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Abstract Surface water quality has a vital role in determining the ecological environment, public health, and social and economic development. This study analyzed the spatial and seasonal differences in surface water quality in the Dan River basin based on three monitoring sections over the period of 2009–2015. The main influencing factors and their contributions to water quality in different seasons were determined using statistical analysis, Hurst exponent and redundancy analysis. Results indicated that vegetation coverage in the Dan River basin increased substantially from 2009 to 2015, particularly forested land. Higher concentrations of major water pollution indicators were recorded in the downstream monitoring sites. Nitrate nitrogen (NN) and total phosphorus (TP) made the largest contributions to the pollution of water quality and indicated spatial and seasonal changes. Lower NN concentrations were more frequent during the summer, whereas TP concentrations were higher during the spring. Thus, the factor making the largest contribution to water quality varied with the season. The contribution of the normalized difference vegetation index (NDVI) to water quality gradually decreased from spring to winter, whereas contributions of land use to water quality gradually increased from spring to winter. Analyses of landscape metrics suggested that patch connectivity was the primary factor influencing water quality in the different seasons. Water level was the main hydrological parameter impacting stream water quality. These results suggested that seasonal differences in the major factors influencing water quality should be taken into account for effective water management. Highlights • The time series of vegetation coverage was a consistent sequence in Dan River. • Factors making the largest contribution to water quality varied with the season. • Patch connectivity was the primary factor influencing water quality. • Water level was the main hydrological parameter impacting stream water quality. [ABSTRACT FROM AUTHOR]

Abstract Shrubs play a vital role in ecosystem restoration in the desert transition zone, which suffers intensive desertification, land degradation, and nitrogen (N) limitation. To evaluate the effects of different shrub species on soil N availability, transformation, and their seasonal dynamics, we determined mineral N contents and mineralization rates in soils under three common shrub species (Artemisia ordosica Krasch., Caragana korshinskii Kom., and Salix psammophila C.) and in bare land during the growing season in the desert-loess transition zone in northwestern China. The average contents of soil nitrate N and mineral N were 153% and 55% greater, respectively, and cumulative net N nitrification and mineralization were 101.2 and 121.0 mg N m−2 higher, respectively, in soils beneath C. korshinskii than in bare land (P < 0.05) at the 0–10 cm depth over the growing season. The net N mineralization rate in 0–10 cm depth was significantly higher in soils under C. korshinskii than that in bare land during 21 Jun-23 Jul and 23 Aug-15 Oct of the growing season. However, C. korshinskii did not influence soil N metrics at the 10–20 cm depth. The incorporation of A. ordosica and S. psammophila into bare land did not influence soil N availability or transformation rates. Our results demonstrated that C. korshinskii was more preferable than A. ordosica and S. psammophila in ameliorating soil N cycling in the desert-loess transition zone. Highlights • Xeric shrub species: Artemisia ordosica , Caragana korshinskii , Salix psammophila • The fragile transition zone between the desert and the Loess Plateau of China • C. korshinskii increased mineral N content and net N mineralization rate • Effects of C. korshinskii were greater in dry and cold period and the 0–10 cm soil. • A. ordosica and S. psammophila did not influence soil N mineralization. [ABSTRACT FROM AUTHOR]

Abstract Dissolved solids (DS) and suspended sediment (SS) loads are considered relevant environmental problems. They are related to a wide range of on-site and off-site impacts, such as soil erosion or salinization of water bodies. In this study, the dynamics of DS and SS concentrations and loads were assessed in five small watersheds covering representative agricultural land uses in Navarre (Spain). To this end, discharge, DS and SS concentration data were collected during ten hydrological years at each watershed outlet, and loads were computed from discharge and concentration values. DS concentration followed a seasonal pattern imposed by the availability of water, with higher concentrations recorded in low-flow periods and lower concentration in the high-flow period. SS concentration was extremely variable, with a range of 2–4 orders of magnitude in concentration for any specific discharge. Temporal variations (both intra- and inter-annual) in DS loads were explained by differences in runoff, whereas those of SS were not, being the SS loads associated mainly with specific high flow events. These temporal patterns were observed for both agricultural (this study) and non-agricultural (literature) watersheds. From the data in the Navarrese watersheds and those available in the literature, we inferred that agricultural land use, in general, tends to increase the concentration of both DS and SS. Regarding DS and SS yields, the effects of agricultural land use on DS yields are controlled by the changes in runoff rather than the (small) changes in DS concentration. In this sense, land uses changes expected to increase runoff (i.e., a shift from forested to arable or from rainfed to irrigated agriculture) would increase DS yields. On the other hand, agricultural land use tends to increase SS yields, although the effect is highly variable depending on site-specific factors, both natural (e.g., watershed shape) and anthropogenic (e.g., degree of soil conservation practices). In the Navarrese watersheds, DS yields ranged from 1.1 to 2.2 Mg ha−1 year−1 whereas SS yields ranged from 0.3 to 4.3 Mg ha−1 year−1. DS yields seem to dominate under non-agricultural conditions and in most agricultural land uses at the small watershed scale. On the other hand, SS yields dominate in watersheds with increased soil erosion as a consequence of arable land use over erosion-prone watersheds. Highlights • Dissolved solids concentration follows a seasonal pattern. • Suspended sediment concentration was extremely variable. • Dissolved loads behave conservatively with water. • The dissolved load dominated the exportation in most of the cases. • Agricultural land use increases suspended sediment concentration and loads. [ABSTRACT FROM AUTHOR]

Abstract The Ñadi soils (ÑS) is a local name for soils occurring at southern Chile (38° to 43° S) covering around 4250 km2 hectares. Derived from volcanic materials, have discontinuous iron-cemented layers (the placic horizon) which favour waterlogging during the winter. The studies of iron-cemented layers are predominant in USA and Taiwan, but we provide an overview of ÑS research to position them within the group of soils with iron-cemented layers, and to highlight the distribution, formation, processes, and the relevance of placic horizons in land use and ecosystem services that ÑS provide. We surveyed the worldwide literature of iron-cemented layers to put the Chilean soils with placic horizons. A fraction analysis was conducted in a longitudinal transect of five ÑS to evaluate the Si, Al, Fe and Mn reactive pools in the soil. A principal component analysis (PCA) was performed to separate the soil Series. Finally, a comparison between chemical properties of placic horizons and bog iron in Chile with other soils in the world was realised. Further south, the Chilean ÑS have more SOC in surface horizons thus enabling more intensive iron translocation with the reactive soils pools decreasing with the latitude. The iron-cemented layers probably consist of goethite, ferrihydrite and gibbsite. A 51.8% of bog iron are compound of Fe while only 36.2% in the placic horizon, which also have 12.1% of Al 2 O 3 in the molecular structure. Land uses in ÑS vary, from forestry to archaeology coexisting in these soils. In agricultural terms, we suggest a soil depth of 50 cm as the limit to drainage, shallower depth is at risk of severe soil degradation. Finally, several research questions are posed which may help to define the use and importance of the Ñadi ecosystem to the people who use the soils currently and to future generations within the context of climate change scenario. Graphical abstract Unlabelled Image Highlights • Placic horizons studies are concentred in North-America. • Reactive pools of surface horizons in Ñadi soils decrease towards south. • Goethite and ferrihydrite dominate in placic horizons and bog iron. • 50 cm is the critical depth for drainage implementation in agriculture lands. • Soil ecosystem services as provided by Ñadi must be further researched. [ABSTRACT FROM AUTHOR]

Abstract Soil exoelectrogenic bacteria have been found to perform various functions. However, little is known about whether exoelectrogenic bacteria are widely distributed in soil and which physico-chemical properties of soil significantly affect their distribution? To address the research questions, 37 soil samples covering six land use types, including arid farmland soils, woodland soils, grassland soils, paddy soils, lakeshore soils, and coastal soils were collected. DNA was extracted from all the samples for quantitative PCR and high throughput sequencing of the 16S rRNA gene. The sequencing result showed a total of 16 exoelectrogenic bacteria-associated genera from different soils. The total abundance of these genera varied from 1.14 × 108 copies g−1 in a farmland soil to 7.89 × 109 copies g−1 in a coastal soil, accounting for 0.26% to 7.70% of the total bacteria. Among the 16 genera, Bacillus was dominant in the arid land soils, including the farmland, woodland, and grassland soils. The coastal soils were dominated by Desulfobulbus whereas the paddy and lakeshore soils were characterized by abundant Geobacter. Principal component analysis showed a distinct separation of the exoelectrogenic bacterial community between the arid land (farmland, woodland, and grassland soils), freshwater wetland (paddy and lakeshore soils), and coastal soils. Redundancy analysis revealed that the water content, electrical conductivity and concentrations of total sulphur and amorphous Fe in the soil were significant factors driving the community structure and abundance of exoelectrogenic bacteria-associated genera. Our results should help in better understanding of the exoelectrogenic bacteria-mediated functions in soil, which might contribute to the biogeochemical cycling of a large number of organic and inorganic materials. Highlights • Exoelectrogenic bacteria are ubiquitous in soils under different land use types. • Exoelectrogenic bacteria might account for 0.26% - 7.70% of total bacteria in soil. • Bacillus dominates arid land soils while Desulfobulbus dominates coastal soils. • Geobacter was the most prevalent genus in paddy soils and lakeshore soils. • Soil water content, EC, TS and amorphous Fe drive exoelectrogenic bacteria community. [ABSTRACT FROM AUTHOR]

Abstract Several decades of intensive rainfed farming in Mediterranean mountains and later land abandonment has led to rapid land use and land cover changes. During recent centuries, the conversion of rangelands into croplands has increased the surfaces prone to erosion. In the southern Pre-Pyrenees, the process was reversed during the middle of the twentieth century, allowing the recovery of vegetation and subsequent variation in land cover. This work aims to assess how land use changes after generalised land abandonment affect some major soil properties related to soil quality. For this purpose, 98 replicate bulk soil samples were collected in a 23 km2 catchment that was mostly cultivated at the beginning of the last century. Soil samples were distributed over areas representing the main land uses (agricultural land, natural forest, pine afforestation and scrubland). Bulk density, stoniness, grain size, pH, carbonates, electrical conductivity, soil organic carbon (SOC), total nitrogen (TN), water retention capacity and magnetic properties (low frequency magnetic susceptibility (LF) and frequency dependence (FD)) were analysed in the samples from different land use areas. A past scenario was recreated using estimated data from the SPEROS-C model in order to evaluate changes in SOC over time. Furthermore, a multitemporal analysis of the Normalised Difference Vegetation Index of Landsat images was performed between 1972 and the present in order to assess the dynamics of revegetation. After land abandonment, 16.5% of the area remained as croplands, but afforestation and natural revegetation occupied 83.5% of the catchment. The highest mean value for SOC was found in the pine afforested area and the highest TN mean value was found in the natural forest. The lowest mean values for SOC and TN were recorded on the agricultural land. These results show the impact of soil changes produced by land use changes in fragile Mediterranean mountain agroecosystems. Graphical abstract Unlabelled Image Highlights • Changes in land use have resulted in differences in soil properties. • NDVI allows identifying vegetation cover variation developed after land use changes. • Spatial patterns of soil properties are highly conditioned by land use distribution. • Modelling SOC stocks along time is possible applying SPEROS-C model. • NDVI is directly related with the distribution of soil nutrients in the catchment. [ABSTRACT FROM AUTHOR]

Abstract Tropical environments are considerable contributors to overall soil carbon loss to the atmosphere. Land use effects on soil chemical attributes have been well documented mainly in humid environments; however, less attention has been paid to the changes in soil enzymatic activities in dry ecosystems that is a sensitive indicator in ecological processes, due to its importance in soil dynamics and microbial activity. The present study is part of interdisciplinary project that investigated the effect of land cover type and seasonal variation on absolute and specific enzymatic activities per unit of soil organic carbon (SOC) and per microbial biomass carbon (MBC). We assessed five different land use type (Tropical dry forest-TDF, protected area with Angico –ANA, protected area with Ipê-TAB, Scrub area-SCR and agricultural area with maize-M) and five areas of each land use in three layers: 0–0.05, 0.05–0.10 and 0.10–0.20 m. The samples were collected at rainy season 1 in April 2014 (RS1), dry season October 2015 (DS) and rainy season 1 April 2016 (RS2). The conversion of the preserved area provided a reduction in absolute enzymatic activities, especially in the SCR and M. The reductions were of 76% for β-glucosidase, 95% for urease and 72% for acid phosphatase. The specific enzymatic activities per unit of MBC increased with the change of soil use, except in M. The enzymatic activity per unit of SOC in the TDF area was higher in relation to the other areas evaluated, except for specific activity of acid phosphatase. The land use type influenced the absolute and specific soil enzyme activities, but not show a clear trend of seasonal effect. Highlights • Conversion of TDF to land uses leads to a drastic reduction in Luvisol chromic enzymatic activities. • Seasonality directly affects enzymatic activities mainly during rainy periods. • Seasonal effect of land use in Brazilian semiarid soils affects mainly C and N enzyme activities. [ABSTRACT FROM AUTHOR]

Abstract Soil water is a key variable for re-vegetation and environmental restoration in water-limited terrestrial ecosystems such as the Chinese Loess Plateau. Large land restoration projects (e.g., the "Grain for Green" launched in 1999 and the "Gully Land Consolidation" launched in 2011) had substantial impacts on the storage, distribution, and spatial patterns of soil water, and these factors remain poorly understood across watershed scales. We measured the amount of water stored in soil layers from the surface down to 5 m depth and characterized the vertical distribution of gravimetric soil water content (SWC) among four land uses (cropland, shrubland, forestland, and orchard), two slope aspects (shady vs. sunny), and two landforms (slope vs. gully) in three watersheds on the Chinese Loess Plateau. All three of the watersheds were affected by Grain for Green project, two were affected by the Gully Land Consolidation project (named NG and GT-T watersheds) and one was unaffected by restoration efforts (named GT-U watershed). In the three watersheds, the slope and gully SWCs varied from 2.4 to 24.2% and from 4.8 to 46.6%, respectively, during the sampling period in October 2015 (end of the rainy season). The amount and vertical distribution of slope SWC differed significantly among the land uses and between shady and sunny slopes in the three watersheds (p < 0.05). The mean gully SWC (20.4%) was significantly higher than the mean slope SWC (8.7%) for each of the three watersheds (p < 0.01). Gullies filled by the Gully Land Consolidation project had a large capacity to store soil water by increasing the infiltration of precipitation, which accounted for 14.7% and 11.3% of the total annual rainfall in the NG and GT-T watersheds, respectively. Filled gullies can serve as large reservoirs of soil water to relieve the problem of water shortage and can also increase the amount of land available for cultivation to ease deficits in food production. A combination of the Grain for Green project on slopes for soil conservation and the Gully Land Consolidation project in gullies for storing more soil water and increasing farmland area is an effective land restoration strategy on the Chinese Loess Plateau and is helpful for managing water cycles in regions around the world with deep soils. Highlights • The role of the GFG and GLC projects in determining soil water regimes in 5-m depth was evaluated at three watersheds. • Mean gully SWC (20.4%) was higher than mean slope SWC (8.7%) (p < 0.01) at each watershed. • Slope SWC in the 0–500 cm profile was greatly affected by land use and slope aspect after GFG. • ~13.0% of the annual rainfall was retained in the watershed owing to the implementation of GLC. • Implementing GFG on slopes and GLC in gullies is recommended for watershed management of soil and water resources. [ABSTRACT FROM AUTHOR]

Abstract In the last decades, the use of biofuels as a mitigation measure for carbon emissions has led to land use and land cover changes in southeastern Brazil, especially in Paulista Peripheral Depression – Paraná Sedimentary Basin. Considering the human-landscape system associated with energy policy, these changes can affect landscape and natural resources over a range of temporal and special scales. Thus, the aim of study was on how human-landscape interactions have influenced the geomorphological dynamics in a São Paulo region that contains sugar cane crops associated with soils derived from sandstones and mudstones. The use of the Universal Soil Loss Equation (USLE) in three different scenarios from land use changes allowed verifying how they have affected soil loss: natural conditions (savannah), current land use and with the expansion of sugar cane crops. In addition, the total sediment transported, the sediment delivery ratio and the rate of soil removal were measured, considering the current land use. The land use scenarios pointed out that the land use change is directly related to increasing rates of soil loss, i.e. 0.03, 3.5 and 12.6 t ha−1 yr−1 for the natural conditions, current land use and with the expansion of sugar cane crops, respectively. These rates in the current land use and with continuous expansion of sugar cane crops are higher than the tolerable erosion limits in 17 and 57% of the study area, respectively. The suspended sediment concentration increases with increasing Cachoeirinha Stream discharge, with a specific daily flux of 88 kg km−2 day−1. The mean monthly flux in 2014 was 32 t month−1, with varying from 3.1 (August) to 144 (January) t month−1. The wet period was responsible for ca. 90% (436 t) of the total solids transported in 2014. The sediment delivery ratio was 9% of the total soil loss. The current rate of soil removal of 25.8 m Myr−1 is almost 3-fold higher than the long-term denudation rates suggested for the Peripheral Depression (9 m Myr−1). With the continuous expansion of sugar cane crops, the rate of soil removal probably will be higher than that obtained in the current scenario and, consequently, the current denudation rates should increase further. Thus, this study reinforce that the human-landscape systems in São Paulo State associated with energy policy are complex and increase the natural processes of soil removal and, consequently, affect the landscape evolution. Highlights • Human-landscape system associated with energy policies was study at São Paulo State. • Land use changes were directly related to increasing rates of soil loss. • The specific daily flux of suspended sediment was 88 kg km−2 day−1. • Approximately 90% of the total solids were transported in the wet period. • The current rate of soil removal was 3-fold higher than the long-term denudation rate. [ABSTRACT FROM AUTHOR]

Abstract The agricultural reuse of urban sewage sludge in degraded croplands has seen a wide acceptance for biowaste recycling and for the improvement of soil fertility. However, soil degradation and health issues may arise from the fact that sludge addition causes chemical and biological contamination if mismanaged. To closely monitor the long term soil-sludge interactions, a field study was conducted over a three-year period under a semi-arid climate. More precisely, changes in topsoil properties were assessed in 4-m2 uncropped plots amended with sludge rates equivalent to 0, 40, 80 and 120 t ha−1 year−1 for two soil textures: soil A (sandy loam) and soil S (sandy). Results showed that all studied parameters changed significantly in a dose-dependent manner for both soils as compared to untreated controls. As such, sludge addition improved consistently TOC, N, P and K content up to soils treated with 120 t ha−1 year−1. The enhancement of soil nutrient status impacted positively on biological properties, including microbial biomass and soil enzyme activities (dehydrogenase, protease and phosphatase). However, the variation of soil properties was more important in soil A characterized by a higher fine fraction thus stronger retention capacity. Accordingly, XRD analysis of soil A revealed several identifiable peaks representing kaolinite and illite clays in contrast to soil S. Unexpectedly, high to excessive sludge doses of 80 and 120 t ha−1 year−1 did not provoke soil degradation after three repeated annual amendments. In fact, pH values in both soils remained within neutral to alkaline range (7.76–8.63); total heavy metals (Cu, Zn, Ni and Pb), soil salinity and fecal coliforms were all below threshold values for contaminated soils. Highlights • Tunisian croplands have low organic matter content due to overexploitation. • Three successive annual sewage sludge amendments improved soil fertility. • Soil biological activities were positively correlated with the sludge dose. • Soil degradation was not observed even at excessive sludge doses. • A finer texture had more impact on soil parameters after sludge addition. [ABSTRACT FROM AUTHOR]

Abstract Land Use Land Cover (LULC) change significantly affects hydrological processes. Several studies attempted to understand the effect of LULC change on biophysical processes; however, limited studies accounted dynamic nature of land use change. In this study, Soil and Water Assessment Tool (SWAT 2012) hydrological model and statistical analysis were applied to assess the impacts of land use change on hydrological responses such as surface runoff, evapotranspiration, and peak flow in Gummara watershed, Ethiopia. Moreover, the effects of static and dynamic land use data application on the SWAT model performance were evaluated. Two model setups, Static Land Use (SLU) and Dynamic Land Use (DLU), were studied to investigate the effects of accounting dynamic land use on hydrological responses. Both SLU and DLU model setups used the same meteorological, soil, and DEM data, but different land use. The SLU setup used the 1985 land use layer, whereas the DLU setup used 1985, 1995, 2005, and 2015 land use data. The calibration (validation) results showed that the model satisfactorily predicts temporal variation and peak streamflow with Nash Sutcliffe Efficiency (NSE) of 0.75 (0.71) and 0.73 (0.71) in the DLU and SLU setups, respectively. However, the DLU model setup simulated the detailed biophysical processes better during the calibration period. Both model setups equally predicted daily streamflow during the validation period. Better performance was obtained while applying the DLU model setup because of improved representation of the dynamic watershed characteristics such as curve number (CN2), overland Manning's (OV_N), and canopy storage (CANMX). Expansion of agricultural land use by 11.1% and the reduction of forest cover by 2.3% during the period from 1985 to 2015 increased the average annual surface runoff and peak flow by 11.6 mm and 2.4 m3/s, respectively and decreased the evapotranspiration by 5.3 mm. On the other hand, expansion of shrubland by 1% decreased the surface runoff by 1.2 mm and increased the evapotranspiration by 1.1 mm. The results showed that accounting DLU into the SWAT model simulation leads to a more realistic representation of temporal land use changes, thereby improving the accuracy of temporal and spatial hydrological processes estimation. Highlights • Introducing dynamic land use improved the SWAT model performance. • Surface runoff in agricultural areas was considerably higher than forest areas. • Forest and shrub area expansion increasing the sub-basin evapotranspiration. • Land use change can contribute up to 65% of total peak flow change. [ABSTRACT FROM AUTHOR]

Abstract Soil quality index (SQI) is widely practiced form plot to national scales to assess the status and use potential of soils. However, how to objectively choose relevant indicators and score these indicators to generate comprehensive SQI is still a major challenge because of the complexity and site-specificity of soils. The objective of this study is to develop SQI using different indicators selecting methods (total data set, minimum data set and revised minimum data set) and scoring methods (linear and non-linear) to evaluate the influences of three land uses (CL, cropland; GR, grazing grassland; FE, grassland enclosure) on soil quality in an alpine grassland. Fourteen soil indicators representing soil physical, chemical and biological properties were measured at 0–20 cm depth. One-way analysis of variance and principal component analysis were used with the fourteen indicators to select the total data set, minimum data set and revised minimum data set. Eleven soil indicators exhibited treatment differences were identified as the total data set. However, only two (AN and MBC) and four (MWD, SOC, AN and MBC) soil indicators were retained in the minimum data set and revised minimum data set, respectively. The six SQIs developed in this study quantified the effects of different land uses on soil quality equally well regarding both sensitivity and accuracy. However, the differentiating ability of SQI calculated using the non-linear scoring-revised minimum data set method (SQI-NLRM) was better than other SQIs based on minimum data set and revised minimum data set because of the highest F value and greatest correlation coefficient with SQI based on total data set. Under GR and CL treatment, SQI-NLRM values were 15.15% and 69.70% lower than that under FE treatment. These results indicated that land use conversions can significantly change the soil quality in the alpine grassland, and the SQI-NLRM developed in this study provides a sensitive and effective approach for quantitative evaluation of soil quality. Highlights • Two (AN and MBC) and four (MWD, SOC, AN and MBC) indicators were identified as the MDS and RMDS, respectively. • The differentiating ability of SQI-NLRM was better than other SQIs. • The mean soil quality values under the land uses ranked as FE > GR > CL treatment. • Moderate grazing can maintain the soil quality in alpine grassland. [ABSTRACT FROM AUTHOR]

Abstract Plateau dunes are unique landforms which formed as erosion relicts in blow-out areas in Late Pleistocene sandy deposits. They are negative forms in contrast to normal dunes where sand is accumulated (positive form). Plateau dunes are located in the European Aeolian Sand Belt in the Netherlands, Germany and Denmark and they are flat-topped features with a bog in the central part often covered by a thin aeolian sand layer. A conceptual model of formation and further development of plateau dunes in time are presented in detail, using 14C dates of buried peat layers and OSL dates of sandy sediments. Special focus is on the influence of climate factors, pedology, and human activity on the formation of plateau dunes. Highlights • Conceptual model of plateau dune formation • Pedology as a landforming factor • OSL dating of aeolian deposits • Climate impact on blanket peat formation • Human destruction of pre-existing vegetation cover [ABSTRACT FROM AUTHOR]

Abstract Terraces and check-dam construction are widely used to control soil and water on the Loess Plateau, China. However, it is not known whether dam fields behave as soil phosphorus sources or sinks. This study quantitatively assessed the effects of check-dam and terrace construction on soil total phosphorus (STP). It also investigated the factors that influenced STP. A total of 1010 soil samples (five land uses and five soil depths) were collected in a small watershed on the Loess Plateau. The probability density function of the Weibull distribution was used to analyze the STP sources on the dam field land. The results showed that the highest STP concentration was recorded in the dam field land. Furthermore, the STP concentration mean values for the five land-use types decreased in the following order: dam field > terraced land > grassland > forestland > sloping cropland. The highest clay content value was also recorded in the dam field land. Soil total phosphorus was significantly and positively correlated to soil organic carbon (SOC), but negatively correlated to sand content (P < 0.01) in all areas. Across the entire soil profile down to 60 cm depth, the STP levels for the five land-uses were dam field, 2.78 kg/m2; terrace, 2.86 kg/m2; grassland, 2.98 kg/m2; forestland, 2.84 kg/m2; and sloping cropland, 2.83 kg/m2. The percentage contributions made by the four land use types to the soil total phosphorus deposited in the dam field were 50% (sloping cropland), 33% (grassland) and 17% (forestland). Therefore, check dam constructions behave as a sink for soil phosphorus on the Loess Plateau, China. Highlights • Relatively high sampling density and sampling depth study on the Loess Plateau, China • Dam field and terraced land showed significantly higher STP than the other three land uses. • The STP deposited in dam field land across the watershed mainly came from sloping cropland. [ABSTRACT FROM AUTHOR]

This study assessed the individual and combined effects of land-use and land-cover changes (LUCCs) on spatial hydrological responses by using an integrated approach involving the Soil and Water Assessment Tool (SWAT) and geographically weighted regression (GWR) models in the Xitiaoxi River Basin (XRB). The LUCCs and their spatial patterns from 1985 to 2008 were evaluated in the XRB. The hydrological processes during the period from 1980–2015 were then generated by the SWAT model under the 1985 and 2008 land-use scenarios. GWR models were constructed to quantify the spatial impacts of LUCCs at the sub-basin scale. The results showed that the predominant trend of land-use conversion was between forest-grass land and agricultural land, and the diminishing portion of forest-grass land (25.93 km 2 ) and agricultural land (46.77 km 2 ) contributed to the expansion of urban land during the period 1985–2008. Moreover, the urban area increased from 5.6% to 17.05%, and the change ratio progressed towards the centre of the XRB. These changes in land use caused the average annual water yield and surface runoff to increase by 1.09% and 11.87%, respectively, and the average annual evapotranspiration (ET), percolation and baseflow to decrease by 0.73%, 16.53% and 17.26%, respectively. In addition, the results of the GWR models indicated that the responses of each hydrological component exhibited spatial differences. The comprehensive land-use intensification index ( La ), selected to reflect the combined effects of LUCCs, was positively correlated with water yield and surface runoff but negatively correlated with ET, percolation and baseflow. La had a greater effect on water yield, surface runoff, percolation and baseflow in rural areas than in the urbanized region. The combined effects of LUCCs in certain local areas increased water yield and surface runoff by up to 13.7% and 114.2%, respectively. The local coefficient indicated that rural regions might be exposed to greater effects of LUCCs. The results of this study could be useful to understand the effects of LUCCs on the spatial patterns of each hydrological component and to help improve flood control and water resource management. [ABSTRACT FROM AUTHOR]

Land desertification is recognized as a major threat to soil resources in arid, semi-arid Mediterranean areas. The use of widely applicable methodologies can facilitate the identification of land desertification risk spatio-temporal trends, which allows transnational comparison and support the development of soil management practices and policies, protecting the valuable soil resources. The aim of this study is to improve and use the Environmentally Sensitive Areas (ESAs) MEDALUS methodology, in order to provide a qualitative assessment for desertification risk trends in Greece, within the last 45 years. The Management, Vegetation, Soil and Climate quality indices (MQI, VQI, SQI, CQI) and the sub-sequent Environmental Sensitive Areas Index (ESAI) have been modeled for three periods in the entire Greek territory. The four quality indices are divided in two main categories, based on data availability and inherent characteristics, such as the pace of change during the studied period. Particular emphasis is given to the assessment of MQI, by integrating criteria which derived from national policies and the elaboration of national statistical data. The results show about 9% increase of the areas characterized as Critical to land desertification risk, while Fragile, Potentially affected and Non-affected areas decrease by 3.7%, 3.6%, 2.5% respectively. The applied approach for MQI can reveal areas where particular attention to management practices is required and improves the performance of the overall desertification risk index. [ABSTRACT FROM AUTHOR]

Although soil erosion and land use change have long been focuses in carbon research, the combined influence of soil erosion and vegetation rehabilitation on aggregate stability and the associated soil organic carbon (SOC) and total nitrogen (TN) remains unclear. The current study evaluated the effects of soil erosion on aggregate stability and the associated SOC and TN dynamics in relation to vegetation rehabilitation after the implementation of the “Grain-for-Green” project in the hilly Loess region. A check dam sediment sequence was dated using 137 Cs activity and erosive rainfall events. The SOC and TN in the bulk soil and aggregate fractions were measured in soils from rehabilitated grasslands and sloping croplands and in sediments retained by the check dam. The results showed that vegetation rehabilitation led to 78%, 27% and 9% average increases in the macroaggregate amount, mean weight diameter (MWD) and mean geometric diameter (MGD), respectively. In addition, rehabilitation resulted in the highest SOC and TN concentrations and contents in macroaggregates among all the aggregate size fractions. Soil erosion facilitated the modification of the aggregate size distributions along with soil mineralization and induced the incorporation of deeper SOC-poor soils during transport. These processes resulted in the aggregate-associated SOC and TN concentrations and contents in the sediments being significantly lower than those in the eroding sloping cropland soils. The highest reductions were found in microaggregates, which exhibited decreases of 48% and 44% for SOC and TN, respectively. Moreover, reaggregation and gully soils incorporated during soil erosion led to higher values of macroaggregate amount and aggregate stability at depositional sites than those at eroding sloping cropland sites in this study. Our study contributes to the understanding of the effects of soil erosion and vegetation rehabilitation on SOC and TN dynamics, which is crucial for understanding the restoration efficiency in soil erosion control and ecosystem security evaluation. [ABSTRACT FROM AUTHOR]

Land-use/land-cover (LULC) pattern influences water quality, however, this relation may be different for various spatial scales. We evaluated the LULC effects on water quality of tropical low-order streams, comparing watershed and riparian zone models. Water quality parameters were analyzed separately and together using linear mixed and multivariate models. The results indicate that the forest cover plays a significant role in keeping water clean, while agriculture and urban areas lead to water quality degradation. Pasture land had mixed effects, but in general was not correlated with poor water quality. Dissolved oxygen, phosphorus, sediment, and fecal coliforms were influenced by LULC pattern at the watershed scale, while nitrogen and organic matter were more affected by the riparian zone composition. The water quality also varies with seasonal changes in streamflow and temperature. The overall water quality variation is explained better by the LULC composition within the watershed than in the riparian zone. [ABSTRACT FROM AUTHOR]

• The soil detachment capacity (Dc) on karst hillslope was tested. • The path analysis can appropriately deal with the collinear factors affecting Dc. • Water-stable aggregates and root length density were direct factors affecting Dc. • A prediction model for predicting Dc on karst hillslopes was established. Land use and its transformation significantly affect the soil detachment capacity (Dc) by changing soil properties and altering root characteristics, but few studies have been conducted to quantify the effects of these factors on Dc in karst areas. The objective of this study was to assess the effects of hydrological conditions, soil properties and plant roots on the Dc of karst hillslopes. A total of 270 soil samples were collected from six different land uses and then subjected to flow scouring in a hydraulic flume under nine shear stresses (ranging from 1.61 to 7.04 Pa). The results showed that the mean Dc ranged from 0.0003 kg m−2 s−1 to 0.52 kg m−2 s−1. The variability in soil Dc under different land uses was closely related to hydraulic conditions, soil properties and plant roots but to different extents. The elevated Dc on land affected by greater human activities indicates they are the main disturbance associated with soil erosion on karst hillslopes. Dc was positively correlated with flow velocity, shear stress, stream power and unit stream power, and flow velocity was the optimal hydrodynamic factor for predicting Dc. Dc was positively correlated with soil porosity and saturated hydraulic conductivity and negatively correlated with soil bulk density, water-stable aggregate content, organic matter content, root length density and root mass density. Path analysis showed that water-stable aggregates and root length density were the dominant factors affecting soil detachment. Accordingly, a model was established to estimate Dc based on water-stable aggregates and root length density on karst hillslopes (R 2 = 0.88, NSE = 0.87). Therefore, the research results provide theoretical guidance for predicting the Dc of karst hillslopes and a basis for decision-making related to soil erosion control in karst areas. [ABSTRACT FROM AUTHOR]

• The stable macroaggregate structure makes the erodibility of forest soil at a low level. • Mean weight diameter and rill erodibility has a negative power function. • Acidobacteria and Basidiomycota are the key groups in resisting soil rill erosion. • SOC has strong regulatory effects on the soil key group of microorganisms. How microbial communities respond to soil aggregation and rill erosion resistance has rarely been addressed. Such a knowledge gap hinders the practice of guiding sustainable soil management. Herein, the community composition of bacteria and fungi was evaluated by 16S rRNA gene sequencing. We measured critical shear stress (τc) and rill erodibility (k d) by self-made jet device. The effects of microorganism on soil aggregation and rill erosion resistance were quantitatively analyzed under different land uses. The results indicated that the forest soil supported the colonization and enrichment of Acidobacteria and Basidiomycota on account of the unique vegetation and higher soil organic carbon (SOC). The forest and shrubland contained higher macroaggregate and mean weight diameter (MWD) than those of cropland and bare land, while rill erodibility (k d) was the opposite. MWD and k d had a negative power function (y = 105.64x−0.69). The biotic factors explained 73.50% of the variation in rill erosion resistance and soil aggregation, indicating microorganism are more important in acting on rill erosion resistance. This study suggests that SOC had strong regulatory effects on the soil key groups of bacteria and fungi assemblages; furthermore, their interaction facilitated the formation of stable macroaggregates. The stable macroaggregate structure and vegetation cover make the erodibility of forest soil at a relatively low level. However, cropland are not conducive to stability of aggregates, which easily causes soil erosion. Improving soil SOC and maintaining the relative abundance of key groups of microorganism would be conducive to soil sustainable developing. [ABSTRACT FROM AUTHOR]

[Display omitted] • Products SOIL_ABU, TSAVI, and Color Index are very promising for gully assessments. • SAR, optical texture and water/vegetation indices were helpful. • The method achieved 89% overall accuracy by the percentage of exposed soil. • Our methodology is useful to guide recovery plans for tropical gullies. The accurate assessment of the gully is key to stopping soil loss, especially in agricultural landscapes. This study aims to combine freely distributed remote sensing data for the evaluation of gullies located in a tropical watershed with a history of cattle production. Eighty-four vectorized gullies were defined in the Pirizal River basin, part of the highly eroded Upper Taquari (Brazil). We examined 56 variables from Sentinel-1/2 and ALOS-PALSAR-1 datasets, including SAR products and optical products like textures, water, vegetation, and terrain indices. Following a correlation analysis, 19 variables were selected for mapping in a Random Forest classifier by considering samples of active (soil) and stabilized (vegetation) pixels. The method reached an overall accuracy of 89%, in which soil abundance was responsible for 44% of the overall importance in the classification. Optical indices and texture products outperformed SAR products, whose importance represented only 14%. In the studied river basin, about 63% of the gullies were found stabilized, 30% in the process of stabilization, and only 7% active. The method proved effective, low cost, and promptly replicable to general river basins with gullies, mainly those in the tropics where vegetation has a significant role in soil loss control. [ABSTRACT FROM AUTHOR]

• Five contrasting scenarios describe a developing Nordic bio-economy towards 2050. • The scenarios led to substantial differences in land use cover and intensity. • This in turn affected hydrology and nutrient load in half of the catchments. • Patterns of final ecosystem service delivery were strongly affected. • The summed total economic value was similar among the two most disparate scenarios. • The sustainability scenario optimised water quality and biodiversity without welfare loss. This paper synthesizes a five-year project (BIOWATER) that assessed the effects of a developing bioeconomy on Nordic freshwaters. We used a catchment perspective and combined several approaches: comparative analyses of long-term data sets from well-monitored catchments (agricultural, with forestry, and near pristine) across Fennoscandia, catchment biogeochemical modelling and ecosystem services assessment for integration. Various mitigation measures were also studied. Benchmark Shared Socio-economic Pathways were downscaled and articulated in dialogue with national stakeholder representatives leading to five Nordic Bioeconomy Pathways (NBPs) describing plausible but different trajectories of societal development towards 2050.These were then used for catchment modelling and ecosystem service assessment. Key findings from the work synthesized here are: (a) The monitoring results from 69 catchments demonstrate that agricultural lands exported an order of magnitude more nutrients than natural catchments (medians 44 vs 4 kg P km−2 y-1 and 1450 vs 139 kg N km−2 y-1) whilst forests were intermediate (7 kg P km−2 y-1 and 200 kg N km−2 y-1). (b) Our contrasting scenarios led to substantial differences in land use patterns, which affected river flow as well as nutrient loads in two of the four modelled catchments (Danish Odense Å and Norwegian Skuterud), but not in two others (Swedish catchment C6 and Finnish Simojoki). (c) Strongly contrasting scenarios (NBP1 maximizing resource circularity versus NBP5 maximizing short-term profit) were found to lead to similar monetary estimates of total societal benefits, though for different underlying reasons – a pattern similar across the six studied Nordic catchments. (d) The ecological status of small to medium sized rivers in agricultural landscapes benefitted greatly from an increase in riparian forest cover from 10 % to 60 %. Riparian buffer strips, constructed wetlands, rewetting of ditched peatlands, and similar nature-based solutions optimize natural biogeochemical processes and thus can help in mitigating negative impacts of intensified biomass removal on water quality. [ABSTRACT FROM AUTHOR]

• A meta-analysis to test rubber stand age and altitude effects on soil properties. • Forest-to-rubber conversion significantly reduced SOC pools by 24%. • Rubber monoculture-to-intercropping significantly increased SOC pools by 6%. • Improvement of intercropping occurred in 0–20 cm soil and at 500–800 m altitude. The rapid expansion of rubber plantations may have greatly influenced the carbon stocks of the ecosystem, with potential impacts on mitigating climate change and future carbon fluxes. Therefore, soil carbon pools and other properties must be reliably estimated after rubber-based land cover transitions. The aim of this meta-analysis is to understand how various land use changes based on rubber plantations affect soil physicochemical properties, especially soil organic carbon (SOC) pools. This study focuses on three land use changes: (1) forest-to-rubber conversion; (2) rubber monoculture vs. intercropping; and (3) the age and altitude of the rubber stand over a chronosequence in rubber plots. Results showed that the conversion of forest to rubber plantation significantly reduced the SOC, microbial carbon (MBC), total nitrogen (TN) and total magnesium pools by 24%, 35%, 13% and 94% respectively, whereas rubber intercropping with different crops profoundly increased the SOC and MBC pools by 6% and 24% on average, respectively. The improvement of rubber intercropping on SOC and properties mainly occurred in the surface soil at 0–20 cm and at altitudes of 500–800 m, but these effects were diminished in the subsurface soil at 20–60 cm and at altitudes higher than 800 m. Rubber intercropping plantations can significantly alleviate soil acidification. Changes in the response ratio of SOC were closely related to the variations in soil clay, bulk density, and C/N ratio. These results suggest that rubber-based land use management policies should promote intercropping plantations, especially those with woody plants, and the altitude of rubber planting should be manipulated to minimize the loss of soil C, N, and other nutrients. [ABSTRACT FROM AUTHOR]

[Display omitted] • Land use/cover change characterized by cropland loss and expansion of other lands. • Urbanization grew exponentially, while other land changes peaked in 1995–2005. • Land use/cover had two conversion patterns before and after 175 m impounding. • Cropland will drop by 1094 km2 by 2030, which is mainly converted to built-up land. • Most land use/cover changes are altitude-sensitive and supplemented by other factors. Coordination of economic development and ecological conservation in land use/cover (LULC) remains a great challenge, particularly in eco-fragile areas. A holistic understanding of LULC change is a premise for coordinating the conflict. In this study, we elucidated the spatiotemporal evolution of LULC in China′s typical eco-fragile area-the Three Gorges Reservoir area during different periods of Gezhou Dam-Three Gorges Dam (GZD-TGD) construction and impoundment (1982–2020), and predicted LULC in 2030 with the patch-generating land-use simulation (PLUS) model. In 1982–2020, the LULC changes mainly included cropland loss, forestland restoration, urban development and water expansion, among which cropland decreased by 4688 km2, while forestland, built-up land and water increased by 3273, 1002 and 272 km2, respectively. For most LULC types, the most significant change occurred in 1995–2005, whereas the built-up land increased exponentially from 0.41% to 5.06% during the entire study period, which was mainly derived from cropland. Under a natural development scenario, cropland would drop continuously by 1094 km2 till 2030. In addition, there were significant interconversions between various land types before GZD-TGD impoundment of 175 m, particularly vegetation, while only built-up land increased dramatically by occupying 2.66% of cropland thereafter. Contributions of various driving factors to LULC changes varied across different periods due to the direct/indirect effects of GZD-TGD construction and impoundment. Most changes in LULC were elevation-sensitive, and supplemented by other factors. Furthermore, the expansion of various LULC types tended to occur more often in areas with low elevations and gentle slopes. The results may assist decision-makers in formulating more reasonable policies to alleviate the conflicts between land utilization and ecological protection, and facilitate the realization of China′s ecological civilization construction goals. [ABSTRACT FROM AUTHOR]

• Land use and land cover classes homogenize within-class differences in vegetation density, type and other characteristics that influence surface erosion. • When these classes are used to estimate current and projected future RUSLE C-factor for native vegetation, this introduces significant error. • Remote sensing methods can be used to assess intra-class variation in C-factor, improving the soil loss estimate. • A strong, predictive relationship exists between remotely-sensed C-factor values and climate. • Current and projected changes in climate can be used to directly estimate C-factor, improving the estimate of current and future soil loss rates. This new method provides a low-cost, efficient and reliable estimate of future C. Understanding how reservoir sedimentation rates may evolve due to climate change is essential for projecting future changes in reservoir water storage capacity. The Revised Universal Soil Loss Equation (RUSLE) is commonly used to assess regional soil loss rates because of its suitability for working with the coarse temporal and spatial scale of climate model outputs. Application of the RUSLE for projecting future erosion rates is constrained by the relatively limited number of classes used in projected changes of native vegetation: this typically reduces a wide range of variation in RUSLE cover (C) factors to a single value per class, and these classes may be insensitive to changes in species composition and canopy density with time and space. This paper develops a low-cost, efficient, and objective approach to projecting future C values directly based on widely available Landsat data, downscaled climate model data, and a limited number of terrain variables. Observed C is estimated from Landsat-derived Normalized Difference Vegetation Index (NDVI) and Modified Soil-Adjusted Vegetation Index (MSAVI) values using standard methods. A linear relationship is established between the observed C values and average annual antecedent temperature, average annual antecedent precipitation, latitude, and percent sand (adjusted R2 = 0.75604, 0.7543, and RMSE = 0.09448, 0.07043, respectively). A proof of principal study demonstrates that, unlike when land cover classes are used to estimates C, a RUSLE model driven by the regression-based C provides a correct order-of-magnitude estimate of observed long-term erosion and sediment yield rates (e.g., an estimate of 2.9–3.2 t ha−1 y-1 is obtained where observed rates range from 1.2 to 3.9 t ha−1 y-1 for the same time period, and up to 8 t ha−1 y-1 historically, while standard formulations of RUSLE yield 16.1 and 0.3 t ha−1 y-1). Using climate model data to estimate both precipitation intensity (R factor) and C in the RUSLE model results in basin wide projected end 21st century soil erosion rates for relative concentration pathway 8.5 of 5.5–7.5 t ha−1 y-1, consistent with expectations for accelerated soil loss in the study area as climate change reduces soil moisture while increasing precipitation intensity. The same model driven by land cover class estimates of C produces soil loss rates an order of magnitude smaller (0.3–0.4 t ha−1 y-1), consistent with a much more heavily vegetated landscape than could be supported under the increasingly arid projected climate. [ABSTRACT FROM AUTHOR]

• Cropland abandonment significantly affects soil physico-chemical properties. • Differences between revegetated practices after farmland abandonment occurred. • Afforestation triggered higher soil organic carbon than natural revegetation. • Grassland sites enhance the accumulation of soil organic carbon. • Labile fractions are higher in both vegetated sites than in grasslands. Mediterranean mountains are sensitive agroecosystems that have suffered intense land use and land cover changes (LULCC) during the last century. From the middle of the twentieth century, most of the cultivated lands in Mediterranean mountains were abandoned, allowing the recovery of vegetation (through natural revegetation and afforestation programmes). To examine the effects of farmland abandonment, secondary succession (natural revegetation) and afforestation, an intensive soil sampling was carried out in the Araguás catchment (Central Spanish Pyrenees) including sparsely vegetated areas (badlands), grasslands, shrublands and afforested sites. LULCC were mapped, and soil physico-chemical properties were analysed in reference sites (unaltered areas during the last centuries) and in the different land uses. Likewise, the soil organic carbon (SOC) content in the bulk soils and in the fractions separated by density fractionation have been studied. This study evidenced that farmland abandonment led to a mosaic landscape with different land use and land covers. Results show that LULCC significantly affect soil physico-chemical properties (soil texture, stoniness, pH, SOC, total carbon, CorgN ratio, bulk density and field capacity). Significant differences were observed between secondary and afforested sites following farmland abandonment. Afforestation triggered higher SOC than shrubland sites (natural revegetation) (1.4 and 1.1% respectively), suggesting a slower process of organic matter accumulation after farmland abandonment in the natural revegetation compared to afforestation. The significant role of grassland sites for enhancing the accumulation of SOC has been also confirmed. The results showed also significant differences in the relative contribution of each organic fraction to the bulk SOC: the amount of labile fraction (free and occluded labile fractions) is significantly higher in afforested and shrubland sites (58.1 and 51.2% respectively) than in grassland sites (36.8%). Understanding the effects of LULCC on soil properties and SOC dynamics is essential when planning post-land management practices after farmland abandonment. [ABSTRACT FROM AUTHOR]

• A challenge in land use is related to use of peatlands for bioenergy production. • We created storylines for land use of peat fields together with climate change. • We modelled their influence on water quality by process-based models. • Conversion to arable land may pose a risk to the ecological status of the river. • Sustainable development in energy production leads to the best water quality. In Northern Finland, the most significant land use challenges are related to bioenergy production from peat extraction and forest biomass. Increasing societal demand for bioenergy may increase production rates. However, environmental impacts of peat extraction are of increasing concern, which has led to a decline in production, thereby freeing up these areas for other uses. Using storylines for different societal futures and process-based models (PERSiST and INCA), we simulated the effect of simultaneous land use change and climate change on water quality (phosphorus, nitrogen and suspended sediments concentration). Conversion of peat extraction areas to arable land, together with climate change, may pose a risk for deterioration of ecological status. On the other hand, continuous forestry may have positive impacts on water quality. Suspended sediment concentrations in the river do not exceed water quality requirements for salmonids, but nitrogen concentrations may exceed threshold values especially during high flows. A storyline emphasizing sustainable development in energy production led to the best outcome in terms of water protection. [ABSTRACT FROM AUTHOR]

• 1. Soil functions changed greatly with land use type and slope position. • 2. Soil functions were dominantly controlled by CEC, AN, Ur, SSI, I, TN, SOM and AKP. • 3. Soil functions of cropland were seriously damaged due to long-term intensive utilization and erosion. • 4. Conservation practices are urgently needed to promote soil functions of eroded cropland in the black soil region. Soil function assessment is critical to mitigate soil degradation and achieve the sustainable use of soil resources. The changes in soil properties induced by land use type and slope position likely affect soil function considerably. Few studies have been carried out to investigate the spatial variation of soil function with land use type and slope position in small watershed impacted by intensive agricultural activities. Hence, eight typical land use types and five slope positions were selected in one agricultural small watershed to quantify the spatial variations of soil functions and their influencing factors in the Chinese black soil region. The five soil functions, e.g., primary productivity (PP), water purification and regulation (WPR), climate regulation and carbon sequestration (CRCS), provision of habitat for biodiversity (PHB), and nutrient cycling and provision (NCP) were computed from 22 measured soil properties. The results showed that all measured soil properties exhibited significant variations with land use type and slope position (p < 0.05). Significant variation was found in soil functions between different land use types and slope positions (p < 0.05). The lower soil functions were detected in road and cropland, especially at the middle slope position of cropland. The redundancy analysis revealed that soil cation exchange capacity, available nitrogen, urease, structure stability index, invertase, total nitrogen, soil organic matter and alkaline phosphatase were the dominant factors attributed to the spatial variation of soil functions. The corresponding contributions were 13.9 %, 11.4 %, 8.9 %, 7.6 %, 7.0 %, 6.1 %, 5.7 % and 5.50 %. Combined with the results of structural equation model, soil erosion was the dominant process to reduce soils by altering soil properties. The measures promoting nutrient accumulation and controlling soil erosion should be implemented to enhance soil functions of degraded cropland in the black soil region. The findings of this study are helpful to design the measures of soil and water conservation in agricultural small watershed to promote its ecological service. [ABSTRACT FROM AUTHOR]

• Soil nitrogen content and isotope values changed after cropland abandonment. • Mineralization is more active in karstic topsoil than in the deep soil layer. • The loss NO 3 – mainly originated from the cropland topsoil in present karst areas. • Land use change from cropland to forest can reduce soil N loss to aquatic system. A large amount of cropland in the Southwestern (SW) China karst area has been abandoned since the implementation of the Grain for Green project at the end of the last century, which significantly impacted the biogeochemistry cycle in soil. However, the effect of cropland abandonment on the soil nitrogen (N) cycle and the N loss process is still little understood. N content and isotope analysis were used to assess karst soil's N fate and explore the N loss process in SW China. Soil samples were collected from four land uses, cropland (CR), abandoned CR (AC), shrubland and grassland (SG), and secondary forest (SF), by seasonal in a typically mixed land-use karst catchment at six soil depths. The results showed that the average soil particulate organic N (PON) content increased from 1.58 ± 0.49 g kg−1 to 2.70 ± 1.82 g kg−1, whereas average dissolved nitrate (NO 3 –-N) content decreased from 10.77 ± 8.87 mg kg−1 to 1.72 ± 1.84 mg kg−1 during revegetation. There was a decreasing amount of PON and dissolved N (NH 4 +-N、NO 3 –-N、TDN) content from surface to the bottom of the soil profile and large variation mainly occurred in 0 – 30 cm in the soil profiles of four different land uses, which suggests N transformation mainly occurred in topsoil (<30 cm). Mineralization was the major nitrogen transformation process that affected PON content and δ15N-PON values. The highest δ15N-PON fractionation (-5.0‰) in the soil profiles of the four types of land use caused by mineralization was detected in SF. Variation of N content and isotope values in soil profiles after cropland abandonment suggested that the loss of NO 3 –-N in karst catchment mainly came from the topsoil of cropland. Overall, N loss from the topsoil of cropland should pay more attention, while cropland abandonment can effectively reduce the loss of dissolved N from the thin karst soil layer. [ABSTRACT FROM AUTHOR]

[Display omitted] • Most elements measured by μ-XRF scans were in-line with ICP-MS/AES concentrations. • Statistical ordinations enabled the visualization of lake's geochemical trajectory. • Sediment composition is driven by geological substrates and contemporary land-use. • Detected a temporal enrichment in metals across 37 sites, with maxima circa 1970 CE. • Recent reduction in metal concentrations matched timing of environmental regulations. Since the start of the Industrial Revolution, the chemical cycling of numerous elements has been fundamentally altered. Using 210Pb-dated sediment cores from 37 Eastern Canadian lakes situated in 4 ecozones, we quantified the geochemical change experienced across this region since ca. 1850 CE using high-resolution computed X-ray Tomography and micro-X-ray fluorescence (µ-XRF) ITRAX scanners. Independent calibrations of µ-XRF ITRAX intensities using ICP-MS and -AES found strong correlations for numerous elements. Using relative abundance measures and absolute concentration estimates, we observed that most of our study lakes recorded temporal enrichments of metals, with several sites exceeding Canadian sediment quality guidelines. Using principal component analysis, we identified that parameters commonly associated with erosion (strontium and titanium), organic matter (molybdenum incoherence to coherence scattering ratio), and metals (zinc and lead) were key variables structuring within and among-lake variation since ca. 1850 CE. Calcium was identified as an additional variable, particularly for lakes in the Mixedwood Plains (MWP) ecozone, which may be linked to catchment activities including land-use changes. Temporally, many lakes shifted towards greater accumulation of inorganic sediment, coeval with higher Pb and Zn concentrations, reaching maxima ca. 1970 CE before decreasing rapidly. These results suggest that most lakes in the region were subjected to environmental pollution but that controls on key atmospheric pollutants in North America were effective across a large part of the country. [ABSTRACT FROM AUTHOR]

• Proposed a new concept of determining cellular units using the natural evolutionary unit of land (LNU). • LNU can reflect the spatial characteristics of land natural evolutionary process more truly. • Proposed a calculation method for identifying LNU efficiently based on the geographical similarity principle. • The LNU-CA has better simulation effect than the traditional CA in modeling land-use change. Cellular automata (CA) is an important model to simulate land-use change, and the cellular unit can influence the organizational structure, scale selection, and evolutionary ability of CA through its size and shape. Therefore, determining a reasonable cellular unit is essential for land-use change modeling using CA models. However, existing methods used to define the cellular unit are inadequate in their description of the characteristics of the natural evolution of land use, leading to a mismatch between the unit used for simulation and the unit of actual land-use change. To address this issue, in this study, we propose a method for determining the cellular unit based on land natural evolutionary unit (LNU). First, the geographic similarity principle was used as the theoretical basis for this new method. Under this similarity basis, a CA modeling method based on coupling the land natural evolution unit with evolution behavior was then designed to improve the natural evolution of land use. Finally, a case study of the Chenggong District of Kunming City, Yunnan Province, China, was conducted to evaluate the effects of using LNU-defined cellular units on simulating land-use change. The experimental results from the case study show that, simulation of land-use changes using the CA model based on the land natural evolution unit (LNU-CA) exhibits better spatial distribution consistency, higher simulation accuracy with the Kappa coefficient increased by 5.11% and the FOM (Figure of Merit) increased by 159.36%, and a lower distortion of simulation results than those of regular grid CA (Grid-CA). These results prove that LNU-CA can simulate land-use change better than traditional Grid-CA, and LNU is a better choice to determine the cellular unit when using CA to simulate land-use change. [ABSTRACT FROM AUTHOR]

• Soil properties vary between land use/ covers and agro ecologies. • Natural forest has higher OC, OC stock and TN than grazing and cultivated lands. • Soil pH is slightly higher in natural forests and lower in the soils of grazing and cultivated lands. • The study suggests implementation of an integrated soil fertility management, and conservation based production systems. Conversion of natural vegetation into farm land and grazing land causes soil quality loss. Soil properties response to land use/land cover changes (LULC) shows both spatial and temporal variations. This study was aimed at assessing the effects of LULC changes on physical and chemical properties of soil in Rib watershed. To assess physical and chemical properties of the soil among LULC, soil samples were taken over natural forest, grazing and cultivated lands in two agro-ecological belts of Dega and High Dega. Multivariate analysis of variance (MANOVA) and Pearson's correlation were computed. The study revealed that LULC and agro-ecology have affected physical and chemical properties of the soil in the study watershed. Significant difference in distribution of soil texture, BD, OC, TN and pH among LULC were observed. Soils of Natural forest had higher OC, OC stock and TN. For instance, soils of natural forest had higher OC stock (188.32 Mg/ha) as compared to soils of cultivated lands(72.75 Mg/ha). Soil pH was slightly higher in natural forests and lower in the soils of grazing and cultivated lands. Significant difference (P < 0.05) among the two agro-ecologies were also observed in OC, Ca2+, and contents of clay and silt. In general, LULC change has affected the concentration of TN, OC, pH and BD which in turn can affect soil productivity. Therefore, the study suggests the implementation of an integrated soil fertility management practices and conservation based production systems with the collaboration of regional, local authority and farming community. [ABSTRACT FROM AUTHOR]

• Holocene geo-archive in Laarder Wasmeren (NL) holds multiple degradation phases. • Mesolithic degradation included sand drifting, podzolisation and opening of forest. • Intentional fires presumed to be major cause for Mesolithic ecosystem degradation. • Intense ecosystem degradation, from Neolithic on, culminating in Middle Ages. The drift sand area near Hilversum, the Netherlands, holds a geo-archive with multiple drift sand phases and intercalated palaeosols. We studied this area to test earlier theories on the development of podzols in such aeolian sands, the occurrence of sand drifting, and the contemporary vegetation development, and to gain insight into the early human impacts on these fragile ecosystems. Based on OSL and radiocarbon datings, palaeoecological studies, and soil chemical analyses, the age and origin of the drift sand phases and palaeosols were established. Sand drifting started around 6000 BCE (Late Mesolithic), the drift sand covering a distinct podzol in the Younger Cover Sand II. A second Late Mesolithic drift sand phase dated from ca. 4900–4500 BCE. Three later drift sand phases were distinguished of which the last is the classic Late Medieval (and younger) phase, while the first two date from the Neolithic. All intercalated palaeosols exhibited more or less prominent podzolisation. The palaeocological data showed that, prior to the Neolithic, in the forest open patches had developed with non-arboreal vegetation, dominated by Poaceae and Ericaceae. This changed during the Neolithic, most probably linked to the introduction of crop farming, the vegetation gradually acquiring the characteristics of the classic heathland with patches of trees/shrubs. The early sand drifting, podzolisation and opening of the forest are attributed to Mesolithic land use, with intentional burning as major factor. We conclude that the local destruction of the deciduous forests by fire and associated creation of open patches with bare sand were essential for the early sand drifting and podzolisation to occur. The results shed new light on the origin of drift sands, heathlands, and podzols in the Netherlands, and on the environmental impacts of Mesolithic people, and testify to the fundamental instability of these dry inland dune ecosystems. [ABSTRACT FROM AUTHOR]

Changes in land use induced by human activity trigger a number of processes in river catchments. These processes are particularly evident in the mountains, where wild vegetation overtakes abandoned arable land, stabilizing slopes and reducing sediment delivery to rivers. The energy of under-loaded rivers then makes incisions into their beds, which results in lower water levels. What is the rate of environmental changes induced by farmland abandonment, and does the environment restore its primary characteristics through a certain inertia? To answer these questions, we analyzed changes in land use in the Jasiołka River catchment located in the Carpathians, based on topographic maps from three periods covering more than 60 years. We also compared data on land use change with changes in the water levels in the Jasiołka River using regression models and principal component analysis. In the period analyzed, substantial transformations of the landscape were evident, mainly caused by dislocation of the population during and after World War II and, to a lesser extent, by changes in the political system in Poland after 1989. All these events led to the reduction of the arable land area, along with the enlargement of forest areas. Before World War II, arable land was the prevailing form of land use, taking up an area almost twice as large as the forest. Currently, the area of arable and forest land combined in the catchment area analyzed is similar, at approximately 42%. The response of the river to the changes in land use in its upper course, the location of the greatest extent of changes in landscape, is triggered almost immediately, decreasing the mean water level. In the mouth of the river, these processes occurred over a different period of time: The river incision was not as intensive and ended nearly 30 years later. The investigations strongly correlated the changes in almost all landscape elements with processes occurring in the river channel. Therefore, even small landscape components such as settlements or gullies that can exert a significant effect on catchment functioning should not be disregarded in this type of analysis. Together with large areas of forest, they regulate processes occurring on the slope and in the river channel. [ABSTRACT FROM AUTHOR]

Although the evaluation of soil organic carbon (SOC) stocks across different types of land use and major reference soil groups is essential for mitigating climate change, there remains, to date, limited comprehensive understanding of whole tropical soil profiles. Therefore, this study aimed to explain the amount of SOC stocks in different land-use systems and across various soil groups, as well as its spatial pattern in the topsoil (0–30 cm) and subsoil (30–100 cm) within the savannah zone of Burkina Faso. Roughly 70 soil profiles were considered along with additional auger sampling to account for spatial variation in both cropland (CR) and savannah (SA). The machine learning technique random forest regression (RFR) and multiple linear regression (MLR) were used for modeling the surface and subsurface SOC stocks. For model calibration, covariates including land use, topographic, texture, and climatic data were considered as surrogate for soil forming factors. The prediction maps produced by the calibrated models were validated by an independent dataset. The results indicated that about 53% of the SOC stock over 1 m depth was held in the upper 30 cm. Only a marginal difference was recorded between the topsoil SOC stock in SA (41.4 t C ha −1 ) and CR (39.1 t C ha −1 ) soils. For the subsoil, a significant difference (p < 0.05) was observed between the SOC stock of CR soils recording about 40.2 t C ha −1 and SA soils with 26.3 t C ha −1 . Among the reference soil groups, the Gleysols located at lower elevation positions revealed the highest SOC stocks over 0–30 cm (44 t C ha −1 ) and 100 cm depth (86.6 t C ha −1 ). The Stagnosols (45.2 t C ha −1 ) followed by the Gleysols (42.7 t C ha −1 ) recorded the highest SOC stocks over 30–100 cm. The variability of SOC stock in the topsoil was primarily related to site-specific elements, such as particle-size fraction and wetness index, while its distribution in the subsoil was mainly associated with the topographical orientation represented by the slope aspect. Compared to the MLR, RFR estimated mean top- and subsoil SOC stocks of the catchment fairly well, along with lower statistical error metrics, though extreme values were not covered. Nevertheless, the findings on SOC stocks reinforce the view that the semi-arid ecosystems of West Africa still offer a significant opportunity for carbon sequestration for both topsoil and subsoil, and these results represent a baseline for future modeling of SOC dynamics in the region. [ABSTRACT FROM AUTHOR]

Soil moisture plays a fundamental role in eco-hydrological processes in the semi-arid Loess Plateau. Catchments on the Loess Plateau can be generally divided into the hillslope domain and gully domain. However, the soil moisture variations linked to topographic domains and land use types remain poorly understood. Therefore, in this study, differences in soil moisture among three typical land use types (forestland, native grassland, and farmland) were investigated and compared between the spatial domains of hillslope and gully in the Jiegou catchment on the semi-arid Loess Plateau of China. Additionally, the spatial variations in the soil moisture of the 0–100 cm layers were explored in both wet and dry periods to evaluate the seasonal effects of different spatial domains and land use types. The results showed that including gully soil moisture weakly increased the spatially averaged soil moisture in the catchment but obviously increased the variability during wet periods. In contrast, the spatial means decreased weakly while the variability obviously decreased during dry periods. Soil moisture in forestland was lower than that in native grassland and farmland at all spatial domains during both wet and dry periods. The results also indicated that surface soil moisture (0–10 cm) differs between spatial domains but not land use types, which mainly due to the differences of evapotranspiration on the two topographic domains. In contrast, deep soil moisture (80–100 cm) differs among land use types but not spatial domains, which because of the differences of root water uptake among land use types. In addition, slope aspect played a more important role than slope gradient and elevation in the distribution of soil moisture at the hillslope domain. This was because the slope aspect affected the ground temperature by receiving different solar radiation, and further affected the soil evaporation and vegetation transpiration. Therefore, the results of this study indicates that both topographic domains and land use types should be considered when attempting to characterize soil moisture variability or modelling surface hydrological processes at catchment scale in heavily gullied regions. [ABSTRACT FROM AUTHOR]

Forest secondary succession and conversion to an agricultural use are rapidly altering tropical forests, and this alteration has consequences on soil microbial communities. Using high-throughput sequencing of 16S rRNA genes and internal transcribed spacer regions, we compared bacteria and fungi community composition and diversity in soils between the three stages of forest succession (primary forest, PF; secondary forest, SF; pioneer plant community dominated by Macaranga denticulate trees, PP) and two agricultural drylands (rubber plantation, RP; Plukenetia volubilis plantation, PV) in Xishuangbanna, a tropical region of China, and identified the factors associated with the shift in community composition across the five land-use types. The results indicated that the most abundant bacterial genera ( Bacillus , Kitasatospora , Nitrospira and Streptacidiphilus ) were found at differentially relative abundances among the five land-use types. Through the analysis of indicator species, several bacterial species were significantly associated with the PP site; one to four species were significantly associated to the other sites. Strikingly, almost all fungal genera had site-specific characteristic. Soil properties, especially pH and available P and K, were associated with microbial community composition. Across the three stages of forest succession, bacterial and fungal richness and bacterial alpha diversity had the lowest levels in the earliest stage (PP), but there were no significant differences in microbial richness or diversity between the late stages (PF vs. SF). Compared to PF and SF with their similar bacterial and fungal diversity, the agricultural drylands (RP and PV) had higher bacterial richness but lower fungal richness, indicating that both PF and SF can act as reservoirs for the recolonisation of forest-associated microbes. Overall, these results showed a distinct difference in soil microbe taxonomic composition, especially in fungi, among the various land-use types, even at a very small geographical scale (<4 km), but no great difference of microbial diversity was found between the late stages of forest succession and agricultural drylands. Tropical forest succession and forest conversion to agricultural drylands strongly affect the distribution of microbial species, whereas microbial diversity may not always tightly follow the same successional trajectories. [ABSTRACT FROM AUTHOR]

The Western Carpathians region in southern Poland is characterized by high erosion risk due to steep slopes, flysch formation and intense precipitation with frequent storm events. The G2 model, based on the principles of the Universal Soil Loss Equation (USLE), was used to investigate soil erosion assessment, except that the yearly rainfall erosivity factor was substituted for by the monthly one. The plant cover factor was determined based on the CORINE land cover 2012 database and field observations of vegetation stages. Slope intercept was estimated by applying a Sobel filter. Terrain properties were calculated from a 5 m DEM of the area. Modeling investigations were carried out in the agricultural basin of the mountain catchment (1.47 km 2 ) in the years 2011–2014. Rainfall data were collected from weather stations, and soil properties were measured in 43 locations. The G2 model estimated total annual soil loss as between 3.37 Mg ha −1 (2012) and 31.05 Mg ha −1 (2014). The erosive events that contributed most to yearly erosion occurred in May (2014: 80.40% of yearly total) and June (2013: 57.08%). Redundancy analysis based on land-use types provided factors affecting soil erosion by water. In conclusion, the G2 model was useful in erosion estimation in a steep-sloped agricultural basin with a variable hydrological regime. [ABSTRACT FROM AUTHOR]

Here we analyse geomorphic, pedologic and hydrologic processes of relevance to archaeological research on the pre-colonial irrigation system at Engaruka, Tanzania. Although archaeological studies have been carried out in Engaruka for several decades, geophysical processes have not been in focus, despite having the potential to contribute to the understanding of both the ancient irrigation system and the current land use in Engaruka. Geomorphology and pedology were explored through field surveys and mapping using air photos and satellite images. The effects of the flash-flood during the 1997–1998 El Niño were mapped and quantified in the field. Maximum flash-flood discharge in Engaruka River was estimated using Manning's Equation. The geomorphic study revealed that Engaruka is an environment where high-magnitude processes (debris flows, flash-floods, rock slides) dominate landform development. Low-magnitude processes (sheet-wash, wind erosion), transfer fine-textured sediment to low terrain, causing successive coarsening of soil texture in fields of the ancient irrigation system. Andisol occurrence in the dry environment is associated with current irrigation, indicating incremental improvement of arable land resulting from human land use. Andisols appear transient; discontinuation of irrigation has caused a reversion to Entisols, as water retention and structure deteriorate upon drying. A flash-flood during the 1997–1998 El Niño caused destruction of parts of the archaeological remains, with severe impact on current land use and settlements. Approximately 80 ha (4%) of the total area of the ancient remains were covered by debris flow deposits and alluvium, or scoured by new drainage lines of the water courses. The denudation caused by the single flash-flood is estimated to 9 mm in the catchment of Engaruka River. Manning's Equation yielded a least possible maximum discharge in Engaruka River, in the order of 270 m 3 /s, some 600–700 times higher than normal, dry season discharge. [ABSTRACT FROM AUTHOR]

Watershed responses are affected by the watershed characteristics and rainfall events. The characteristics of soil layers are among the fundamental characteristics of a watershed and they are input to hydrologic modeling similar to topography and land use/cover. Although the roles of soils have been perceived, there are limited studies that quantify the role of soil characteristics on watershed runoff responses due to the lack of field datasets. Using two adjacent watersheds (Ribb and Gumara) which have a significant different runoff response with a similar characterstics except geological settings (including soil characteristics), we studied the effects of soil characteristics on runoff and water balance. The Soil and Water Assessment Tool (SWAT) was used to simulate the surface runoff response at the outlet of the watershed and the optimal model parameters distribution was tested with a non-parametric test for similarity. Results indicated that SWAT model captured the observed flow very well with a Nash-Sutcliffe Efficiency (NSE) of greater than 0.74 and with a PBIAS of less than 10% for both calibration and validation period. The comparison of the optimal model parameter distributions of the SWAT model showed that the watershed characteristics could be uniquely defined and represented by a hydrologic model due to the differences in the soils. Using field observations and modeling experiments, this study demonstrates how sensitive watershed hydrology is to soils, emphasizing the importance of accurate soil information in hydrological modeling. We conclude that due emphasis should be given to soil information in hydrologic analysis. [ABSTRACT FROM AUTHOR]

The aim of this study is to model potential changes in land use and evaluate their effects on sediment load in a Mediterranean watershed, the Carapelle, in Southern Italy. For this purpose, a set of Landsat Thematic Mapper (TM) images were processed to generate three different land use maps for 1987, 2002, and 2011. The images were corrected for geometric distortion and atmospheric interference before performing an unsupervised classification and decision expert system post classification. The land use maps for 1987 and 2002, derived from the Landsat TM processing, were analyzed using a Land Change Modeler (LCM) module to identify transitions from the first land cover type to the second. The transitions were modeled using a multi-layer perceptron (MLP) neural network to create transition potential maps, which provide the controls for subsequent dynamic land use change predictions. The model produced a predicted land use map for 2011 using Markov Chain analysis, which was validated with the actual 2011 land use map. Consequently, a land use scenario (S1) for 2035 and 2050 was predicted, taking into account the current constraints and management options. LCM was further used to define two additional scenarios (S2 and S3) both for 2035 and 2050 based on different land management options. Finally, the Annual Agricultural Non-Point Source Pollution Model (AnnAGNPS) was used to estimate the effect of the predicted land use changes on sediment load after model calibration, using a five-year dataset registered at the Ordona monitoring station. The land use change analysis revealed low transformations from 1987 to 2011. Equally, land use changes were low for the base scenario (S1) so moderate variations in sediment load were estimated. The changes in land use were more significant for the additional scenarios (S2 and S3) and consequently the model estimations underwent major variations, with a significant reduction of soil erosion. The associated utilization of land use change analysis and AnnAGNPS modeling demonstrates how land use management options can be adopted to reduce potential watershed sediment load. [ABSTRACT FROM AUTHOR]

Erosion, flood, and overflow events are frequently experienced due to changes in the land use in watersheds where human impacts are intensive. It is important to understand the effects of land use types on erosion at a watershed scale. This knowledge can then be used to manage soil and water resources in watersheds better. The aim of this study is to determine the effects of different land uses/covers on the surface runoff and soil loss by using a rainfall simulator in natural land conditions in the Niğde Akkaya Dam watershed with semi-arid conditions. For this purpose, 5 cultivated lands with different product patterns with similar conditions (apple orchard (A), potato cultivation area (P), bean cultivation area (B), clover cultivated land (CL), abandoned cultivated land (AB), plantation areas (cedar (C) and almond (AL)), and pasturelands covered with Thymus sp. (T), Agropyron sp. (AG) and Stipa sp. (S) were selected for the applications. The applications were carried out in two repetitions on circular test parcels of 0.28 m 2 established in these lands. During the land applications, the characteristics of surface runoff (ponding time, surface runoff start time, average surface runoff rate, runoff coefficient) and the average sediment concentration in the surface runoff water were determined. The data obtained were evaluated by using the ANOVA, Duncan's test, and Pearson correlation analysis test and SPSS statistical program. The results of the study revealed that the surface runoff occurred in the abandoned cultivation area, bean cultivation area, potato cultivation area, and thyme-covered pastureland in a short time. The runoff coefficient values by the land cover are sorted from high to low as B > T > P > A > AB > AL > C > CL > S > AG. The sediment concentration in the runoff water is sorted from high to low as T > P > B > AB > AL > A > C > S. When the situation was evaluated in terms of the soil loss (erosion), it was concluded that the sorting is as P > T > A > AB > B > AL > C > S > CL. [ABSTRACT FROM AUTHOR]

In alpine regions, global climate change will likely alter rain and snowfall patterns and increase the frequency of extreme meteorological events such as floods. These events, combined with land use changes, may pose an immediate hazard to the life and properties of downslope inhabitants and to water resource structures downstream. The aim of this study is to evaluate the impact of land use changes (e.g., areas covered by grassland, green alder, and dwarf shrubs) on peak discharge for different return periods and different scenarios (past, current, and future) in the Urseren Valley in the Central Swiss Alps. In addition to the entire Urseren Valley, we also considered four microcatchments of various sizes and land covers within the valley. We used the ZEMOKOST model, which considers the impact of a wide range of vegetation and channel characteristics on surface hydrology. Results at the catchment scale show an increase in peak discharge for all return periods from 2 to 300 years. In two microcatchments, simulation results indicate that expected changes in the vegetation cover will drastically decrease peak discharge in the future for all return periods, by up to 41% (for a 100-year return period). At the catchment scale, although the surface area covered by green alder increases by 38% and the area covered by dwarf shrubs decreases by 26% from the current to the future scenario, the peak discharge increases for all return periods except for the 2- and 5-year return periods. It appears that the drastic decrease of grassland area from the current to future (− 52%) scenario is responsible for the slight increase in peak discharge (about 4% for a 100-year period). In addition, surface area covered by dwarf shrub not only decreases from the current to future scenario, but also clusters into more continuous zones damping lateral flow and resulting in such moderate increase. The consistency between observed and simulated peak discharge for a 100-year return period attests the reliability of our modelling outcomes. Careful land use planning taking into account the results of our analysis can help to better manage land and water resources in the region. [ABSTRACT FROM AUTHOR]

Landslides are a manifestation of slope instability causing different kinds of damage affecting life and property. Therefore, high-performance-based landslide prediction models are useful to government institutions for developing strategies for landslide hazard prevention and mitigation. Development of data mining based algorithms shows that high-performance models can be obtained using ensemble frameworks. The primary objective of this study is to investigate and compare the use of current state-of-the-art ensemble techniques, such as AdaBoost, Bagging, and Rotation Forest, for landslide susceptibility assessment with the base classifier of J48 Decision Tree (JDT). The Guangchang district (Jiangxi province, China) was selected as the case study. Firstly, a landslide inventory map with 237 landslide locations was constructed; the landslide locations were then randomly divided into a ratio of 70/30 for the training and validating models. Secondly, fifteen landslide conditioning factors were prepared, such as slope, aspect, altitude, topographic wetness index (TWI), stream power index (SPI), sediment transport index (STI), plan curvature, profile curvature, lithology, distance to faults, distance to rivers, distance to roads, land use, normalized difference vegetation index (NDVI), and rainfall. Relief-F with the 10-fold cross-validation method was applied to quantify the predictive ability of the conditioning factors and for feature selection. Using the JDT and its three ensemble techniques, a total of four landslide susceptibility models were constructed. Finally, the overall performance of the resulting models was assessed and compared using area under the receiver operating characteristic (ROC) curve (AUC) and statistical indexes. The result showed that all landslide models have high performance (AUC > 0.8). However, the JDT with the Rotation Forest model presents the highest prediction capability (AUC = 0.855), followed by the JDT with the AdaBoost (0.850), the Bagging (0.839), and the JDT (0.814), respectively. Therefore, the result demonstrates that the JDT with Rotation Forest is the best optimized model in this study and it can be considered as a promising method for landslide susceptibility mapping in similar cases for better accuracy. [ABSTRACT FROM AUTHOR]

Soil physicochemical properties can be regarded as an important tool to assess soil health, which further form a base for biological activity in soil. These soil physicochemical properties are comparable in identical land-uses and so reflect similar soil microbial properties. However, the changes in land-use types and their effects on soil physicochemical and microbial properties are largely debated and rather unclear. The aim of this study is to assess the impact of land-use types and soil depth on physicochemical properties (Organic C, total N, C/N ratio, available phosphorus, bulk density, pH and electrical conductivity), nitrogen forms (Nitrate-N, ammonium-N, organic N, mineralizable N, microbial biomass N and extractable organic N) as well as microbial indices (basal respiration, respiratory quotient, microbial quotient, microbial biomass). Land-use types - farmland, orchard, grassland and abandoned land served as horizontal factors while soils at 0–10 cm, 10–30 cm and 30–60 cm depth were used as vertical factors for accessing the physicochemical and microbial properties. Discriminant analyses (DA) indicated that soil microbial properties were affected by both land-use types and soil depths than nitrogen and physicochemical properties in our study. We found that the overall trend of percentage of discriminant function 1 (DF1) was highest for microbial indices (~ 90%) > nitrogen (~ 80%) > physicochemical properties (~ 70%). All investigated soil properties differed with higher significance by land-use types than by soil depths. The results further indicated that among all investigated soil properties in different land-use types, electrical conductivity, mineralizable nitrogen and microbial biomass carbon served as best discriminating indices. Regarding soil depths, total organic carbon followed by mineralizable nitrogen and basal respirations were found to be the decisive indicators of soil conditions. Overall, our results demonstrate the sensitivity of various soil properties and their differential provenience along horizontal and/or vertical gradients. These outcomes suggest that differences in land-use types are reflected in soil physicochemical properties that are actual drivers of soil microbial properties in this region. Thus they are promising guideline tools for further studies related to soil quality, soil management and sustainability in long run. [ABSTRACT FROM AUTHOR]

Gully erosion is one of the most severe environmental problems in large areas of Iran. The spatial distribution of gully erosion and its susceptibility zonation was studied using different bivariate statistical models, such as frequency ratio (FR), weights of evidence (WofE), and index of entropy (IofE). For this purpose, 109 gully erosion locations were identified and divided into training (70%) and validating (30%) datasets. Effective factors, including elevation, slope aspect, slope degree, slope-length (LS), topographical wetness index (TWI), plan curvature, profile curvature, land use, lithology, distance from river, drainage density, and distance from road were selected to develop maps of gully erosion susceptibility. The spatial relationship between gully erosion and each effective factor was calculated by the mentioned models. The relative operating characteristic (ROC) curve was implemented for evaluating the accuracy of the applied predictive models. Results indicated that frequency ratio model had better performance (80.4%) than the weight of evidence (79.5%) and index of entropy (79%) models. The produced gully erosion susceptibility maps can be helpful to make decisions for soil and water planning and management and finally sustainable development in the Valasht watershed. [ABSTRACT FROM AUTHOR]

In South-Central Chile, slopes degraded by former erosion have been afforested with exotic tree species since the 1950s for erosion protection. From 1975 on, primary and secondary forests have increasingly been replaced by tree plantations. This practice is often justified by claiming plantations would similarly protect the soil from erosion, even on areas which used to be natural forest. We assessed if plantations offer a comparable level of erosion protection as the natural forests. A six-year-old Eucalyptus globulus (Labill.) plantation was compared to an adjacent secondary forest using soil profiles and erosion proxies, i.e. topsoil parameters linked to erosion and 137 Cs inventories. These pointed to higher erosion in the plantation: the mean bulk density of the plantation was 22% higher compared to the forest site, the gravel content in the plantation was 61% higher, the organic matter content was 20% lower, the mean thickness of the litter layer was 2.2 cm lower and the total sand content was 20% higher. The soil loss of the plantation was estimated to be between 4.8 cm (mean profile truncation) and 6 cm ( 137 Cs approach). These results clearly hint to the conclusion, that the tree plantations in South-Central Chile might promote soil erosion instead of preventing it. Thus, current land use management practices seem to impose erosion risks on Chilean soils raising concern about the sustainable development within the study site. [ABSTRACT FROM AUTHOR]

The impact of the Wallachian settlement on small mountain catchments has been studied at the example of Škorňanský and Hartisov Streams (Moravskoslezské Beskydy Mts, Western Outer Carpathians). Between the 16th and the 19th centuries the Wallachian people introduced pastoral management originating from the woodless Balkans to the forested mid-altitude mountain area under study. This area was subjected to rapid settlement, intense grazing in forests and slash-and-burn deforestation. To assess the geomorphic effects of Wallachian activity in the catchments studied, grain size, structure, organic matter content, and the plant macrofossil composition of the alluvia forming terrace levels in the mouths of the Škorňanský and Hartisov Streams were analysed. Radiocarbon dating, 137 Cs and 210 Pb analyses and dendrochronological dating were also applied to determine the age of the alluvia studied. The results were compared with land-use and land-cover changes recorded on archival maps and pictures, and with population changes in the study area. It was found that the two successive trends of catchment settlement and later depopulation have led to the development of inset terraces on the outlet fans of the Škorňanský and Hartisov Streams. In the study catchments both settlement/deforestation and depopulation/land abandonment occurred very rapidly which also caused abrupt geomorphic changes. Before human disturbance, fluvial erosion and the redeposition of older Pleistocene deposits predominated. As a result coarse, gravel alluvia were deposited within stream channels. The stage of massive overbank accumulation of fine-grained alluvia was a reflection of intensified delivery of slope material into valley floors from catchments deforested by the Wallachians. The later stage of vertical incision of channels resulted from the decrease of sediment supply from hillslopes to river channels during catchment depopulation and afforestation. [ABSTRACT FROM AUTHOR]

Fixed dunes are indicators of successful recovery of desertified land after several years of vegetation restoration. Land use profoundly influences soil properties; however, the effects of changes in land use, after the dunes are fixed, on soil physical, chemical and microbial biomass properties are still unclear. This study investigates the soil physical and chemical properties and soil microbial biomass in a desertified land located in the Xiaojihan desertification control station in northern Shaanxi province, where land use changed from shrub land to arboreal land, arable land and nursery garden. No significant changes in soil properties were found when shrubland was changed to arboreal land. However, changing the fixed desertified land from shrub land to arable land and nursery garden decreased soil porosity, but significantly increased soil bulk density (BD), soil organic matter (SOM), cation exchange capacity (CEC), total nitrogen (TN) and available nutrients (N, P, K). Soil microbial biomass carbon (MBC), nitrogen (MBN) and phosphorus (MBP), as well as microbial quotient (MBC/SOC, MBN/TN, MBP/TP), decreased significantly. No significant changes were detected in soil texture, total phosphorus (TP) and total potassium (TK). Results of this study indicated that agricultural land use can improve the fertility of fixed desertified land; however, soil microbial biomass could decrease. Therefore, conversion of fixed dunes to agricultural usage is full of risks. [ABSTRACT FROM AUTHOR]

Composition and stability of soil organic matter (SOM) affect the sustenance and productivity of soil over the long-term. This issue is particularly important for karst regions in China where the water supply and fertilizer use are limiting factors. Here, we used four indicators to evaluate changes in the composition and stability of SOM quantitatively in five main land-use types in karst area, including primary forest [PF], 15-year secondary forest [SF], grazing secondary forest [GF], abandoned farmland [AF] and farmland [FL]. We collected soil samples at a depth of 0–20 cm to conduct the analyses. Four indicators were used: soil physical and chemical properties, active organic carbon (C), humus C composition, and SOM functional groups. Our results showed that the content of SOM, total nitrogen, and easily oxidized organic C at 0–20 cm soil depth differed among the five land-use types ( P < 0.05). For humic acid C concentration, the land-use types were ordered as: SF > PF > GF > FL > AF. Solid-state 13 C NMR spectra showed that the highest ratio of Alkyl C/O-alkyl C was in AF, while the lowest was in SF. Overall, the comprehensive quality of SOM in different land-use types was PF (setting 100%) > SF (83.1%) > GF (58%) > AF (30.9%) > FL (29.9%). For karst areas, we suggest that farmlands in sloping area should be converted back to forests, with only moderate grazing being permitted, whereas farmlands in the plains should implement grain-forage rotation and grain-soybean rotation to meet the needs of the growing population and economic development. In conclusion, our findings provide a scientific basis from which to delineate rational land-use types for different land (geographical and geological) formations. [ABSTRACT FROM AUTHOR]