Multi‐factorial causes of land‐use change: land‐use dynamics in the agropastoral village of Im Mial,northwestern Syria

Land‐use dynamics in drylands are complex processes. In the context of a typical agropastoral village in northwestern Syria Im Mial, the effects of demographic and social changes, reduced soil productivity, changes in agricultural technologies and historical events on land use and land productivity are examined. Decreasing yields, mainly the result of reduced fallow periods and low investments in the land, and the deterioration of the grazing resources are the two main signs of the loss of land productivity in the area. The growing population forces the villagers to practise continuous rainfed barley cultivation with no or only occasional fallow, and without any application of plant nutrients. Also, technological changes, from the use of donkey ploughs and hand harvesting to less labour‐intensive and time‐consuming cultivation practices with tractors and combine harvesters, and the increased importance of stubble in the livestock diet have contributed to the reduction of the fallow periods. The villagers attribute the yield decreases mainly to the low rainfall in the area. The high rainfall variability discourages the fallowing of fields because continuous cultivation maximizes the chances for good harvests in years with high rainfall. There is also an expansion of cultivation into the less fertile and sloping traditional grazing areas. Population growth, increased numbers of livestock and the expansion of cultivated land into grazing areas has also put pressure on the grazing resources of the village. The possession of livestock is seen as a sign of wealth and the villagers aim to have large flocks of animals. For them, livestock is also an important means for investment of cash earned from off‐farm work, which is the main source of income for most of the households in the village. There is a recent trend of increasing levels of crop‐livestock integration with less free grazing that produces higher return to the land users. This may also have a positive effect on the restoration and conservation of the degraded natural traditional grazing grounds. The stabilization and productive use of the land resources in this dry environment requires the combined and interdisciplinary effort from both the land‐users and the policy‐makers. Copyright © 2001 John Wiley & Sons, Ltd.     

Global coffee market influence on land‐use and land‐cover change in the Western Ghats Of India

In this study, we used image‐processing techniques to examine the spatial pattern of land‐use and land‐cover (LULC) change that occurred in the coffee growing area in the Western Ghats of India during the international coffee crisis in the 1990s. The study also ascertains the driving forces of these changes using qualitative research methods that include archival studies and interviews of knowledgeable individuals. We analyzed Landsat Thematic Mapper (TM) for 1991 and Landsat ETM+ for 2002 to quantify LULC. Historical land‐use changes in different land ownership regimes were also analyzed. Global coffee market fluctuations were found to be the major cause of landscape change in the study region. When the global coffee prices increased, more forested areas were cleared for coffee cultivation. Failure of global coffee market forced farmers to convert land from subsistence farming (rice) to short‐period commercial crops like ginger. This also resulted in land degradation in rice paddies. For the farmers in the Western Ghats, LULC decisions are one of the methods used to cope with the vulnerability created due to the international coffee crisis. Copyright © 2009 John Wiley & Sons, Ltd.     

福建省土地适宜性及使用变化研究

To present the current status of land quality and distribution and the trends in land use change, the physical suitability of cropland and forestland and the associated changes in Fujian Province were evaluated and analyzed using data obtained from geographical information systems （GIS） and remote sensing （RS）. Of the total land area of Fujian Province, first class suitable cropland accounted for only 4.21%, whereas unsuitable cropland accounted for 84.78%. The percentage of first class suitable cropland in the southeastern region （5.32%） was much higher than that in the northwestern area （2.91%）. Only 13.63% of the existing cropland area consisted of first class cropland and 70.08% was classified as unsuitable for cultivation. Of the total land area of Fujian Province, the first class forestland comprised 55.25% and the unsuitable forestland （including third class） comprised 21.2%. The percentage of unsuitable forest area in the existing forestland was only 5.5%. From 1996 to 2001, cropland and unused land decreased significantly, whereas forestland and land used for urban and transport increased rapidly. Therefore, the major tasks ahead will be the land development for full grain production potential, the better coordination of allocating land to different uses, and the regulation inappropriate activities that damage agricultural ecosystems.     

厦门市土地利用变化的时空格局及驱动力

Using Landsat TM data of 1988, 1998 and 2001, the dynamic process of the spatial-temporal characteristics of land use changes during 13 years from 1988 to 2001 in the special economic zone of Xiamen, China was analyzed to improve understanding and to find the driving forces of land use change so that sustainable land utilization could be practiced. During the 13 years cropland decreased remarkably by nearly 11 304.95 ha. The areas of rural-urban construction and water body increased by 10 152.24 ha and 848.94 ha, respectively. From 1988 to 2001, 52.5% of the lost cropland was converted into rural-urban industrial land. Rapid urbanization contributed to a great change in the rate of cropland land use during these years. Land-reclamation also contributed to a decrease in water body area as well as marine ecological and environmental destruction. In the study area 1） urbanization and industrialization, 2） infrastructure and agricultural intensification, 3） increased affluence of the farming community, and 4） policy factors have driven the land use changes. Possible sustainable land use measures included construction of a land management system, land planning, development of potential land resources, new technology applications, and marine ecological and environmental protection.     

Integrating socio‐economic and biophysical models: revision of a land‐use allocation model

Integration of large‐area, economically driven macro‐models and small‐area, biophysically based models in the Canadian agricultural sector was described recently in the development of a land‐use allocation model (LUAM). We have since developed and integrated an improved methodology for allocating crop area changes generated for large areas by the Canadian Regional Agricultural Model (CRAM) to much smaller Soil Landscapes of Canada (SLC) polygons. Validation of outputs showed considerable improvement. The new coefficients of determination (R²) between simulated and actual data, with previous values in brackets, were 0.69 for fodder corn (0.54), 0.88 for wheat (0.62), 0.77 for hay (0.26), 0.54 for alfalfa (not previously reported), 0.88 for soya bean (0.26) and 0.86 for grain corn (0.22). The best result was obtained for soya bean, with a normalized root mean square error (NRMSE) of 0.31%, and the poorest for alfalfa, with NRMSE = 17.34%.     

Land‐use change and urbanization of Adana,Turkey

This study analyses land‐use/land‐cover (LULC) changes in Adana city, Turkey, using satellite data of 1984 and 2000. Study of the expansion of the city over adjacent agricultural fields and semi‐natural areas was the major focus. The satellite images were classified using supervised classification prior to comparison of LULC on two different dates. The change map was produced by pixel‐to‐pixel comparison of the classified images. Urban and built‐up area increased by a factor of 2ċ07 during the 16 years; about 30 per cent on agricultural land and 70 per cent on previously semi‐natural land. Permanent immigration and urban development strategies were the main driving forces. Some policy perspectives are also given. Copyright © 2003 John Wiley & Sons, Ltd.     

Seasonal migration and land‐use change in Ghana

When farmers migrate yearly to a village to carry out intense farming during the rainy season, and thereafter return to a more permanent place of abode this is referred to as seasonal migration. The impact of such migration on land‐use/land‐cover change in an area within the Volta Basin of Ghana was examined using satellite image analysis and socioeconomic surveys. The most drastic land‐cover change involved the conversion of woodland to agricultural land, while there was also a general transition to less vegetation cover. Socioeconomic surveys revealed that most of the migration occurred during the post‐structural adjustment period in Ghana with declining soil fertility accounting for the highest per cent of causes of migration. Multiple regression results highlighted the role of population size and distribution, marketing of agricultural produce and technological evolution of the household in determining agricultural land‐use change. Policy initiatives that could lead to environment conservation are suggested. Copyright © 2004 John Wiley & Sons, Ltd.     

Continuing land degradation: Cause–effect in Ethiopia's Central Rift Valley

The Central Rift Valley (CRV) is one of the most environmentally vulnerable areas of Ethiopia. Most of the lowland in the CRV is arid or semiarid, and droughts occur frequently. We studied the dynamics of land use and cover and land degradation by analyzing Landsat data from 1973, 1985, and 2006 using Geographic Information Systems and remote sensing techniques. The analysis revealed that in the last 30 years, water bodies, forest, and woodland decreased by 15·3, 66·3, and 69·2 per cent, respectively; intensive cultivation, mixed cultivation/woodland, and degraded land increased by 34·5, 79·7, and 200·7 per cent. The major causes of land use and cover change (LUCC) and land degradation in the area were population and livestock growth in regions of limited resources, unsustainable farming techniques, the Ethiopian land tenure system and poverty. Lake level and area decline, and accelerated land degradation are the major environmental impacts of LUCC observed in the CRV. The environmental and socio‐economic consequences of LUCC and land degradation are far‐reaching. As a result of the expansion of land degradation over time, agricultural productivity has decreased and worsened food insecurity (shortages) and poverty in the Ethiopian CRV. In addition, if current trends in LUCC continue, Lake Abiyata will dry up by 2021. A detailed study of the degradation amount in relation to soil erosion, sediment yield to the lakes and catchment characteristics should be made using adaptable models; so as to guide the implementation of comprehensive and sustainable land use management by giving more attention to erosion prone areas. Copyright © 2010 John Wiley & Sons, Ltd.     

Organic C levels of Ap horizons in North German Pleistocene sands as influenced by climate,texture, and history of land‐use

We evaluated the contents of organic carbon (C_org) of Ap horizons from 11 North German study areas along a Southeast to Northwest precipitation gradient with respect to their general levels and as related to C : N ratio, soil texture (clay content), bulk soil density, climate, and historical land‐use since 1780. The focus was on sandy soils, with the largest group of samples originating from 308 km² of the Fuhrberg catchment north of Hannover/Lower Saxony. Data from loess areas were used for comparisons. Major aims were (1) to quantify current C_org stocks, (2) to provide data on site‐specific, steady‐state C_org levels in old arable soils, and (3) to identify the main controls of C_org levels in the studied sands. The mean C_org content in sandy, well‐drained, old Ap horizons (uplands, > 200 years under cultivation, near steady‐state) increased with precipitation from < 8 g kg^—1 in the dry eastern parts of the study area (530 mm year^—1, 8.3°C) to 25 g kg^—1 in the moist Northwest (825 mm year^—1, 8.4°C). The C_org levels in lowlands which have been drained for more than 40 years were approximately 3 g kg^—1 higher than those of uplands under a similar climate. The factor clay content had no predictive value because low contents were associated with high C_org levels. Large proportions of refractory organic matter in sands resulting from specific features of historical land‐use and soil development (calluna heathland, heath plaggen fertilization, podzolization) appeared to be the most probable reason for such high C_org levels. However, the high C_org levels of these old arable sites were still exceeded by those of younger arable areas formerly under continuos grassland. A chrono‐sequence suggested that a period of about 100 years is necessary until a new steady‐state C_org level is established after conversion of grassland into arable land. Elevated C_org levels in current Ap horizons were also found for former woodland and heathland soils. The main conclusion is that sands can contain a lot of stable organic matter, sometimes more than finer textured soils.     

Consequences of feasible future agricultural land‐use change on soil organic carbon stocks and greenhouse gas emissions in Great Britain

The aim of this study was to assess the consequences of feasible land‐use change in Great Britain on GHG emissions mainly through the gain or loss of soil organic carbon. We use estimates of per‐area changes in soil organic carbon (SOC) stocks and in greenhouse gas (GHG) emissions, coupled with Great Britain (GB) county‐level scenarios of land‐use change based on historical land‐use patterns or feasible futures to estimate the impact of potential land‐use change between agricultural land‐uses. We consider transitions between cropland, temporary grassland (<5 yr under grass), permanent grass (>5 yr under grass) and forest. We show that reversion to historical land‐use patterns as present in 1930 could result in GHG emission reductions of up to ca. 11 Mt CO₂‐eq./yr (relative to a 2004 baseline), because of an increased permanent grassland area. By contrast, cultivation of 20% of the current (2004) permanent grassland area for crop production could result in GHG emission increases of up to ca. 14 Mt CO₂‐eq./yr. We conclude that whilst change between agricultural land‐uses (transitions between permanent and temporary grassland and cropland) in GB is likely to be a limited option for GHG mitigation, external factors such as agricultural product commodity markets could influence future land‐use. Such agricultural land‐use change in GB could have significant impacts on Land‐use, Land‐Use Change and Forestry (LULUCF) emissions, with relatively small changes in land‐use (e.g. 5% plough out of grassland to cropland, or reversion of cropland to the grassland cover in Nitrate Vulnerable Zones of 1998) having an impact on GHG emissions of a similar order of magnitude as the current United Kingdom LULUCF sink. In terms of total UK GHG emissions, however, even the most extreme feasible land‐use change scenarios account for ca. 2% of current national GHG emissions.     

基于遥感的矿业用地演变规律分析

矿业集聚区内的矿业用地分布直接关系到区域土地利用安全格局。该文以武安市为例,以1996年、2006年TM图为数据源,采用遥感资料自动识别软件（ENVI）和人工目视解译相结合的方法,利用ARC/INFO软件提取土地利用类型动态变化矩阵反映土地利用面积变化,表明区域内变化率最大的用地类型是工矿用地;通过景观分析软件FRAGSTATS3.3获取土地利用景观指数,表明工矿景观要素在区域中所起的作用在增加,各类用地分布的复杂程度提高,总体景观格局离散程度与变化幅度有限,矿业用地与矿产资源分布的总体集聚性非常强。     

基于遥感的沿海土地利用变化及地表温度响应

该文基于两期时相接近的高分辨率遥感影像数据,利用遥感分类和定量反演技术,提取两期土地利用/土地覆盖（LUCC）信息和对应的地表温度信息,结合山东省莱州湾沿岸近20 a来海水入侵研究成果,分析LUCC对地表温度影响的空间格局和变化规律。经研究发现：在海水入侵影响下,研究区域土地覆盖以旱地、盐碱地、建设用地和盐田为主,未利用土地覆盖类型（盐碱地、滩涂）占很高的比例,随着距海的远近,土地利用程度变化显著。在沿海经济发展和LUCC影响下,整个研究区域水面覆盖和植被覆盖面积增加,使研究区域的地表温度降低：研究区域1987年平均地表温度为30.8℃,2000年平均地表温度为29.2℃;2000年相对1987年,研究区域的地表温度降低了1.62℃。海水入侵显著地影响了土地覆盖空间格局和变化,土地覆盖的显著变化进而明显地影响了沿海区域地表温度的空间分布和变化,沿海区域的地表温度变化与地表覆盖变化密切相关。该研究可为沿海湿地生态环境保护和滩涂开发提供科学参考。     

一种新的辨别土地利用/覆被的遥感图像融合方法

In China, accelerating industrialization and urbanization following high-speed economic development and population increases have greatly impacted land use/cover changes, making it imperative to obtain accurate and up to date information on changes so as to evaluate their environmental effects. The major purpose of this study was to develop a new method to fuse lower spatial resolution multispectral satellite images with higher spatial resolution panchromatic ones to assist in land use/cover mapping. An algorithm of a new fusion method known as edge enhancement intensity modulation (EEIM) was proposed to merge two optical image data sets of different spectral ranges. The results showed that the EEIM image was quite similar in color to lower resolution multispectral images, and the fused product was better able to preserve spectral information. Thus, compared to conventional approaches, the spectral distortion of the fused images was markedly reduced. Therefore, the EEIM fusion method could be utilized to fuse remote sensing data from the same or different sensors, including TM images and SPOT5 panchromatic images, providing high quality land use/cover images.     

SAR遥感技术在农业土地利用遥感调查的应用

成像雷达遥感全天候、全天时工作和穿透一些地物的特点，以及独特的成像原理，使其得以广泛的应用。该研究针对热点雷达数据ERS-2，以地处云量较多的杭州湾海涂围垦区为研究样区，根据地物目标的时域散射特性，采用分区分类策略，对预处理后的多时相雷达数据进行农业土地利用类型分类。研究结果表明全天时、全天候的雷达遥感数据能够替代多光谱遥感数据进行农业土地利用遥感调查，并显示出巨大的应用潜力。     

淮南市土地利用程度变化过程的时空演化特征

土地利用变化研究中存在重格局轻过程、重模拟轻度量的现象,缺乏对序列快照间土地利用单元演化过程的时空模式的探查和度量研究。该文以土地利用变化的序列时空数据为研究对象,以时空栅格为建模手段,以土地利用程度累积变化度为时空过程的基本度量工具,对淮南市土地利用变化过程的时空模式进行分析。结果表明:2008—2017年间研究区的土地利用程度的剧烈变化在特定尺度下呈现显著的时空聚集性特征;同时土地利用程度的平缓变化也呈现出较为显著的时空聚集性特征;介于二者之间的较为剧烈的土地利用程度变化的时空聚集性不显著,表明研究时段人类干扰活动具有明显的时空异质性。进一步研究发现,3种土地利用程度在距离交通网络较近的范围内(300和600 m范围内)均呈现聚集性,而在更远的距离上(900 m范围内)趋于随机分布,表明交通网络对土地利用变化具有较强烈的影响;在距离交通网络的不同空间尺度上,土地利用程度的剧烈变化和平缓变化在较小的空间尺度上时空聚集性呈现显著性,而较为剧烈的土地利用程度变化在多个尺度上的时空聚集性都不显著,表明交通网络对土地利用程度时空变化的影响存在尺度差异,且较为极端的土地利用变化过程更容易呈现时空聚集性。     

沙地整治下榆林土地利用及土壤有机质时空分异特征

毛乌素沙地是典型的生态脆弱区,近年来针对其在榆林境内的沙地整治利用取得显著成效,也对土壤环境产生了深刻影响。为了探究沙地不同整治利用方式对土壤有机质的影响,该研究选取榆林市显性沙地,利用多光谱遥感影像及相关光谱指数,结合沙地土地利用变化特征,通过XGBoost机器学习方法,反演1990-2020年土壤有机质含量;分析不同土地类型下土壤有机质含量变化,通过半变异函数揭示了其空间变异性,厘清人为因素和自然环境的影响程度。结果表明,30 a间榆林5 460 km2沙地中超过半数得到整治和利用,沙地-草地是最主要的地类转变方式,建设用地面积增长最迅速;沙区土壤有机质含量上升,但整体呈现先增加后降低的趋势,有机质均值由0.34%增长至0.79%,近10年降低至0.51%;榆林沙区土壤有机质具有较强的空间自相关性。起初,人为利用对其有积极作用,但随着沙地的利用强度增大,对土壤有机质产生负向作用,进而致使其含量下降,面临土地退化危机。建议加强退化林草的修复改良,放缓建设用地开发力度,研究以期为沙地整治提供理论和实践借鉴意义,保护榆林沙地土壤环境安全。     

松花江流域哈尔滨段土地利用时空格局演变特征分析

利用1996年、2005年Landsat TM/ETM+遥感影像和野外调查数据,运用ArcGIS分析土地利用变化,并基于DEM探究松花江流域哈尔滨段土地利用空间格局的时空演变。结果表明：区域土地利用空间位置转换面积小于其数量变化,土地利用变化面积大小顺序为：林地＞耕地＞草地＞水域＞未利用地＞建设用地;土地利用转化过程以耕地-林地、草地－林地和未利用地－林地为主,其中耕地－林地相互转换最为剧烈,林地、水域和建设用地具有较高的保留率,草地、未利用地和耕地具有较高的转换率;海拔300～600 m、坡度大于25°的区域,以林地－耕地和草地－耕地为主,局部存在滥垦草地、毁林开荒等现象。该区域是黑龙江省重要粮食产区,此研究有助于加强土地资源的保护和实施退耕还林、还草等农林复合经营措施,对缓解人地矛盾、实现土地资源合理利用及维持区域生态平衡具有重要意义。     

Bioreclamation of sodic waste land—a case study

The study reports a case of bioreclamation of a once barren sodic landscape in the middle part of Gangetic alluvial plain at Banthra Research Station (National Botanical Research Institute, Lucknow, India) (80° 45′ – 53′E and 26° 40′ – 45′N) which began about four decades ago. The investigations were carried out to ascertain the changes in soil characteristics caused by different land‐use systems adopted consistently over three decades. The results showed that the anthropogenic effect on alteration of surface texture through addition of sand in soils of Typic Natrustalfs is still distinct but persistent sodicity is retained. The soils of Inceptic Haplustalfs are markedly improved showing pH value around 8 and ESP > 4 with negligible CaCO₃. The soils of Aeric Endoaquepts supporting stands of forest trees are now devoid of sodicity to about 0\5 m depth, whereas the soils of Aeric Halaquepts though under cultivation have mild sodicity. Soils of Typic Halaquepts occurring on a low physiographic position with aquic soil moisture regime have high sodicity. Summarizing the results of changes in the surface (0 – 15 cm) soil characteristics caused by continuous cultivation irrespective of any crop grown on any soil type reveals that there is perceptible reduction in soil pH and ESP after three decades of reclamation using organic amendments coupled with regular cultivation and afforestation in different locations. Copyright © 2000 John Wiley & Sons, Ltd.     

塔里木河干流土地利用动态监测遥感分析

选择塔里木河干流地区1999年TM、2002年ETM 和2004年的ASTER遥感影像及基础背景数据,采用数据仓库技术及图属一体化和多源数据无缝集成的建库思想,实现了基础背景、遥感、专题及属性数据的入库管理;在RS、GIS及GPS等技术支撑下,通过对干流1999、2002和2004年的遥感影像信息提取及分析,揭示了应急输水后各土地类型面积变化的幅度、年变化率,以及耕地的时空变化规律.结果表明:应急输水工程实施后,干流地区的耕地、天然草地、苇地、滩涂等土地利用类型的面积急剧增长,林地、建筑用地、水域、荒草地、盐碱地等土地类型的面积均有所降低;耕地面积剧增是以植被破坏、水域面积减少为代价的,人类生产活动与自然环境矛盾加剧,生态环境日趋恶化.