosion include eutrophication and contamination, sedimentation of reservoirs and waterways, and emissions of greenhouse gases (e.g., CO₂, CH₄ and N₂O). While advancing food and nutritional security, adoption of restorative land use and recommended management practices are important to strengthening numerous ecosystem services such as improving water quality and renewability, increasing below and above-ground biodiversity, enhancing soil resilience to climate change and extreme events, and mitigating climate change by sequestering C in soil and reducing the emission of CO₂, CH₄ and N₂O. An effective control of accelerated erosion is essential to sustainable development and improving the environment.     

New frontiers of land and water commodification: socio‐environmental controversies of large‐scale land acquisitions

A growing number of regions in the developing world are targeted by transnational investors who are acquiring large amounts of land and natural resources. Driven by the increasing global demand for agricultural products, such investments are often considered an opportunity for economic development in the target country. However, there are concerns about the social and environmental impacts on local communities. In this brief review, we discuss some key socio‐environmental controversies surrounding large‐scale land acquisitions (LSLAs). LSLAs often target common property systems and lead to privatization and commodification of land through long‐term land concessions. There is a debate between supporters of foreign land investments as a means to attract modern agricultural technology that would decrease the yield gap in underperforming agricultural land and those who question such a development model because it is seldom coupled with policy instruments that would ensure that the benefits improve food security in local populations. Large‐scale land investments displace a variety of systems of production ranging from small‐scale farming to (arguably) “unused” land such as forests and savannas on which local communities often depend. Moreover, LSLAs entail an appropriation of water resources that may negatively impact local farmers or downstream human and natural systems. In most cases, investors keep the land fallow but, when they put it under productive use, they typically change land cover and land use to start intensified commercial farming, often for nonfood crops. Copyright © 2017 John Wiley & Sons, Ltd.     

ADAPTING TO CLIMATE CHANGE BY IMPROVING WATER PRODUCTIVITY OF SOILS IN DRY AREAS

Considering extreme events of climate change and declining availability of appropriate quality water and/or highly productive soil resources for agriculture in dryland regions, the need to produce more food, forage and fibre will necessitate the effective utilization of marginal‐quality water and soil resources. Recent research and practices have demonstrated that effective utilization of these natural resources in dry areas can improve agricultural productivity per unit area and per unit water applied. This paper focuses on the following three case studies as examples: (1) low productivity soils affected by high levels of magnesium in soil solution and on the cation exchange complex; (2) degraded sandy soils under rainfed conditions characterized by low water‐holding capacity, organic matter and clay content and (3) abandoned irrigated soils with elevated levels of salts inhibiting growth of income generating crops. The results of these studies demonstrate that application of calcium‐supplying phosphogypsum to high‐magnesium soils, addition of clays to light textured degraded soils and phytoremediation of abandoned salt‐affected soils significantly improved productivity of these soils. Furthermore, under most circumstances, these interventions were economically viable, revealing that the efficient use of marginal‐quality water and soil resources has the potential to improve livelihoods amid growing populations in dry areas while reversing the natural resource degradation trend. However, considerably more investment and policy‐level interventions are needed to tackle soil degradation/remediation issues across both irrigated and dryland agricultural environments if the major challenge of producing enough food, forage and fibre is to be met. Copyright © 2011 John Wiley & Sons, Ltd.     

Sodicity‐induced land degradation and its sustainable management: problems and prospects

Currently at least 20 per cent of the world's irrigated land is salt‐affected. However, projections of global population growth, and of an increased demand for food and fibre, suggest that larger areas of salt‐affected soil will need to be cropped in the future. About 60 per cent of salt‐affected soils are sodic, and much of this land is farmed by smallholders. Ameliorating such soils requires the application of a source of calcium (Ca²⁺), which replaces excess sodium (Na⁺) at the cation exchange sites. The displaced Na⁺ is then leached from the root zone through excess irrigation, a process that requires adequate flows of water through the soil. However, it must now be recognized that we can no longer conduct sodic soil amelioration and management solely with the aim of achieving high levels of crop productivity. The economic, social, and environmental impacts of different soil‐amelioration options must also be considered. A holistic approach is therefore needed. This should consider the cost and availability of the inputs needed for amelioration, the soil depth, the level to which sodicity needs to be reduced to allow cropping, the volume and quality of drainage water generated during amelioration, and the options available for drainage‐water disposal or reuse. The quality and cost of water available for post‐amelioration crops, and the economic value of the crops grown during and after amelioration should also be taken into account, as should farmers' livelihoods, the environmental implications of amelioration (such as carbon sequestration), and the long‐term sustainable use of the ameliorated site (in terms of productivity and market value). Consideration of these factors, with the participation of key stakeholders, could sustainably improve sodic soil productivity and help to transform such soils into a useful economic resource. Such an approach would also aid environmental conservation, by minimizing the chances of secondary sodicity developing in soils, particularly under irrigated agriculture. Copyright © 2006 John Wiley & Sons, Ltd.     

区域土地利用与生态系统服务价值变化研究——以广东省湛江市为例

利用1996—2004年湛江市土地利用变更数据,在研究土地利用变化的基础上,从时空角度分析生态系统服务价值(ESV)变化。研究结果表明:①1996—2004年,湛江市耕地、林地、牧草地面积在减少,其中耕地减少最多,减少了11954.1hm2;园地、居民点及工矿用地、交通用地、未利用土地面积在增加,其中居民点及工矿用地增加最多,增加了7696.4hm2。②1996—2004年,湛江市总ESV在缓慢减少,减少了0.57亿元,变化率-0.44%;湛江市生态系统单项服务功能价值(ESVf)变化的总体趋势是:气体调节、气候调节、土壤形成与保护、生物多样性保护、食物生产、原材料在减少,水源涵养、废物处理、娱乐文化在增加;不管是整体生态系统服务功能,还是单项服务功能,湛江市各县区都在减弱。     

Productivity enhancement of salt‐affected environments through crop diversification

Recent trends and future demographic projections suggest that the need to produce more food and fibre will necessitate effective utilization of salt‐affected land and saline water resources. Currently at least 20 per cent of the world's irrigated land is salt affected and/or irrigated with waters containing elevated levels of salts. Several major irrigation schemes have suffered from the problems of salinity and sodicity, reducing their agricultural productivity and sustainability. Productivity enhancement of salt‐affected land and saline water resources through crop‐based management has the potential to transform them from environmental burdens into economic opportunities. Research efforts have led to the identification of a number of field crops, forage grasses and shrubs, aromatic and medicinal species, bio‐fuel crops, and fruit tree and agroforestry systems, which are profitable and suit a variety of salt‐affected environments. Several of these species have agricultural significance in terms of their local utilization on the farm. Therefore, crop diversification systems based on salt‐tolerant plant species are likely to be the key to future agricultural and economic growth in regions where salt‐affected soils exist, saline drainage waters are generated, and/or saline aquifers are pumped for irrigation. However, such systems will need to consider three issues: improving the productivity per unit of salt‐affected land and saline water resources, protecting the environment and involving farmers in the most suitable and sustainable crop diversifying systems to mitigate any perceived risks. This review covers different aspects of salt‐affected land and saline water resources, synthesizes research knowledge on salinity/sodicity tolerances in different plant species, and highlights promising examples of crop diversification and management to improve and maximize benefits from these resources. Copyright © 2008 John Wiley & Sons, Ltd.     

Economic and Soil Environmental Benefits of Using Controlled‐Release Bulk Blending Urea in the North China Plain

Crop production must be increased in order to ensure a sustainable food supply for the growing world population. Controlled‐release urea (CRU) improves nutrient use efficiency and saves labor, but its use in crop production is limited due to its high cost. Bulk blending urea (BBU) consists of both CRU and conventional urea and could be an excellent substitute or replacement for CRU. Nevertheless, its economic benefits and soil environment impact are unknown. A 3‐year field experiment was conducted to investigate the effects of two different nitrogen management practices in terms of economic benefits, soil mineral nitrogen availability, aggregate stability, and soil microbial communities. Split applications of conventional urea (UREA) and a single application of BBU were tested on winter wheat (Triticum aestivum L.) and summer maize (Zea mays L.) in the North China Plain between 2010 and 2013. Crop yields were measured after each harvest, and soil environmental parameters were determined after the 3‐year crop sequence. Relative to UREA, BBU significantly increased net revenue, soil inorganic nitrogen concentration, and the functional diversity of the soil microbial community without adverse effects on the soil bacterial community composition. On the other hand, BBU reduced the amount of soil macro‐aggregates and the mean weight diameter value of soil water‐stable aggregates. Although BBU showed great potential for improving wheat–maize cropping systems in the North China Plain, future studies should focus on optimizing the nitrogen dosage and the CRU ratio in BBU to decrease nitrogen leaching, avoid soil aggregate deterioration, and maintain crop yield. Copyright © 2017 John Wiley & Sons, Ltd.     

Approaches to calculating P balance at the field‐scale in Europe

Policies for mitigating phosphorus (P) loss from agriculture are being developed in a number of European countries and calculation of P balance at farm‐gate or field‐scale is likely to be a part of such policies. The aim of the paper was to study P balance at the field‐scale in 18 countries that participated in the European Union's (EU) European Co‐operation in the Field of Scientific and Technical Research (COST) action on “Quantifying the Agricultural Contribution to Eutrophication (COST 832)”. A questionnaire related to P balance at the field‐scale was sent to representatives in the 18 countries and all replied. The field as a unit is defined differently in the various European agricultural systems. The identification of the inputs and outputs differ among the countries. For example, P losses may or may not be taken into account in balances. Phosphorus balance at the field‐scale is used in all countries in the context of soil analysis and P recommendations for crops and advisory and research purposes, while only a few countries use it for policy purposes (agri‐environmental). There is wide variation in P balances between countries in relation to soil fertility and vulnerability of water to eutrophication from nutrients from agricultural sources. In several eastern European countries, Hungary for example, fertilizer P use has dropped to about one tenth of the levels used in the 1980's. Many of these countries now have a negative P balance. In western European countries, by contrast, although fertilizer P use has decreased in recent years, the average input is higher than the average off take, and soil test phosphorus (STP) values remains high and continue to increase in some areas. Twelve different soil extractants for STP are used in Europe, and their interpretation can hinder direct comparisons. Calculating P balance at the field‐scale involves approximations in estimating inputs and outputs and spatial variations in fertility in individual fields. Accuracy of data and standardization of methods for calculating balances with inputs and outputs will be a challenge for the future development of a sustainable agriculture in Europe.     

Drought risk to agricultural land in Northeast and Central Germany

Aim of the study was the evaluation of the present state and further development of drought risk to agricultural sites in Northeast (NE) and Central Germany in consideration of climate changes. Based on the Medium Scale Agricultural Site Map, soil‐hydrological data were derived for heterogeneous soil areas. They refer to the landscapes in NE and Central Germany characterized by low precipitation, marked spatial soil heterogeneity, and a high share of hydromorphic soils. The soil data were linked with long‐term climate records of 368 stations for the period 1951–2000 as well as a climate scenario for the period 2001–2055. The plant water supply was calculated for three crop groups: cereals, root crops, and grass. The current and future development of drought risk of agricultural land of NE and Central Germany was evaluated. Starting in 1951, the water supply over the vegetation period has been decreasing with time for all crop groups up to now and may continue up to the year 2055 at most sites. However, there are also regions with increased plant water supply. The federal states of Brandenburg and Saxony‐Anhalt showed the strongest water deficit. Especially in these states, the plant water supply is strongly limited for cereals already today and probably may get worse for all crops in the future. On an average of the years, drought may limit plant growth in parts at >40% of agricultural land. In the federal states Mecklenburg‐Western Pomerania, Saxony, and Thuringia, the plant water supply mostly will stay in an approximately sufficient range due to higher precipitation and more favorable soil quality. The results are a background for the assessment of land‐use planning and evaluation of current and future soil‐ and site‐specific crop growing suitability on a medium scale.     

Zinc and copper availability in herbage and soil of a Pinus radiata silvopastoral system in Northwest Spain after sewage‐sludge and lime application

Silvopastoral systems are ancient farming systems in the world, consisting of the combination of a woody component (trees or shrubs) and crops and/or animals within the same land‐management unit. In various European Union (EU) countries, the possibility of using sewage sludge as a fertilizer is under consideration as a viable method of disposal, considering the increase in sewage‐sludge production in recent years and the restrictions imposed by European policy on the usual methods of disposal. The concern is the concentration of heavy metals, which can reach humans through the food chain. In Spain, R.D. 1310/1990, as well as European Directive 86/278, limit the total in‐soil heavy‐metal concentration, but not the solubility changes, which directly affect plant absorption and leaching of heavy metals throughout the soil profile. The objective of this experiment was to compare, in a silvopastoral system over a period of 3 years, the effect of applying three doses of sewage sludge combined with and without liming, on total and available soil Zn and Cu and their concentration in plants. Liming did not affectct Zn and Cu availability; however, sewage sludge increased Zn and Cu availability, though total in‐soil Zn was increased only in November 2000. In‐plant Zn concentration was increased by sewage sludge in the last 2 years of the study. In all cases, the quality of forage obtained and measured with regard to the concentrations of Zn and Cu was adequate for animal consumption. With respect to sewage‐sludge application as a fertilizer, the management of heavy‐metal availability must be included in the policy, because environmental risk could then be adequately evaluated.     

发展保护性耕作技术 有效防治耕地土壤侵蚀

 我国是世界上人均耕地最少的国家之一,人均耕地仅为0.093 3 hm2,不到世界平均水平的40%。同时,我国也是世界上耕地土壤侵蚀最严重的国家之一,全国耕地土壤侵蚀面积为4 033万hm2,占耕地总面积的33.15%。仅坡耕地每年产生的土壤流失量约达15亿t,占全国土壤侵蚀总量的33%。耕地土壤侵蚀已对我国的粮食安全、生态安全和经济社会可持续发展构成了严重威胁。论述了水土保持领域发展保护性耕作技术的重要意义、产生与发展、主要技术内容与技术模式及保护性耕作技术的生态、经济和社会效益。发展保护性耕作技术,是水土保持的新理念,对于有效防治耕地土壤侵蚀和非点源污染具有重要意义。     

Soil structural stability and erosion rates influenced by agricultural management practices in a semi‐arid Mediterranean agro‐ecosystem

Unsuitable agricultural practices can cause loss in soil quality and erodibility to thus increase or trigger desertification under Mediterranean conditions. A field experiment was performed at the El Teularet‐Sierra de Enguera Experimental Station (eastern Spain) to assess the influence during a 5‐yr period of different agricultural practices on physical and chemical indicators of soil quality (total and water‐soluble carbohydrates, glomalin‐related soil proteins (GRSP), total organic carbon, aggregate stability (AS), vegetation cover and soil erosion). The management practices included residual herbicide use, ploughing, ploughing + oats, addition of oat straw mulch and a control (land abandonment). Adjacent soil under natural vegetation was used as a reference for local, high‐quality soil and as a control for comparison with the agricultural soils under different management practices. Oat straw mulching led to higher levels of water‐soluble carbohydrates, GRSP and AS and lower soil erosion rates, resulting in values similar to those in the soil under native vegetation. The lowest levels of carbohydrates and GRSP were for the plots that were treated with herbicide or were ploughed. The maintenance of and increases in stable aggregates promoted by the different agricultural management practices over the years were attributed to increases in labile organic fractions such as carbohydrates and to the GRSP content. The results demonstrate that land abandonment (control plot) or the use of a cover (plants or straw) contributes to increases in soil quality and reduces the risk of erosion. The research also shows that sustainable agricultural management allows soil to recover and that the use of straw mulching is the most effective management strategy.     

Turkish Waters: Source of Regional Conflict or Catalyst for Peace?

Unlike most Middle East countries which are highly dependent on water from sources originating in other countries or on desalination, Turkey is naturally endowed with relatively abundant water resources. The Turkish government has assigned the highest priority to completing its massive $32 billion Southeastern Anatolia Project (GAP), consisting of 22 dams and 19 hydroelectric power plants on the Euphrates and Tigris rivers. Scheduled for completion in 2005, GAP will generate 27 billion kilowatt hours of hydroelectric power and will divert water from the Atat rk Dam reservoir through the two giant ?anliurfa Tunnels into a canal system to irrigate 1.7 million hectares in south-eastern Anatolia just north of the Syrian border. For Turkey, GAP will not only provide food and energy for a growing population, but is the crux of a comprehensive and sustainable economic development plan designed to end instability and reduce out-migration by radically transforming the feudal economic and social structure of this poor and largely Kurdish inhabited region of the country. Syria and Iraq, the downstream riparians in the Tigris-Euphrates Basin, also have rapidly growing populations and ambitious development plans. They contend that GAP will greatly diminish and degrade their water supply in future years. The severe current drought conditions in Syria and Iraq have added urgency to their demands for a greater share of the rivers' flow. This article examines the legal, political, military and technological strategies employed by the parties to advance their interests. After reviewing efforts to achieve a negotiated solution, we examine various Turkish proposals to foster regional peace by exporting water from other Turkish rivers to Cyprus, Israel, the Gaza Strip, Jordan, and other Arab countries.     

基于土地利用变化的安徽省生态服务价值研究

[目的]揭示安徽省生态系统服务价值变化规律,为区域可持续发展提供依据。[方法]以安徽省3期的土地利用数据为基础,根据研究区不同土地利用类型的单位面积生态服务价值和各土地利用类型面积分别分析了研究区内2000—2010年不同时段的生态系统服务价值、不同土地利用类型生态服务价值变化的贡献率以及不同年份各单项功能生态服务价值。[结果]研究区林地和耕地是主要的土地利用类型,其次是建设用地和未利用土地;2000,2005,2010年生态服务总价值量分别为:532.31,537.59和531.35亿元;土地利用类型的贡献度从大到小依次为:林地耕地水域草地未利用地建设用地;林地和建设用地是生态系统服务价值变化贡献率最大的土地利用类型;9个单项生态服务价值从大到小依次为:维持生物多样性保持土壤气候调节气体调节原材料生产提供美学景观食物生产废物处理水文调节。[结论]研究区内的生态服务价值呈现相对稳定态势,其中林地对生态服务总价值的贡献最大,建设用地是生态服务总价值增长的主要牵制力。     

Plant‐available nitrogen in the soil: Relationships between pre‐plant and pre‐sidedress nitrate tests for corn production

Corn (Zea mays L.) producers in the rainfed regions sometimes sidedress fertilizer N according to pre‐plant–nitrate test (PPNT) results based on the assumption that there is a linear relationship between pre‐sidedress nitrate test (PSNT) and the PPNT. There has been no report on such relationship in Ontario (Canada) and elsewhere in the nonirrigated corn‐growing regions. A field study was conducted near Ottawa, Canada for 7 y to (1) determine changes in soil available N from pre‐planting to shortly after the sidedress stage (late June) for corn and (2) establish a quantitative relationship between PPNT and PSNT. In each year, soil samples from fields of three to four plot experiments with different cropping histories, soil textures, and management levels, taken at 7 to 10 d intervals, and from on‐farm trials taken at pre‐planting and pre‐sidedress, were extracted with 2 M KCl. The concentrations of NO ‐N were determined colorimetrically. It was found that soil NO ‐N concentration of PSNT was a linear function of PPNT with an average slope of 1.7. However, the slope of the regression equations differed dramatically among cropping sequences, and to a lesser extent, soil textures. The NO ‐N concentration after planting to pre‐sidedress was influenced by air temperature and precipitation during this period of time. Both PPNT and PSNT positively correlated with corn‐grain yield. Our data suggest that cautions must be taken when deciding the rate of fertilizer N for sidedress application to corn based on PPNT test, especially under more humid northern climate conditions.     

Land‐use evolution and degradation in Lesvos (Greece): a historical approach

An analysis has been undertaken of the land‐use evolution in the island of Lesvos for the last 5000 years, based on historical and archaeological documents and recent soil and vegetation survey data. A series of maps were compiled using historical documents for the period from 3300 bc to 1886 bc and vegetation field survey data for the period from 1886–1996. A soil survey (scale 1:50 000) was conducted in 1996 in order to relate the land‐use changes to the present physical environment. Cultivation of the land started around 3300 bc and intensified during the 18th century bc . During the Roman period forests were already significantly reduced to satisfy the increasing demands for agricultural products, timber and heating. In the Byzantine period (4th–15th century), vineyards and pastures expanded, mainly by clearing the forests. Olive plantations increased during the 13th century, motivated by the allocation of subsidies. During the first centuries of the Ottoman period, there was a further expansion of olive groves and pastures by reducing forests, while vineyards declined. Great changes occurred in the last century in the geographical distribution and the total area occupied by the various types of land use. Olive groves significantly expanded and were redistributed covering more fertile and productive land on hilly areas by clearing mainly pine forests. Oak forests increased on previous pasture areas. Today, pasture is the main type of land use in hilly areas. These previously forested areas have been cleared without any accompanying measures against soil erosion. This highly degraded land with shallow and severely eroded soils is not able to sustain any profitable agricultural use or natural forest. However, areas cultivated with olives remained sustainable for more than seven centuries without being significantly degraded. Copyright © 2000 John Wiley & Sons, Ltd.     

To What Extent Did We Change Our Soils? A Global Comparison of Natural and Current Conditions

The food security–climate change nexus rapidly gains momentum. Soil degradation plays an important role in this context while dealing with, for example, the productive capacity of our soil resources or carbon sequestration for climate change mitigation. However, little has been done to assess the pristine soil conditions despite the fact that these provide the basis to put changes into context. Various methodologies have been developed to assess the global distribution of current soil conditions. We used the S‐World methodology that was developed to generate global soil property maps for environmental modelling studies. Up till now, the S‐World methodology assessed current soil conditions by disaggregating the Harmonized World Soil Database using detailed information on climate, topography, land cover, and land use. This study used the S‐World methodology to derive global soil conditions under natural vegetation. A large number of natural areas around the globe were identified for which land cover, expressed by the Normalized Difference Vegetation Index, could be successfully correlated to environmental conditions such as temperature, rainfall, and topography. Using this relation in regression kriging, the vegetation index under natural conditions was derived for the entire globe. Subsequently, the S‐World methodology was used to calculate the soil properties under natural land cover and absence of human land use. Soil property maps for natural and current conditions were compared and showed large local differences. The results indicate that there are major changes due to land cover and land use change and that these changes are concentrated on the globe. The results are the basis for future assessments on, for example, land degradation, food security, or the sustainable development goals. © 2017 The Authors. Land Degradation & Development Published by John Wiley & Sons Ltd.