Evaluating the impact of an agricultural land‐use change adaptation strategy on household crop production in semi‐arid Ghana

In this study, the Land Use Dynamic Simulator model was applied to investigate the impact of farm credit as an adaptation strategy to cope with effects of climate variability on agricultural land‐use change and crop production in the Vea watershed in Ghana. The authors identified the determinants of crop choices within the landscape (e.g., farm household and biophysical characteristics of farm plot). The crop choice sub‐model was then linked to the crop yield sub‐model to determine the yields of selected crops. In adapting to the impacts of climate variability, the maize credit adoption sub‐model under the maize cultivation credit scenario was integrated into decision‐making. This was simulated for a 20‐year period, and compared with the business‐as‐usual scenario. Under the simulated maize credit scenario, maize adopters increased from about 20 per cent to about 50 per cent and the area allocated for maize cultivation significantly increased by about 266 per cent. Consequently, the average annual aggregated household crop yield increased by 6.3 per cent higher than in the business‐as‐usual scenario. This simulation study shows that access to maize credit can significantly influence agricultural land‐use change and food availability in the study area. However, although access to farm credit may translate into food availability, the sustainability of this strategy is questionable.     

The climatic impacts of land use and land cover change compared among countries

Land use and land cover change (LULCC) strongly influence regional and global climate by combining both biochemical and biophysical processes. However, the biophysical process was often ignored, which may offset the biogeochemical effects, so measures to address climate change could not reach the target. Thus, the biophysical influence of LULCC is critical for understanding observed climate changes in the past and potential scenarios in the future. Therefore, it is necessary to identify the mechanisms and effects of large-scale LULCC on climate change through changing the underlying surface, and thus the energy balance. The key scientific issues on understanding the impacts of human activities on global climate that must be addressed including: (1) what are the basic scientific facts of spatial and temporal variations of LULCC in China and comparative countries? (2) How to understand the coupling driving mechanisms of human activities and climate change on the LULCC and then to forecasting the future scenarios? (3) What are the scientific mechanisms of LULCC impacts on biophysical processes of land surface, and then the climate? (4) How to estimate the contributions of LULCC to climate change by affecting biophysical processes of land surface? By international comparison, the impacts of LULCC on climate change at the local, regional and global scales were revealed and evaluated. It can provide theoretical basis for the global change, and have great significance to mitigate and adapt to global climate changes.     

The making and unmaking of gendered crops in northern Ghana

In rural West Africa, the gendered division of labour extends to labelling certain crops as 'male' or 'female'. With the introduction of new varieties of crops and technologies, these constructions of gendered plants undergo a process of renegotiation at social intrafaces. This process of attaching meaning to new features in cultivation results in the remaking of gendered crops. These negotiations, in turn, have an effect on the construction of gender in specific ethnic and environmental settings, unlinking labour from its gendered connotations and, thus, unmaking the social meaning and creating room for manoeuvre. Based on fieldwork among the Dagomba and Kusasi people in northern Ghana, this study examines how gendered responsibilities and access to the cultivation of crops are linked and expressed in obligations related to the cultural ideal of a proper meal, in this case consisting of the food categories (male) staple and (female) soup, which serve as the blueprint for assigning crops to a specific gender.     

陕北农牧交错带土地利用动态变化研究

根据1991-2001年土地利用详查数据,利用土地利用动态度模型、区域差异模型、土地利用程度模型和信息熵模型,对陕北农牧交错带这一典型地区土地利用的时空变化及变化趋势进行了详尽分析。研究表明：陕北农牧交错带耕地、未利用地和水域减少,林地、牧草地、园地、居民点及工矿用地、交通用地增加；研究区土地利用变化速度较快,年变化率达到0．31%,其中园地的年变化率最大；耕地、园地、林地、牧草地和交通用地的空间变化明显；11年来,陕北农牧交错带土地利用处于发展期,利用方式日趋无序。     

Mapping the agricultural land use of the North China Plain in 2002 and 2012

Journal of Geographical Sciences - Based on the MODIS NDVI data and Landsat TM/ETM data of 2002 and 2012, this paper extracts the planting area of winter wheat—summer maize, single spring...     

山区农业土地利用模式的设计

本文分析了市场经济条件下我国山区农业可持续发展所面临的问题 ,提出了山区农业土地利用模式的构想。指出影响我国山区农业土地利用模式的因素主要包括自然地理因素、市场因素和土地制度因素 ,特别是市场因素和土地制度因素对于农业土地利用模式设计的影响在新的历史时期尤为突出 ;强调山区农业土地利用模式设计必须遵循自然地带规律性、与农业经济多样化和规模经营相结合、与开拓产品市场相结合的原则 ;以河南省洛宁县为例具体说明了山区农业土地利用模式设计的技术路线。     

Land use sustainability on the South-Eastern Amazon agricultural frontier: Recent progress and the challenges ahead

The recent decoupling of deforestation and soybean production has raised optimistic expectations towards enhanced land use sustainability in the South-Eastern Amazon agricultural frontier. Nonetheless, assessing land use sustainability implies not only the consideration of how agricultural activities affect natural ecosystems but also how they impact on society and how society can cope with them. We review some of the forthcoming challenges that the agricultural sector should address to confirm its significant progress towards land use sustainability. Firstly, we assess the recent efforts to adopt environmentally friendly practices with regard to the ongoing intensification process mainly based on double cropping systems. Secondly, while rapid agricultural development has brought major social advances, we evidence a recent trend towards a decoupling of soy production and the Human Development Index at municipality level. We then put this result into perspective considering that the trend towards agricultural intensification based on the use of large amounts of agrochemicals could lead to major health concerns which are still too rarely considered. Finally, we discuss how the recent efficient policies to contain deforestation in the Amazon can cause indirect land use changes in the Brazilian Cerrados and in African Savannas, thus potentially leading to an “illusion of preservation” at global scale. We conclude that new indicators involving social sciences are necessary to better address the complexity of land use sustainability on the still very dynamic agricultural frontier in the South-Eastern Amazon.     

Influences of agricultural phenology dynamic on land surface biophysical process and climate feedback

Response and feedback of land surface process to climate change is one of the research priorities in the field of geoscience. The current study paid more attention to the impacts of global change on land surface process, but the feedback of land surface process to climate change has been poorly understood. It is becoming more and more meaningful under the framework of Earth system science to understand systematically the relationships between agricultural phenology dynamic and biophysical process, as well as the feedback on climate. In this paper, we summarized the research progress in this field, including the fact of agricultural phenology change, parameterization of phenology dynamic in land surface progress model, the influence of agricultural phenology dynamic on biophysical process, as well as its feedback on climate. The results showed that the agriculture phenophase, represented by the key phenological phases such as sowing, flowering and maturity, had shifted significantly due to the impacts of climate change and agronomic management. The digital expressions of land surface dynamic process, as well as the biophysical process and atmospheric process, were improved by coupling phenology dynamic in land surface model. The agricultural phenology dynamic had influenced net radiation, latent heat, sensible heat, albedo, temperature, precipitation, circulation, playing an important role in the surface energy partitioning and climate feedback. Considering the importance of agricultural phenology dynamic in land surface biophysical process and climate feedback, the following research priorities should be stressed: (1) the interactions between climate change and land surface phenology dynamic; (2) the relations between agricultural phenology dynamic and land surface reflectivity at different spectrums; (3) the contributions of crop physiology characteristic changes to land surface biophysical process; (4) the regional differences of climate feedbacks from phenology dynamic in different climate zones. This review is helpful to accelerate understanding of the role of agricultural phenology dynamic in land surface process and climate feedback.     

气候变化与土地利用/覆被变化对中国北方农牧交错带水资源影响研究进展

中国北方农牧交错带对全球变化响应敏感,研究气候变化及土地利用/覆被变化（LUCC）背景下北方农牧交错带水资源问题,对变化环境下生态脆弱区的水资源利用与管理具有重要意义。通过对北方农牧交错带气候与LUCC演变特征及其对水资源影响等方面的综合研究,总结得出：（1） 近几十年,该地区气候呈暖干化趋势,气温升高速率与降水减少速率均高于全球平均水平。（2） LUCC以农牧相互转化为主,土地利用结构未发生明显变化。（3） 该地区流域径流、地下水位与气温负相关,与降水量正相关,且降水作用更明显;近几十年来,LUCC成为影响该地区生态水文过程的主导因素,对水资源影响的贡献率越来越大。同时,针对目前研究中存在的问题及薄弱环节,提出未来研究的发展趋势和亟需重点加强的研究方向。     

Six decades of agricultural land use change in Bangladesh: Effects on crop diversity,productivity, food availability and the environment, 1948–2006

This paper provides a detailed analysis of agricultural land use change in Bangladesh over a 59‐year period (1948–2006) and examines how these have impacted crop diversity, productivity, food availability and the environment. The key findings of the analysis are: first, land use intensity has increased significantly over this period, mainly from the widespread adoption of a rice‐based Green Revolution technology package beginning in the early 1960s; second, contrary to expectation, crop diversity too has increased; third, although land productivity has increased significantly, declines in the productivity of fertilizers and pesticides raise doubts over sustaining agricultural growth; fourth, food availability has improved, with a reversal in the dietary energy imbalance in recent years despite a high population growth rate; and finally, the production environment has suffered with widespread soil nutrient depletion experienced in many agroecological regions. The policy implication points towards crop diversification as a desired strategy for agricultural growth to improve resource economy, productivity and efficiency in farming in Bangladesh.     

1990-2010年中国土地利用变化对生物多样性保护重点区域的扰动

基于人类土地利用活动对不同生态系统生物多样性保护服务的影响,构建生态系统综合人类扰动指数,结合不同级别的生物多样性保护区域 (一般重要、中等重要、重要、极重要四个级别) 从全国尺度及区域尺度分析了中国1990-2010年土地利用变化对生物多样性保护重点区域的扰动。结果表明：就2010年现状而言,我国中东部地区人类扰动程度较大,西部地区人类扰动程度较低,全国生物多样性保护中等重要、重要、极重要区域的人类扰动程度低于全国整体 (包括所有级别) 均值。就20年来人类扰动程度变化态势而言,全国中东部人类扰动程度变化幅度总体高于西部,生物多样性保护中等重要、重要、极重要区域人类扰动程度均呈轻微上升趋势,但增加幅度低于全国整体增加幅度。随着东部地区的快速城市化以及东北、新疆等地区的农田开垦等土地利用活动,生物多样性保护中等重要、重要、极重要区域等重点区域人类扰动程度呈现上升趋势,应引起重视;而随着黄土高原等地区退耕还林还草工程的实施,人类扰动程度整体则呈现一定的下降趋势。青藏高原区扰动变化幅度很小,几乎没有变化。总体而言,中国目前陆地国土开发利用的空间格局与生物多样性保护保护重要区域的空间分布是相互匹配的,这有利于国家生物多样性保护的整体布局。同时,20年来生态系统综合人类扰动指数变幅的区域分异也与生物多样性保护重要性空间格局相吻合,说明20年来针对生态保护的各项政策与措施在减少生物多样性保护重点区域人类扰动方面产生了积极的成效。     

陕西省土地利用动态变化分析

基于陕西省 1 991～2 0 0 1年土地利用现状年度变更调查数据 ,分析了陕西省 1 991年初到2 0 0 1年末的土地利用动态变化。在这 1 1年间陕西省土地利用变化较大 ,其中以园地变化最大。城市用地、农村居民点及交通用地增长较快。从地区来看 ,杨凌土地利用最活跃 ,汉中土地利用最不活跃。土地利用程度最大的是杨凌 ,最小的是商洛。渭南、西安和杨凌的土地利用程度提高了 ,其余各地土地利用程度减小了。土地利用变化存在明显的地域差异 ,陕北、陕南以生态退耕还林还草为主 ,关中以结构调整为主。政策因素、自然因素、经济杠杆的调节及人口因素是陕西省土地利用变化的主要原因。     

Groundwater quality and land use change in a typical karst agricultural region: a case study of Xiaojiang watershed, Yunnan

Taking the typical karst agricultural region, Xiaojiang watershed in Luxi of Yunnan Province as a research unit, utilizing the groundwater quality data in 1982 and 2004, the aerial photos in 1982 and TM images in 2004, supported by the GIS, we probe into the law and the reason of its space-time change of the groundwater quality over the past 22 years in the paper. The results show: (1) There were obvious temporal and spatial changes of groundwater quality during the past 22 years. (2) Concentrations of,SO42-,NO3-,NO2-,Cl-,and the pH value, total hardness, total alkalinity increased significantly, in which NH4+,NO3-, and NO2- of groundwater exceeded the drinking water standards as a result of non-point pollution caused by the expansion of cultivated land and mass use of the fertilizer and pesticide. (3) Oppositely, Ca2+ and HCO3- showed an obvious decline trend due to forest reduction and degradation and stony desertification. Meantime, there was a dynamic relation between the groundwater quality change and the land use change.     

Underlying motivation for land use change: A case study on the variation of agricultural factor productivity in Xinjiang, China

Understanding the driving forces and mechanism of land use change is a key issue in land change science, and has received much attention over the past 30 years. While many driving forces have been identified, the mechanism of land use change is still unclear, mainly because of limited knowledge of the underlying motivation for land use change. Traditionally, the underlying motivation for land use change was ascribed to people＇s pursuit of satisfying their own demands or that of profit maximization. However, those theoretical hypotheses combine all productive factors without highlighting certain predominant factor, in this paper, a case study was conducted on the variation of land productivity, capital productivity and labor productivity in agricultural land use in Xinjiang Uygur Autonomous Region of China. The case study revealed that only labor productivity presented a long-term increasing trend in regional cotton and grain production. This result implies that people＇s pursuit of increasing labor pro- ductivity is probably the underlying motivation for land use change. Additional details identi- fied in agricultural and non-agricultural land use in China support the above implication. As labor productivity is a determinant of people＇s living standards, increasing labor productivity means improving people＇s living standards. Therefore, it is concluded that land use change results from people＇s pursuit of increasing labor productivity in a changing environment.     

Development of quantitative methods for detecting climate contributions to boundary shifts in farming-pastoral ecotone of northern China

The quantitative effect of climate change on fragile regions has been a hot topic in the field of responses to climate change. Previous studies have qualitatively documented the impacts of climate change on boundary shifts in the farming-pastoral ecotone (FPE); however, the quantitative methods for detecting climate contributions remain relatively limited. Based on long-term data of meteorological stations and interpretations of land use since 1970, climate and land use boundaries of the 1970s, 1980s, 1990s and 2000s were delineated. To detect climate contributions to the FPE boundary shifts, we developed two quantitative methods to explore the spatial-temporal pattern of climate and land use boundary at the east-west (or south-north) (FishNet method) and transect directions (Digital Shoreline Analysis System, DSAS method). The results indicated that significant differences were exhibited in climate boundaries, land use boundaries, as well as climate contributions in different regions during different periods. The northwest FPE had smaller variations, while the northeast FPE had greater shifts. In the northwest part of the southeast fringe of the Greater Hinggan Mountains and the Inner Mongolian Plateau, the shifts of climate boundaries were significantly related to the land use boundaries. The climate contributions at an east-west direction ranged from 10.7% to 44.4%, and those at a south-north direction varied from 4.7% to 55.9%. The majority of the results from the DSAS were consistent with those from the FishNet. The DSAS method is more accurate and suitable for precise detection at a small scale, whereas the FishNet method is simple to conduct statistical analysis rapidly and directly at a large scale. Our research will be helpful to adapt to climate change, to develop the productive potential, as well as to protect the environment of the FPE in northern China.     

A Local Example of Land‐Use Change: Southern Illinois—1807, 1938, and 1993*

This article provides an analysis of a wetland site in southern Illinois from presettlement to the present. The study area is part of the Cache River‐Cypress Creek Wetland, which has international importance, as recognized by the Ramsar Convention on Wetlands. Land‐cover data for 1807, 1938, and 1993 were created and analyzed with a geographic information system (GIS). Land‐use change by topographic setting (uplands, transitional, and bottomlands) and soil productivity was quantified and studied. Interviews with local experts informed this analysis. Results illustrate the complexity of environmental change and its driving forces. First, notable forest and swamp acreage was converted to cropland between 1807 and 1938 and, to a lesser degree, from 1938 to 1993. Second, there were land‐use variations by topographic region. Between 1807 and 1938, the largest transformation occurred in the uplands, with substantial acreage converted from forest to cropland. Between 1938 and 1993, however, agriculture decreased in the upland areas as hilly areas reverted to forest cover. At the same time, agriculture expanded in the bottomlands as this land was drained for farming. Third, there are interesting patterns within these categories of land‐use change, as soil productivity is an indicator of what lands were taken out of cropland and converted back to grassland and forest.     

气候变化对北方农牧交错带界线变迁影响的定量探测方法研究

气候对北方农牧交错带界线变迁的定量影响是目前生态脆弱敏感区对气候变化响应领域的研究热点问题。前人已在气候变化对农牧交错带界线的定性影响方面有较为深刻的认识,但仍缺乏在时间和空间上对气候贡献率进行有针对性的定量辨识。本文利用1970年以来长时间序列的国家气象站点数据和土地利用遥感解译数据,分别提取了基于气候要素和土地利用的20世纪70年代、80年代、90年代和21世纪前10年4个时期的北方农牧交错带界线,通过垂直和水平方向变动探测方法（FishNet）和界线变迁方向变动探测方法（DSAS）对气候界线与土地利用界线的时空变化进行探测,定量分析了不同时期气候对农牧交错带界线变迁影响的贡献率。结果表明,气候与土地利用界线空间分布格局及气候贡献率在不同时期、不同区域差异较大,在西北地区变幅最小,东北地区变幅最大。在大兴安岭东南缘农田控制水源涵养生态功能区西北段以及内蒙古高原东南缘农、林、牧业生态—生产功能区西北段,气候与土地利用界线空间耦合关系最为密切,在该地区基于FishNet方法下水平方向上气候贡献率达10.7%~44.4%,垂直方向上达4.7%~55.9%;基于DSAS方法下气候贡献率为1.1%~16.8%。两种方法探测结果大部分趋于一致,但DSAS方法精度高,适用于小范围精确探测;FishNet方法更简单,适用于精度要求不高、快速直观的统计分析。本研究可为北方农牧交错带内农牧业生产适应气候变化、合理开发土地生产潜力、保护农牧交错带区内生态环境提供科学依据和指导。     

典型岩溶农业区地下水质与土地利用变化: 以云南小江流域为例

1 Introduction Ecological environment such as water, soil, etc. are very fragile in the karst area because of the special geological background. With the fast increase of the population and rapid social and economic development in karst area, contradictio…     

The impact of land use on soil properties in a karst agricultural region of Southwest China:a case study of Xiaojiang watershed, Yunnan

Supported by RS and GIS, the land use change from 1982 to 2003 were analyzed and the impacts of land use changes on pH value, organic matter, total N, total P, total K, available N, available P, and available K in soil of Xiaojiang watershed, a typical karst agricultural region of Yunnan Province, Southwest China were assessed. The following aspects are concluded. (1) The total land use converted during the past 20 years in Xiaojiang watershed covers an area of 610.12 km2, of which 134.29 km2 of forestland was converted into cultivated land, and 210 km2 of unused land was converted into cultivated land. (2) The rapid growth of population and the economic development were the main driving forces of land use change. (3) With the change in land use, the soil properties have been changed significantly. The pH, organic matter, total N, total P, total K, available N, available P and available K in soil in 1982 were 6.3, 38.02 g kg-1, 1.86 g kg-1, 1.63 g kg-1, 10.94 g kg-1, 114.42 g kg-1, 11.65 mg kg-1 and 64.69 mg kg-1g, respectively; and those in 2003 were 6.73, 25.26 g kg-1, 1.41 g kg-1, 0.99 g kg-1, 12.6 g kg-1, 113.43 mg kg-1, 11.11 mg kg-1 and 151.59 mg kg-1, respectively. Pared samples t-test of the tested indices of soil properties indicate that those indices have changed significantly during the last 20 years. But the soil properties changed differently, due to the differences in land use change. (4) Also, with the change in land use and management measures of soil, the modifications in soil properties which developed from carbonate rocks were more sensitive than those in the soil developed from sandstone.