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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]

Mangrove forests are important carbon sinks in the tropics, yet tropical mangrove deforestation and land use conversion still persists. Reporting of greenhouse gas (GHG) emissions from natural and anthropogenic sources in wetlands are important in regional and national emissions inventories. However, very few studies have been conducted to measure on the GHG fluxes in coastal wetlands, particularly in mangrove forest and non-forest land uses in deforested mangroves. We investigated the soil fluxes of CO 2 , CH 4 and N 2 O in mangrove forest and non-forest land uses on deforested mangrove areas (i.e. abandoned aquaculture ponds, coconut plantations, abandoned salt ponds, and cleared mangroves) in the coasts of Honda Bay, Philippines. Results showed that the emissions of CO 2 and CH 4 were higher by 2.6 and 6.6 times in mangrove forests (110 and 0.6 kg CO 2 e ha − 1 day − 1 , respectively) while N 2 O emissions were lower by 34 times compared to the average of non-forest land uses (1.3 kg CO 2 e ha − 1 day − 1 ). CH 4 and N 2 O emissions accounted for 0.59% and 0.04% of the total emissions in mangrove forest as compared to 0.23% and 3.07% for non-forest land uses, respectively. Site-scale soil GHG flux distribution could be mapped with 75% to 83% accuracy using Ordinary Kriging. Unlike mangroves that can offset all GHG emissions through CO 2 uptake from photosynthesis, the non-forest land uses cannot offset their emissions on-site as they are usually devoid of vegetation. Our results could be utilised in higher tier national GHG inventories, to refine regional and global estimates of GHG emissions in mangrove wetlands, and improve policy on coastal wetlands conservation. [ABSTRACT FROM AUTHOR]

Land use change is affected by many driving factors such as the economy, population, and government policy. This study investigated the relationship between government policy and land use change to develop an understanding applicable to the formulation of strategies for sustainable land use. The Lijiang River Basin in the Guangxi Zhuang Autonomous Region in southern China was selected for this study. The predicted characteristics of land use change were explored using the CLUE-S numerical model and logistic regression. Using Landsat remote sensing imagery as source data, we simulated the tendency of land use change from 1993 to 2020 under two scenarios: a Natural Growth Scenario (NS) and a Government Intervention Scenario (GS), and we analyzed the possible social driving factors. The results revealed that from 1993 to 2015, both construction and cultivated land have shown a tendency of areal increase. Water and woodland areas both decreased from 1993 to 2006 but then they increased dramatically from 2006 to 2015. Shrubland areas increased from 1993 to 2006 but decreased slightly from 2006 to 2015. The CLUE-S model was used to predict the spatial patterns of land use for 2020. It showed that under the NS, the areas of construction and cultivated land increased, while the areas of other land uses decreased. Under the GS, the areas of construction land, woodland, cultivated land, and water all increased, while the areas of the others declined. Furthermore, the area of woodland decreased for every county under the NS, but areas of woodland expansion were located in Lingchuan and Lingui counties under the GS. Hotspots of cultivated land occurred in Lingchuan County under the NS and in Xingan County under the GS. Water area decreased in every county under the NS, whereas increases in water areas occurred in Lingchuan and Guilin counties under the GS. Construction land expanded in Lingchuan County under the NS and in Guilin County under the GS. The Returning Farmland to Forest Program could be considered a successful addition to the eco-environmental policies implemented in the Lijiang River Basin. [ABSTRACT FROM AUTHOR]

The strong affinity of phosphorus (P) to iron (Fe) oxides and hydroxides in highly weathered tropical soils limits P availability and therefore plant productivity in tropics. In flooded soils, however, P fixed by Fe oxides and hydroxides can be released into more available forms because of Fe 3 + reduction to Fe 2 + . These P dynamics in flooded soils are well documented for rice paddies. Such effects are much less studied in other land-use types influenced by seasonal flooding, especially in the tropics during heavy monsoon rains. The aim of this study was to investigate the P mobilization during flooding leading to anaerobic conditions in topsoil and subsoil depending on land-use type. Samples were collected in highly weathered Acrisols from four replicate sites under natural rainforest, jungle rubber, rubber and oil palm plantations in Sumatra, Indonesia. Topsoil and subsoil were taken to ensure a wide range of soil organic matter (SOM) and P contents. Soils were incubated under anaerobic, flooded conditions at 30 ± 1 °C for 60 days. Our results confirmed the hypothesis that soil flooding mobilizes P and increases P availability. Two distinct and opposite periods were observed during the flooding. During the first three weeks of flooding, the dissolved P (DP) concentration peaked, simultaneously with the peak of dissolved Fe 2 + (DFe 2 + ) and dissolved organic carbon (DOC). After three weeks, P availability in soils decreased, although Fe-P (P NaOH ) and available P (P NaHCO3 ) did not reach the initial, pre-flooding levels. The impacts of flooding on P and Fe forms was strong in the topsoil, where P dissolution and availability were generally higher under forest and, to a lesser extent, under jungle rubber. A positive correlation between DOC and DFe 2 + (R 2 = 0.42) in topsoil indicates that the intensity of microbially-mediated Fe 3 + reduction is limited by the amount of available carbon (C) as an energy source for microorganisms and as electron donor. Microbial mineralization of organic P from SOM also increases P availability, and this process requires available C. This interpretation was supported by the strong correlation (R 2 = 0.58) between available P and DOC, as well as between DP and DOC (R 2 = 0.56) in topsoil. The increasing pH in topsoil and subsoil after flooding of all land-use types may also influence the P release over time. In summary, the increase of available P and DP during flooding is due to three main mechanisms: (1) P release via the microbially-mediated reductive dissolution of Fe 3 + oxides; (2) P release during SOM mineralization and (3) solubility of Fe phosphate due to increasing pH. These mechanisms are relevant not only in riparian areas, where flooding occurs, but also in soils waterlogged after regular heavy rainfalls during the wet season. Therefore, we speculate that the P turnover is faster in compacted soils under plantations because of regular changes of oxic and anoxic conditions. Consequently, more P is pumped by the vegetation and then removed from plantations due to yield export. [ABSTRACT FROM AUTHOR]

Several studies have demonstrated the great range of possibilities offered by remote sensing in identifying, estimating and mapping biological soil crust (BSC) patterns, i.e. a feature recognised to play major functions in drylands. However those techniques are suitable mainly where BSC patterns are abundant (> 30%) and vegetation cover low (< 10%), otherwise reflectance values matched different levels of BSCs mixed with vegetation and bare soil surfaces. This study developed an alternative methodology in mapping BSC presence in areas with a wide range of BSC cover associated with different mosaics encompassing vegetation and bare surfaces in the Sahel. Data were collected during intensive field surveys and remote sensing imagery of two typical Sahelian watersheds in western Niger (Banizoumbou and Tamou). Statistical methods were used to explore relationships between BSC occurrence and abundance and key environmental factors (rainfall, land use, land cover, vegetation, physical crusts). A predictive model of BSC spatial distribution was developed based on logistic regressions. This model allowed predicting and mapping BSC occurrence in areas where BSC cover ranged from 0 to 65% at Tamou (15% in average) and 1 to 48% at Banizoumbou (4% in average) and where vegetation cover ranged from < 1% to > 75%. Predicted values were obtained with an overall accuracy of 77.7% (kappa = 0.54), classifying the model as good and discriminant. This work is the first step in assessing the local scale ecological functions of BSC. Further work is needed for extrapolation at the regional scale in order to provide a useful tool for ecological surveys and for predictions of soil surface dynamics related to global changes in dryland areas. [ABSTRACT FROM AUTHOR]

In recent decades, temperate steppe have become seriously degraded, and rest grazing or moderate grazing approaches have been widely adopted since 1998 to restore degraded grasslands in northern China. The importance of choosing an appropriate grazing management regime for optimizing carbon sequestration in light of climate change or promoting other multiple ecological benefits of grassland ecosystems to humankind have long been recognized. In particular, the various uncertainties in plant and soil properties affected by grazing management require clarification. In this study, we selected fifteen blocks within three kinds of grazing management practices, including free grazing, warm-season grazing, and rest grazing, to test the responses of plant and soil properties to grazing management. The results showed that the species richness, the Shannon-Wiener index, and the proportion of forb functional group were higher for the warm-season grazing sites than for the free grazing sites. Soil bulk density, pH, the Pielou evenness index and the proportion of legume functional groups showed no difference among the three kinds of grazing managements. However, aboveground biomass, root biomass, canopy cover, and height of the vegetation community were larger in the rest grazing sites than in the free grazing sites. Soil organic carbon and total nitrogen contents decreased as management intensity increased, with the lowest and highest values occurring in the free grazing and rest grazing sites, respectively. Furthermore, soil organic carbon and total nitrogen contents were correlated positively with root biomass. Rest grazing was a suitable management strategy for carbon and nitrogen sequestrations, while moderate grazing was a suitable management strategy for diversity conservation in the temperate steppe, in northern China. [ABSTRACT FROM AUTHOR]

Soil moisture variations in space and time are critical in ecological, hydrological, pedological and environmental studies. This study used fractal analysis to detect the spatio-temporal variability of soil moisture on two contrasting land use hillslopes in the hilly area of Taihu Lake Basin of China. Surface (0–20 cm) soil moisture data from January 2013 to September 2015 (a total of 37 sampling days) were analyzed at 39 and 38 sites on the tea garden and forest hillslopes, respectively, with a spatial resolution of about 8 m. Results showed that the forest hillslope was significantly ( P < 0.05) wetter than the tea garden hillslope. The spatial mean soil moisture on both hillslopes had a significant negative linear correlation (R 2 = 0.753 for tea garden ( P < 0.05) and R 2 = 0.459 for forest ( P < 0.05)) with corresponding CV for 37 sampling dates. The fractal dimension (D) was found to be better than the nugget/sill ratio in describing the spatial dependence of soil moisture. The advantage of the D is that it does not require the modelling of the semivariogram since it can be calculated on the basis of the experimental semivariogram. Soil moisture on the forest hillslope showed stronger spatial dependence than that on the tea garden hillslope according to D. However, the soil moisture on both hillslopes showed similar temporal dependence and a low-to-moderate autocorrelation structure. In addition, the temporal variability of soil moisture content was spatially correlated on tea garden hillslope. If a location is temporally autocorrelated, the locations nearby tend also to be temporally autocorrelated. It would be possible to make more accurate moisture trend predictions for temporal autocorrelated locations with small D. These findings had important applications related to sampling design, simulation of soil water flow and agricultural water resources management. [ABSTRACT FROM AUTHOR]

During the past sixty years, the social and economic development causes a change of traditional activities and a movement of the population towards urbanized areas in different regions of Italy. The replacement of vegetated land surface with impervious surface areas changed the hydrologic fluxes of a drainage basin with important consequences on the basin resilience to rainfall events. The main objective of this paper is to present the methodology and the results of a study for quantifying and analysing the hydrological responses to land use and climate changes by means of ArcSWAT model. The case study was the runoff dynamic of the Elsa river basin which was analysed by climate and land use change along more than fifty years (1954–2007). Results showed that, the model was effective in simulating daily base, peak and total runoff, scoring a very good performance. Analysis indicated that given the same climatic conditions, changes in land use played a considerable role since in peak and total runoff formation that were increased with the increase of artificial surfaces and specialised agriculture. This type of analysis proved to be effective in analysing past and future hydrological dynamics of the basin. Our findings suggest that such an approach could help policymakers involved in the land use planning in taking into account land use change, since it can amplify the effects of climate and demographic changes on basin hydrodynamics. [ABSTRACT FROM AUTHOR]

Many surveys with differently sized rainfall simulators have been conducted in the past to study runoff and erosion processes on the plot scale. Concerning the understanding of runoff processes on the slope scale, comparative studies have shown that sprinkling devices with large plot sizes (≥ 40 m 2 ) produce more representative results than small-plot rainfall simulators (4 m 2 and less). Nevertheless, the latter ones are frequently used due to their portability and the reduced effort and water demand compared to large-plot simulations. In this study the results of torrential rain (100 mm h − 1 ) experiments using a small (1 m 2 ) dripper device and a large (40–80 m 2 ) spray device are compared regarding to identify site characteristics which allow estimating the representativeness of surface runoff coefficients measured with a small-plot rainfall simulator. We conducted 39 small-plot (1 m 2 ) and 14 large-plot (40–80 m 2 ) rainfall simulations at eight selected experimental sites in the Eastern Alps with differing land cover, land use, intensity of grazing and antecedent soil moisture content. At sites with intensive grazing, due to topsoil compaction and the shortened flow path, the small-plot device delivered significantly higher runoff coefficients than the large-plot device. At mainly mowed grassland sites with at most a short grazing period in autumn both sprinkling devices showed similar results or even lower runoff coefficients compared with the results of the large-plot simulator. The measured surface runoff coefficients strongly depended on antecedent soil moisture content and grazing intensity. [ABSTRACT FROM AUTHOR]

This study was conducted to characterize soil hydrophobicity, unsaturated hydraulic conductivity and sorptivity under different land uses (i.e croplands, plantation agriculture and natural forests) and soil types in southwestern Nigeria. In this study, a total of 105 different points in 35 different locations comprising of the 3 land uses were sampled in the study areas. Random sampling pattern of 3 sampling points per sample location were carried out and undisturbed soil samples were collected at depths up to 15 cm from the different locations. Handheld mini disk infiltrometer at a steady-state flow of − 2 cm water suction rate was used to determine the unsaturated hydraulic conductivity, water and ethanol sorptivity at each land use site. In addition, the effects of antecedent soil moisture contents (MC), soil bulk density (BD), total porosity (PT), soil water holding capacity (WHC), organic matter content (SOM), and cation exchange capacity (CEC) on soil hydrophobicity, unsaturated hydraulic conductivity and sorptivity were determined. The mean hydrophobicity index, R, showed a decreasing trend in the order: natural forest ˃ plantation agriculture ˃ croplands, whereas, mean hydraulic conductivity values showed an increasing trend in the order: natural forest < plantation agriculture < croplands. Hydraulic conductivity resulted to a negative correlation with hydrophobicity among all sampled soils. In all the sampled soils, index of soil hydrophobicity (R) correlated significantly ( p ≤ 0.01) with organic matter content, organic carbon and cation exchange capacity (CEC). Soil sorptivity to water correlated negatively with moisture content among all samples at p ≤ 0.05. Soil ethanol sorptivity showed significantly positive correlation with organic carbon, organic matter content and cation exchange capacity among all the soil samples at a p ≤ 0.05. Soil properties such as organic matter content, bulk density, and aggregate sizes influence the infiltration characteristics of soils of the study areas. Findings from this research has provided a better understanding of soil characteristics and water management under different land uses, which will be of utmost usefulness to land managers, growers, hydrologist and soil scientists. [ABSTRACT FROM AUTHOR]

Reduced streamflow is a major concern in the Haihe river basin, which supplies water for agriculture, industry and the growing population along the river. The upper Sang-kan (USK) river basin is the headwater of the Haihe river. To understand the drivers of streamflow change in this basin, effects of land use change and climate variability on temporal flow variability were studied using the Soil and Water Assessment Tool (SWAT). The calibration and validation results of the Scenario 0 ( S 0) model (with land use of 1986 and climate derived from 1979 to 1990) indicated that SWAT simulated monthly streamflow well. This was indicated by the Nash–Sutcliffe model efficiency ( NS ) and the Coefficient of Correlation ( r 2 ) for monthly flow, which were 0.89 and 0.91 for the calibration period (1981–1985) and 0.79 and 0.82 for the validation period (1986–1990), respectively. After calibration and validation of the SWAT model ( S 0), three different scenarios were simulated and compared in order to study the effects: Scenario 1 (land use of 2000 and climate during the 1979–1990 period, abbreviated as S 1), Scenario 2 (land use of 2012 and climate during the 1979–1990 period, abbreviated as S 2), and Scenario 3 (land use of 2012 and climate during the 2001–2012 period, abbreviated as S 3). By comparing the simulated hydrological results of S 0 vs. S 1 and S 2, and S 2 vs. S 3, and the annual changes in water use, it can be concluded that the recent perennial drought in the USK river has mainly been caused by human activities; warmer temperatures and less rainfall resulted in streamflow declining by 39.1%, while land use changes and the accompanied water use change for irrigation resulted in surface runoff increasing by 37.6% and streamflow increase between 2.2% and 3.9%, during the period of 1986–2012; increasing ground water and surface water usage for urbanization, industrialization, and reservoir constructions can be attributed from 63.1% to 64.8% of the perennial drought in USK river in recent years. The hydrological simulations provided a better understanding of streamflow changes in the USK basin. The study results can be helpful to maintain ecosystem services and sustainable water use in this region and in the Haihe River basin. [ABSTRACT FROM AUTHOR]

• Effects of crop type and rainfall regime on runoff and soil loss were clarified. • Rainfall regime III caused 3.61–12.93 times greater soil loss than regimes Ⅰ and Ⅱ. • Rainfall and runoff properties showed a larger effect on soil loss than plant traits. • Grain and forage crops with shorter stems and higher cover and earning are preferred. Clarifying the responses of runoff and soil erosion to crop type and rainfall regime is important for the optimization of crop planting systems and land use and management. This study was conducted to quantify the effects of five grain-forage crop types and rainfall regimes on sloped runoff generation and soil loss, and to further identify the factors influencing runoff and soil erosion in Mollisols region of Northeast China. Runoff and soil loss were monitored from 24 runoff plots including wheat, corn, soybean, alfalfa, and bromegrass, with the bare land as a control. 31 erosive rainfall events were classified into three rainfall regimes: regime Ⅰ with low precipitation (P) and duration (D), moderate intensity (I 30) and frequent occurrence; regime Ⅱ with moderate P , long D and low I 30 ; and regime III with high P and I 30 , moderate D and less frequent occurrence. Soil loss caused by regime III was 3.61–12.93 times greater than that under regimes Ⅰ and Ⅱ. Five crops reduced runoff and soil loss by 21.5%-69.3% and 54.1%-77.0%, respectively, of which bromegrass showed the highest reduction, especially the reductions of alfalfa and bromegrass under regime III, which were significantly higher than those of the three grain crops. Wheat showed a higher runoff reduction than soybean and corn but its soil loss reduction was lower due to harvest in mid-July. Crop type greatly influenced the correlations between runoff and soil erosion and rainfall and plant properties. Changes in runoff were significantly related to P , rainfall erosivity (EI 30), coverage, plant height and root density, and the variations in soil erosion were dominated by runoff depth, D , EI 30 , and coverage. Path analysis showed that the rainfall and runoff properties produced larger influences on runoff depth and soil loss rate than plant traits. More attention should be paid to rainfall regime III, and grain and forage crops with shorter stems and higher coverage and earnings are preferred. [ABSTRACT FROM AUTHOR]

• The shear strength of soil-root system was measured by in-situ shear tests. • Shear strength of soil-root system changed significantly with land use type. • Shear strength was significantly affected by soil properties and root traits. • RSAD was the best parameter quantifying the effect of root trait on shear strength. Shear strength of soil-root system (SRSS) is one of the most useful dynamic properties for evaluating soil erodibility and structural stability. The adjustment of land use may strongly affect SRSS by altering soil properties and plant root system. Few studies have been conducted to investigate the effect of land use on SRSS in semi-arid region. This study was performed to quantify the variation in SRSS with five typical land use types (cropland, orchard, grassland, shrub land and woodland) and identify the related dominant contributing factors on the Loess Plateau where land use has changed greatly in the past several decades. In-situ shear tests with large shear box (25 × 25 × 10 cm) were conducted to measure shear stress-displacement curves. The strain energy calibrated to 15 % soil water content (SE c), peak shear stress (PSS) and the displacement of peak shear stress (DPS) calculated from the curves were used to reflect SRSS. The results showed that woodland had the maximum SE c (124.4 J m−2) and PSS (1048.6 kPa), whereas cropland had the minimum SE c (65.6 J m−2) and DPS (7.2 mm). Woodland, especially coniferous species and its mixed forest, might be the most suitable land use type for vegetation restoration on the Loess Plateau to enhance soil erodibility or structural stability. The variation in SRSS with land use was closely related to the changes in soil properties and root traits. PSS increased with penetration resistance, while it decreased with soil water content. DPS was positive correlated to root biomass and morphological traits. SE c was mainly affected by the direct and indirect effects of root surface area density, penetration resistance, soil organic matter content and aggregate stability. The results are helpful for understanding the mechanical mechanism of vegetation restored soils to mitigate erosion and optimizing land use type in semi-arid region. [ABSTRACT FROM AUTHOR]

[Display omitted] • The denitrification rate was higher in the abandoned land than shrubland. • Denitrification were lower in summer compared to winter in all land use types. • Soil environmental factors controlled over denitrification under different land use types. • The denitrifying genes was correlated with denitrification in each season separately. Despite the importance of nitrogen (N) cycling in terrestrial ecosystems, the underlying mechanisms of changes in the soil denitrification rate and microbial function under land use change remain unclear. Here we conducted a field experiment to explore soil denitrification rate, abundance and diversity of denitrifying genes (nirS , nirK , and nosZ) across summer and winter for three land use types (abandoned land, shrubland, and woodland) in subtropical China. The highest denitrification rate was observed in abandoned land (0.31 ± 0.03 mg m-2h−1) while the lowest was in woodland (0.24 ± 0.01 mg m-2h−1); however, denitrification enzyme activity was higher in both abandoned land (6.68 ± 0.18 ng g-1h−1) and woodland (6.35 ± 0.46 ng g-1h−1) than in shrubland (5.45 ± 0.24 ng g-1h−1). Both the denitrification rate and denitrification enzyme activity in all land use types were lower in summer than in winter. Notably, the alpha diversities of the denitrifying genes did not change significantly among the land use types. But the beta diversity of nirS significantly differed among the land use types, that of nirK did not significantly vary with seasons, and that of nosZ changed significantly with both different land use types and seasons. Overall, our findings reveal that soil moisture, soil organic carbon, and NO 3 –-N concentration predominantly regulate denitrification under different land use types, whereas soil moisture and denitrifying genes primarily control variations in denitrification between seasons, thereby providing novel insights into predicting the effects of land use change on N cycling and belowground microbial function. [ABSTRACT FROM AUTHOR]

• Multiple runoff components in a soil-epikarst system were directly monitored. • Critical zone structure exerted more evident influence on carbon loss than land uses. • Thicker soils with less undulating soil-epikarst contact facilitated carbon loss. • Artificial forage grasslands reduced carbon loss. In karst hillslopes, the soil-epikarst system is not only the main reservoir of soluble carbon, but also the hot spots of hydrological and biogeochemical processes. However, the soluble carbon loss mechanism through various runoff components occurring in the soil-epikarst system is not clear. We hypothesize that the karst critical zone structure determines the runoff and soluble carbon loss, and that these response processes can be regulated by land use. 12 experimental plots on a typical karst hillslope (each with 5 × 20 m projected area) of four land uses (naturally recovered shrubland, forage grassland, economic forest land, and cropland) were intensively instrumented for separately monitoring surface, subsurface, and epikarst seepage runoffs and their dissolved organic carbon (DOC) and dissolved inorganic carbon (DIC) concentration. Results show that economic forest land had the highest total runoff and soluble carbon loss, followed by cropland, naturally recovered shrubland, and forage grassland. Generally, karst critical zone structure was the most important factors for controlling DOC and DIC loss through surface, subsurface, and epikarst seepage runoffs. Critical zones with thicker soil and less undulating soil-epikarst contact were more susceptible to runoff and soluble carbon loss. Although not as important as critical zone structures, land use can effectively regulate runoff and prevent soluble carbon loss by affecting rainfall partitioning in karst hillslopes. Planting forage grassland is an effective method of reducing carbon loss, due to its remarkable ability of reducing runoff in the soil-epikarst systems. Our results provide useful insights for determining appropriate land uses and optimizing soil and water conservation strategies in karst hillslopes. [ABSTRACT FROM AUTHOR]

• Monthly soil loss estimation at farmland level delivered highly realistic results. • Joint spatiotemporal R-factor and C-factor delineation in the same application. • C-factor was based on a spatially explicit land use dataset. • Erosion variability, hotspots amid risky seasons, critical land uses identification. • Upscaling and reproducibility potential for larger scale time-varying modelling. The spatiotemporal variability of rainfall and vegetation play a key role in the soil erosion process. However, most research efforts tend to overlook their strong spatial diversification and time-varying character. The parameters are often expressed in a stationary manner focusing on long-term (usually annual) averages, and/or at rather rough spatial analysis. Apparently, a spatially definite non-static parameterization in the same modelling application leads to more realistic soil loss results. In this context, the study attempted to quantify temporal land degradation at the Sperchios river watershed using the RUSLE model. The dynamic R-factor and C-factor coefficients were delineated on a monthly time step accounting for the climatic and biomass seasonality, respectively. Furthermore, C-factor was estimated at farmland level based on a highly detailed land use/land cover (LULC) dataset that provided explicit definition of its cultivated classes (as to holdings demarcation and crop type identification). Intra-annual soil loss variability, hotspots in conjunction to high-risk seasons, and critical land uses were successfully identified. The outputs will assist agronomists and stakeholders to implement targeted (hence cost-/labour-effective) mitigation measures and optimum erosion control strategies, especially amid the riskiest period-area coupling. The methodology's reproducibility potential merits the upscaling of dynamic erosion simulation at larger spatial units. [ABSTRACT FROM AUTHOR]

[Display omitted] • Soil quality deteriorated significantly under cultivation. • NA-based-SQI, as a novel statistical approach, was useful for management. • Soil degradation and resistance indices were used to soil quality evaluation. • The MDS indicator selection approach resulted in more suitable and relevant SQI. Over-increasing population and their needs necessitate sustainable use of soil and the other natural resources. In these circumstances land use changes may occur for supplying the food and settlement requirements of the increased population. Therefore, it is needed to evaluate and monitor quality and degradation of the soils. Recently, identification of appropriate soil quality (SQI) and degradation (SDI) indices for assessing sustainable use of soil resources has received increased attention. However, evaluation of quality, degradation, and resistance indices through various new approaches (e.g., network, NA and factor, FA analysis) particularly under different land uses to determine their susceptibility have been rarely conducted. The present study aimed to i) determine SQI, SDI, and resistance (SRI) indices NA and FA approaches under different land uses; ii) investigate the most influential attributes to soil quality (SQ); and iii) to compare SQIs obtained using two different Integrated (IQI) and Nemoro (NQI) Quality Indices, and indicator selection (Minimum Data Set, MDS and Total Data Set, TDS) approaches. Composite soil samples of cropland, forestland, and rangeland were collected and twenty-one soil physicochemical and fertility indicators were measured. MDS was determined using principal component analysis (PCA). The SDI and SRI were computed and compared. Results revealed that the SDI was -13.8% and -4.6% for the cropland and rangeland, respectively indicating inappropriate soil managerial practices in cropland. SRI was 0.01 and 0.41 for the cropland and rangeland, respectively. The lowest SRI values were obtained for critical level of organic matter (CLOM), organic matter (OM), zinc (Zn) and manganese (Mn) showing that these properties, compared with the others, are more sensitive to land use change. Regression equations between SDI and SRI revealed that these substantial relationships show similar trends indicating that these are useful indices to determine SQ and evaluate the effect of land use change and managerial practices. Soils in cropland had a significantly lower deterioration index (DI) (-66.70) than that of the other land uses. SQI in the cropland was the lowest, especially when screened with the NA method. Furthermore, SQI showed the highest correlation with clay and CLOM. The linear SQI value derived from correlation-based-NA method showed greater max/min ratios than that of the FA. Therefore, the NA-based-SQI, as a novel statistical approach, would be more effective than the SQI-derived-FA for evaluating the effects of land use changes and managerial practices. In general, the mentioned technique is a relatively comprehensive approach integrating different influential soil indicators with various weights showing their contributions to soil quality or degradation process. [ABSTRACT FROM AUTHOR]

• Hydrological impacts of LULC change over the Siliana catchment were investigated. • An ensemble of acceptable hydrological model parameter sets was driven by multiple LULC maps. • Parameter uncertainty can encompass LULC uncertainty. • Changes in LULC reduced the magnitude of monthly flow, high flows but no impact on low flows. It is widely admitted that changes in land use land cover (LULC) influence the hydrology of the catchment. However, how these changes affect hydrological model prediction uncertainty is still a raising question. In this paper we addressed this question by investigating the impacts of the rapid change in LULC in the Siliana catchment in Tunisia on monthly flow and magnitude of flow extremes using the SWAT hydrological model while quantifying the contribution of LULC to the model parameter and prediction uncertainty. At a first step, the SWAT model parameter and prediction uncertainty were estimated using the GLUE method and acceptable parameter sets were identified. Subsequently, the SWAT model was fed with historical LULC as derived from Landsat 5 and 8 satellite images for the years 1990, 2000, 2013 and 2019, and run with the acceptable parameter sets. The results show that the increase in olive plantations (+380 %), urban area (+200 %), and irrigated lands (+309 %) from 1990 to 2019, has LULC decreased monthly flow, high flows magnitude but did not impact low flows in particular over the previous two decades. The findings also suggest that model prediction uncertainty can mask LULC effects, suggesting that model results can be misleading without explicit consideration of uncertainty when assessing the hydrological impacts of changes in LULC. [ABSTRACT FROM AUTHOR]

[Display omitted] • With biological and non-biological elements through the maximum generalized entropy principle, a model was constructed to evaluate the stability of river ecosystem. • Comparison was made on stability and driving factors of sediment-starved clear and sediment-laden turbid river ecosystem. • Sediment-starved clear river ecosystem is affected under more factors than sediment-laden turbid river ecosystem. • Among the internal elements, turbidity has the greatest impact on the ecosystem stability of the two types of river ecosystems. • External background factors determine the direction of river ecosystem evolution. The stability of the river ecosystem can determine the health status of the river. And evolutionary driving forces of river ecosystem can reflect the useful information that the river basin disturbance response to the river, which can provide a theoretical basis for the protection and management of the river. The main goal of this study is to establish a river ecosystem stability evaluation model based on biological and non-biological parameters, and to quantify the effects of driving force, such as: human activities, hydrological situation, climatic factors and land utilization on river ecosystem evolution. In the southeastern part of China's Loess Plateau, we selected the mainstream of the Weihe River (hyper-concentration) and the tributaries (low-sediment-concentration) of the Weihe River at the northern foot of the Qinling Mountains. Results show that the evaluation model based on maximum generalized entropy principle (MGEP) is suitable for stability evaluation of different river ecosystems. The stability of hyper-concentration river ecosystem (3.371) is lower than that of low-sediment-concentration ecosystem (5.343). There are 5 key parameters affecting the ecosystem stability of hyper-concentration river while 8 of low-sediment-concentration river. Among the key parameters, turbidity has the greatest impact on the ecosystem stability of both types of rivers. Interestingly, the turbidity of hyper-concentration river is mainly affected by sediment content, while the turbidity of low-sediment-concentration river has a positive correlation with chlorophyll concentration. It's principally because the two river ecosystems are affected by different external driving forces. Hyper-concentration river ecosystem is mainly driven by land utilization, while low-sediment-concentration is primarily influenced by hydrological situation and climate factors. [ABSTRACT FROM AUTHOR]

• Spatial variation of SOC under different land uses in alpine regions was studied. • Total nitrogen was the main factor driving SOC changes in alpine soils. • Over 90% of variation in SOC was explained by the structural equation model. • Pedotransfer functions (PTFs) were used for predicting SOC content. • Our PTFs had better accuracy than published PTFs when SOC was > 40 g kg−1 Understanding soil organic carbon (SOC) distribution and influencing factors are important to accurately assess soil carbon sink potential and ecosystem quality. However, variations and controls of SOC content and stock under various land use types in the alpine region of Qinghai-Tibetan Plateau remain challenging. In this study, soil properties (pH, bulk density, porosity, clay content, soil organic carbon, soil water content, total nitrogen, total phosphorus, available nitrogen and available phosphorus) and environmental parameters (annual average temperature, annual average rainfall, normalized differential vegetation index, altitude, slope, surface roughness, longitude and latitude) were determined across a 600 km east–west transect in the Tibet alpine region for investigating the distribution characteristics and controls of SOC for three land use patterns — farmland (FA), forestland (FO) and grassland (GR). Results indicated that SOC content in the 0–30 cm decreased with increasing soil depth at different reduction rates under various land use types. The average SOC content and stock in GR was significantly higher than that in FO and FA due to the existence of mattic epipdon in GR under high altitude. The non-consideration of gravel content in soil can lead to an overestimation of SOC stock of 0–30 cm soil layer by 15.37 %, 16.70 % and 17.43 % for FA, FO and GR, respectively. Soil properties and environmental conditions simultaneously affect the spatial distribution of SOC under various land use patterns. Pedotransfer functions (PTFs) using multiple regression were used to forecast SOC content in the studied alpine region, which had a better predictive performance than previous published PTFs in the plain area, especially when SOC contents were higher than 40 g kg−1. Our study provides a foundation to build SOC prediction models for other alpine regions in the world, where SOC contents generally exhibit a wider range than the plain areas. [ABSTRACT FROM AUTHOR]

[Display omitted] • The minimum data set was obtained using principal component analysis and Norm value. • The optimal value was the 75th percentile of the trace element background value. • The urban–rural fringe had a lower soil quality than the other three land use types. The expansion of the urban–rural fringe (URF) has greatly boosted the economy, but haphazard building and chaotic management have severely harmed the soil, particularly valuable arable land resources. The majority of studies have focused on the regional identification of URF, with little research on the influence of URF on soil quality. The soil quality index (SQI) method was used in this study to compare the soil quality of reclaimed land (FKD) in the URF to nearby grain fields (GD), open-air vegetable plots (CD), and facility vegetable plots (DP) in Daxing District, Beijing, China. The results indicated that the SQI of FKD was much lower than that of other land utilization types. Soil organic carbon (SOC), nitrogen, and phosphorus levels were low in FKD and might be improved with proper fertilization in subsequent management. The contents of Na, Mg, Ca, Fe, and total potassium (TK) in FKD were not statistically different from those in GD and CD, but the urease and sucrase activities in FKD were significantly lower than those in the other three land use patterns. A minimum data set including SOC, available phosphorus, TK, clay, Mn, and Zn was obtained for soil quality assessment using principal component analysis with Norm value and correlation analysis. Soil trace elements were standardized using an "optimum is better" scoring function using the 75th percentile of the element background values as the threshold. To our knowledge, this is the first time in soil quality assessment that the 75th percentile of the element background value for a specific soil type has been chosen as the optimum value. [ABSTRACT FROM AUTHOR]

[Display omitted] • The point-to-line BLI-NDVI feature space model has high applicability with R2 = 92.0 %. • The rocky desertification city showed an overall weakening trend during 1985–2020. • The degree of rocky desertification in western Bijie city was higher than that in eastern parts. • The POP density and land use became the dominant factors in recent years. Significant differences exist in the dominant driving factors of rocky desertification evolution in varying temporal periods of mountainous karst areas in southwest China. However, previous studies were primarily conducted in specific periods. In this study, taking Bijie city (one of the areas most seriously affected by rocky desertification in southwest China) as an example, we analyzed the spatio-temporal evolution pattern of rocky desertification in Bijie city in recent 35 years by introducing the feature space model and the gravity centre model, and then clarified the dominant driving factors of rocky desertification in the study area in varying temporal periods based on GeoDetector. The findings were as follows: (1) the proposed point-line BLI-NDVI feature space model has higher applicability for rocky desertification monitoring with the overall inversion accuracy of 92.0 %; (2) during 1985–2020, there was an overall decreasing trend (weakening-aggravating-weakening) of the rocky desertification; (3) the spatial distributions and migration trajectory of gravity centre of rocky desertification indicated that the rocky desertification degree in the western parts was more severely than that in the eastern regions; (4) during 1985–2020, the land use and POP density have become the dominant factors of rocky desertification instead of vegetation coverage and temperature. [ABSTRACT FROM AUTHOR]

[Display omitted] • Widespread soil erosion occurred in the hilly-gully region of the Loess Plateau. • Reclamation and deforestation in 1950–1970s caused severe soil erosion. • The increased vegetation coverage since the 1990s efficiently reduced soil erosion. • Restoring forest is more appropriated measure for soil erosion mitigation. • Convex micro-topography mitigate soil loss in sloping fields. Soil erosion strongly threatens the sustainability of natural ecosystems over the world, especially in the Loess Plateau in China, where has suffered severe soil erosion along with extensive land reclamation and deforestation from the 1950s to the 1970s. The large-scale vegetation restoration practices are supposed to be effective for reducing soil erosion, but the quantitative evaluation of soil erosion, particularly the response of land utilization types and vegetation coverage changes on the mitigation of soil degradation is still not well understood. Plutonium isotopes in soil cores collected from the forest, grassland slope, apple orchard, and cornfield in a typical watershed in the hilly-gully region of the Loess Plateau were analyzed to estimate the soil erosion rates in different land-use types. Widespread soil erosion at rates of 5.1–40.5 t/ha/yr. in this region in the past six decades was estimated. The influences of human activities in the past decades, type of land utilization, level of vegetation coverage, and terrain on the soil erosion in this region were discussed, and the accumulation of the eroded soil in the study sites was explored. Different types of land utilization showed diverse soil erosion rates (forest (slight) < grassland (light) < apple orchard ≈ cornfield (moderate)), indicating that natural vegetation rehabilitation, particularly restoring forest with high vegetation coverage is a practically effective conservation measure for soil erosion control; convex micro-topography on sloping fields is critical in alleviating soil loss by depositing eroded soil. [ABSTRACT FROM AUTHOR]

Soil is the largest terrestrial organic carbon pool and can act as a source or sink for atmospheric CO 2 . Although reliable soil carbon (SOC) stock measurements of major ecosystems are essential for predicting the influence of advancing climate change, comprehensive data on SOC stocks is still scarce for most ecosystems in subtropical areas. In this study, SOC and N stocks of different land use systems were investigated along a climatic gradient in Northwest Ethiopia. The land use systems ranged from dry subtropical Afromontane forest, as the baseline, to cropland as the most degraded system. In addition, we investigated the changes of SOC stocks after interventions to recover vegetation cover; these were eucalyptus plantations and an exclosure to prevent grazing. Total SOC varied between land use systems and ranged from 3.1 kg C m − 2 in croplands to 23.9 kg C m − 2 in natural forest, and average N stock ranged from 0.4 kg N m − 2 in croplands to 2.1 kg N m − 2 in natural forest. In forests, there were a clear vertical gradient in SOC and N stock down the soil profile, and 60% of the total SOC and N stocks were found in the upper 10 cm soil depth. Using the Sr/Ca and Ba/Ca ratios and the vertical distribution of the C/N ratio of the soil, the losses of SOC were shown to be due to loss of the of the upper soil layer. Afforestation of degraded croplands and grazing lands with eucalyptus increased SOC stocks to nearly 70% of the natural forest levels within 30 years. Exclosure, which removed grazing pressure and allowed regeneration of native vegetation, increased SOC in the top soil only. [ABSTRACT FROM AUTHOR]

Land degradation, a current environmental threat of global proportions, is a complex issue which needs an interdisciplinary approach in order to tackle a given territory's sensitivity to the process. This study aims to spatially analyse the land degradation sensitivity in south-western Romania, a region currently known for this type of environmental deterioration. The analysis is based on mapping and assessing land susceptibility to degradation by means of a multifactorial approach using GIS techniques, such as the well-established MEDALUS (Mediterranean Desertification and Land Use) method. Widely used in the Mediterranean region and other areas worldwide due to advantageous features such as simplicity, flexibility and rapid implementation, the method was used in this study for the analysis of the main indicators identified to be driving forces of land degradation, i.e. Climate Quality Index, Soil Quality Index, Vegetation Quality Index and Management Quality Index. The paper aims to adjust the method in relation to local conditions by considering certain additional variables (sub-indicators) for computing the main indicators, as well as by integrating a new regionally relevant indicator for this environmental issue – Water Quality Index. The final results, assessed with the proposed Land Degradation Sensitivity Index (based on 21 sub-indicators, of which 15 are included in the original MEDALUS method, and 6 are additional), showed that approximately 70% of the total study area is critically sensitive to degradation, mainly due to high agricultural pressures and very low vegetation cover. Surprisingly, in terms of administration, it was found that > 80% of the region's territorial administrative units include sectors which are critically exposed to degradation that exceed half their area. The results can constitute a basic support for regional-level decision makers who can implement the appropriate measures in order to attenuate the restrictive environmental conditions. [ABSTRACT FROM AUTHOR]

Riparian woodlands have recently been recognized as important carbon (C) storage regions with a considerable potential of sequestering C to mitigate global warming. Understanding soil organic carbon (SOC) storage in riparian woodland and the differences in SOC storage between riparian woodlands and other adjacent land types is important to effectively assess SOC storage in riparian woodlands and the influences of riparian land-use changes on SOC pool. Therefore, we thoroughly investigated C storage in the riparian woodlands along the Lijiang River watershed, located in a karst area in southwestern China. The goals of the study were to quantify the SOC density (SOCD) in the riparian woodland (0–20 cm depth of upper soil) [ N = 54, the plot area was 1130.88 ± 136.13 m 2 (mean value with standard deviation)]; to compare the differences in SOCD in the riparian woodland [bamboo-dominated ( N = 9) and non-bamboo-dominated woodlands ( N = 45)], the adjacent grasslands ( N = 13) and the farmlands [croplands ( N = 17) and orchards ( N = 17)]; and to assess the influence of soil texture, plant litter and soil root biomass on the SOCD of the riparian woodlands. The results showed that the average SOCD in the riparian woodlands of the Lijiang River watershed was 35.79 ± 9.51 t/ha. The SOCD in the non-bamboo-dominated woodland was 36.91 ± 9.63 t/ha, which was higher than that in the bamboo-dominated woodlands (29.86 ± 4.90 t/ha) by 7.05 t/ha (about 23.59%) ( p < 0.05) and was higher than that in the adjacent grasslands (27.77 ± 7.35 t/ha), croplands (28.93 ± 7.30 t/ha) and orchards (21.26 ± 8.20 t/ha) by 32.91%, 27.58% and 73.61%, respectively ( p < 0.01). However, the SOCD in the bamboo-dominated woodlands was only higher than that in the orchard by 8.60 t/ha (about 40.45%) ( p = 0.012). In the non-bamboo-dominated woodlands in the Lijiang riparian watershed, the SOCD showed a significant negative correlation with soil sand content ( r = − 0.69) and a significant positive correlation with the silt ( r = 0.59) and clay content ( r = 0.61) ( p < 0.01). The SOCD showed a significant positive correlation with plant litter ( r = 0.44) and soil root biomass ( r = 0.38) ( p < 0.05). Finally, the results indicate that the non-bamboo-dominated riparian woodland in the karst area stores more SOC compared with the adjacent grassland and farmland. However, converting riparian vegetation into bamboo woodland did not increase the accumulation of SOC and even caused some SOC loss in the Lijiang riparian area. [ABSTRACT FROM AUTHOR]

Varved lake sediments provide an invaluable archive of natural and human-induced environmental changes. We present results of sedimentological, geochemical and pollen analyses of recent sediments from Lake Jaczno (northeastern Poland). The sediment record was dated using varve chronology validated with 137 Cs fallout peaks. Principal Component Analysis (PCA) and stratigraphically constrained cluster analysis were used to identify four major phases of lake development during the last 200 years. These results were compared with maps and archival data. At the beginning of the studied period (1839–1853), the lake catchment was already partly deforested and used for agriculture, which resulted in intensive soil erosion and high input of minerogenic matter. Next, a short period (1854–1864) characterized by fire events is recorded by microcharcoal in the sediments. The following phase (1865–1971) shows major changes in the catchment area including further deforestation and shortening of the major inflow feeding the lake. This caused a major change from allochthonous (minerogenic) to autochthonous (biogenic) sedimentation, expressed by the transition from clastic-organic to biogenic varves. The most recent phase (1972–2013) is characterized by natural afforestation, reduction of allochthonous inputs and increase in autochthonous deposition. Our study shows how intensification of agriculture and related land use changes in small catchments influences sedimentation processes and the formation of varves. [ABSTRACT FROM AUTHOR]

The impact of land use on the content of labile soil organic carbon (SOC) has been studied well. However, limited information is known about its effect on the recalcitrant SOC pool, which is a key proxy for long-term carbon sequestration. We investigated the impact of land use change on the distribution of labile and recalcitrant SOC fractions in soil profiles (0–30 cm) in the Jinchuan peatland, Northeast China, where native peatland (with peat soil) and forest (with mineral soil) are converted to paddy and cropland, respectively. Peat and mineral soil profile samples were collected from 10 sites in native and cultivated land. Total organic carbon (TOC) and KMnO 4 -oxidizable carbon (KOC) defined as the labile SOC fraction were measured in both peat and mineral soils. Fibre and lignin were also determined in peat samples. The mineral-associated organic carbon (MOC) and black carbon were examined as two recalcitrant SOC fractions. In peat soil profiles, the TOC and KOC contents increased with the increasing depth across all land uses. The conversion of peatland to paddy field can affect TOC content at each peat soil depth. The KOC content was lower in cultivated soils, indicating that cultivation decreased KOC. The KOC decrease was smaller than the TOC decrease, indicating that some recalcitrant SOC fractions were decomposed because of land use change. Unlike peat soil profiles, the TOC and KOC contents decreased with depth in mineral soil profiles across all land uses. The TOC and KOC contents in surface soil decreased remarkably after cultivation to cropland but were not affected in deep soil. Interestingly, recalcitrant SOC fractions, such as MOC, increased in mineral soil profile after cultivation but showed no change in peat soil profile. This study suggests that conversion of peatland to paddy can release the recalcitrant SOC fraction. In addition, conversion of cultivated forest to cropland decreased the TOC content but prolonged the long-term storage of some recalcitrant SOC fractions, such as MOC. [ABSTRACT FROM AUTHOR]

Pedodiversity studies greatly depend on the discretization of the soil continuum via various soil classification standards. Soil taxonomic systems are constructed considering soil properties and their organization in the soil profile. Therefore, it seems logical that the pedodiversity of an area could be calculated by considering the simultaneous variation of multiple soil properties within that area. With the aim of creating a bridge between these two lines of thinking, this study presents the development of two new indices of pedodiversity ( HULLdiv and EIGENdiv ) which consider continuous variables as input. The soil input information tested was a) Visible and Near Infrared (Vis-NIR) reflectance values and b) values of five soil properties predicted from Vis-NIR spectra. Both indices were employed to measure the pedodiversity at different extents in two perpendicular transects containing 27 (North to South) and 22 (East to West) locations respectively in New South Wales (NSW), Australia. Each location considered natural and intervened land use. The indices successfully represented the pedodiversity of the area of study, however they were different depending on the input soil information i.e., raw Vis-NIR and predicted properties. HULLdiv was affected by extreme soil observations and as a result its discrimination power between areas with different soil diversity was inferior. On the other hand, EIGENdiv represented well the pedodiversity of an area, despite the extreme observations. The results showed good agreement with conventional methods for assessing pedodiversity i.e., Shannon's and Simpson's indices. However, the new indices were more discriminating by being able to better represent the landuse effect. This study represents the first attempt to measure pedodiversity in a continuous way using Vis-NIR information. [ABSTRACT FROM AUTHOR]

The influence of land use patterns on stream water quality is scale-dependent in space and time. Understanding the relationship between landscape characteristics and water quality is of great importance to improve water contamination prediction in unmonitored watersheds and for providing guidelines for watershed land use planning. In this study, five water sampling sites in the upper Dan River basin were established to monitor seasonal water chemical contamination over the period of 2000 to 2008. The relationships between land use patterns and water quality were analyzed across multiple-scales using redundancy analysis. The results showed that stream water quality variables displayed highly temporal variations, with electrical conductivity (EC), ammonium nitrogen (NH 4 + -N), nitrate nitrogen (NO 3 − N), and total suspended solids (TSS) all generally displaying higher levels in the wet season, while there were higher concentrations of biochemical oxygen demand (BOD 5 ), chemical oxygen demand (COD cr ), and dissolved oxygen (DO) in the dry season. The total contribution of land use patterns on overall water quality was stronger at the riparian scale than at the catchment and reach scales during the wet season. However, different land use metrics had different scale effects. Urban land had a higher positive relationship with degraded water quality at small scales than at large scales, whereas agricultural land displayed the opposite scale effects. Forest and grassland explained more water quality variations at the riparian scale than at other scales. Analyses of spatial development patterns suggested that size, density, aggregation, and diversity of landscape patterns were important factors impacting on stream water quality. The results provide important information regarding sustainable land use and landscape planning at multiple-scales that can be used to improve water quality. [ABSTRACT FROM AUTHOR]

Chesapeake Bay, the largest estuary in North America, is impaired by excess nutrient discharges, especially from urban and agricultural land. Watershed simulation models have provided key insights to understanding land-to-water connections, but rarely are these models applied to guide local land management to explore and communicate uncertainty in the model predictions. In this study, three watershed simulation models; the Soil and Water Assessment Tool (SWAT), the Generalized Watershed Loading Function (GWLF) model, and the Chesapeake Bay Program's Chesapeake Watershed Model (CBP-CWM) were implemented to predict water, total nitrogen, and total phosphorus discharges from small tributaries in the town of Queenstown, Maryland, USA. Based on our evaluation metrics, none of the models consistently provided better results. In general, there was a good agreement on annual average water flow between the SWAT and CBP-CWM models, and the GWLF and CBP-CWM models predicted similar TN and TP loads. Each model has strengths and weaknesses in flow and nutrient predictions, and predictions differed among models even when models were initialized with the same data. Using multiple models may enhance the quality of model predictions and the decision making process. However, it could also be the case that the complexity of implemented watershed models and resolution of our understanding currently are not yet suited to provide scientifically credible solutions. [ABSTRACT FROM AUTHOR]

In this study, we analyze the changes of indicators of ecosystem services and functions, in order to understand the main cause of grassland degradation due to climatic variation or land use changes in the middle-south Inner Mongolia. The soil nutrient and the water supply of supporting service got recovery during 1988–2008. The loss of net primary production declined, and the quality of the retained unconverted grassland (RUG) even increasingly degraded from 2000 to 2008. Analytical results show that environmental degradation on the land-use-changed-area is lower than that on the RUG from 2000 to 2008. It illustrates that climatic variation has more negative impacts on grassland ecosystem service, and which is significantly higher than the so-called “overgrazing” induced grassland degradation. Moreover, it cannot be excluded that those species died out on the RUG due to natural selection or competitive evolution in an evolutionary process under the deteriorative weather condition rather than overgrazing. The positive impacts of human activities such as conservation programs and wildlife protection laws also benefit to regional grassland ecosystem obviously in the study area, so that can delay the environmental degradation even if each planet has its life cycle. It indicates that an integrated regional planning involving the considerations of climatic conditions, geographical characteristics, socioeconomic factors, and ecological functions and biodiversity can benefit to regional grassland conservation based on monitoring and management via scientific methods. [ABSTRACT FROM AUTHOR]

Uncertainties remain as to the potential for tree plantations to affect soil microbial biomass. Our aim was to determine the factors accountable for the maintenance and the increase of soil microbial biomass following tree plantation. Based on mixed effect models, we conducted a meta-analysis with three fixed and two random factors to test the impact of tree plantation on soil microbial biomass. Previous land use was more important than climate or plant species in its effect on soil microbial biomass after tree plantation. There was a positive impact on soil microbial biomass for tree plantations on bare land but a negative impact for which on previously forested land. Climate and plant species were found to be not as important in their effects on soil microbial biomass. Our meta-analysis gives a general pattern that previous land use type is the major controlling factor of soil microbial biomass following tree plantations and promotes our understanding of the effects of rehabilitation of degraded sites on vegetation recruitment. [ABSTRACT FROM AUTHOR]

Detailed digital soil maps showing the spatial heterogeneity of soil properties consistent with the landscape are required for site-specific management of plant nutrients, land use planning and process-based environmental modeling. We characterized the short-scale spatial heterogeneity of soil properties in an Alfisol catena in a tropical landscape of Sri Lanka. The impact of different land-uses (paddy, vegetable and un-cultivated) was examined to assess the impact of anthropogenic activities on the variability of soil properties at the catenary level. Conditioned Latin hypercube sampling was used to collect 58 geo-referenced topsoil samples (0–30 cm) from the study area. Soil samples were analyzed for pH, electrical conductivity (EC), organic carbon (OC), cation exchange capacity (CEC) and texture. The spatial correlation between soil properties was analyzed by computing cross-variograms and subsequent fitting of theoretical model. Spatial distribution maps were developed using ordinary kriging. The range of soil properties, pH: 4.3–7.9; EC: 0.01–0.18 dS m − 1 ; OC: 0.1–1.37%; CEC: 0.44–11.51 cmol (+) kg − 1 ; clay: 1.5–25% and sand: 59.1–84.4% and their coefficient of variations indicated a large variability in the study area. Electrical conductivity and pH showed a strong spatial correlation which was reflected by the cross-variogram close to the hull of the perfect correlation. Moreover, cross-variograms calculated for EC and Clay, CEC and OC, CEC and clay and CEC and pH indicated weak positive spatial correlation between these properties. Relative nugget effect (RNE) calculated from variograms showed strongly structured spatial variability for pH, EC and sand content (RNE < 25%) while CEC, organic carbon and clay content showed moderately structured spatial variability (25% < RNE < 75%). Spatial dependencies for examined soil properties ranged from 48 to 984 m. The mixed effects model fitting followed by Tukey's post-hoc test showed significant effect of land use on the spatial variability of EC. Our study revealed a structured variability of topsoil properties in the selected tropical Alfisol catena . Except for EC, observed variability was not modified by the land uses. Investigated soil properties showed distinct spatial structures at different scales and magnitudes of strength. Our results will be useful for digital soil mapping, site specific management of soil properties, developing appropriate land use plans and quantifying anthropogenic impacts on the soil system. [ABSTRACT FROM AUTHOR]

Stoichiometry is an important indicator of the elemental balance in ecological interaction and process. However, the effect of land-use on stoichiometry of soil nutrient along soil profile remains uncertain. In this study, soil samples (0–20 cm, 20–40 cm, 40–60 cm, 60–80 cm and 80–100 cm) were collected from six different land-uses including maize field (MZ), wheat field (WT), paddy field (PD), apple orchard (OC), grassland (GL) and wetland (WL) in a traditional agro-pastoral region of the Ili River Valley, northwest China, to evaluate the influences of land-use on contents and stoichiometry of soil carbon (C), nitrogen (N), phosphorus (P) and potassium (K) along a 100 cm soil profile. The results showed that natural land (GL and WL) had significantly higher soil organic C (SOC), soil total nitrogen (STN) and soil available N (SAN) contents than those of croplands (MZ, WT, PD and OC) in all soil layers. However, differences in soil P and K contents between the two land-uses were not significant in most soil layers. Such characteristics of soil nutrient contents led to significant differences in soil C: P (R CP ), C: K (R CK ), N: P (R NP ) and N: K (R NK ), while no significant differences in soil C: N (R CN ) and P: K (R PK ) between cropland and natural land, indicating that nutrient stoichiometry of deep soils can be also affected by land-use. In the 0–20 cm soil layer, soil R CN of different land-uses, as well as their average in our study were similar to those on Chinese and global scales. However, since our study area has relatively lower SOC and STN contents while higher STP contents than the global averages, the average soil R CP , R NP and C: N: P (R CNP ) of our study were lower than the those on the global scale. Therefore, we suggest that more nutrient inputs, such as manure and crop residues should be applied to the croplands of the Ili River Valley to improve the levels of soil C and N. [ABSTRACT FROM AUTHOR]

Farmland abandonment in Europe is a major problem because of environmental, socioeconomic and landscape implications. In this paper, a general view of the extent of abandoned land, the stages of abandonment and the drivers that manage this process in Europe is presented. A scientific literature review shows an abandonment at the beginning of the 19th century, although the largest abandonment in terms of area took place in the mid-20th century. This abandonment had a far greater impact on mountain areas because of rural depopulation as well as biophysical constraints. Since the last decades of the 20th century, abandonment driven by the CAP in European Member States and by the end of the communist regime in Central and Eastern Europe has been taking place. This abandonment affects peripheral marginal areas due to biophysical or socioeconomic conditions. Semi-arid areas in Southern Europe have also seen an important extent of abandoned land over the last few decades. The literature draws on the ongoing abandonment from the following decades, and 3–4% of current farmland is considered to be affected. It is noted that, among the drivers, external factors (migration, socioeconomic model, public policies, etc.) act as enhancers that emphasize land abandonment. However, internal causes (agro-ecological and socioeconomic factors and also the features of agricultural holdings) control the dynamics and the extent of this phenomenon. The international literature about land abandonment in Europe is vast, and most of the specialized production is devoted to the effects of land abandonment, while few works determine the extent, stages and drivers of land abandonment. Finally, it is necessary to review the grey literature to obtain more quantitative information on the amount of abandoned land in Europe. [ABSTRACT FROM AUTHOR]

Changes in land use related to mining in the north-western mountains of Spain are analysed. We studied 15 representative types of mining activity in the Sil River basin (León province), including three types of mineral resources: gravel, roofing slate and coal. We use colour orthopothos of 2014 to calculate areas occupied by dumps, lagoons, open pits, auxiliary construction and access roads in mines. Also areal photographs of 1956–1957 were used to measure land uses in these years. In all cases the extraction of mineral resources by surface mining has caused the destruction of the former topography, and these alterations are irreversible. The new post-mining topography represents a drastic change in the landscape and land use in these areas. Areas occupied by coal and slate mining (around 1500 ha.) are significantly greater than gravel quarries (74 ha.). Waste material is greater in slate mining (69%) and coal mining (44%) than in gravel mining (8%). Former agricultural areas now occupied by mining were more extensive in gravel quarries (44%) than in slate quarries (10%) and coal mines (6%) because of the gentler topography in the areas where the gravel quarries are located. In six cases mining are located in natural protected areas and in other cases alter and/or eliminate valuable geological heritage. [ABSTRACT FROM AUTHOR]

Deforestation and land-use change in tropics have increased over the past decades, driven by the demand for agricultural products. Although phosphorus (P) is one of the main limiting nutrients for agricultural productivity in the tropics, the effect of land-use change on P availability remains unclear. The objective was to assess the impacts of land-use change on soil inorganic and organic P fractions of different availability (Hedley sequential fractionation) and on P stocks in highly weathered tropical soils. We compared the P availability under extensive land-use (rubber agroforest) and intensive land-use with moderate fertilization (rubber monoculture plantations) or high fertilization (oil palm monoculture plantations) in Indonesia. The P stock was dominated by inorganic forms (60 to 85%) in all land-use types. Fertilizer application increased easily-available inorganic P (i.e., H 2 O-Pi, NaHCO 3 -Pi) in intensive rubber and oil palm plantations compared to rubber agroforest. However, the easily-available organic P (NaHCO 3 -extractable Po) was reduced by half under oil palm and rubber. The decrease of moderately available and non-available P in monoculture plantation means that fertilization maintains only the short-term soil fertility that is not sustainable in the long run due to the depletion of P reserves. The mechanisms of this P reserve depletion are: 1) soil erosion (here assessed by C/P ratio), 2) mineralization of soil organic matter (SOM) and 3) P export with yield products. Easily-available P fractions (i.e., H 2 O-Pi, NaHCO 3 -Pi and Po) and total organic P were strongly positively correlated with carbon content, suggesting that SOM plays a key role in maintaining P availability. Ecologically based management is therefore necessary to mitigate SOM losses and thus increase the sustainability of agricultural production in P-limited, highly weathered tropical soils. [ABSTRACT FROM AUTHOR]

Changes in the spatial distribution of resources constitute an indicator of degradation of arid grazing lands. In arid and semi-arid ecosystems, the distribution of soil resources has been commonly associated with the structure and the spatial arrangements of the vegetation. Although the formation of “fertile islands” beneath vegetation patches is well documented, much less is known about the changes induced by grazing systems on the distribution of soil resources. We examine how pastoralist settlements are affecting the spatial distribution of soil resources and the soil nutrient balance in central-western woodlands of Argentina. We analyzed the distribution of soil water, chloride, nitrate, total nitrogen, and organic matter at increasing distances from livestock corrals and in undisturbed woodlands, at different soil depths. We also calculated variation indexes of soil organic matter and total nitrogen produced by livestock settlements, as an indicator of degree of deterioration or improvement of the soils. The transects located in pastoralist settlements demonstrated an increasing centripetal gradient in availability of soil water and nutrients compared to transects outside of these disturbed areas. Livestock corrals create local hotspots of nutrient enrichment, but when we analyzed the effects of livestock settlements at a higher spatial scale, we found net losses of soil organic matter and total nitrogen. We conclude that the coupling between nutrient and patch dynamics is disrupted by the pastoralist settlements, which caused a redistribution of soil resources, controlled by the location from the livestock corrals. The processes that promote nutrient losses, such as ammonium volatilization, denitrification, nitrate leaching, organic matter oxidation, manure exports, and soil erosion, are relatively higher than the extra inputs of dung and urine. Therefore, this study emphasizes the role of grazing systems as modulators of water and nutrient fluxes, and soil nutrient balance. [ABSTRACT FROM AUTHOR]

The overall impact of individual environmental factors on the content of soil organic carbon (SOC) is well known, but the simultaneous impacts of natural and anthropogenic factors on the amount and diversity of SOC pools in mountain areas are still insufficiently recognized. This study has three objectives: (1) to determine SOC pools in the mountain toposequence in relation to the climate-elevation gradient and vertical vegetation zonality, largely as a result of interference caused by human activity; (2) to predict the fluctuations of SOC pools in mountain soils affected by changes in land use/forest management and expected climate warming; and (3) to verify whether the humus form is a predictor of SOC pools in mountain soil. A spatial, climate-/altitude-dependent trend of SOC pools is clearly marked on the northern slopes of the Karkonosze Mountains, SW Poland. These SOC pools gradually increase up to the altitude of ca. 1000 m a.s.l. and then decrease in the uppermost forest and subalpine zones. The SOC pools are also strongly related to land use/vegetation (arable soils < grasslands = European beech stands < Norway spruce stands) and soil type (Luvisols < Cambisols < Podzols). Humus forms reflect the differences in SOC pools (mull < moder < mor), but the recent European classification does not clearly allocate semiterrestrial sub-types among mor and moder humus forms. Expected climate warming and present changes in land use and forest management lead to similar changes in SOC pools. However, replacing spruce monocultures with mixed or broadleaf stands reduces the SOC pools in the lower forest zones, while the timberline rise and the succession of Norway spruce on grasslands increases SOC pools in the upper forest and subalpine zones. Thus, the balance of SOC pools caused by changes in land use and climate warming will be specific in particular mountain areas, depending on their maximum altitude and existing vegetation zones, the degree of anthropogenic transformation of ecosystems, and the resilience of ecosystems to climate changes. It is expected that the SOC pools in the Karkonosze Mts and similar medium-elevation mountain ranges of Central Europe will decrease due to the larger scale of phenomena which decrease SOC pools. [ABSTRACT FROM AUTHOR]

Soil water content (SWC) is a critical variable in studies of hydrological processes and the soil–plant–atmosphere continuum, especially in arid and semi-arid regions such as the Loess Plateau. Knowledge of the effects of vegetation types on soil water dynamics would aid in understanding the mechanisms responsible for water shortages and addressing the problem of poor long-term vegetation recovery. To evaluate the response of soil water storage (SWS) to different land use types during long-term natural vegetation succession, we examined soil moisture under different land use types (grassland, shrubland and forestland) at different times (2005 and 2014) in the Ziwuling forest region, located in the central part of the Loess Plateau, China. Our results showed that vegetation type had a significant effect on SWS in the 0–500 cm soil layer. The SWS in grassland and shrubland was significantly higher in August 2014 than in August 2005, but the pattern was reversed for forestland. In the same year, the SWS was highest in grassland, intermediate in shrubland, and lowest in forestland. SWS and SWC showed a highly significant and positive relationship in the 0–60 cm soil layers ( P < 0.01), and both soil bulk density (BD) and soil total nitrogen (TN) showed a significant relationship with SWS. In addition, the SWC and soil total porosity (TP) showed a significant positive relationship in the 0–20 cm soil layer ( P < 0.05). These results are expected to provide insights into land water management and inform efforts to estimate the productivity and sustainability of semiarid ecosystems. [ABSTRACT FROM AUTHOR]

Soil carbon (C) pool contains organic carbon (SOC) and inorganic carbon (SIC). A detailed understanding of SOC and SIC is meaningful and essential for precisely assessing the effects of land-use on soil C stocks. Alpine grassland around Qinghai Lake basin has experienced extensive land-use changes due to the cultivation of native grassland and vegetation recovery on cropped land. However, limited information is available about the changes and distribution patterns of soil C pool with land-use in this region. Here, three land-use types were chosen, including natural alpine grassland (NG), and a pair of restored grassland (RG) and farmland (FL), to examine the effects of cultivation and restoration on SOC and SIC horizontal patterns and vertical distributions in the upper 30 cm soil layer. Land-use changed the ratio of SOC/SIC without affecting the net soil total C accumulation in this area. The NG had the highest SOC (96.0 Mg C ha − 1 ) and lowest SIC (19.8 Mg C ha − 1 ) stocks, while the FL had the opposite result, with the average of SOC and SIC stocks was 65.0 and 57.7 Mg C ha − 1 , respectively. After 10-year restoration, SOC stock increased to 73.2 Mg C ha − 1 , while SIC decreased to 47.8 Mg C ha − 1 in the RG. The vertical distribution of SOC and SIC changed sharply with depth in the NG but gently in the RG, and with little changes in the FL. Stepwise regression analysis manifested that soil nitrogen and pH were the main determinants for the redistribution patterns of SOC and SIC with land-use. In addition, ordinary regression analysis revealed a significant negative correlation between SIC content and aboveground biomass of the respective vegetation. The results demonstrated that land-use had affected the horizontal and vertical patterns of SOC and SIC synchronously, and indicated SIC stocks played crucial roles for estimating the C sequestration capacity in the restoration and farmland ecosystems around Qinghai Lake basin. Moreover, the results of this study provided an interesting snapshot of the compensation relationship between SOC and SIC stocks with land-use, and suggested that the changes of soil properties and plant above- and belowground biomass resulting from cultivation and restoration were potentially responsible for the transformation of soil C forms. [ABSTRACT FROM AUTHOR]

Soil microorganisms are the main drivers of all of the biochemical processes that occur in soils. Land-use conversion, a common occurrence driven by market economy, changes plant species and the associated management strategies, thus significantly influences soil microbial communities. However, few studies have been conducted to disentangle the effect of the alteration of plant species from that of soil environment during the initial years of conversion. In this study, the effect of land-use conversion from double rice cropping (RR) to maize-maize (MM) and soybean-peanut (SP) double cropping systems on soil physical and chemical properties and microbial communities was studied two years after the conversion in southern China. The results showed that land use conversion significantly changed the soil properties, microbial communities and microbial biomass. The soil water content decreased significantly by 26.3%, and the pH decreased by 0.50 and 0.52 for MM and SP, respectively, compared with RR. Soil inorganic N also decreased significantly by 55% after the conversion to drained fields. The total phospholipid fatty acids (PLFAs), and bacterial, G +, G − and actinomycetic PLFAs decreased significantly after the conversion. No significant differences were found in the soil properties, microbial communities and microbial biomass between the converted MM and SP. Our results indicated that the changes of anaerobic to aerobic conditions, rather than of crop type, induced the variations in the soil properties and microbial communities during the initial years after conversion from paddy soils to drained soils. In particular, soil pH was the key factor that regulated the variations in the soil microbial communities after conversion. [ABSTRACT FROM AUTHOR]

Universal Soil Loss Equation USLE-based erosion models have been used extensively to complement erosion measurements, to understand the interactions of the different geophysical features into erosion processes and to assess adequate alternative management practices and scenarios analyses. Despite its proved usefulness on different land-uses around the world, there is an urgent need to set up simple tools which do not require an advanced management expertise in terms of both choose of model parameters and calculation ability and which are accurate particularly at the event scale. In this paper the suitability of the Modified USLE (USLE-M) model at the event and the annual scale were evaluated in an olive orchard catchment of 6.1 ha in Spain where a rainfall-runoff-sediment yield dataseries of over 8 years (2005–2013) was available. The model was applied dividing the catchment into morphological units, i.e. areas having a defined aspect, length and steepness. In addition, different model parameterizations of both the crop factor of the Revised USLE factor and β-coefficient of the sediment delivery ratio of each morphological unit were studied in order to describe the seasonal variability of soil conditions along the year. At event scale the best performance of the USLE-M model was obtained using a single value of the β coefficient equal to median value β e,m without considering the seasonal variability of crop factor since it is well-represented by the term rainfall-runoff erosivity index. At the annual scale, the calculation of crop factor values provided a good model performance in estimating sediment yield, with a coefficient of efficiency of 0.96. The analysis demonstrated that the USLE-M model was a useful tool to simulate soil losses at the event and annual scales and its application might provide guidelines for other users. [ABSTRACT FROM AUTHOR]

The aim of the study is to calculate and evaluate the changes in spatial distribution of soil erosion rates related to land use/cover changes and climate changes in the Sudetes Mts. within the last 150 years. Various methods were used, including GIS analysis of historical and contemporary land use/cover and climate data, spatial analysis of soil erosion modeling using RUSLE. Changes in spatial distribution of precipitation sums were estimated based on spatial deterministic-stochastic models (regression-kriging) applied to the measurement data from the entire Sudetes region in both analyzed periods. There was a pronounced increase in the area of forests and grasslands at the expenses of arable grounds due to depopulation and consequent land abandonment. These changes started already in the 1880s but they were intensified after World War II. On average soil erosion in the study area decreased by 76.2% (from 4.03 t ha − 1 y − 1 in the 19th century to present 0.96 t ha − 1 y − 1 ). However, the changes in erosion are highly diverse locally in the studied region with the maximum decrease of 8–16 t ha − 1 y − 1 on steep and higher slopes, which were transformed from arable grounds to forests and grasslands. While both land use and climate changes took place in the study area, changes in land use/cover have a much larger impact on calculated soil erosion rate than climate change. The abandonment of land and the development of spontaneous succession of vegetation limited soil erosion in a very effective way. The values obtained by RUSLE modeling were compared with other values of soil erosion from various field measurements in the Sudetes Mountains in order to evaluate the model. The measurements were based on the experimental plots and sediments stored within the agricultural terraces and in the water reservoirs of various sizes. While the specific sites show large differences in denudation rates, the mean contemporary erosion calculated from our model (0.06 mm y − 1 ) corresponds with the average rate of denudation, which was calculated for the entire Sudetes: 0.05–0.01 mm y − 1 (Jahn 1968). [ABSTRACT FROM AUTHOR]

In the present study, the impact of land use–land cover (LULC) change and urbanization on floods are investigated for an expanding urban catchment of the Oshiwara River in Mumbai, India. For the study area, the land use change was estimated between 1966, 2001 and 2009 by using the topographic map and satellite images. The analysis of LULC change revealed that the change between 1966 and 2001 was slower than that between 2001 and 2009. The LULC analysis revealed a 74.84% increase in the built up area with a 42.8% decrease in open spaces between the years 1966 and 2009, with substantial increase in urbanization. The impact of LULC on flood hydrograph for different return periods was ascertained by using the HEC-GeoHMS and HEC-HMS models. In the past 43 years, the increase in peak runoff and runoff volume is marginally varied by 3.0% and 4.45% for the 100-year return period and 10.4% and 12.2% for the 2-year return period respectively, although the built-up area increased by 74.84%. The flood inundation area is increased by 5.61% for the 100-year return period and 6.04% for the 10-year return period between the same time period. The results showed that lower return periods led to a maximum change in peak discharge/volume of runoff compared to higher return periods for change in land use conditions. Further, a flood hazard analysis has been carried out and it showed that the area in highly hazardous zone is increased by 64.29% as compared to less hazardous zone where it is decreased by 32.14%. Overall, the total flood hazard area is increased by 22.27%. The developed flood plain and flood hazard maps can be used by the local Municipal body to prepare flood mitigation and early evacuation management plans during floods and as a criteria for insurance of any property by insurance organizations. [ABSTRACT FROM AUTHOR]

Fe and Al compounds of low degree of crystallinity are important components for the development and conservation of soil structure in many soils. In this work, the influence of parent material and land use on the abundance of poorly-crystalline forms of Fe and Al was studied in six macroaggregate fractions from 28 soils. The soils selected are developed on two geological materials with very different composition: granites or amphibolites, and under two land uses: shrubland or agricultural. Poorly crystalline Fe and Al were extracted with oxalic acid–ammonium oxalate (inorganic and organic forms), and with pyrophosphate (organic forms). Soils developed on amphibolite were richer in organic matter and poorly-crystalline Fe and Al compounds than soils developed on granite. Agricultural soils were impoverished in organic carbon and organic-complexed Al with respect to shrubland soils, and enriched in inorganic poorly crystalline forms of Fe. The differences related to land use were more evident in the amphibolite soils. Aggregate stability, assessed by water-dispersible clay quantification, decreased in agricultural soils with respect to shrubland soils, in particular for those developed on amphibolite. This reduction of aggregate stability in agricultural soils is likely due to a combination of several processes: loss of organic matter, higher pH, and an overall loss of poorly-crystalline Fe and Al compounds, in particular Al-organic matter complexes. [ABSTRACT FROM AUTHOR]

Prehistoric land use at the Guobei site and its relationship with the local environment are examined by applying OSL dating, micromorphological examination and geo-physical analysis. The majority of the OSL dates are of early to middle Holocene ages and are thus comparable to many OSL dates derived from other studies in the same region. According to the particle size analysis, silt-sized particles (2–60 μm) were predominant throughout the profiles examined. However, there are spatial and temporal variations of different size groups of particles throughout the profiles, which provide complementary information for the micromorphological interpretation. The total organic component of the samples examined through LOI is relatively high (all > 2%), with those of the overlying Holocene deposits higher than those of the underlying Malan loess by about 0.2%. Moreover, in all three profiles, the highest organic contents appear in the palaeosols, confirming that there was greater organic accumulation during soil formation periods. The groundmass of most slides collected from the early to middle Holocene horizons displays a very homogeneous pattern, while the abundance and distribution of different kinds of pedo-features, mainly including clay textural, calcitic, iron/Mn and crustal features, vary greatly temporally and spatially. These different lines of information demonstrate diversified pedo/sedimentary processes due to variations in micro-environmental conditions and cultural activities. We discuss the importance of a palaeo-ecological perspective, allowed by the geoarchaeological study, to an improved understanding of the relationship between loess, changing hydrology, prehistoric farming practice and land use, and long-term landscape change in the Chinese Loess area. This will thus contribute to a comparison on the dynamic relationship between loess and prehistoric farming in other regions of the world such as Europe and North America. [ABSTRACT FROM AUTHOR]

Comprehensive studies that examine the transfer of metals across soil-river bed sediment systems at the basin scale are scarce. An understanding of the distribution of metals among various fractions of soils and sediments within a basin is fundamental to understand their environmental behavior and, thus, to define watershed management plans. This study aims to determine the distribution of metals (Fe, Mn, Cu, and Zn) in topsoils under different land uses (cultivation, pastures, and forests) and river surface sediments in the upper Mero River basin (NW Spain) and to assess these metals' mobility and bioavailability in both environmental compartments to detect potential threats to crops and the water quality. Sequential extraction is used to fractionate the four metals into six fractions: soluble/exchangeable/specifically adsorbed, metals that are bound to Mn oxides, amorphous compounds, metals that are bound to organic matter, crystalline Al and Fe oxides, and residual metals (metals within the crystal lattices of minerals). The fractionation results for both soils and sediment indicate an abundance of metals in the residual fraction (except for Mn in soils) followed by relatively high percentages of oxide-bound fractions (mostly crystalline Fe oxides for both Fe and Zn, amorphous for Cu, and Mn oxides for Mn). On average, the Mn residual fraction in soils (30.2%) is only slightly exceeded by the Mn oxide fraction (34.7%). The land uses do not affect the sequence of metal-binding phases in soils, except for Mn, which is only slightly altered. The results also suggest that Fe, Mn, Cu and Zn in both soils and sediments are not readily mobile under current environmental condition and hence pose no threat to crops or the water quality. In overall terms, the mobility and bioavailability of the four metals (considering the sum of the three least mobile fractions, namely, organic matter, crystalline Al and Fe oxides, and residual) in the soils decrease in the following order: Mn > Cu > Fe > Zn. The same sequence occurs in the sediments, but the order between Fe and Zn is reversed. The soils and sediments that are studied cannot be considered polluted in terms of these metals because of their low levels and prevalence in the residual fraction, which is typical of contributions from natural sources and indicates the pedogenic/lithologic origin of these metals. [ABSTRACT FROM AUTHOR]