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This paper examines a feature-level fusion framework for detecting and mapping land degradation (LD) and enabling sustainable land management (SLM) in semi-arid areas using optical sensors and Synthetic Aperture Radar (SAR) satellite data. The objectives of this review were to (i) determine the trends and geographical location of land degradation mapping publications, (ii) to identify and report current challenges pertaining to mapping LD using multiscale remote sensing data, (iii) to recommend a way forward for monitoring LD using multiscale remote sensing data. The study reviewed 78 peer-reviewed research articles published over the past 24 years (1998–2022). Image fusion has the potential to be more useful in various remote sensing applications than individual sensor image data, making it more informative and valuable in the interpretation process. In addition, this review discusses the importance of SAR and optical image fusion, pixel-level techniques, applications, and major classes of quality metrics for objectively assessing fusion performance. The literature review alluded that the SAR and optical image fusion in the detection and mapping of land degradation and enabling sustainable land management has not been fully explored. Advanced techniques such as the fusion of SAR and optical satellite imageries need to be incorporated for the detection and mapping of LD, as well as the promotion of SLM in halting LD in South African drylands and around the world. We conclude that there is scope for further research on the fusion of SAR and optical images, as new micro-wave and optical sensors with higher resolution are introduced on a regular basis. The results of this review contribute to a better understanding of the applications of SAR and optical image fusion in future research in the severely degraded drylands of southern Africa. The fusion of SAR and optical data still remains an open challenge. The future of different remote sensing applications lies in this kind of fusion. Land degradation is one of the greatest challenges amongst the environmental problems in South Africa, causing a reduction in the capacity of the land to perform ecosystem functions and services that support society and development. Yet, in South Africa, there are no studies that have widely investigated the potential for a fusion of SAR and optical data to detect and map land degradation and SLM practices. This paper established a baseline for understanding the application of a fusion of SAR and optical data as rapid tools for mapping, monitoring, and evaluating LD, as well as the impacts of SLM practices in South Africa's degraded drylands. [ABSTRACT FROM AUTHOR]

Global drylands face a host of urgent human and environmental challenges with far-reaching impacts. Improving smallholder agriculture remains a key development pathway to tackle these challenges. The dryland development paradigm (DDP), introduced in 2007, presented a highly influential framework for dryland development based on systems research. This paper empirically derives a new, updated DDP. It assesses recent, cutting-edge dryland science, combining literature review with qualitative and quantitative analysis of research published by the world's largest dryland science and development research initiative. The new DDP comprises eight characteristics that are distilled into three integrative principles: Unpack, Traverse and Share. The new DDP is applied and tested to identify key dryland knowledge and development gaps. A future research agenda is then elucidated, grounded in a research in development approach, in which research anchored in the three integrative principles is embedded within the context it seeks to improve. Supported by greater trans-disciplinarity and knowledge co-production, operationalization of the new DDP can deliver both novel scientific insights and development impact in line with the aspirations of the 2030 Sustainable Development Goals. © 2017 The Authors. Land Degradation & Development Published by John Wiley & Sons Ltd. [ABSTRACT FROM AUTHOR]

Camel breeding remains marginal in Algeria but represents an invaluable animal resource for desert regions. The camel is one of the few domestic species that provides milk, meat, leather, wool, manure and work. The Algerian camel herd has experienced a significant increase in recent years, reaching a population of about 416,500 in 2019. This livestock is located in 17 Wilayates, including 8 Saharan and 9 Stepppiques. The main breeds raised in Algeria are: the Chaambi, Ouled Sidi Cheikh, Ait Khebbach, Steppe Camel, Saharaoui, Targui, Ajjer, Reguibi and Ftouh. The camel sector in Algeria is facing several constraints of a sanitary, genetic, logistical and organizational nature. The management of land and common spaces, following the sedentarization of some breeders, is another difficulty that the sheep sector must face. Several favorable factors for camel breeding in Algeria, such as the pedoclimatic diversity of the country, culture/religion, economic and genetic diversity, can help to improve Algerian red meat production. The objective of this paper is to present the current situation of camel farming in Algeria. [ABSTRACT FROM AUTHOR]

CSIRO's research in the arid zone was initiated after World War 2 when a strong push to develop the sparsely populated and isolated region of northern Australia was promoted as being in the national interest. This impetus had social and political origins but implementation depended on scientific insights into regional 'potential', which was couched at the time in terms of agronomic and pastoral use. Ray Perry was a key figure in early land resource surveys of the region and later a key motivator for, and supporter of, research in the arid and semi-arid rangelands of Australia. His commitment was fundamental to the establishment of CSIRO's Central Australian Laboratory. Pastoral land use and improving the land for that purpose were the primary concerns when CSIRO's presence in Alice Springs was established in 1953. From an initial focus on 'making the desert bloom', in particular making the vast spinifex grasslands more 'useful', the focus of research shifted to maintaining the productivity of country preferred by cattle and establishing methods for monitoring its health. It was not until the 1970s that Aboriginal and conservation land management appeared in the laboratory's research agenda, somewhat intermittently, in response to important social and political changes in the wider Australian community. When CSIRO's Arid Zone Unit was established in Alice Springs in 1953, the social and political imperative was to develop Australia's north and, more specifically, to make the vast interior more productive for pastoral and agronomic purposes. The research that followed showed the unreality of that goal and the need to nurture the land that cattle preferred to graze. Not until the 1970s were other values for land, such as Aboriginal and conservation uses, considered to be subjects for research, stimulated by social and political change in the wider Australian community. [ABSTRACT FROM AUTHOR]

Land-use conflicts (LUCs) are pivotal in assessing human–land interaction, reflecting the intricate interplay between natural and anthropogenic drivers. However, existing studies often overlook nuanced non-linear responses and critical threshold recognition, focusing solely on linear correlations between isolated factors and LUCs. This study, situated in Xinjiang, China's arid and semiarid region, introduces a novel analytical framework and threshold application model for LUCs. Integrating land-use and socioeconomic data, we quantified LUCs using Fragstats, correlation analysis, and restricted cubic spline (RCS) regression. Exploring non-linear dynamics between LUCs and 14 potential drivers, including natural and anthropogenic factors, we identified critical thresholds. LUC zones were delineated using a four-quadrant method, allowing tailored mitigation strategies. Our findings reveal Xinjiang's distinct LUC spatial pattern, with intense conflicts surrounding mountainous areas and milder conflicts in basin regions, showing marked diminishment from 2000 to 2020. RCS effectively identifies LUC thresholds, indicating persisting severity pre- or post-specific thresholds. Xinjiang's LUCs are categorized into key control areas, urgent regulation zones, elastic development territories, and moderate optimization regions, each with significant regional disparities. Tailored optimization suggestions mitigate linear analysis limitations, providing a fresh perspective on land zoning optimization. This research supports comprehensive land management and planning in Xinjiang, China. [ABSTRACT FROM AUTHOR]

Climate change and human activities have significant impacts on terrestrial vegetation. Syria is a typical arid region with a water-limited ecosystem and has experienced severe social unrest over the last decades. In this study, changes in vegetation and potential drivers in Syria are investigated. By using an enhanced vegetation index (EVI), a general browning trend is found in Syria during 2001–2018, with the EVI decreasing at a rate of - 0.8 × 10 -3 yr -1 (p<0.1). The decrease of the EVI is mainly found in the north region, whereas the west region still maintains an increasing trend. The residual analysis indicates that besides precipitation, human activities also contribute significantly to the EVI decrease, which is confirmed by the decrease in rainfall use efficiency. Moreover, a paired land-use experiment (PLUE) analysis is carried out in the Khabur River basin where croplands are widely distributed in adjacent regions of Syria and Turkey. The time series of the EVIs over these two regions are highly correlated (r=0.8027 , p<0.001), indicating that both regions are affected by similar climate forcing. However, vegetation in Syria and Turkey illustrates contrary browning (- 3 × 10 -3 yr -1 , p<0.01) and greening trends (4.5 × 10 -3 yr -1 , p<0.01), respectively. Relevant reports have noted that social unrest induced insufficient irrigation and lack of seeds, fertilizers, pesticides and field management. Therefore, we concluded that the decline in vegetation in the north Syria is driven by the change of land management. [ABSTRACT FROM AUTHOR]

Addressing soil salinity in irrigated drylands is tightly linked with water and land management decisions thus requiring interdisciplinary engagement. The salinity mapping approaches in Central Asia are undertaken through field sampling and laboratory analysis, which is a time consuming process. As a consequence, salinity maps are not available on time to estimate water requirements to cope with varying levels of soil salinity. Reducing the time lag between assessment and delivery of such maps would enable authorities to determine in advance appropriate water volumes for leaching the salts before and during the growing season. Research initiated in Uzbekistan context explored transdisciplinary and participatory approach to innovation development with local stakeholders. As one of the innovations, an electromagnetic induction meter (EM), a tool for rapid salinity assessment, was chosen and jointly with local salinity mapping related institutions tested, validated, and local capacities for its use developed. This paper redraws this process of innovation-focused stakeholder interaction and transdisciplinary research and discusses it with reference to ongoing debates on participatory and/or transdisciplinary innovation research. The existence of strong path dependencies within implementation oriented organizations could be observed, meaning that the innovation demands many changes to the existing system. Furthermore, the encountered challenges of participatory, transdisciplinary research in the hierarchically shaped setting of post-soviet Uzbekistan are illustrated in selected qualitative field notes and assessed. For improved joint learning and research in a transdisciplinary team, feedback cycles of mutual learning and critical reflection of how to theoretically and practically work in a transdisciplinary manner turned out to be crucial and not to be underestimated. [ABSTRACT FROM AUTHOR]

Gypseous lands occur mainly in arid regions of the world, where irrigation is required for profitable agriculture. The study of gypseous soils has been neglected for years in the main stream of the soil science. Agriculture and, more recently, the environmental concerns are challenging research in the countries that have extensive gypsum outcrops. Those challenges have been obvious since at least the 1960s, when economic development in some of these countries led to the construction of new irrigation schemes and associated infrastructures. This paper presents examples of documents about agriculture on gypseous soils in Spain that might be applicable to similar situations elsewhere in the world. Copyright © 2016 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Aridity is a climatic phenomenon characterized by shortage of water availability in a given time and space resulting in low moisture and reduced carrying capacity of ecosystems. It is represented by a numerical indicator known as Aridity Index (AI), a function of rainfall and temperature. Aridification is a slow and steady effect of climate change and assessing its spread and change is vital in context of global climatic variations. Aridity is predominantly significant for agrarian countries like India, where a slight rise in drylands area can have a significant impact on the economy and community sustenance. AI is an inclusive indicator of climatic conditions in most arid and semi-arid regions. It helps in identifying and interpreting large scale trend in temperature and precipitation; and thus, classifying region into different climatic classes. The present study assessed long-term AI based on precipitation and temperature data obtained from the India Meteorological Department at the resolution of 1 × 1 degree for years 1969–2017. AI is estimated as a ratio of mean precipitation to mean potential evapotranspiration, calculated using Thornthwaite method. The results highlight the trend of aridity over pan-India with Innovative Trend Analysis and Mann–Kendall test. The study concludes that there is a relatively slow, however steadily progressive drier conditions being established in most of the regions. A shift from 'Semi-arid' towards 'Arid' class appeared in central mainland. The north-eastern Himalaya showed decrease in humid conditions ('Humid' to 'Sub-humid'). The study implies that there is a rising aridity trend over the years due to changing climatic conditions. The shifts in aridity can have serious implications on agriculture, long-term water resource utilization and land use management plans. Our results have scope for future landscape management studies in drylands and better adaptation methods in arid regions. [ABSTRACT FROM AUTHOR]

Abstract Past water resource developments in dryland regions rarely estimated the full suite of environmental and social impacts arising from damming and diverting water for food production. Nowadays there is a greater focus on sustainable resource development which considers the economic, social and environmental costs and benefits. A challenge is to apply tools and methods which can capture the often disparate knowledge and data describing many costs and benefits. This paper describes a proof of concept application of a large Bayesian Decision Net to estimate the total utility of water resource development according to criteria of social, economic and environmental sustainability. We focus on two water-scarce catchments in remote northern Australia which are under investigation for development. The study catchments contain a diverse set of ecosystem services and socio-cultural values, including important Indigenous values and high value freshwater ecosystems. The Bayesian Decision Net was shown to have many properties that made it useful for performing a social, economic and environmental sustainability assessment, in particular its ease of construction; its ability to handle quantitative and qualitative data types; its preservation of system knowledge and; its ease of use in aiding decision making. From the perspective of the sustainability assessment in our case study, the total utility of water resource development for new irrigation is negative in both the studied catchments. The overall utility of water resource development could be positive if irrigation development is highly sensitive to the environment and there are very low environmental impacts, and much higher net economic returns to irrigators eventuate, possibly through higher commodity prices, lower capital costs of irrigation development or some combination of both. Highlights • Development of water resources involves trade-offs between economy and environment. • Integrated social-environment-economy sustainability (SEES) assessments support trade-offs analyses. • Bayesian Decision Networks (BDNs) support SEES assessments with diverse data types. • BDN applied to irrigation development scenarios of two remote catchments in north Australia. • The economic and ecosystem service benefits of the case study irrigation developments are questionable. [ABSTRACT FROM AUTHOR]

Exploring the future trends of land use/land cover (LULC) changes is significant for the sustainable development of a region. The simulation and prediction of LULC in a large-scale basin in an arid zone can help the future land management planning and rational allocation of resources in this ecologically fragile region. Using the whole Ili-Balkhash Basin as the study area, the patch-generating land use simulation (PLUS) model and a combination of PLUS and Markov predictions (PLUS–Markov) were used to simulate and predict land use in 2020 based on the assessment of the accuracy of LULC classification in the global dataset. The accuracy of simulations and predictions using the model were measured for LULC data covering different time periods. Model settings with better simulation results were selected for simulating and predicting possible future land use conditions in the basin. The future predictions for 2025 and 2030, which are based on historical land change characteristics, indicate that the overall future spatial pattern of LULC in the basin remains relatively stable in general without the influence of other external factors. Over the time scale of the future five years, the expansion of croplands and barren areas in the basin primarily stems from the loss of grasslands. Approximately 48% of the converted grassland areas are transformed into croplands, while around 40% are converted into barren areas. In the longer time scale of the future decade, the conversion of grasslands to croplands in the basin is also evident. However, the expansion phenomenon of urban and built-up lands at the expense of croplands is more significant, with approximately 774.2 km2 of croplands developing into urban and built-up lands. This work provides an effective new approach for simulating and predicting LULC in data-deficient basins at a large scale in arid regions, thereby establishing a foundation for future research on the impact of human activities on basin hydrology and related studies. [ABSTRACT FROM AUTHOR]

In semi-arid regions, interactions between biophysical and socio-economic variables are complex. Such interactions and their respective variables significantly alter land use and land cover, degrade landscape's structure, and impede the efficacy of the adopted land management interventions. This scenario is particularly prevalent in communal land tenure system or areas managed by a hybrid of traditional and state led institutions. Hence, this study sought to investigate the impacts of land use and land cover changes (LULCCs) on land degradation (LD) under communal rural districts, and the key drivers of habitat fragmentation in the Greater Sekhukhune District Municipality (GSDM), South Africa. The study used the wet and dry season multi-temporal remotely sensed image data, key-informant interviews, and workshop with tribal council to determine the major drivers of LULCC and LD. Results revealed that mines and quarries, subsistence and commercial cultivation, and thicket/dense bush LULCs declined significantly during the study period. These LULCs mostly declined in wet season, with loss in vegetation cover highly prevalent. Specifically, the highest conversions were from shrub/grassland to bare soil, thicket/dense bush to shrub/grassland, and shrub/grassland to residential, respectively. Generally, LULCC affected vegetation productivity within the study area, with increased negative NDVI values observed during the dry season. The findings from key informants and the tribal council workshop emphasized that soil erosion, abandonment of cropland, and injudicious land use (i.e. overgrazing and consequent bush encroachment) have severely degraded the land. The study also established that the degrading land can be attributed to the weakening local communal land management system, particularly the weakening tribal councils. The study recommends an urgent need for collaborative (i.e. government, tribal authorities, and land users) land management through designing relevant multi-stakeholder LD mitigation measures. [ABSTRACT FROM AUTHOR]

The article presents an overview of research conducted in recent years, i.e., from 2004 until now. The study has been prompted by the threat of drought over large land areas which, as a result of current climate change, may lead to desertification in dry and hot regions of the world. For the same reason, large areas of farmland are affected by drought stress. At the same time, rising air temperatures result in a significant intensification of evaporation and a gradual increase in soil salinity. This applies in particular to acres of farmland, forested areas, and green areas of cities, as well as degraded land or brownfields. As the crop stability is threatened, the food base of the world's population is at risk and, additionally, in areas of industrial districts, people's health is in decline. Due to these multistress conditions for plant growth, we propose a review of the current literature which addresses the possibility of counteracting these unfavorable phenomena through the appropriate selection of plant species and, when only applicable, also through specific agroecological treatments. A selection of herbaceous and woody plants useful for cultivation on saline marginal lands was proposed. [ABSTRACT FROM AUTHOR]

Wind erosion and resultant dust emissions create significant risks for land degradation and ecosystem health in arid and semi-arid regions. In these regions, fallowing constitutes a major component of conventional agriculture. The present study was conducted to determine wind erosion quantities and agricultural activity-induced mass transport from fallow lands and to assess the correlations of mass transport with climate and soil characteristics. Experiments were conducted over the fallow lands of two adjacent agricultural enterprises (Altinova and Gözlü, Turkey). Sediment flux was measured with passive traps in wet and dry seasons (QtWET and QtDRY). Mass transport in wet and dry seasons was respectively measured as 11.38 and 11.40 kg/ha in Altinova and as 31.61 and 19.71 kg/ha in Gözlü. Both the differences between mass transport of the enterprises and the differences between QtWET and QtDRY of each enterprise were found to be significant (P < 0.05). Pearson's correlation analysis for the correlations of mass transport with soil characteristics revealed significant correlations with electrical conductivity and soil lime content (r = 0.721 and -0.635) (P < 0.05). Total mass transport from the fallow lands of both enterprises throughout a 7-month period of measurement was estimated at 600 t. Based on current findings it was concluded that fallowing should be abandoned and sustainable soil and land management practices from conventional agriculture like minimum tillage or crop rotations should be introduced. [ABSTRACT FROM AUTHOR]

Pastoralism as a mode of production has had an important bearing on the livelihoods of many people in arid and semiarid environments. In the recent decades' policies for land management in pastoral communities have changed from customary to statutory policies. This study analysed the dynamics of land management and their influence on the pastoral livelihood system at Kimana and Njoro villages in Kiteto district, northern Tanzania. Data for the study were collected from two focus groups, six key informants at the district level, and 296 households (equivalent to 10.1%) using household questionnaires, Findings show that whereas land is managed under customary and statutory laws, the emphasis is more on statutory laws. Statutory laws foster individualization of land ownership to some activities such as crop production, whereas communal lands are left for animal grazing only. Under statutory laws, individual land ownership is likely to be influenced by crop production, male-headed households, climate change, and resource use conflicts. However, statutory laws cannot guarantee sustainable resource management as the natural resources management institutions cannot dictate activities done in individual lands, as opposed to traditional systems. There is a need to harmonize traditional and modern forms of land management for increasing productivity and enhancing sustainable natural resources management. [ABSTRACT FROM AUTHOR]

In this research, we used the Revised Universal Soil Loss Equation (RUSLE) and Geographical Information System (GIS) to predict the annual rate of soil loss in the District Chakwal of Pakistan. The parameters of the RUSLE model were estimated using remote sensing data, and the erosion probability zones were determined using GIS. The estimated length slope ( L S), crop management ( C), rainfall erosivity ( R), soil erodibility ( K), and support practice ( P) range from 0–68,227, 0–66.61%, 0–0.58, 495.99–648.68 M J / m m. t. h a − 1. y e a r − 1 , 0.15–0.25 M J / m m. t. h a − 1. y e a r − 1 , and 1 respectively. The results indicate that the estimated total annual potential soil loss of approximately 4,67,064.25 t. h a − 1. y e a r − 1 is comparable with the measured sediment loss of 11,631 t. h a − 1. y e a r − 1 during the water year 2020. The predicted soil erosion rate due to an increase in agricultural area is approximately 164,249.31 t. h a − 1. y e a r − 1 . In this study, we also used Landsat imagery to rapidly achieve actual land use classification. Meanwhile, 38.13% of the region was threatened by very high soil erosion, where the quantity of soil erosion ranged from 365487.35 t. h a − 1. y e a r − 1 . Integrating GIS and remote sensing with the RUSLE model helped researchers achieve their final objectives. Land-use planners and decision-makers use the result's spatial distribution of soil erosion in District Chakwal for conservation and management planning. [ABSTRACT FROM AUTHOR]

Soil salinity and sodicity are significant issues worldwide. In particular, they represent the most dominant types of degraded lands, especially in arid and semi-arid regions with minimal rainfall. Furthermore, in these areas, human activities mainly contribute to increasing the degree of soil salinity, especially in dry areas. This study developed a model for mapping soil salinity and sodicity using remote sensing and geographic information systems (GIS). It also provided salinity management techniques (leaching and gypsum requirements) to ameliorate soil and improve crop productivity. The model results showed a high correlation between the soil electrical conductivity (ECe) and remote-sensing spectral indices SIA, SI3, VSSI, and SI9 (R2 = 0.90, 0.89, 0.87, and 0.83), respectively. In contrast, it showed a low correlation between ECe and SI5 (R2 = 0.21). The salt-affected soils in the study area cover about 56% of cultivated land, of which the spatial distribution of different soil salinity levels ranged from low soil salinity of 44% of the salinized cultivated land, moderate soil salinity of 27% of salinized cultivated land, high soil salinity of 29% of the salinized cultivated land, and extreme soil salinity of 1% of the salinized cultivated land. The leaching water requirement (LR) depths ranged from 0.1 to 0.30 m ha−1, while the gypsum requirement (GR) ranged from 0.1 to 9 ton ha−1. [ABSTRACT FROM AUTHOR]

The study evaluated patterns of land use and land cover (LULC) change in the Zambezi Region, Namibia between 1984 and 2010 using geospatial tools. Spatio-temporal dynamics of LULC changes were quantified using the post classification change detection method. The images were classified into five land use and land cover classes: forest land, shrub land, bare land, crop/grass land and other land. Landscape metrics were calculated using Fragstats to understand the landscape patterns and structural integrity of the landscape. The results showed that political transition (before and after independence) has resulted in dramatic decreases in patch density and increases in the interspersion and juxtaposition index values. The general pattern of LULC showed that the communal area compared to protected area became structurally diverse and ecologically more fragmented from 1984 to 2010. This study provides a foundation and baseline data demonstrating LULC alteration and landscape context suitable for monitoring future changes of protected and communal areas. Our approach is a novel way to assess the drivers and patterns of LULC under different land tenure types for natural resources conservation and sustainable land management in the dry lands of Southern Africa. [ABSTRACT FROM AUTHOR]

Rangeland degradation caused by increasing misuses remains a global concern. Rangelands have a remarkable spatiotemporal heterogeneity, making them suitable to be monitored with remote sensing. Among the remotely sensed vegetation indices, Normalized Difference Vegetation Index (NDVI) is most used in ecology and agriculture. In this paper, we research the relationship of NDVI with temperature, precipitation, and Aridity Index (AI) in four different arid rangeland areas in Spain's southeast. We focus on the interphase variability, studying time series from 2002 to 2019 with regression analysis and lagged correlation at two different spatial resolutions (500 × 500 and 250 × 250 m2) to understand NDVI response to meteorological variables. Intraseasonal phases were defined based on NDVI patterns. Strong correlation with temperature was reported in phases with high precipitations. The correlation between NDVI and meteorological series showed a time lag effect depending on the area, phase, and variable observed. Differences were found between the two resolutions, showing a stronger relationship with the finer one. Land uses and management affected the NDVI dynamics heavily strongly linked to temperature and water availability. The relationship between AI and NDVI clustered the areas in two groups. The intraphases variability is a crucial aspect of NDVI dynamics, particularly in arid regions. [ABSTRACT FROM AUTHOR]

In arid and semi-arid regions, unregulated land use changes as a result of poor planning, and the expansion of agricultural and livestock activities increase the risk of desertification and other potentially severe environmental impacts. Several consequences of improper land management practices are soil deterioration and erosion, which may be intensified by meteorological events. This paper presents a historical evaluation of the temporal and spatial evolution of soil deterioration in the southern Chihuahuan Desert in Mexico. A multi-temporal analysis of the study area during the 1995–2016 period was carried out using satellite data (Landsat series). Two seasons were analyzed to determine the influence of external events such as rainfall and wind: dry and rainy. The identification of soil conditions was based on the Brightness Index (BI) considering the complete satellite data set. The soil conditions were classified into five categories according to their reflectance values: highly deteriorated, deteriorated, in the process of being deteriorated, in good condition and other (clouds, water, non-soil). The change detection maps clearly show a growing trend wherein areas of deteriorated and eroded soil increase over time. Agriculture and strong winds are the two main factors involved in the soil deterioration process of the study region. • Deficient agricultural practices and strong winds precursors to desertification. • Spatial-temporal identification of deteriorated soil in arid/semi-arid zones. • Spectral analysis based method for categorization of soil conditions. • Comparative analysis of sensitivity in rainy and dry seasons. [ABSTRACT FROM AUTHOR]

Farmers' land management is a key factor for sustainable agriculture, yet the traditional knowledge which constitutes its base is seldom incorporated in the land and soil academic literature. The need for a hybrid approach that combines local (farmers') and scientific knowledge is formally recognized. Plot quality criteria are a component of both sources of knowledge, playing an important role in shaping land management practices. Yet there are few case studies comparing the criteria used by farmers and soil scientists when assessing plot quality, particularly in developed countries. We compare the plot quality assessment done by a sample of 31 farmers in a semiarid area of Spain with an edaphic quality index (EQI) obtained through laboratory analyses of soil samples from 61 farm plots. There is a coincidence between farmer and laboratory assessments in 70% of cases. Plots identified by farmers as being of good quality have a significantly higher EQI than those identified as bad quality. The two key differentiating parameters were clay content (average 21% in good versus 18% in bad quality plots) and soil organic carbon content (1.6 and 1.3%, respectively), both closely related to soil water retention ability. A holistic land vision, a higher level of education and large differences in EQI between good and bad plots as assessed by farmers have a positive influence in the degree of coincidence between farmers' and laboratory assessments. [ABSTRACT FROM AUTHOR]

Rhamnus prinoide (Gesho) intercropping is a common practice with significant socioeconomic and ecological importance in Ganta-afoshum district. However, this practice is not well explored so far, especially from the perspective of its impact on sustainable land management while land degradation and low productivity is a challenge in the district. The objective of this study was to examine the effect of R. prinoide intercropping on soil nutrient and moisture. The study was conducted in Ganta-afoshum district, eastern zone of Tigray regional state where smallholder farmers practice R. prinoide intercropping. Soil samples were taken from farmland with dense, medium and sparse density of R. prinoide intercropping and from farmland without trees as a control for analysis. The density of the trees significantly affected the soil bulk density (P<0.05). Soil moisture content significantly increased with increasing soil depth and by the interaction effects of soil depth and density (P<0.05). Soil nitrogen concentration significantly influenced by the density and soil depth (P<0.05). Soil phosphorus and potassium concentration significantly affected by soil depth (P<0.05). Lower mean soil pH values were observed for soils under the farm with dense trees as compared to soils in open farm. Overall, the enhancing and exploitative effects of R. prinoide intercropping on soil nutrient and moisture is minimal. This could be the reason for being practiced and maintained by most farmers. [ABSTRACT FROM AUTHOR]

Soil respiration, a major component of the global carbon cycle, is significantly influenced by land management practices. Grasslands are potentially a major sink for carbon, but can also be a source. Here, we investigated the potential effect of land management (grazing, clipping, and ungrazed enclosures) on soil respiration in the semiarid grassland of northern China. Our results showed the mean soil respiration was significantly higher under enclosures (2.17μmol.m−2.s−1) and clipping (2.06μmol.m−2.s−1) than under grazing (1.65μmol.m−2.s−1) over the three growing seasons. The high rates of soil respiration under enclosure and clipping were associated with the higher belowground net primary productivity (BNPP). Our analyses indicated that soil respiration was primarily related to BNPP under grazing, to soil water content under clipping. Using structural equation models, we found that soil water content, aboveground net primary productivity (ANPP) and BNPP regulated soil respiration, with soil water content as the predominant factor. Our findings highlight that management-induced changes in abiotic (soil temperature and soil water content) and biotic (ANPP and BNPP) factors regulate soil respiration in the semiarid temperate grassland of northern China. [ABSTRACT FROM AUTHOR]

Drylands occupy more than 80 % of Kenya's total land mass and contribute immensely to the national economy and society through agriculture, livestock production, tourism, and wild product harvesting. Dryland ecosystems are areas of high climate variability making them vulnerable to the threats of land degradation. Consequently, agropastoralists inhabiting these ecosystems develop mechanisms and technologies to cope with the impacts of climate variability. This study is aimed to; (1) determine what agropastoralists inhabiting a semi-arid ecosystem in Kenya attribute to be the causes and indicators of land degradation, (2) document sustainable land management (SLM) technologies being undertaken to combat land degradation, and (3) identify the factors that influence the choice of these SLM technologies. Vegetation change from preferred indigenous forage grass species to woody vegetation was cited as the main indicator of land degradation. Land degradation was attributed to recurrent droughts and low amounts of rainfall, overgrazing, and unsustainable harvesting of trees for fuelwood production. However, despite the challenges posed by climate variability and recurrent droughts, the local community is engaging in simple SLM technologies including grass reseeding, rainwater harvesting and soil conservation, and dryland agroforestry as a holistic approach combating land degradation and improving their rural livelihoods. The choice of these SLM technologies was mainly driven by their additional benefits to combating land degradation. In conclusion, promoting such simple SLM technologies can help reverse the land degradation trend, improve agricultural production, food security including access to food, and subsequently improve livelihoods of communities inhabiting dryland ecosystems. [ABSTRACT FROM AUTHOR]

Water resource development and non-native species have been cited as primary drivers associated with the decline of native fishes in dryland rivers. To explore this topic, long-term trends in the fish community composition of the Bill Williams River basin were studied over a 30-year period (Arizona, USA). We sampled 31 sites throughout the basin that were included in fish surveys by Arizona Game and Fish in 1994-97 and the Bureau of Land Management in 1979-80. We found that non-native species have proliferated throughout the entire basin, with greater densities in the lower elevations. Native species have persisted throughout most of the major river segments, but have experienced significant declines in frequency of occurrence and abundance in areas also containing high abundances of non-native species. Next, we assessed the short-term response of the fish assemblage to an experimental flood event from the system's only dam (i.e. Alamo Dam). In response to the flood, we observed a short-term reduction in the abundance of non-native species in sites close to the dam, but the fish assemblage returned to its preflood composition within 8 days of the event, with the exception of small-bodied fish, which sustained lower postflood densities. Our findings demonstrate the importance of natural flow regime on the balance of native and non-native species at the basin scale within dryland rivers and highlight minimal effects on non-native fishes in response to short duration flood releases below dams. [ABSTRACT FROM AUTHOR]

Atriplex nummularia has been extensively planted in Northern Africa to combat desertification. However, few studies evaluated the effectiveness of these interventions. This study aimed at assessing the dynamic performance of a number of Atriplex plantations located in the Marrakech province in terms of multitemporal dry biomass production. Three SPOT 5 images (2004, 2008 and 2012) and field biomass measurements were integrated to quantify the dry biomass production dynamics of plantations established from 1996 to 2007. Different plant ages covered the whole plant life cycle curve. Vegetation indices were derived from the images and those of 2012 were coupled to the measured biomass of 2012 to formulate biomass models. An analysis of shrub biomass production was conducted in plantations and in adjacent rangelands, covering varying degree of plant development, and an estimate of the economic benefits generated by the plantations in terms of available fodder biomass was performed. The results show that, on average, the plantation sites produced 2·21 to 3·61 Mg ha−1 of dry biomass more than the surrounding rangelands. The best performing plantations yielded even greater differences, up to more than 7 Mg ha−1. It was observed that the most performing plantations, while contributing to mitigating land degradation, have generated economic value and could compensate the economic cost of the intervention even under drought conditions. However, in several cases the plantation performance was far from sustainability, particularly due to poor management (early and/or over grazing), revealing that management is a critical factor for the success of this restoration practice. Copyright © 2014 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Previous research on the effects of drought on vegetation productivity seldom distinguished the different responses of vegetation ecosystems to drought under different management practices and different land use systems. Studies investigating whether irrigation can buffer the negative impacts of drought on vegetation usually used discontinuous yield data in distribution. In this study, the trends in drought and vegetation productivity in farmlands in the drylands of northern China (DNC) from 2000 to 2018 were studied using the self-calibrated Palmer drought severity index (scPDSI) and enhanced vegetation index (EVI). The differences in the impact of drought on vegetation productivity in irrigated farmland, rainfed farmland, and natural vegetation areas were quantified. The results showed that the growing season scPDSI and EVI showed an increasing trend from 2000 to 2018. Significant correlations between drought anomalies and EVI anomalies were found in both arid drylands and semi-arid drylands. In addition, irrigation mitigated 59.66% of the negative impact caused by drought on irrigated farmland EVI in the growing season. The impact of drought on irrigated farmland EVI in the growing season was 19.98% lower than that on natural vegetation EVI. The impact of drought on natural vegetation EVI was 49.59% lower than that on rainfed farmland EVI. The results of this study refine the vegetation response to drought under different land management practices and land use patterns. [ABSTRACT FROM AUTHOR]

Changing land use patterns is of great importance in environmental studies and critical for land use management decision making over farming systems in arid and semi-arid regions. Unfortunately, ground data scarcity or inadequacy in many regions can cause large uncertainties in the characterization of phenological changes in arid and semi-arid regions, which can hamper tailored decision making towards best agricultural management practices. Alternatively, state-of-the-art methods for phenological metrics' extraction and long time-series analysis techniques of multispectral remote sensing imagery provide a viable solution. In this context, this study aims to characterize the changes over farming systems through trend analysis. To this end, four farming systems (fallow, rainfed, irrigated annual, and irrigated perennial) in arid areas of Morocco were studied based on four phenological metrics (PhM) (i.e., great integral, start, end, and length of the season). These were derived from large Moderate resolution Imaging Spectroradiometer (MODIS) normalized difference vegetation index (NDVI) time-series using both a machine learning algorithm and a pixel-based change analysis method. Results showed that during the last twenty-year period (i.e., 2000–2019), a significant dynamism of the plant cover was linked to the behavior of farmers who tend to cultivate intensively and to invest in high-income crops. More specifically, a relevant variability in fallow and rainfed areas, closely linked to the weather conditions, was found. In addition, significant lag trends of the start (−6 days) and end (+3 days) were found, which indicate that the length of the season was related to the spatiotemporal variability of rainfall. This study has also highlighted the potential of multitemporal moderate spatial resolution data to accurately monitor agriculture and better manage land resources. In the meantime, for operationally implementing the use of such work in the field, we believe that it is essential consider the perceptions, opinions, and mutual benefits of farmers and stakeholders to improve strategies and synergies whilst ensuring food, welfare, and sustainability. [ABSTRACT FROM AUTHOR]

The launch of Sentinel-2A and B satellites has boosted the development of many applications that could benefit from the fine resolution of the supplied information, both in time and in space. Crop classification is a necessary task for efficient land management. We evaluated the benefits of combining Landsat-8 and Sentinel-2A information for irrigated crop classification. We also assessed the robustness and efficiency of 22 nonparametric classification algorithms for classifying irrigated crops in a semiarid region in the southeast of Spain. A parcel-based approach was proposed calculating the mean normalized difference vegetation index (NDVI) of each plot and the standard deviation to generate a calibration-testing set of data. More than 2000 visited plots for 12 different crops along the study site were utilized as ground truth. Ensemble classifiers were the most robust algorithms but not the most efficient because of their low prediction rate. Nearest neighbor methods and support vector machines have the best balance between robustness and efficiency as methods for classification. Although the F1 score is close to 90%, some misclassifications were found for spring crops (e.g., barley, wheat and peas). However, crops with quite similar cycles could be differentiated, such as purple garlic and white garlic, showing the powerfulness of the developed tool. [ABSTRACT FROM AUTHOR]

Background: Land use change plays a vital role in global carbon dynamics. Understanding land use change impact on soil carbon stock is crucial for implementing land use management to increase carbon stock and reducing carbon emission. Therefore, the objective of our study was to determine land use change and to assess its effect on soil carbon stock in semi-arid part of Rajasthan, India. Landsat temporal satellite data of Pushkar valley region of Rajasthan acquired on 1993, 2003, and 2014 were analyzed to assess land use change. Internal trading of land use was depicted through matrices. Soil organic carbon (SOC) stock was calculated for soil to a depth of 30 cm in each land use type in 2014 using field data collection. The SOC stock for previous years was estimated using stock change factor. The effect of land use change on SOC stock was determined by calculating change in SOC stock (t/ha) by deducting the base-year SOC stock from the final year stock of a particular land use conversion. Results: The total area under agricultural lands was increased by 32.14% while that under forest was decreased by 23.14% during the time period of 1993–2014. Overall land use change shows that in both the periods (1993–2003 and 2003–2014), 7% of forest area was converted to agricultural land and about 15% changes occurred among agricultural land. In 1993–2003, changes among agricultural land led to maximum loss of soil carbon, i.e., 4.88 Mt C and during 2003–2014, conversion of forest to agricultural land led to loss in 3.16 Mt C. Conclusion: There was a continuous decrease in forest area and increase in cultivated area in each time period. Land use change led to alteration in carbon equity in soil due to change or loss in vegetation. Overall, we can conclude that the internal trading of land use area during the 10-year period (1993–2003) led to net loss of SOC stock by 8.29 Mt C. Similarly, land use change during 11-year period (2003–2014) caused net loss of SOC by 2.76 Mt C. Efforts should be made to implement proper land use management practices to enhance the SOC content. [ABSTRACT FROM AUTHOR]