Genesis and characterization of manganiferous soils in the Eastern Piedmont, USA

Manganese is normally a trace element in soils, but it is important due to its effects on soil chemistry and morphology. There are rare, Mn-rich soils in the Eastern Piedmont of the USA that have not been previously studied. The morphology, mineralogy, and chemical and physical properties of these manganiferous soils were documented in order to better understand their pedogenesis. The soils were found to contain as much as 169 g kg⁻¹ Fe and 140 g kg⁻¹ Mn as oxides (dithionite-citrate-bicarbonate extractable). These high levels of Mn oxides impart an extremely dark color to the soil material (moist Munsell value and chroma commonly < 2/1). Manganiferous soil materials have unusual physical properties such as high particle density (up to 3.25 × 10⁻⁶ Mg m⁻³ on bulk soil), low bulk density (as low as 0.39 × 10⁻⁶ Mg m⁻³), and extremely high porosity (maximum calculated 88%). X-Ray Diffraction and Fourier Transform Infrared spectra show that the dominant Fe oxide and Mn oxide minerals in the soils are hematite and lithiophorite, respectively. Samples of the parent marble were dissolved in acid for Fe and Mn analysis and collection of non-carbonate residues (NCR). Based on the quantities of Fe and Mn in the bedrock, the mineralogy of the NCR, and micromorphological observations, it appears that the black, porous, Mn-rich material is derived directly from the dissolution of marble bedrock and accumulation of silicate residues plus Mn and Fe from within the rock. These soils, which appear to have a similar origin to Mn wad deposits, offer a unique opportunity for future studies of soil Mn due to the naturally high concentration of this metal.     

陕西省农业气象业务服务系统

介绍了陕西省农业气象业服务系统的总体设计，系统特点及各系统主要功能，该系统具有信息采集，信息集成管理，信息加工处理，信息集成服务等功能，是集农业气象，遥感，服务于一体的业务服务平台。     

Characterization of iron oxides in Fe-rich concretions from an imperfectly-drained Greek soil: a study by selective-dissolution techniques and X-ray diffraction

Fe-rich concretions commonly occur in Greek soils with alternating drying and waterlogging periods. This study was conducted to characterize the iron oxides in Fe-rich concretions from the upper solum of an Alfisol with seasonal perched water table by the combination of selective dissolution and X-ray diffraction (XRD) techniques. The results showed that more than 75% of the total iron (Fet) was associated with the crystalline and the amorphous Fe oxides, indicating a strong accumulation of free iron oxides (Fed) in concretions. Amorphous iron compounds (Feo) was present at high concentrations and fluctuated with profile depth. The active Fe ratio (Feo/Fed) values that ranged from 0.35 to 0.41 reflected an association of poorly crystalline goethite with some ferrihydrite. The XRD data showed that the Fe-rich concretions consisted of quartz, feldspars, illite and gypsum. The mineralogy of iron oxides in concretions was determined by comparison of XRD patterns for dithionite-citrate-bicarbonate (DCB) treated (deferrated) and untreated (non-deferrated) samples. Poorly crystalline goethite as demonstrated by broad lines in the diffraction patterns and ferrihydrite were the iron oxides detected in the concretions. This mineral assemblage appears to be related to the pedoenvironmental conditions in which the concretions were formed and indicates that the mechanisms governing the formation of crystalline Fe oxides from ferrihydrite are retarded by the presence of crystallization inhibitors.     

Ensemble models of habitat suitability relate chimpanzee (Pan troglodytes) conservation to forest and landscape dynamics in Western Africa

Pan troglodytes verus is considered one of the most endangered primates in the world due to habitat loss or degradation, and it is considered extinct in several regions of West-Africa. This study aims at developing a model that predicts habitat suitability for chimpanzee under different land cover scenarios and supports a multi-temporal analysis of the recent habitat evolution in southern Guinea-Bissau. The model, built using a maximum entropy framework, is spatially explicit, uses eco-geographic variables derived from landscape compositional, structural and functional attributes, and is based on nest location data collected in the field. The results show that the developed model has good levels of reliability and the map produced through its application reveals a current extension of 752 km² of adequate habitat in a 2723 km² study area. Forest related EGVs (ecogeographical variables) had the higher importance for the model production. Habitat suitability maps produced for three dates in the last three decades show that there has been a marked decrease in habitat extension and in connectivity to neighbouring regions. We analyse the implications of these results in possible strategies for the conservation of chimpanzees in Guinea-Bissau.     

Spatial and spectral analysis of soil surface properties for an archaeological area in Aksum,Ethiopia, applying high and medium resolution data

The primary aim of this paper is to determine the spatial distribution of soil surface properties using high and medium resolution imagery data. Identification of these properties is important for determining environmental conditions resulting from anthropogenic influences, and for identifying land degradation processes within the study area which is an archaeologically important region situated to the north of Aksum (northern Ethiopia). Site specific field data were used to identify and verify the spatial distribution of soil surface properties such as soil colour, texture, and organic matter content obtained with IKONOS and ASTER images. As a result, distribution maps present the preliminary associations between land cover and soil characteristics as well as the location of archaeological sites. For all Aksumite cultural phases, the general pattern of ancient settlement remained the same and is similar to that of today: residential structures were built on well drained, high relief terrain.     

NDMI与TCW在西藏低植被区土壤湿度监测中的比较

土壤湿度的遥感监测在农牧业生产中发挥着重要作用。基于Landsat TM影像,利用研究区不同深度的土壤湿度实测数据,对两种可以反映地表湿度的指标归一化差异湿度指数(Normalized Difference Moisture Index,NDMI)和缨帽变换的湿度分量(Tasseled Cap Wetness,TCW)在西藏低植被覆盖区土壤湿度的监测结果进行精度验证与对比分析。结果表明:在0~5 cm、10 cm和20 cm深度处,NDMI与土壤湿度实测值回归方程的回归系数分别为0.6181、0.6853、0.5764,TCW与土壤湿度实测值回归方程的回归系数分别为0.4586、0.5101、0.5628。此外,NDMI、TCW与实测值的变化趋势一致,但NDMI对土壤湿度变化更加敏感。通过对比NDMI与TCW反演结果的空间分布情况也表明,NDMI对土壤湿度的变化具有更好的区分能力,尤其是在高海拔的低植被覆盖区。该研究可为高原低植被覆盖区土壤湿度监测方法的选择与误差分析提供参考依据。     

基于土地监测调查的高分雷达正射纠正精度控制方法研究

为了控制高分雷达遥感数据正射纠正精度,选择满足要求的控制点采集方法,对图像采集和实地布设角反射器(CR)两种采集正射纠正控制点的方法进行对比分析,结果表明,传统图像采集控制点方法可以保证纠正精度整体控制在5个像素内,采用角反射器采集控制点的方法可以控制在半个像素左右。因此,在土地调查与监测中,以发现地物变化为主要目的,对地物绝对精度要求不高,可从参考影像采集控制点,否则需选择角反射器实测控制点。     

Impact of sugarcane cultivation on soil carbon fractions, consistence limits and aggregate stability of a Yellow Latosol in Northeast Brazil

The effects of continuous sugarcane (Saccharum officinarum) cropping on the properties of a cohesive Yellow Latosol were studied in the region of the Coastal Tablelands, Northeast Brazil. Four areas were studied at Caeté mill, municipality of São Miguel dos Campos, Alagoas State, involving a native forest (Tn), and sugarcane fields cultivated for periods of 2 years (T2), 18 years (T18) and 25 years (T25). Samples were collected from each area at 0–0.2 and 0.2–0.4 m depth, to determine total organic C, physical fractionation of soil organic matter and consistence limits. Undisturbed samples were collected to determine wet aggregate mean weight–diameter, dry mean weight diameter and aggregate stability. In relation to the soil under native forest, total organic C and particulate organic matter contents were reduced after 2 years of cultivation. Sugarcane cropping for a longer period promoted a recuperation of soil organic matter content. The decrease of total organic C and reduction in aggregate stability and plastic limit after 2 years of sugarcane cultivation rendered the soil more susceptible to compaction.     

Forest degradation deepens around and within protected areas in East Asia

Forest degradation in protected areas has been monitored around the world with remote sensing data, but degradation processes undetectable by widely used satellite sensors have been largely overlooked. Increased human pressures and socioeconomic development make forest protection more challenging, particularly for forest ecosystems that lie across national borders because of the differences in national socioeconomic policies and conditions within them. Here with Landsat data, Google Earth images, and field observations, we show that, in two adjacent biosphere reserves across the border of China and North Korea, over one half of primary forest landscapes have been deteriorated by exploitive uses, including seed harvesting and systematic logging. The combined effects of detectable and hidden degradation processes have further damaged forest ecosystems in the core areas in the two biosphere reserves, threatening sustainable biodiversity conservation in the region. It is urgent to develop cross-border collaborative conservation strategies that can help combat both detectable and hidden degradation processes at a regional scale.     

Forest fragmentation and edge effects from deforestation and selective logging in the Brazilian Amazon

Forest fragmentation results from deforestation and disturbance, with subsequent edge effects extending deep into remaining forest areas. No study has quantified the effects of both deforestation and selective logging, separately and combined, on forest fragmentation and edge effects over large regions. The main objectives of this study were to: (1) quantify the rates and extent of forest fragmentation from deforestation and logging within the Brazilian Amazon, and (2) contextualize the spatio-temporal dynamics of this forest fragmentation through a literature review of potential ecological repercussions of edge creation. Using GIS and remote sensing, we quantified forest fragmentation - defined as both increases in the forest edge-to-area ratio and number of forest fragments - and edge-effected forest occurring from these activities across more than 1.1 million km² of the Brazilian Amazon from 1999 to 2002. Annually, deforestation and logging generated ∼32,000 and 38,000 km of new forest edge while increasing the edge-to-area ratio of remaining forest by 0.14 and 0.15, respectively. Combined deforestation and logging increased the edge-to-area ratio of remaining forest by 65% over our study period, while generating 5539 and 3383 new forest fragments, respectively. Although we found that 90% of individual forest fragments were smaller than 4 km², we also found that 50% of the remaining intact forests were located in contiguous forest areas greater than 35,000 km². We then conducted a literature review documenting 146 edge effects and found that these penetrated to a median distance of 100 m, a distance encompassing 6.4% of all remaining forests in our study region in the year 2002, while 53% of forests were located within two km of an edge. Annually deforestation and logging increased the proportion of edge-forest by 0.8% and 3.1%, respectively. As a result of both activities, the total proportion of edge-forest increased by 2.6% per year, while the proportion within 100-m increased by 0.5%. Over our study period, deforestation resulted in an additional ∼3000 km² of edge-forest, whereas logging generated ∼20,000 km², as it extended deep into intact forest areas. These results show the large extent and rapid expansion of previously unquantified soft-edges throughout the Amazon and highlight the need for greater research into their ecological impacts.     

Buffelgrass (Pennisetum ciliare) land conversion and productivity in the plains of Sonora, Mexico

Bufflelgrass (Pennisetum ciliare syn. Cenchrus ciliaris) is an African grass that has been widely introduced in subtropical arid regions of the world to improve rangelands for cattle production. However, it can have a negative effect on the diversity of native plant communities. Buffelgrass was introduced to Sonora, Mexico in the 1970s as a means to bolster the cattle industry. “Desmonte,” the process by which native desert vegetation is removed in preparation for buffelgrass seeding, alters the land surface such that buffelgrass plots are easily detectable from aerial and Landsat satellite images. We estimated the extent of conversion to buffelgrass in a 1,850,000 ha area centered on Hermosillo, from MSS and TM images from 1973, 1983, 1990 and 2000. We then compared the relative above-ground productivity of buffelgrass to native vegetation using Normalized Difference Vegetation Index values (NDVI) from Landsat and Moderate Resolution Imaging Spectrometer (MODIS) satellite sensor systems. Buffelgrass pastures have increased from just 7700 ha in 1973 to over 140,000 ha in 2000. Buffelgrass pastures now cover 8% of the land surface in the study area. Buffelgrass pastures have lower net primary productivity, estimated by MODIS NDVI values, than unconverted desert land. The desmonte process removes trees and shrubs, while the buffelgrass plantings are often sparse, leading to an apparent net loss in net primary production from land conversion. We recommend that the desmonte process be discontinued until its efficacy and safety for native ecosystems can be established, and that a comprehensive plan for preserving biodiversity while accomodating economic development be established for this region of the Sonoran Desert in Mexico.     

基于AMSR-E数据估测华北平原及东北地区土壤田间持水量

对田间持水量的遥感获取方法进行了探讨,基于传统的田间持水量测定方法--围框淹灌法的思路,利用AMSR-E(Advanced Microwave Scanning Radiometer,即高级微波扫描辐射计)数据高时间分辨率的特点,提出了基于AMSR-E数据估测田间持水量的方法,并采用2003~2007年的AMSR-E数据制作了我国华北平原及东北地区的田间持水量分布图。结果显示东北地区北部、河南东部、安徽北部以及江苏北部等地区的田间持水量较高;由AMSR-E数据获取的田间持水量明显小于气象站点的测定值,与实测值的相关系数R2为0.522,与实测值有显著的相关关系,表明AMSR-E数据具有正确反映田间持水量的潜力。     

Spatial and temporal patterns of vegetation recovery following sequences of forest fires in a Mediterranean landscape,Mt. Carmel Israel

The Mediterranean ecosystem of Mt. Carmel is subjected to increasing number of forest fires at various extents and severities due to increasing human activities. Accordingly, we tested whether in areas exposed to different fire histories vegetation regeneration is different in north versus south facing slopes, and the potential impact on erosion processes. Using remote sensing techniques we evaluated the Enhanced Vegetation Index (EVI) to monitor vegetation recovery following a single fire and three successive fires, using a series of Landsat images taken between 1985–2002. Following a single fire, vegetation cover reached pre-disturbance values within less than 5 years. Repeated fires caused further reduction of EVI values, especially at south facing slopes (SFS). The effects of three successive fires within 10 years, followed by a three year recovery period, however, are negligible when considering vegetation cover values. This was deduced as north facing slope EVI values returned to pre-disturbance conditions at the end of the 3 years and SFS EVI values to 80% of the pre-disturbance conditions. Our results indicate that Mediterranean eco-geomorphic systems are quite resilient, showing quick response, at least in terms of return to pre-disturbance states of vegetation cover, and hence of soil erosion rates. This is true not only in response to a disturbance caused by a single fire, but also for repetitive fire incidents.     

Monitoring land degradation using remote sensing and GIS techniques in an area of the middle Nile Delta,Egypt

Detecting soil degradation and recognizing its various types is a necessity to take the practical measures for combating it as well as conserving and keeping the agricultural soil healthy.     

A tool for rapid assessment of erosion risk to support decision-making and policy development at the Ngenge watershed in Uganda

This study tests a rapid, user-friendly method for assessing changes in erosion risk, which yields information to aid policy development and decision-making for sustainable natural resources management. There is currently a lack of timely, up-to-date and current information to support policy development on sustainable natural resources management in Uganda. The study was carried out in the Ngenge watershed, a typical catchment in the Ugandan Highlands, characterised by deforestation in favour of subsistence agriculture without adequate soil and water conservation measures. The watershed is experiencing soil erosion, sedimentation and flooding problems which are threatening agricultural productivity and food security. Sustainable management of environmental resources is needed to ensure a livelihood for the rural population which is dependent on the land. Historical erosion risk was evaluated in three steps using multi-temporal satellite data. First, current erosion risk was assessed by combining slope and vegetation cover during periods of high intensity rainfall. The data used for the assessment was obtained from public (free) satellite images. Erosion risk was then linked to land use and finally to the change in vegetation cover over the years 1980-2000. The analysis of erosion risk using rainfall, slope and NDVI (Normalised Difference Vegetative Index) as a proxy for vegetation cover gives an indication of the current erosion risk in the area. The results of historical vegetation cover change analysis indicate an overall increase in areas under erosion risk in the study area from 1980 to 2000. This method of erosion risk mapping provides a quick and straightforward means for identifying priority areas for interventions for soil and water resource management. Considering that resources are limited, the interventions to be appropriate have to be focused mainly on areas affected by degradation.     

Agroecology-based land use/land cover change detection,prediction and its implications for land degradation:A case study in the Upper Blue Nile Basin

This study examined land use/land cover(LULC)changes in Chemoga watershed of the Upper Blue Nile Basin,comprising four distinct agroecological regions:Wet Wurch,Moist Dega,Moist Weyna Dega,and Moist Kolla.We used multi-temporal Landsat images from 1985 to 2020,a hybrid classification method and the Cellular Automata-Markov model to analyze historical and predict future(2020-2060)LULC changes under business-as-usual(BAU)and land conservation(LC)scenarios.Magnitudes and patterns of spaciotemporal LULC changes were analyzed using intensity analysis.Cropland expanded across all agroecologies from 1985 to 2020,with Moist Kolla experiencing the highest increase at the expense of woodland,due the introduction of commercial farming to this hotter,less populated and inaccessible area.Moist Dega exhibited the highest allocation changes within cropland and forest,attributable to farmers'adoption of rotational land use to rehabilitate extensively degraded cultivated lands.Under the BAU scenario,projections suggest further cropland expansion at expense of woodland in Moist Kolla and built-up areas at the expense of cropland and grassland in Moist Dega.Under the LC scenario,forest cover is expected to increase at the expense of cropland across all agroecologies.The historical and projected BAU LULC change scenario substantially increased soil erosion and reduced ecosystem services.These effects can be minimized if LC scenario is properly implemented.The agroecology-based LULC intensity analysis reveals local drivers of change and associated impacts,providing vital insights for targeted land use planning in this study watershed and other watersheds facing similar challenges.     

Interactions between protected areas and their surroundings in human-dominated tropical landscapes

Protected areas (PAs) often depend on landscapes surrounding them to maintain flows of organisms, water, nutrients, and energy. Park managers have little authority over the surrounding landscape although land use change and infrastructure development can have major impacts on the integrity of a PA. The need for scientifically-based regional-scale land use planning around protected areas is acute in human-dominated landscapes to balance conservation goals with livelihood needs for fuelwood, fodder, and other ecosystem services. As a first step, we propose the designation of a “zone of interaction” (ZOI) around PAs that encompasses hydrologic, ecological, and socioeconomic interactions between a PA and the surrounding landscape. We illustrate the concept by delineating the ZOI in three Indian PAs - Kanha, Ranthambore, and Nagarahole - using remote sensing, population census, and field data. The ZOI in Ranthambore is three times the size of the park and is largely defined by the socioeconomic interactions with surrounding villages. Ranthambore is located in headwaters and wildlife corridors are largely severed. In Nagarahole, the ZOI is more than seven times larger than the park and includes upstream watershed and elephant corridors. Kanha’s ZOI is approximately four times larger than the park and is mostly defined by contiguous surrounding forest. The three examples highlight the differing extents of ZOIs when applying equivalent criteria, even though all are located in densely-populated landscapes. Quantitative understanding of which activities (e.g. collection of forest products, grazing, road construction, tourism development) and which locations within the ZOI are most crucial to conservation goals will enable improved land use planning around PAs in human-dominated landscapes.     

Determining the extent and spectral separability of industrially despoiled land in South Wales from satellite sensor data

Satellite remote sensing offers the potential to accurately identify and monitor spectrally separable land-cover classes at a range of spatial and temporal scales. This paper investigates the separability of despoiled land in imagery acquired by sensors carried by the Landsat satellites. These systems offer the opportunity to map areas at large to medium scales at a relatively high temporal frequency and so provide information on environmental quality necessary for many monitoring and planning activities. From an investigation using imagery of South Wales it was found that despoiled land was separable from other classes in the Landsat TM imagery, with an accuracy of over 90 per cent. Furthermore, with Landsat TM data three spectral wavebands were found to provide a level of separability similar to that based on all wavebands available, illustrating potential savings to the analyst. Despoiled land cover was classified from Landsat TM and MSS data and these classifications were evaluated against a manually produced map of despoiled land cover derived from the interpretation of aerial photographs. Estimates of the extent of despoiled land cover in administrative units derived from the Landsat TM data were significantly correlated (r = 0.81) with the map based estimates, although a weaker correlation was observed with Landsat MSS data.     

1981-2006年藏西北地区草地植被盖度动态变化分析

基于长期遥感数据和地面实测数据,以植被盖度为例,监测了藏西北地区牧草长势及其变化趋势。结果表明:藏西北地区草地植被盖度不高,多年平均值仅为27.2%。1981-2006年,藏西北地区大部分区域(约占草地总面积的60.7%)高寒草地植被盖度年际变化属于正常波动范围;显著降低区域约占总面积的3.6%,主要分布于植被盖度相对较高的东南部地区;植被盖度显著增高区域约占35.7%,主要分布于植被盖度相对较低的中部和北部地区。在整体上,藏西北地区草地植被平均盖度略有增高趋势。     

Landscape-level effects on avifauna within tropical agriculture in the Western Ghats: Insights for management and conservation

A critical handicap to tropical biodiversity conservation efforts in agroecosystems is the unknowns regarding the influence of landscape-scale factors on the persistence of species. To address these uncertainties, we explored two essential landscape-scale questions, within India’s biologically-rich Western Ghats, examining two nearby human-dominated landscapes that dramatically differed in their pattern of land cover. First, how does the proximity of intact forest patches affect bird community composition within agricultural landscapes? Second, can simple remote sensing-derived measures (brightness, wetness, and NDVI) be used to estimate native bird species composition within those landscapes? In both landscapes, as distance to intact forest decreased, the similarity in bird community composition between agricultural areas and intact forest increased. This suggests that the retention of tropical forest bird communities within human-dominated landscapes critically depends on the maintenance of nearby intact forest. In an answer to the second question, the remote sensing measures correlated with forest-affiliated avian species richness in only one of the two landscapes, reflecting an ecological difference between the two in the response of forest bird species to local agricultural conditions. In the landscape where a correlation was found, there was high variation in vegetative structure, which strongly impacted both the remote sensing measures and forest bird species richness. In the other landscape, forest species richness strongly correlated with changes in tree species composition in the agriculture, a factor that could not be detected by the remote sensing metrics. In order to successfully conserve biodiversity in tropical agricultural landscapes, our findings show that it is essential to conserve intact forest within those landscapes and to understand the effect of local agricultural practices on species.