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This study assessed how land use change from native deciduous forest to tropical fruit orchards viz. guava ( Psidium guajava L. cv. Allahabad Safeda) and sapota ( Manilkara achras Mill. cv. Cricket Ball) under humid subtropics of India impacts the soil physical, chemical and biological properties. This study also validated whether the existing orchard management practices are adequate to maintain sustainable soil quality in different guava and sapota orchards established along a chronosequence by comparing the changes in soil quality attributes between native forest (considering as baseline ecosystem) and orchards. The land-use-induced change caused significant reduction in soil physical properties (12.0 to 31.4%), chemical properties (8.8 to 61.5%), earthworm density (32.0 to 58.7%), earthworm biomass (43.6 to 68.0%) and soil enzyme activities (8.8 to 54.1%) beneath orchards relative to native forest. There was significant increase in bulk density (12 to 14%), available-P (104 to 296%) and DTPA-Fe content (36.3 to 81.4%) in orchard soils. The combined results of the principal component analysis and the analysis of similarity revealed that stronger influencing factor of variability in soil quality attributes was in the order of land-use change > orchard age > orchard type. The soil deterioration index (SDI) values (ranged from − 35.3 to − 77.8%) for orchard soils relative to FS indicated that orchard soils were in the serious state of deterioration in terms of physico-chemical and biological properties; and the extent of deterioration of soil quality increased with the increase of orchard age (r = 0.57*, P < 0.01). Soil organic carbon showed a significant positive correlation with earthworm populations, soil enzyme activities and pH and these soil attributes were the important factors influencing SDI values. In conclusion, the progressive deterioration of orchard soil quality over time was the outcome of poor/inadequate management of soil organic matter (SOM) in guava and sapota orchards. As a result, there is a need for modification of existing SOM management practices. The reason is that they are not as efficient enough to help prevent the deterioration of soil quality in orchards over time, after conversion from baseline ecosystem. [ABSTRACT FROM AUTHOR]

This study considered the cropland-treebelt-desert system in the arid inland river basin as an entire continuum to investigate the soil water content variation and hydrological relation. For this objective, the volumetric soil water content and plant root distribution was measured to 300 cm depth along a cropland-treebelt-desert site at the oasis-desert ecotone in the Heihe River Basin, China. The results showed that the mean soil water content in the 0–200 cm layer was greater in the cropland (8.88%) than that in the treebelt (5.78%) and desert (4.37%) as a result of frequent irrigation events. However, the cropland had noticeably lower mean soil water content below 200 cm depth (14.27%), compared to treebelt (18.07%) and desert (17.30%) with deeper roots to suck up groundwater. The decline process in soil water content pulse of the cropland and treebelt after irrigation event could be well described by an exponential decay function, and the soil water loss rate was greater in the cropland (0.45–0.70%/day) than that in the treebelt (0.32–0.47%/day). The hydrological relation between treebelt and cropland in the upper soil layer was mainly occurred by treebelt root water uptake from cropland. The biomass of fine treebelt root extended into the cropland decreased logarithmically with the distance from the cropland-treebelt interface, which resulted in the smaller soil water content in the cropland with more proximity to the treebelt. The hydrological relation in the lower soil layer among cropland-treebelt-desert was caused by groundwater recharge, as cropland irrigation raised up the groundwater level to replenish the deep soil layer. The results indicated that the percolation in the cropland was an important water source for the growth of treebelt and desert plants. This study could provide scientific basis for land use pattern design and water resources management in the arid inland river basin. [ABSTRACT FROM AUTHOR]

Soil organic carbon (SOC) makes up a significant portion of the worlds terrestrial carbon stocks, and changes in land-use and land cover are changing soil carbon stocks. This study investigated the effects on soil organic carbon and some other soil properties of afforestation efforts using 15-year-old Pinus nigra Arn. Subs p. nigra (Black Pine) and Cedrus libani A. Rich (Lebanon cedar) on bare land in the semi-arid Nigde Akkaya dam watershed for erosion control and green belt creation. Soil samples were collected from three land use types (Black Pine planted, Lebanon cedar planted area and bare land) at two soil depths (0–10 cm and 10–20 cm) and replicated three times. Among the soil properties substantially affected by the change in land cover are soil organic carbon, bulk density, particle density, water holding capacity and total porosity. Generally, soil organic carbon was observed to increase after afforestation. Soil organic carbon (SOC) values were 1.09% and 1.13% in Black Pine and the Cedar area, respectively. These values were significantly higher than the values for the bare land soils (0.54%). For all types of land use, the amount of SOC in the soils decreased with depth. The amount of carbon sequestrated in Black Pine, Cedar and bare land sites at depths of 0–10 cm and 10–20 cm were 18.20 t/ha and 16.33 t/ha, 23.54 t/ha and 12.38 t/ha and 11.2 t/ha and 7.22 t/ha, respectively. The bulk density values obtained from the 0–10 cm layer soils in the afforested lands (1.53 g/cm 3 for Black Pine and 1.58 g/cm 3 for Cedar) were different from and lower than those in bare land (1.75 g/cm 3 ). Afforestation efforts led to an increase in water holding capacity (WHC) of the soil. Total porosity (TP) of the 0–10 cm layer soils increased after afforestation. This study indicated that on degraded land in a semiarid region, afforestation increased soil carbon sequestration, improved some soil properties and reduced erosion over a 15-year period. [ABSTRACT FROM AUTHOR]

Soil erosion by water and tillage are major drivers for soil degradation in the mountainous regions of NW Vietnam. Data on cumulative and recent erosion of bulk soil and soil organic carbon (SOC) are needed for carbon budgeting and to evaluate e.g. the impact of erosion on climate change, environmental services and subsequent socioeconomic consequences. Thus, the aims of the present study were (1) to quantify cumulative erosion and recent erosion rates of bulk soil (2) to quantify cumulative eroded SOC and (3) to estimate the proportions of water and tillage induced soil erosion after land use change from primary forest to continuous maize cultivation for up to 21 years. Soil erosion rates were determined by 137Cs and ranged from 12 to 89 t ha- 1 a- 1. A large part of the variation of cumulative bulk soil (R² = 0.79) and SOC loss (R² = 0.67) between the sites was simply but effectively explained by the ratio of site specific cumulative RUSLE LS factors to clay contents. The newly developed CIDE approach, which attributes SOC changes on steep slopes to either carbon input, decomposition or erosion, delivered 20% higher (up to 0.7 kg m- 2) and more reliable estimates on cumulative SOC erosion than a traditional approach, because CIDE considered the effects of soil profile truncation, decomposition and humification, which all affected SOC simultaneously to soil erosion. Tillage induced soil flux accounted for 38 ± 3 kg m- 1 per tillage pass, which was lower than found in similar studies. Soil erosion by water was higher than tillage induced erosion in middle and foot slope positions, accounting for 86 to 89% of total soil erosion. To prevent further soil degradation, erosion protection measures should be implemented. [ABSTRACT FROM AUTHOR]

• Litter and tree roots modify the proportion of soil aggregate fractions. • Extensive agriculture implies similar soil carbon storage than agroforestry. • Agroforestry increases the carbon associated with the small soil aggregate fractions. The land use sector currently represents ∼25% of the global greenhouse gas emissions, thus this human activity is having a huge impact on climate change. Semi-arid climate areas, which are widely distributed, are particularly influenced by such climate change. In these areas, land use changes have transformed the entire landscape and increased the greenhouse gas emissions. However, in semi-arid climate areas, the information on the effect of climate change is scarce and usually centred on one single type of land use. For the land uses (forest, agricultural and agroforestry) traditionally found in the semi-arid area in South Portugal, this study aimed to evaluate (i) the soil chemical (pH) and physical properties (bulk density and percentage of different soil aggregate fractions: 250–2000; 53–250 and <53 μm) and (ii) the carbon (C) storage in whole soil and each soil aggregate fraction in land with over 100 years of the same use. The results show that after >100 years with the same land use, C storage in the whole soil was similar in the plots with extensive agriculture based on the agroecology principles to that in the agroforestry plots. However, the concentration and storage of C in the microaggregates (53–250 μm) and the silt + clay soil fraction (<53 μm) were generally higher for the forest and agroforestry land uses than for the agricultural land use due to the tree effect. This C associated with the smallest soil fractions is very stable and is retained in the soil in the long term. In this context, agroforestry systems improve the soil C storage in the long term at the same time that agricultural production is allowed compared to the traditional forest systems. Therefore, the establishment and maintenance of agroforestry systems in the semi-arid climate areas is a sustainable land use for climate change mitigation. [ABSTRACT FROM AUTHOR]

• C-factor is estimated through a spatiotemporally exhaustive approach. • The monthly application accounts for the coefficient's intra-annual variability. • A novel LULC map of unprecedented detail was used to describe land distribution. • All monthly C-factor values are almost double than the mean annual stationary one. • The new C-factor displays high upscaling and reproducibility potential at EU scale. The cover management factor (C-factor) calculation requires the assessment of the intra‐annual spatiotemporal variability of biomass cover, owed to the natural growth cycle of vegetation and the impact of agriculture on land cover. However, this is frequently omitted, and the vegetation conditions are approximated by assigning constant values to static classified Land Use/Land Cover (LULC) maps, such as the Coordination of Information on the Environment (CORINE) Land Cover (CLC). Using as test site the Sperchios River catchment, Central Greece, this study introduces a new approach to estimate C-factor in a spatiotemporally exhaustive manner. The goal is to increase estimation accuracy in erosion modelling applications. The C-factor computations are performed on monthly scale, based on LULC maps that portray the basin's agricultural areas in unprecedented detail. The methodology involves the use of a biophysical index, namely Fraction of Vegetation Cover (F cover) and empirical literature data on crop types. F cover was developed from Sentinel-2 (S2) imagery in 10-m analysis. Such analysis (compared to the 300-m one provided by the EU) is a major improvement towards a more precise estimation of C-factor. The study identified the monthly C-factor fluctuation at basin scale, and the most susceptible months seasons at localities in terms of land cover/soil loss potential. The higher C-factor values were acquired in October and the lower in May. Mean annual (numerical) C-factor complies with the value of July. All monthly values are significantly higher – almost double – than the mean annual stationary one. The revealed patterns would not have been detected in a lower temporal (e.g., annual) resolution without the incorporation of vegetation density seasonality. The study shows high reproducibility and upscaling potential, as the utilized datasets are available in all European Union (EU) Member States, having similar structure, thus they can be harmonized towards a unified continental approach. [ABSTRACT FROM AUTHOR]

• Evaluation of different land use on SOC stock under climate change scenarios. • Both decreases and increases of SOC stocks would be possible in the future. • Under high emission scenario SOC stock increases to 6.23 million tons in cashew LUS. • RothC Model indicated cashew plantations as the most prominent sink of SOC storage. • Promotion of agroforestry systems are imperative to improve SOC storage. Soil organic carbon (SOC) is one of the significant soil components influencing soil functions and soil processes. However, little is known about the impact of land-use change on SOC dynamics on coastal agroecosystems. We, therefore, simulated the impact of land use on SOC stock using RothC model under different climate change scenarios. In the present study, natural forest and pasture lands are the native land uses, while cashew, arecanut, and coconut plantations were established about 70–80 years ago from the natural forest. Measured SOC stocks were significantly higher in cashew and forest land uses (109.5 and 88.6 t C/ha) and much lower in coconut, arecanut and pasture lands (64.1–71.0 t C/ha). The study showed that under projected climate change conditions in Goa state and depending on emission scenarios, both decreases and increases of SOC stocks would be possible. By the end of the century, SOC stock in cashew would decrease by 4.3 t C/ha (RCP 4.5) and increase by 2.4 t C/ha (RCP 8.5), in coconut the SOC change was negligible (0.2 t C/ha) in RCP 4.5 while increased by 3.2 t C/ha in RCP 8.5. Arecanut, pasture and forest land uses showed a marked SOC decrease in RCP 4.5 (ranging from 5.2 to 5.4 t C/ha) and negligible positive (0.6–0.7 t C/ha) or negative (0.6 t C/ha) changes in RCP 8.5. Overall, the model indicated cashew plantations as the most prominent sink of SOC storage, while coconut and pasture are not viable sinks of SOC in the study area. We suggest promoting cashew, arecanut, and coconut land use system integrated with tree components and pasture to improve the SOC storage and other ecosystem services in the coastal agroecosystem. [ABSTRACT FROM AUTHOR]

• Pristine and agricultural top soils from a humid region (484170 km2) were surveyed. • Agriculture caused a 25–36% soil organic carbon (SOC) depletion (dSOC). • The main factor controlling dSOC was the SOC in pristine soils (SOC PRIS). • The SOC PRIS was determined by clay content, precipitation, and temperature. • Soils with a high soybean frequency in the crop rotations presented greater dSOC. The conversion of native grasslands into croplands with a high frequency of soybean (Glycine max L.) in crop rotations has diminished soil organic carbon (SOC) stocks in the Argentinean Pampas. The aims of our study were to determine the amount of SOC lost due to cultivation (dSOC) and to assess the main factors (land use, climate, and soil properties) associated with dSOC. We took paired topsoil samples (0 to 20 cm) from arable and pristine soils (n = 465) and used a path analysis approach to evaluate the direct and indirect effect of different variables on dSOC. The selected variables were SOC in pristine soils (SOC PRIS), clay content, carbon input (C input), relative soybean harvested area (Sb %), and mean annual precipitation and air temperature (PP and Temp, respectively). The percentage of sites with SOC < 20 g kg−1 was 29% in pristine soils and 66% in arable soils. The dSOC ranged from 0 to 82 Mg ha−1. Depending on the area, dSOC represented 25 to 36% of SOC PRIS stocks. The path analysis explained 60% of the dSOC variation, and the main factor controlling dSOC was SOC PRIS (by direct effect and indirect effects through clay, PP, and Temp), followed by Sb %. The Sb % depended on the productive potential of the area (soybean yield) which was associated with Temp and PP. As a conclusion, in the analysed temperate and fully humid environments, soils with greater SOC PRIS and high soybean frequency in the crop rotations presented a greater SOC depletion after conversion to agriculture. This information will be valuable when developing models to predict current and future SOC stocks. [ABSTRACT FROM AUTHOR]

[Display omitted] • Wet-dry cycles reduced SAS at high flooding intensity sites in the riparian zone. • Wet-dry cycles enhanced soil respiration in the riparian zone. • Wet-dry cycles weakened the carbon sequestration of soil aggregates in the riparian zone. Increasing the frequency and magnitude of wet-dry cycles can fundamentally affect soil carbon (C) turnover. However, the response of soil respiration to intense wet-dry cycles in the riparian zone is unclear. Hence, this study aimed to identify whether soil respiration and soil aggregates in different land use types were affected by different flooding intensities in the riparian zone of the Three Gorges Reservoir, China, and determine the responses of soil organic carbon (SOC) sequestration by soil aggregates to wet-dry cycles in the riparian zone. At the Wuyangwan of the Pengxi River, a tributary of the Yangtze River in the Three Gorges Reservoir, soil respiration and soil aggregates were investigated at different elevations of the riparian zone with representative land use types, namely a cornfield (173C) and a paddy field (173P), both at an elevation of 173 m above sea level, and two paddy fields, 168 m and 163 m above sea level (168P and 163P). The results showed that soil aggregate stability increased (e.g., the mean weight diameter increased by 38% and 18% for 173C and 173P, respectively) in the low flooding intensity sites and decreased (e.g., the mean weight diameter decreased by 44% and 33% for 168P and 163P, respectively) in strong flooding intensity sites after four wet-dry cycles in the riparian zone of the Three Gorges Reservoir. Moreover, the wet-dry cycles increased soil respiration (i.e., the soil respiration increased by 36%, 218%, 129%, and 31% for 173C, 173P, 168P, and 163P, respectively). In addition, soil aggregate stability had a direct negative effect on soil respiration (namely, the mitigation of CO 2 emissions), and the negative effect weakened after four intense wet-dry cycles (pathway coefficient was −0.76 in 2014 and −0.28 in 2018). Thus, the carbon sequestration of soil aggregates was weakened in the riparian zone. The size of the soil aggregate fractions and their organic carbon contents directly or indirectly affected soil respiration. Most notably, the proportion of microaggregates and their associated nitrogen and organic carbon contents strongly influenced soil respiration. Finally, from the perspective of maintaining soil aggregate stability and SOC sequestration, we suggest that agricultural activities should be prohibited in areas with high flooding intensity in the riparian zones. [ABSTRACT FROM AUTHOR]

• 91.72% of the soil in Xunwu County exhibited an acidification trend over 35 years. • Main conversion modes were cropland and forest changed to garden and other land. • Soil pH variability and land use type correlated in 1984 and 2018 (P < 0.01). • Land use change altered the influence of factors on soil pH variability. Abnormal changes in soil acidity and alkalinity impact regional food security and sustainable development of terrestrial ecosystems, especially under land use change. The regulation of soil acidity and alkalinity requires a clear understanding of soil pH variability and its influencing factors under regional land use change. This study explored the patterns of soil pH variability under land use change between 1984 and 2018 in a red soil hilly region (Xunwu County, Jiangxi Province) in southern China. We identified the key factors influencing regional spatiotemporal variability in soil pH and analyzed the response of soil pH variability to land use change. The results showed that the mean pH values of surface soil samples in 1984 (n = 595) and 2018 (n = 580) were 5.35 and 5.05, respectively. The soil pH change between the two periods ranged from −0.91 to 0.32, with a mean value of −0.30. In total, 91.72% of the study area showed an acidification trend from 1984 to 2018. The spatiotemporal variability in soil pH was influenced by elevation, slope, distance to rivers, changes in distance to roads, and changes in the nitrogen fertilizer application rate. The main land use conversion modes were cropland and forest transferred to garden and other land. The soil pH decreased in 15 of 16 conversion modes of cropland land, garden, forest, and other land, whereas a pH increase of 0.32 occurred under conversion from cropland to garden. Changes in distance to roads, changes in the nitrogen fertilizer application rate, and slope played a dominant role in soil pH variability under land use change. This study provides fundamental data for the formulation of soil acidity and alkalinity control measures, which in turn contributes to regional improvement of agricultural production stability and sustainable development. [ABSTRACT FROM AUTHOR]

• Irrigation and long-term cultivation (26 years) did not affect SOC stock. • SOC dynamics in the subsoil is particularly vulnerable to irrigated agriculture. • Land use favors large amounts of aliphatics products along the soil profile. • Management changes microbiological parameters, especially bacterial communities. • Changes in the bacterial community suggests alterations in groups of subsoil C. Changes in the global water cycle affect irrigation requirements and soil processes as well as the structure of soil microbial communities and function and the carbon (C) balance. The microbial structure and C sequestration under land use changing scenarios are rarely studied in the semi-arid region of Brazil. Here, we assessed the effects of land-use changes (irrigation and cultivation) on C storage in the soil and the structure of total bacteria (16S rRNA gene profile) and fungus (18S rRNA gene profile) at soil depth. We evaluated two soil profiles in the semi-arid region in northeastern Brazil. Profile P1 in an area with long-term irrigation (1,500 mm of water per year) and cultivation (small-scale farming systems, mainly with subsistence crops, which is a frequent land use system in the region of irrigated soil) for about 26 years. Profile P2 under natural conditions with 400 mm of water per year of rainfall (rain-fed hyperxerophilic Caatinga). Land-use changes showed a small influence on C storage; however, the changes strongly affected the soil organic matter (SOM) quality as well as the bacterial and fungal community structure, indicated by higher contents of labile-C and microbial biomass along with lower C-CO 2 emission. The relatively large amounts of aliphatic groups in the soil surface and subsurface in the cropped system (P1) suggested enrichment of methylene structures and probable increase of microbial-derived compounds. Methoxylic and aromatic groups tend to increase at depth (Bt horizon) indicating that the subsoil C responds to soil management changes. The structures of the bacterial community are distinct at depth in P1 and more similar at depth in P2. On the other hand, the structures of the fungal communities are more similar at depth in P1 than in P2. Furthermore, the irrigated agriculture also presented a carbon management index greater than 140% in most horizons, indicating that the soil management system did not cause soil degradation. [ABSTRACT FROM AUTHOR]

The Revised Universal Soil Loss Equation (RUSLE) was used in conjunction with geographic information system (GIS) mapping to determine the influence of land use and topography on soil erosion on the Loess Plateau during the period 2000 to 2010. The average soil erosion on the Loess Plateau was 15.2tha-1yr-1 in 2000-2010. Most of the Loess Plateau fell within the minimal and low erosion categories during 2000 to 2010. Forest, shrub and dense grassland provided the best protection from erosion, but the decadal trend of reduced soil erosion was greater for the lower vegetation cover of woodland and moderate and sparse grassland. Midslopes and valleys were the major topographical contributors to soil erosion. With slope gradient increased, soil erosion significantly increased under the same land use type, however, significant differences in soil erosion responding to slope gradients differed from land uses. The results indicate that the vegetation restoration as part of the Grain-to-Green Program on the Loess Plateau has been effective. [ABSTRACT FROM AUTHOR]

The soil carbon reservoir is the largest carbon reservoir in terrestrial ecosystems and consists of soil organic and inorganic carbon stocks. Previous studies have mainly focused on the soil organic carbon (SOC) stock, and limited information is available about the soil inorganic carbon (SIC) stock. The Chinese Loess Plateau (CLP), which is located in the arid and semi-arid region of China, is an important inorganic carbon reservoir, with a thick soil layer that is rich in calcium carbonate. However, there are few reports on the SIC stock and its spatial distribution in this region. In the current study, the SIC densities and stocks for various soil types and land use patterns were evaluated based on 495 profiles with 2470 soil samples across the CLP, which were collected from the Chinese Second National Soil Survey. The results showed that in the top 1m of soil across the CLP, the average SIC density is 17.04kg/m², and the total SIC stock is approximately 10.20 Pg C (1 Pg=1015g). The SIC stock of the CLP accounts for approximately 18.4% of the total SIC stock throughout China. The average values of the SIC stock in the 0-20, 20-50 and 50-100cm depths of the CLP are 2.39, 2.92 and 4.89 Pg, respectively. Under different land use patterns, the order of the average SIC density is farmland≈grassland > forest in all soil layers. For the various soil types, the SIC density in the 0-100cm layer is the highest in alkaline soil and lowest in subalpine meadow soil, whereas the SIC stock is highest in loessial soil, eolian sandy soil and sierozem, and the lowest in subalpine meadow soil. These differences are largely a result of the area occupied by each soil type and the climate conditions. The results of this study provide basic information about carbon reservoir in China and contribute to our understanding of the SIC stock on the CLP as it relates to the carbon balance of terrestrial ecosystems. [ABSTRACT FROM AUTHOR]

[Display omitted] • The soil quality changed as a result of the landscape pattern alteration. • The land use patch density was among the most important landscape properties affected the soil quality. • The soil quality had significant spatial relationships to elevation, slope, and NDVI. • The soil quality level was higher in the forest land use compared to farmland and rangeland. The soil quality is the inherent capacity of soils to function in an ecosystem, which depend on soil properties and change under the influence of landscape patterns. This study aimed to evaluate the soil quality in the Shoor River basin, southwestern Iran, by using the soil quality indicators based on two approaches, i.e. , minimum data set and total data set. The spatial relationships of the soil quality to landscape pattern properties (e.g. , density, dominance, shape, aggregation, and diversity of patches) were also analyzed through the exploratory regression in the Arc GIS 10.5 software in addition to the effects of land use, elevation, slope, and normalized difference vegetation index (NDVI) on the soil quality. The results indicated that the soils of northern and eastern regions of the study area had higher levels of quality than those of southern and western regions. Very low and very high of soil quality covered<15% (43413 ha) and 20% (56759 ha) of the basin, respectively. The hot spots of soil quality were observed in the eastern and northern regions of the study area whereas the cold spots of soil quality were seen in the southern and western regions. According to the findings, the soil quality level was higher in the forest land use compared to farmland and rangeland. The results confirmed that the soil quality had significant spatial relationships with elevation, slope, and NDVI (0.12 < r < 0.35, p-value < 0.1). Moreover, the soil quality had significant positive spatial relationships with aggregation and dominance of patches (0.40 < r < 0.62, p-value < 0.05), whereas it had significant negative spatial relationships with the density and diversity of patches (0.35 < r < 0.63, p-value < 0.1). However, there were no significant relationships between the soil quality and the shapes of patches. This study confirmed that the soil quality would vary in different landscape patterns and that it might change as a result of development and anthropogenic activities. [ABSTRACT FROM AUTHOR]

• Driving factors of SOC and total N were explored in 28 lucerne fields. • The SOC and total N were mainly explained by soil resources. • Soil P, moisture, and altitude were the key factors affecting SOC and total N. • Plant species diversity positively affected SOC and total N contents. • A strong interaction effect was observed among topography, vegetation and soil on SOC. Lucerne (Medicago sativa L.) is one of the most successfully introduced species for revegetation on the Loess Plateau of China and provides important ecosystem services. However, the driving mechanism of soil organic carbon (SOC) and total nitrogen (TN) in lucerne grasslands remains unclear. This study explored the controlling factors of SOC and TN in lucerne grasslands in the semiarid Loess Plateau. A total of 112 quadrats were employed in 28 lucerne fields. Vegetation characteristics, topographic factors, and soil properties at a 0–20 cm depth were measured in each quadrat. The SOC and TN contents increased with altitude and showed positive correlations with species richness, aboveground biomass of native plants, soil moisture, soil inorganic nitrogen, total soil phosphorus (P), and C:P and N:P ratios. Variations in SOC and TN contents were mainly attributed to soil resources, followed by the interaction of topography, vegetation and soil. Soil P, soil moisture, altitude, and native plant species were the main factors controlling SOC and TN contents in these lucerne grasslands. Results suggest that specific abiotic (soil P and moisture) and biotic (plant species diversity) factors controlled SOC and TN in semiarid lucerne grasslands. These factors should be included in SOC and TN evaluation models to predict the future terrestrial ecosystem carbon and nitrogen dynamics. [ABSTRACT FROM AUTHOR]

• Pollen records reconstruct the late Holocene land use and vegetation dynamics. • Human land use has impact on the regional vegetation and landscape since 50 CE. • A large-scale transformation of the landscape occurred since 750 CE. • Late Holocene vegetation changes were mainly controlled by temperature. Knowledge of the past interactions between climate and human land use is essential for understanding the possible future relationships between global change and human societies. In this study, we used pollen and other multi-proxy analyses of the sediments from Xingyun Lake in central Yunnan Plateau to reconstruct the history of land use and ecosystem dynamics during the last 3,200 years. The pollen results indicate that the vegetation became more open gradually and many secondary forests began to grow during the last 100 years. During the Medieval Climatic Anomaly (MCA), the vegetation is dominated by broad-leaved trees, while during the Little Ice Age (LIA) the broad-leaved trees declined but Picea/Abies expanded. Human land use has impacted on the regional vegetation and landscape since 50 CE; large-scale human land use occurred after 750 CE. The sediment accumulation rate (SAR), pollen record, and 14C age offsets reveal that soil erosion is well correlated with human activity and changes in vegetation cover. Before 750 CE, soil erosion was probably limited, but after 750 CE it increased drastically as a result of human activity, and then decreased during the last 100 years. According to the results of the redundancy analysis (RDA), we conclude that climate had an important impact on the regional vegetation, and the late Holocene vegetation changes of Xingyun Lake catchment were mainly influenced by temperature. [ABSTRACT FROM AUTHOR]

[Display omitted] • - Landscape characters and place names are highly connected. • - Place names are a kind of verbalisation of the distinct landscape characters. • - Accurracy and validity of place names have been still pricesely expressive in rural landscapes. • - Interpretation of place names offer readily available, multilayered form of knowledge. Place names are a linguistic form that people attach to the landscape. Rural landscapes are maybe one of the most refined cultural manifestations revealing a fundamental effort for human existence and locating their actions through place names. In this research, place names were used as a means to explore rural landscape characters of the Serik district in the Turkish Mediterranean. A total number of 1243 place names were subcategorised in four large character groups: natural features, land use, cultural, and visual features and were further analysed into twenty indicative landscape characteristics. The results showed that characteristics of the rural landscape in Serik were dominated by two main components: biophysical features as a response to the natural environment and the position of a locality in relation to maintenance of local livelihoods. In conclusion, the accuracy and validity of place names is still quite precise in the definition of the characters in rural landscapes where intact human-nature relations are unique but whose characters have been under the pressure of fragmentation. Here, the knowledge of multi-layered forms of place names offers a readily available rich inventory that can be applied to the planning and management of rural landscapes, particularly in the absence of other biophysical and cultural data. [ABSTRACT FROM AUTHOR]

[Display omitted] • Soil C, N and P stoichiometric ratios were influenced by land use types under different erosion conditions. • Soil C, N and P stoichiometry changed more significant under SE condition. • Higher P stocks and lower C:N:P stoichiometric ratios were detected in PD and UL than in WL. • Land-use type affected C, N and P stoichiometry mainly by changing soil porosity and texture. Irrational land-use can accelerate soil erosion by deteriorating soil structure and depleting soil nutrients, especially profoundly alter soil organic carbon (C), total nitrogen (N), total phosphorus (P) contents and stocks. However, it remains unknown how soil C, N, P stoichiometry patterns are affected by land-use type and soil erosion. This study was carried out to examine the soil C:N:P stoichiometry patterns in woodland (WL), upland (UL), and paddy (PD) at soil depths of 0–10, 10–20, and 20–30 cm under collapsed gully erosion (CGE) and sheet erosion (SE) conditions in lateritic red soil region. Compared to WL, C content and stock decreased by 19.1–31.9 g kg−1 and 12.8–31.7 Mg ha−1, but P content and stock increased by 4.9–7.4 g kg−1 and 6.7–9.9 Mg ha−1 in UL soil at 0–30 cm, resulting in a decrease in C:N, C:P and N:P ratios by 8.6–14.8, 23.0–28.6 and 0.7–1.0, respectively. In addition, N, P contents and stocks increased by −0.04–1.8 g kg−1, 4.1–10.5 g kg−1 and 1.8–1.1 Mg ha−1, 7.0–8.2 Mg ha−1 in PD soil at 0–30 cm, resulting in a decrease in the ratio of C:N, C:P and N:P by 8.1–10.6, 20.7–26.0 and 0.6–0.8, respectively. Furthermore, C, N, P contents, stocks and C:N ratio in UL and PD soils were more significant under SE than CGE condition with, while it was opposite trend in WL at 0–30 cm depth. Soil C, N, P contents and stocks significantly decreased with soil depth, while no significant changes were detected on their stoichiometric ratio. Soil porosity and texture had significant contribution to C, N and P stoichiometry by PCA and RDA analysis. Our results demonstrate that the intensive agricultural practices changing soil porosity and texture under SE condition led to more pronounced differences of soil C, N, P and their stoichiometric ratios in lateritic red soil region. [ABSTRACT FROM AUTHOR]

• Macropore characteristics were quantified as a function of land use and tillage. • Land use and tillage influenced pores in surface soils (0–100 mm) substantially. • Effect of land use and tillage on pores of different sizes was not similar. • Larger soil cores can help capture variability in soil macropore characteristics. Quantification of soil macropores is important to enhance our understanding of preferential flow behavior in soils. However, knowledge of 3D soil architecture for different land uses in a continental climate region is limited. X-ray computed tomography is a novel technique that can provide valuable information about the 3D features of the soil, such as connectivity, length density, and tortuosity, that largely control water flow through the macropores. In this study, X-ray computed tomography and image analysis were employed to quantify the soil macropore characteristics from four combinations of different land uses and soil tillage practices - native grassland (Nat), alfalfa (Alf), conventional till-corn (CT), and no-till corn (NT) systems. A total of 15 undisturbed soil columns, 150 mm in diameter and 500 mm in length, were collected from different fields. The macropore characteristics were distinctively different for different land use and tillage treatments, especially near the surface depth (top 100 mm). The soil macropores under CT were highly connected and concentrated mostly in the surface soil layer. In contrast, macropores under NT were larger and had well-developed pore networks. The Alf field had relatively larger and more vertically oriented macropores as compared to the Nat field. Relatively larger macroporosity and a higher number of macropores were observed in the surface of soils collected from Nat field. Macropore characteristics were mostly similar between Alf and NT treatments. The results of this study facilitate quantitative evaluation of 3D soil macropore features with significant implications for non-equilibrium flow prediction and contaminant transport modeling in soils. [ABSTRACT FROM AUTHOR]

[Display omitted] • Pond variables were analyzed in three regions: two mediterranean and one tropical. • Regional and local, natural and anthropogenic factors influenced the water bodies. • Clear differences between mediterranean and tropical ponds were detected. • Mediterranean ponds presented high environmental heterogeneity. • Water chemistry, vegetation and land use differed the most between regions. Temporary ponds are distributed worldwide, providing significant ecological services. Their limnological features are influenced by a set of regional (mainly climate) and local (natural or anthropogenic) factors. To evaluate the differences in their ecological functioning in distant geographic regions, we analysed the main features of 90 temporary ponds located in three distinct areas: two mediterranean-climate regions (Eastern Iberian Peninsula and Central Chile) and a tropical setting in Costa Rica. Each pond was surveyed thrice during the hydrological cycle of 2017–2018, and five sets of parameters were obtained: limnological, hydrogeomorphological, biotic, landscape and climatic variables. Through multivariate analyses, we determined the environmental heterogeneity of each region and the main environmental differences among them. As expected, hydrogeomorphological factors did not differ between regions, but climate variables showed marked differences between the tropical and the two mediterranean regions. We also detected clear differences between mediterranean and tropical ponds in terms of their mineralization patterns (mainly conductivity and alkalinity), natural vegetation cover and land use. Despite the regional similarities between mediterranean regions, some strong differences were found concerning vegetation cover, nutrient concentration and trophic state, probably associated to human activities (agriculture and extensive stockbreeding). [ABSTRACT FROM AUTHOR]

• Landuse and climate change impact on sediment yield was assessed in Songkhram River Basin. • Songkhram River Basin is expected to be warmer and drier in future. • Climate change impact on sediment yield is expected to be lesser than climate change. • Sediment yield is expected to decrease with the combined impact of landuse and climate change. The Songkhram River Basin (SRB) is the second largest river basin in Northeast Thailand. The nourishment of the SRB community mainly depends on water resources, especially fisheries. However, changes in land use and climate are causing problems to the livelihood of the SRB community. For sustainable water resources management, an integrated impact assessment of climate and land use change on sediment yield is crucial. Therefore, this study quantifies the combined impact of climate and land use change on sediment yield using the Soil and Water Assessment Tool (SWAT). An ensemble of three Regional Circulation Models (RCM) from Coupled Model Intercomparison Projects (CMIP5s) was used for future climate projection under representative concentration pathways RCP 4.5 and RCP 8.5. The projected climate shows a rise in both minimum and maximum temperature over 4.7 °C and a fall in precipitation over 6% by the 2080s. For land use, two scenarios, namely; economic and conservation, were developed using the land use change model, Dyna-CLUE. The simulated outcomes illustrate that, in the future, climate change is projected to cause a decrease in flow by 42.8% and 51.7% under RCP 4.5 and RCP 8.5, respectively. On the other hand, the land use change is expected to increase the sediment yield in future. It is responsible for an increase of 2.3% and 7.1% under economic scenarios, a decrease of 0.9%, and an increase of 3.9% under the conservation scenario, respectively, under RCP 4.5 and RCP 8.5. Overall, climate and land use change play a contrasting role in the study area. The combined impact of both results in a decreasing trend of sediment yield by 40.5% and 44.6% under the economic scenario, and 45% and 47.8% for the conservation scenario under RCP 4.5 and RCP 8.5, respectively. [ABSTRACT FROM AUTHOR]

• NPS TP township loads for different cultivated land use-patterns were simulated. • The average GGE TP load was the highest, and the GES and GOCS loads were similar. • The NPS TP load with different cultivated land-use patterns was heterogeneous. • The correlations varied between the cultivated land uses and NPS TP loads. • Cultivated land-use classification can clarify the NPS pollution driving mechanism. Non-point source (NPS) pollution caused by unsustainable cultivated land use is becoming more severe. It is therefore critical to understand the complex relationships between cultivated land use forms and NPS pollutant loads from the perspective of integrated cultivated land use. This study used the cultivated land use pattern to integration represent the various forms of cultivated land use, and constructed a model to estimate NPS pollutant outputs at an administrative-region scale. This model was used to quantitatively simulate the NPS total phosphorus (TP) loads of townships with different cultivated land-use patterns in Chaohu Lake Basin, China, since 2000. The relationships between the TP loads and the different cultivated land use patterns were then assessed to clarify the corresponding function mechanisms and provide scientific support for effective NPS pollution controls. The cultivated land-use patterns of the townships in Chaohu Lake Basin were classified as suburban compound operations (SC); grain and economical crop scale operations (GES); grain and economical crop extensive operations (GEE); and grain, oil, and cotton scale operations (GOCS). The TP loads of townships with various cultivated land-use patterns were significantly different. The average TP load of GEE pattern townships was the highest (5.39 kg ha−1a−1), which was 1.85 times the lowest value of the SC pattern townships. The TP loads of GES and GOCS pattern were similar (3.52 kg ha−1a−1 and 3.19 kg ha−1a−1, respectively). The heterogeneous NPS TP loads are due to the face that cultivated land-use forms exhibit different marginal inhibition/promotion effects on NPS pollutant outputs with different patterns. Different correlations and significances were observed between various cultivated land-use form factors and NPS TP loads with different patterns. Therefore, accurate classifications and recognition of cultivated land-use patterns can be utilized to clarify the function mechanism between cultivated land use and NPS pollutant loads. [ABSTRACT FROM AUTHOR]

• Vegetation was the main landuse change type, with an increase of 46.65% in 1964–2018. • Connectivity index (IC) was spatially variable and lower in the main gully. • IC was impacted by re-vegetation, terrace, and dam land in descending order. • Connectivity variations were quantitatively related to sediment yield reduction. The spatial distribution of landscape pattern in catchments has a great impact on the potential sediment detachment and transport capacity. In this study, a sediment connectivity model was applied to evaluate the effect of the spatial distribution of landscape pattern on the sediment transfer in a typical catchment on the Loess Plateau in China based on land use and topography data in 1964, 2004, and 2018. Thereupon, the impacts of changes in different land use types on sediment connectivity and those of sediment connectivity changes on sediment yield reduction in the catchment were quantified. The results showed that (i) grassland and slope farmland were the main land use types in the catchment, and a decrease of the slope farmland area and an increase of the vegetation coverage occurred from 1964 to 2018; (ii) compared with 1964, most parts of the catchment in 2004 and 2018 had an overall lower connectivity index (IC); (iii) the distribution of sediment connectivity presented obvious spatial variability. The hill slopes and tributary gullies tended to be relatively well connected, and the main gully was highly disconnected. Scenario simulations showed that the potential sediment reduction effect was 20%−45% for vegetation, and <10% for terraces or dam lands in 1964, 2004, and 2018. The effect of impounding sediment by check dams was not included in IC calculation in this study, and it was found that the sediment impounded by these dams accounted for about 16% of sediment discharge reduction during 1995–2004 and 1% during 2005–2018. The IC reduction was responsible for 84% of the decrease of sediment discharge during 1995–2004 and 99% during 2005–2018, reflecting that vegetation restoration and terrace construction on slopes has become the main drivers for reducing IC value and sediment yield. [ABSTRACT FROM AUTHOR]

• Successful prediction of weathering indices with MIR spectroscopy. • Land use explains minor part of variations in soil thickness and weathering degree. • Soil thickness and weathering degree mainly determined by slope gradient. • Locally high erosion does not necessarily result in changes at landscape-scale. Land use and land cover changes (LUCC) can drastically alter various components of the critical zone, including soil thickness and soil chemical weathering processes. Often these studies, however, tend to focus on extreme cases, not representing what actually happens on average at larger, regional scales. Here, we evaluate the impact of LUCC on soil thickness and soil weathering degree at the regional scale, where we use soil spectroscopy to derive weathering indices. In a subtropical region in Southern Brazil, we collected calibration/validation soil samples (n = 49) from 4 different locations for which we measured the mid-infrared (MIR) spectral reflectance and 3 soil chemical weathering indices: chemical index of alteration (CIA), the total reserve in bases (TRB), and the iron ratio (Fe d /Fe t). We used partial least square regressions on this calibration/validation dataset to relate the MIR spectra of the soil samples to these weathering indices, resulting in good calibration relationships with R2 values of 0.97, 0.91 and 0.84 for CIA, TRB and Fe d /Fe t , respectively. Applying these relations to MIR spectra of regionally collected soil samples allowed us to calculate soil weathering degrees for a large number of soil samples (n = 229), without requiring costly and time-consuming chemical analyses. We collected these soil samples at 100 mid-slope positions: 50 under forest and 50 under agricultural land use. Land use explained only a minor part of the variation in soil thickness and weathering degree. Thus, while local water and tillage erosion rates might be considerable after deforestation, this has not led to significant reductions in average soil thickness and has not affected soil weathering degree. Slope gradient is the main factor influencing the spatial variability in soil thickness and weathering degree on mid-slope sections in our study area. Human activities over the last century did not fundamentally alter these patterns. [ABSTRACT FROM AUTHOR]

• Landscape-scale spatial variability of SOC in a temperate grassland was analyzed. • SOC presents strong and moderate spatial autocorrelation at two layers respectively. • Topography and land use have independent and combined influences on SOC. • Wind erosion and deposition both can alter SOC and increase its spatial variability. • The influence of wind erosion on SOC should be considered in carbon accounting. Understanding the spatial variability of soil organic carbon (SOC) and its main influencing factors is crucial for sustainable land use management and climate change mitigation. Existing studies mostly focus on the influence of environmental factors on the spatial variability of SOC, while little attention has been paid to the effects of wind erosion which has important influences in arid and semi-arid landscapes. In this study, spatial variability of SOC content at landscape scale and its main influencing factors were analysed at 0–1 cm and 1–6 cm in a typical temperate grassland. Results show that SOC content ranges from 0.45% to 4.11% and is higher at 0–1 cm. SOC presents strong and moderate spatial autocorrelation at 0–1 cm and 1–6 cm, respectively. SOC is high in part of the hilly area, and low in the west plain and southeast undulation. Elevation and vegetation coverage have significantly positive effects on SOC. SOC varies with land uses with the order that arable land (AL) < heavily grazed grassland (HG) < moderately grazed grassland (MG) < lightly grazed grassland (LG) < ungrazed grassland (UG) at 0–1 cm and AL < HG < MG < UG < LG at 1–6 cm. Under the same land use, SOC is generally the highest in the flatland at both layers and lowest in the leeward slope at 0–1 cm and the windward slope at 1–6 cm, respectively. Wind erosion and deposition can both alter SOC content and increase its spatial variability. SOC is high in areas without wind erosion and deposition and decreases with erosion and deposition rates due to the selective erosion and remote region sourced deposition materials which generally have low SOC. Such effects have important influence on land productivity, global carbon cycle and climate change, and it could not be neglected in carbon accounting. [ABSTRACT FROM AUTHOR]

• Land-use conversion was conducted to assess its effect on the changes of soil 13C. • Significant changes in δ13C were observed at the 0–10 cm depth after conversion. • SOC stock was largely increased in the 20–40 cm layer for grassland and forest. • New SOC was formed greater in grassland than in forest above 60 cm soil depth. Soil organic carbon (SOC) content and its 13C natural abundance along soil profile are sensitive to the changes of land use since these changes alter external carbon (C) inputs and belowground C turnover processes. A study was conducted to investigate how the conversion of cropland to forest, grassland or bare land (no vegetation) affect the distribution of SOC and its 13C values in 200-cm soil profiles. After 28 years of land conversion, the cropland that was remained as cropland (treated as control) had a significantly higher δ13C value than the bare land, grassland or forest at the top 10 cm soil depth. Regardless of the land use type, the mean soil 13C values in the subsurface soil layers depleted and δ13C signature decreased by 1%−5% compared with the top 10 cm soil layer, while the corresponded SOC content decreased by 3.5% to 91.2% as soil depth went down deeper. The SOC stock in the 0–200 cm profile was 16% and 12% higher in the grassland and forest, respectively, than in the control. The conservation of cropland to grassland and forest largely increased the SOC stock in the 20–40 cm soil layer compared with the control. The newly formed SOC was higher in the grassland than in the forest, and accounted for 15.4% and 9.7% of the SOC stock in the soil depth of 0–60 cm in the grassland and forest, respectively. Soil δ13C values and SOC contents were negatively correlated with pH and clay content, while they were positively correlated with nitrogen and C/N ratio along the soil profile. We infer that the conversion of cropland to forest or grassland is a beneficial practice for SOC storage, especially in the 0–60 cm depth. Such conversion has little impact on the SOC turnovers in deep soil layers during the study period. [ABSTRACT FROM AUTHOR]

• Dynamics of vegetation coverage and its response to LUCC were explored. • The influence of LUCC on NPP in Yangtze River basin was assessed. • The relative contribution of LUCC and climate change was distinguished. • The combination effect of LUCC and climate change resulted in total NPP increase. Land use and land cover change (LUCC) will directly affect the types, structures and functions of ecosystems, and then have important impact on vegetation net primary productivity (NPP). The evaluation of the spatio-temporal dynamic changes of LUCC and regional NPP, and assessing the impact of LUCC on NPP can facilitate the corresponding management of different environmental types of regions and provide scientific guidance for scientific development of ecological resources, and better restore and control the ecological environment, thus promoting rapid economic development. Using MODIS normalized difference vegetation index (NDVI) data and meteorological data from 2001 to 2018, combined with Carnegie-Ames-Stanford model (CASA), the regional NPP was estimated, and the influence of LUCC on NPP in Yangtze River basin from 2001 to 2018 and its causes were analyzed. The results showed that the area with a land cover and land use change account for 10.98% of the total study area in the past 18 years, and the most important change is the transformation from grassland to forest and grassland to crop/natural vegetation mosaic (NVM). Forests, wetlands, crop/natural vegetation mosaic, low vegetation cover (LVC) land, urban, and water bodies are growing. The forest land area increased the most and that of grassland decreased the most. Total NPP has increased by 53887.51GgC in the past 18 years, which was due to the combination effect of LUCC change and climate change. [ABSTRACT FROM AUTHOR]

• Productivity index based soil loss tolerance limits were estimated. • PI in different phases of erosion varies between 0.748 and 0.551. • Soil loss tolerance limit based on PI ranged from 6.67 to 12.92 Mg ha−1 year−1. • Severely eroded soils have lower microbial biomass carbon, and poor soil quality. Land area is dwindling due to degradation, both natural and anthropogenic, therefore, it is reasonable to save this important resource and put focus on achieving land degradation neutrality (LDN). An Investigation was taken to know the impact of erosion on soil physico-chemical and biological properties both in fertilized and unfertilized conditions in four phases of erosion viz., slightly eroded (0.5% slope), moderately eroded (2.5% slope), severely eroded (4.5% slope) and very severely eroded (9.5% slope). Productivity index (PI), vulnerability curve, soil loss tolerance limits (STL), soil quality index (SQI) and relative soil quality index (RSQI) were estimated for all phases of erosion. As the severity of erosion increases the soil quality and productivity index (PI) decreases. Very severely eroded soils have lower PI, SQI and RSQI as compared to slightly eroded soils. However, land use under fertilized condition have better soil quality with SQI value of 143.00 and 118.00 in slightly eroded and very severely eroded soils, respectively, compared to 126.00 and 106.00 in non-fertilized condition. Similarly, the productivity index ranged 0.748 in slightly eroded phase to 0.651 in severely eroded phase under fertilized condition. Compared to slightly eroded soil, severely and very severely eroded soils have lower microbial biomass carbon (MBC), CO 2 evolution and dehydrogenase activities. Assessment of soil loss tolerance limit based on PI revealed that it ranged from 6.67 to 12.92 Mg ha−1 year−1 which implies that land degradation took place in the more eroded soils which needs higher priority in order to bringing these eroded land to degradation neutrality (LDN), and also requires suitable soil conservation interventions in different phases of erosion. [ABSTRACT FROM AUTHOR]

• We conduct a multiproxy investigation of a runoff system in Oman. • We understand formation processes, function, and soil/water management strategies. • Runoff agriculture sustained small-scale farming from the 8th c BCE to the mid-20th century. • Data suggests farmers maximized orogenically-driven precipitation in narrow catchments. • Crop production specializes and hydraulic technology diversifies after the 9th c CE. Runoff farming is a key hydro-agricultural strategy that has proven efficient in arid areas. Research in Arabia on the function, development, maintenance, durability and abandonment of this technology is scarce. A multiproxy investigation (cartography, sedimentology, pedology, geochemistry, paleo-ecology and chronology) was conducted on a recently abandoned terraced area in Rustaq, Northern Oman. The aim was to characterize the formation, function and management of this runoff system and the driving factors behind its success. Cycles of cultivation were identified during the Iron Age II/III periods (specifically 750–450 BCE), the Early Pre-Islamic Period (PIR) (specifically 350–200 BCE), the Early and Middle Islamic periods (specifically 8–10th C CE, 13th-14th C CE) and the late Islamic period (specifically 17th C CE and later). This expansion and perenniality was possible thanks to: 1- available water (local to micro-regional orogenic precipitation despite a regional aridification during these periods); 2- suitable soils (weathered geological outcrops, probable aeolian /dust particles); 3- a system of production combining crops and husbandry; 4- a progressive increase in agricultural specialization (crops grown and techniques) in parallel with a diversification in hydraulic technology. These results are to some degree in accordance with known phases of settlement intensification and economic growth, but also reveal the persistence of small-scale rural livelihoods during periods of harsh conditions for which archaeological traces are very scarce. [ABSTRACT FROM AUTHOR]

• OM in the bare fallow is close to degraded. • OM in the bare fallow is depleted in O-Alkyl fragments. • OM in the bare fallow is enriched with aromatic fragments. • OM in the bare fallow is characterized by a high degree of hydrophobicity. • The quality of OM significantly contributes to the size of the structural units. The different soil organic matter (SOM) pools were isolated from the surface horizons of Haplic Chernozem in contrast variants of land use: (a) free particulate OM, (b) occluded particulate OM, (c) clay-associated OM, and (d) OM of the fraction of the Residue (Res). The features of the chemical structure studied by solid-state 13C NMR spectroscopy of these SOM pools in virgin Chernozem were used to demonstrate the changes that solid plant residues undergo during decomposition when they are incorporated into microaggregates. The extent of decomposition of organic materials in soils follows a continuum from fresh and partially decomposed organic materials in the discrete OM (Free and Occluded) to significantly/completely processed in the mineral-associated OM (Clay and Res). We studied the alteration of the chemical structure in the SOM pools under the influence of the bare fallow (52-yr duration) and revealed some features of the OM quality that can contribute to the size of the structural units in the C-depleted Haplic Chernozem. It was revealed that the functioning of Haplic Chernozem in the bare fallow regime for 52 years caused sharp increases in the decomposition and aromaticity degrees of the organic matter, as well as the hydrophobicity degree. A sharp increase in its hydrophobicity indicates a sharp decrease in its adhesive ability. This can be the reason for the almost complete destruction of one of the most valuable agronomic aggregate-size classes (2–1 mm) in the bare fallow, and the redistribution of the water-stable aggregate-size classes towards a decrease in their dimension. The decline in the aggregate size was indirectly confirmed by the decline in the average effective diameter of the clay particles (building blocks of aggregates) in the bare fallow compared to that in the steppe (382.7 vs. 443.8 nm, respectively). [ABSTRACT FROM AUTHOR]

• The measured attributes contributed significantly to discriminate between land use systems; • Agroforestry systems contribute to the reduction of the cohesive layers of soils; • Agroforestry systems therefore have the ability to improve the physical soil quality. • Land use, management and physical attributes of dense Ferralsols in tropical northeastern Brazil. In Brazil, Haplic Ferralsols (Densic) are commonly known to have physical limitations, including higher bulk density and less drainable porosity, less water infiltration and greater resistance to root growth. However, there are extensive areas with these soils in Brazil that are important for agricultural production. Because maintaining and/or recovering the physical quality of these soils is an important task to maintain agricultural sustainability, the objective of this study was to evaluate the impact of different use and management systems on the physical quality and total organic carbon content of Haplic Ferralsols (Densic) in northeastern Brazil. The evaluated systems were: conventional planting (CC), pasture (PP) and two agroforestry systems: one 7 years (AF7) and the other 12 years old (AF12). An area of secondary forest with remnants of the Atlantic Forest Biome (SF) was selected and sampled as a reference. The total organic carbon content (TOC), flocculation index (FI) and particle density (Dp) were determined. Saturated hydraulic conductivity (Ko), macroporosity (MaP), microporosity (MiP), total porosity (TP), soil bulk density (Ds) and aggregate stability were also determined in samples collected in the 0– to 0.10, 0.10 to 0.20 and 0.20– to 0.40 m soil layers. The variables that best distinguished the agroforestry systems from the other systems were GMD, MaA, WMD and TOC. Correlations of these variables, all related to the soil structure in the AF7 and AF12 systems, contribute to maintaining or regenerating soil aggregation. None of the soil management systems were grouped with the forest area, although areas in the agroforestry systems had lower impact on the physical soil quality parameters compared to the CC and PP systems. [ABSTRACT FROM AUTHOR]

• Land use systems is superior to topography in influencing soil properties. • Sites at the upper hillslope positions depict better soil qualities. • Soil properties content reflect optimal site conditions for productivity in the catchment. • The trend of soil properties is tending towards better qualities. Patterns of soil properties in highland environments remain poorly understood and limited knowledge exists on soil quality with respect to land use systems and topographic configurations. In this study, patterns of 12 surface soil physicochemical properties were assessed over a period of three years with respect to land use systems and toposequence positions in the Rwizi catchment of the Lake Victoria Basin. Four land use systems constituting mulched banana, unmulched banana, grassland and tree plantation, and three toposequence positions stratified as footslope, midslope and summit were considered and three replications were applied resulting in a total of 36 sites for soil properties measurements over a three-year period. Topographic attributes (elevation, slope gradient, slope aspect, and location) were collected at each site and correlated with surface soil properties. With the exception of pH and Ca, surface soil physicochemical properties are revealed to be optimal in the catchment. Greater spatial variation was found with soil chemical properties (8–57%) compared to physical properties (7–19%). Land use system registered significant effects (p < 0.05) for all soil chemical properties, as well as bulk density. Toposequence position is shown to have significant (p < 0.05) effects on soil pH, Soil Organic Matter, available P, N and soil texture. The effect of toposequence position revealed better soil quality along the catenary sequence summit > footslope > midslope. Strong and significant regression coefficients (r2 > 0.6, p < 0.05) for topographic attributes were found with soil pH, available P, K, Ca, Mg and sand. Overall, the land use system effect supersedes toposequence position in accounting for variations in surface soil physicochemical properties. Although environments of the Lake Victoria Basin are subject to intense agricultural activity and are usually assumed to be degraded, surface soil physicochemical properties in this part of the catchment reflect relatively healthy soil quality conditions. [ABSTRACT FROM AUTHOR]

[Display omitted] • Grass land was the dominant land use type and its area increased during 1980–2015. • Decrease of bare land provides the basis for the expansion of other land use types. • High conversion rate and intensity of LUCC were found in TSMs from 2000 to 2015. • The aggregation and fragmentation of overall landscape pattern increased in TSMs. • Accelerated glacier melting promotes the progress of LUCC in TSMs. During the past decades, land use/land cover change (LUCC) has occurred in the glacial affected areas at unpredictable rates driven by natural and human factors. Monitoring and identifying the spatial and temporal land cover changes and driving forces in this unique type of region provides a scientific basis for understanding the changing process of the Earth's surface, helping to reveal the impact of climate change and human activities on LUCC. In this study, the Tianshan Mountains (TSMs), which are located in the hinterland of Eurasia, were selected to investigate the LUCC of its typical glacial affected areas that have significant regional particularities. LUCC processes in the TSMs in China over the past 35 years were analyzed using a dynamic change model, a landscape pattern index, a centroid transfer model, and geoinformation Tupu based on the land use data of 1980, 1990, 2000, and 2015. The results show that the areas of cultivated and built-up lands immensely increased by 45.87% and 187.10%, respectively. Correspondingly, the areas of bare land and ice and snow cover decreased by 26.76% and 37.93%, respectively. The land use change in the TSMs was characterized by different stages, and high conversion rates and intensities were obtained from 2000 to 2015. The landscape change was mainly reflected in the significant increase in the number of patches and the simplification and regularization of patch shapes. The spatial connectivity of different land use types also increased. The temperature and precipitation in the region showed increasing trends, and the melting rate of ice and snow cover significantly accelerated. This study can help achieve a dynamic LUCC model to investigate the interacting influences of climate change and human activities in glacial affected areas. [ABSTRACT FROM AUTHOR]

[Display omitted] • Total phosphorus (TP) content in channel banks ranged between 129.6 and 1206.9 mg P kg−1. • Water extractable P comprised between 0.01 and 0.12% of TP. • Marginal evidence indicated TP to vary as a function of land use or catchment scale. • Stronger evidence indicated TP to vary as a function of stream order. • A novel spatial analysis shows TP averages & variances vary along the stream network. Phosphorus (P) is often a limiting nutrient that leads to the eutrophication of aquatic systems. While dissolved P forms are the most bioavailable, the form, mobility, transport and fate of P are directly related to its association with fine-grained riverine sediment. Therefore, to implement successful P catchment management strategies it is important to understand the relative contribution of different sediment sources to P loads across the river continuum. While agricultural topsoil and, to a lesser extent, riverbed sediment are important sources of sediment-associated P, channel banks have been shown to be an important sediment source in some catchments. However, comparatively little is known about the P concentration and corresponding spatial variability in channel bank sediment and the associated implications for catchment management. The present study examines the spatial variability of P associated with channel bank profiles within a series of three nested catchments using both non-spatial and spatial statistical methods, where for the latter, a novel spatial approach was used to estimate the spatial averages and variances of P in channel bank sediment along the stream network. Channel bank P concentrations were compared to factors such as catchment scale, stream order, land use, bank exposure and location along the stream network. Concentrations of TP ranged between 129.6 and 1206.9 mg P kg−1 of which the water extractable P (WEP) content ranged from 0.01 to 0.12%. Stream order was found to influence TP concentrations, while land use and catchment scale provided only a moderate influence. This suggested that focussing channel bank sampling strategies at the largest catchment scale would capture key drivers of TP variability provided stream order is sufficiently represented. Whether the bank was had limited vegetation and was exposed and potentially eroding had a slight influence on TP variability in second-order stream banks in the larger of the two nested catchments. However, the slightly lower TP concentrations measured at these sites indicated that banks that are actually eroding may be contributing less TP than the total channel bank TP values measured across the catchments as a whole. The results of an explicitly spatial analysis demonstrated that local channel bank TP averages and TP variances vary along the stream network. Specifically, the most accurate spatial predictor of TP was local TP means with the use of 'crow flies' rather than stream network distances. Local TP variances were used to provide optimal designs for future channel bank TP sampling campaigns, given available resources. Throughout, both standard and outlier-resistant statistical analyses were applied to improve interpretation of the study findings. [ABSTRACT FROM AUTHOR]

[Display omitted] • Olsen-P in 6-m deep profiles was determined in Loess Plateau farmland and orchards. • Farmland-to-orchard conversion affected Olsen-P at 0–40 cm but not at 40–600 cm. • Soil Olsen-P at 71.2 kg P kg−1 was the change point against leaching of P. • Olsen-P was regulated by P fertilization at 1 m and by roots at 1–6 m. Data on the dynamics of Olsen-P in deep soil profiles are crucial for improving P use efficiency but remain scarce worldwide. Hence, we sampled sixty 6-m-deep soil profiles from farmland and in 8-yr, 17-yr, and 25-yr-old apple orchards on China's Loess Plateau, and aimed to investigate the vertical distribution of soil Olsen-P following the farmland-to apple orchard conversion. Land-use change from farmland to apple orchard significantly affected Olsen-P at 0–40 cm soil, with the concentration generally increasing with age of apple orchard. By contrast, Olsen-P at 40–600 cm was not significantly different among the cropping systems. In both farmland and apple orchards, the concentration of Olsen-P decreased at 40–100 cm, compared with that in the 0–40 cm layer, increased with depth from 100 to 400 cm and then stabilized from 400 to 600 cm. The highest accumulation of residual soil Olsen-P in the 6-m profile (RSP 0−600) was in the 25-yr orchard, followed by the 17-yr and 8-yr orchards, with the lowest accumulation in farmland. The differences in RSP 0−600 cm were primarily associated with RSP 0−100 cm , which was significantly positively related to the accumulative application of P fertilizer. The change point in soil Olsen-P against P leaching was 71.2 mg kg−1, but in farmland and 8-yr, 17-yr, and 25-yr apple orchards, the averaged-depth contents of Olsen-P were all below the critical value, indicating no P leaching risk. Regression analysis revealed that the vertical distribution of soil Olsen-P was regulated by P fertilization at 0–100 cm and by crop roots at 100–600 cm, irrespective of cropping system. The insights gained on Olsen-P accumulation and migration within deep soil profiles after the farmland-to-apple orchard conversion can help to optimize land use and P fertilization management in major apple-producing countries with burgeoning growth in apple production. [ABSTRACT FROM AUTHOR]

[Display omitted] • Temporal patterns of sediment OC burial over the past ~100 years were studied. • Increasing OCAR during 1880–1980 was favored by land use promoting P input. • Decreasing OCAR since 1980 was associated with enhanced OM decomposition and OC mineralization. • OC pool may be mediated under projected climate warming scenarios for deep lakes. Inland waterbodies play an important role in the global carbon cycle, acting both as carbon sources with organic carbon (OC) mineralization and as sinks with OC burial in sediments. Under recent impacts of global warming, anthropogenic land-use change and nutrient supply, however, there is a limited knowledge regarding OC dynamics in sediments of large, deep lakes especially in subtropical alpine regions. Here, we studied the patterns of OC burial and the potential regulating factors using multiple sedimentary proxies and observational records in Lugu Lake (southwest China) over the past ~100 years. Comparisons of 15 sediment cores in different areas of the lake reveal similar temporal trends in OC content and other sediment parameters, indicating coherent patterns of whole-lake sedimentary environmental change dominated by watershed human perturbation. Based on C/N ratios and δ13C org analyses, the sediment OC has primarily been autochthonous in source. OC accumulation rates (OCAR) increased during 1880–1980, from ~14 to 43 g C m−2 yr−1 in a central core (LGS), mainly resulting from elevated primary production under increased phosphorus input and soil erosion. Subsequently, OCAR decreased considerably to ~15 g C m−2 yr−1, although the phosphorus supply and lake primary productivity remained high. We infer the OCAR decline likely resulted from increased organic matter decomposition and OC mineralization in the water column because of climate warming and lake-water thermal stratification. This phenomenon might mask the positive contribution of primary production to OC burial. Our findings suggest that the commonly observed synergistically positive effects of warming and eutrophication on sediment OC burial may be impaired in deep lakes, which needs further investigations across ecological, climatic and land-use gradients. [ABSTRACT FROM AUTHOR]

[Display omitted] • Páramo soils are porous, humid and rich in organic matter, which buffers streamflow. • Agriculture increases macroporosity and promote loss of nutrients and organic matter. • Grazing compacts the soil and reduces porosity, infiltration and water retention capacity. • Afforestation reduces soil moisture, organic matter and water retention capacity. • Land-use change in páramos reduces streamflow buffering and increases flashiness. The páramos biome of the northern Andes is a collection of high-mountain tropical grassland wetland ecosystems that provides important ecosystem services including hydrological buffering and water supply. Human activities in these ecosystems transform vegetation cover and soil hydro-physical properties, affecting their hydrological performance and water quality and quantity. Here, we conducted a systematic review on the influence of land use (agriculture, livestock grazing, and afforestation) on the hydro-physical properties of páramo soils and analyzed its implications for streamflow buffering. Our review protocol identified 32 relevant papers, from which key hydro-physical properties linked to streamflow variability were available: soil organic matter (SOM), soil organic carbon (SOC), porosity, bulk density, saturated hydraulic conductivity, and water retention capacity (WRC). The analysis shows that soils with native cover are characterized by a porous structure that allows a high WRC and SOM content. Agriculture increases macroporosity but it leads to bare fallow plots that promote loss of nutrients and SOM. Burning generates hydrophobic aggregates that affect WRC. Livestock grazing produces soil compaction and increases bulk density, reducing infiltration and WRC. Lastly, afforestation with exotic species (e.g. pines, eucalyptus) decreases SOM and WRC by changing soil structure. In general, the analyzed land-use activities generate hydrophobic aggregates, increase bulk density, promote erosion and runoff, and impair hydrological buffering capacity. This integrated evidence from multiple empirical studies can be used to effectively communicate the effects of different land use practices on páramo soils, provide information for modelling in data-scarce situations, and contribute to decision making processes for land use planning and conservation. [ABSTRACT FROM AUTHOR]

[Display omitted] • The interactive effects of soil erosion and land use on SOC were studied. • Soil erosion rates were higher in orchard land relative to farmland. • The direct impact of soil erosion accounts for 1.5% of SOC variability in soil surface. • The direct or indirect effects of land use accounts for 89.0% for SOC variability in deeper soil. Changes in land use can result in soil erosion and the loss of soil organic carbon (SOC). However, the individual contribution of different land use types on SOC variability as well as the combined impacts of land use and soil erosion are still unclear. The aims of the present study were to: (1) evaluate soil erosion and SOC contents under different land use types, (2) identify the influences of soil depth and land use on SOC content, and (3) determine the contribution of land use and soil erosion on SOC variability. We assessed the SOC and total soil nitrogen (TSN) contents under three types of land use in the dry-hot valley in southern China. Caesium-137 (137Cs) and excess lead-210 (210Pb ex) contents were also measured to determine soil-erosion rates. Land use was found to significantly affect soil erosion, and erosion rates were higher in orchard land (OL) relative to farmland (FL), which is in contrast with previous study results. SOC and TSN contents varied significantly between the three land use types, with highest values in forest land (FRL) and lowest values in OL. SOC was found to decrease with decreasing soil depth; the highest rate of reduction occurred in the reference site (RS), followed by FRL and FL. The interaction between soil erosion and land use significantly impacted SOC in the soil surface layer (0–12 cm); the direct impact of soil erosion accounted for 1.5% of the SOC variability, and the direct or indirect effects of land use accounted for the remainder of the variability. SOC content in deep soil was mainly affected by factors related to land uses (89.0%). This quantitative study furthers our understanding on the interactive mechanisms of land use and soil erosion on changes in soil organic carbon. [ABSTRACT FROM AUTHOR]

• Soil particles had the similar parabolic relationships with soil aggregate stability. • Nitrate nitrogen plays an important role in surface soil aggregate stability. • Abandoned apple orchards can improve soil aggregate stability through a short time. Soil aggregate stability is a feasible and effective factor to understand the complex interactions between physicochemical properties and soil structure. To reveal the distributions of soil aggregate stability and its influential factors following land use change from apple orchards abandonment and development in the Nangou watershed of the Loess Plateau, China, this study selected five ages of apple orchards and their planting years were 1 year, 3 years, 6 years, 8 years and 10 years, one 15-year grassland developed from an apple orchard, one 15- year grassland developed from farmland, one natural grassland and one 15-year locust. Results showed that restored vegetation had better soil aggregate stability, soil organic carbon (SOC), and nitrogen (N) than apple orchards, and the composition of soil particles with the best aggregate stability was clay 6%, silt 8%, and sand 86%. At a 0–10 cm soil depth, soil aggregate stability had a significant positive correlation with SOC and soil total nitrogen (STN), and a negative correlation with NO 3 − and NH 4 +. In addition, vegetation diversity and coverage only affected the soil aggregate stability of the 0–10 cm soil depth; however, soil pH, bulk density, and soil aggregate-associated inorganic nitrogen were the main influential factors that drove the soil aggregate stability of the 0–30 cm soil depth. Further research discovered that macro-aggregate associated NO 3 − and micro-aggregate associated NH 4 + may be the key factors affecting the soil aggregate stability. Therefore, it is essential to further explore the effect of soil aggregate-associated inorganic nitrogen on soil aggregate stability. [ABSTRACT FROM AUTHOR]

• Thermal techniques are robust and rapid methods for determining changes in SOC. • SOC of our sites was mainly represents polysaccharides and aliphatic structures. • PA + SM and NV showed higher contribution of microbial-derived in the SOC. • The application of SM increases SOC content. • SM application combined to no-tillage practices may lead to SOC stabilization. The pool of carbon (C) present in soil systems is larger than the amount of organic C stored in living biomass and the atmosphere. Soil degradation has increased soil C emissions at the expense of C accumulation. Climate-smart management practices may be adapted to increase C sequestration as soil organic carbon (SOC). To avoid the SOC loss, different strategies have been applied, including no-tillage and organic fertilizer. Here, we investigated thermal stability of SOC after long-term manure application across land uses and tillage systems in weathered soils of Brazil. We chose five commercial areas with different land uses: pasture with swine manure (SM) application (PA + SM), conventional tillage (CT) with SM application (CT + SM), natural vegetation (NV), no-tillage with SM application (NT + SM), and no-tillage (NT). Thermal analysis revealed that SOC oxidation and CO 2 emission started around 240 °C, close to gibbsite and goethite structural collapse, suggesting preferential adsorption of SOC onto these minerals. Approximately 50% of SOC for all sites was oxidizable at lower temperature (~315 °C) which suggests the prevalence of polysaccharides, decarboxylation of acidic groups and dehydration of hydroxylate aliphatic structures, regardless of land-use. The energy content of SOC for NV (6.5) and PA + SM (10.6) were in average, 46% lower than other treatments which suggest a higher necromass contribution to SOC in these systems. However, the higher energy content in CT + SM (14.9), NT + SM (16.5), and NT (15.8), suggests a higher contribution of plant-derived compounds in SOC. Our results showed that SM application on pastureland reached similar SOC accumulation to NV and increment of ~33% when applied to no-till system. We conclude that SM could a drive higher C accumulation and stabilization if preferentially associated to soil conservative system. [ABSTRACT FROM AUTHOR]

• Post-agricultural restoration increased SOC due to the build-up of non-protected SOC. • Post-agricultural restoration shifts SOC composition towards more easily available C. • Physico-biochemically protected SOC was hampered by restoration in temperate soils. • Within SOC composition, convergent and divergent self-restoring trends coexist. Post-agricultural natural restoration is a worldwide strategy for eco-environmental sustainability. However, it is unclear how it affects soil organic carbon (SOC) pools and composition among soil types across climate gradient. Here, we investigated 23-year post-agricultural restorations of SOC in three soils: Luvic Phaeozem, Calcaric Cambisol and Ferralic Cambisol typical for mid-temperate, warm-temperate and subtropical zones, respectively. Six SOC fractions with different protection mechanisms (non-protected, physically, chemically, biochemically, physico-chemically and physico-biochemically) were separated. Compared with pre-restoration in 1990, post-agricultural restoration rebuilt SOC similarly (+68–+91%) among the three soils despite of different SOC background. Compared with continuous cultivation, post-agricultural restoration increased total SOC pools in all the three soils (+33–+60%) mainly because of the increments of non-protected pool (coarse particulate organic C, cPOC). However, the pure physically, chemically, and biochemically protected SOC fractions were less sensitive to post-agricultural restoration. The physico-biochemically protected SOC was hampered by restoration in the two temperate soils but remained stable in the subtropical soil, suggesting a divergent self-restoring trend. Positive correlations of the total SOC and most fractions with wetness (precipitation/temperature ratio) demonstrated the climate dependency of SOC. In conclusion, post-agricultural natural restoration builds up SOC pool mainly due to the cPOC increment and shifts SOC composition towards more easily available C in three soils across the climatic gradient. [ABSTRACT FROM AUTHOR]

• Annual sediment yields using SEMEP are typically 50–300 ton/km2·yr. • RMSE of model with SEMEP is 53 ton/km2·yr less than that of existing models. • Sediment transport into alluvial rivers is affected by river wetlands and water. • Watershed morphometric characteristics can represent sediment transport. • Geospatial analysis shows urbanization's erosion features, yielding rich sediment. South Korea experiences numerous local sedimentation problems, such as landslides, upland erosion, aggradation and degradation, and flood plain sediment deposition. This has necessitated the development of a reliable and consistent approach for modeling sediment processes in the country. In this study, samples obtained from 35 gauging stations at five alluvial river basins in South Korea were used together with the modified Einstein procedure and series expansion of the modified Einstein procedure to determine the total sediment load at the sampling locations. Using two different methods, the total sediment load of majority of the 35 considered rivers were found to be typically 50–300 ton/km2·yr. A model tree data mining technique was used to develop a model for estimating the specific degradation based on certain meaningful parameters, namely, the 1) elevation at the middle relative area of the hypsometric curve [m], 2) percentage of wetland and water, 3) percentage of urban land, 4) mean annual precipitation [mm], 5) main stream length [km], and 6) watershed form factor [km2/km2]. The root mean square error of the predictions of the proposed model was found to be 55 ton/km2·yr less than those of existing statistical models. Erosion loss maps obtained by the revised universal soil loss equation (RUSLE), satellite images, and aerial photographs were also used to represent the geospatial features affecting erosion and sedimentation. The results of the geospatial analysis indicated that the transport of sediment into the alluvial rivers was affected by the wetlands located near the rivers, and also enabled clear delineation of the unique erosion features of construction sites in the urban areas. In addition, the watershed morphometric characteristics could be used to accurately represent the sediment transport. The proposed data mining methodology promises to facilitate the solution of various erosion and sedimentation problems in South Korea. The geospatial analysis procedure would also enable the understanding of spatially varied erosion and sedimentation processes under different conditions. [ABSTRACT FROM AUTHOR]

• A GIS method to simulate LULC change based on past LULC data. • Increased cropland resulted in higher sediment concentration, TN, and TP yields. • Different crop species contributed on TN, and TP yields. • Agricultural LULC change impacts on downstream stream quality. Land use and land cover (LULC) change impacts on hydrology and water quality are of critical importance in regions where water quality is degraded. One such location is the Mississippi Delta in the United States, where widespread agriculture across the landscape is a major contributing source to sediment- and nutrient-heavy runoff. To address how the landscape has changed in the recent past and consider how it may continue to change in the future, we analyzed the temporal and spatial variability of the LULC changes (e.g. forest, cropland, corn and soybean) in the Big Sunflower River Watershed. We applied these LULC changes in the Soil and Water Assessment Tool (SWAT) model to demonstrate the impacts on stream discharge, total suspended sediments (TSS) concentrations, total nitrogen (TN), and total phosphorus (TP) yields. Model performance was considered satisfactory to good (R2 = 0.46–0.88, NSE = 0.34–0.64) for all simulated water quantity and water quality parameters. TSS concentrations increased 1.9%, while TN and TP yields increased by 12.7%, and 10.2%, respectively as the area of the cropland increased. Stream discharge was unchanged. Moreover, TN yield increased as the percentage of land occupied by cornfields increased while TP yield increased as the percentage of land occupied by soybean increased, due to differences in crop management practices such as fertilization and tillage. [ABSTRACT FROM AUTHOR]

• We studied the pedostratigraphy of 52 relict charcoal hearth (RCH) sites. • RCHs display slope correlated differences in layer amount and -thickness. • Two generalized RCH types can be derived based on a slope threshold of 4°. Relict charcoal hearths (RCHs) are anthropogenic geomorphic features with an average diameter of 12 m found in many forests of Central Europe and in the eastern USA wherever pre-coal iron production took place or other industries demanded the production of charcoal. To expand the knowledge about their geoarchaeological significance and their legacy effect on soil properties and forest ecosystems, we propose a method for a generalized description of soil stratigraphy on RCHs. We studied 154 soil profiles at 52 RCH sites alongside two 1 km transects in Litchfield County, Connecticut, USA. The sites can be classified based on the slope inclination, with sites on <4° mostly having a single-layered stratigraphy and an elevated circular shape, while sites on slopes >4° mostly are built as levelled and multilayered platforms. The latter have two or more charcoal rich technogenic Auh-layers separated by intermediate Auh-layers mostly consisting of mineral substrate. Based on average layer thicknesses and their dependence on the sites slope inclinations, we propose a model with two idealized RCH shapes with slope controlled properties that allow for an easy computation of site diameters and elemental stocks. With ongoing advances in remote sensing of RCH sites, our proposed model can help to further understand the effects of historic land use on a landscape scale. [ABSTRACT FROM AUTHOR]

• Since 1950s the European mountains experienced land abandonment. • Land abandonment was followed by spontaneous recolonization of trees and shrubs. • We reconstruct forest encroachment by dendrochronology, phytosociology and mapping. • Forest encroachment accelerated from +0.8%/y (1954–1993) to +4.9%/y (2015–2018). • Since 2000 warming accelerated forest dynamics triggered by land abandonment. During the past decades, the montane and subalpine belts of many European mountains experienced agricultural land abandonment followed by spontaneous recolonization of trees and shrubs on semi-natural mountain grasslands, potentially leading to severe losses in biodiversity. Here we analyse the spatial and temporal patterns of forest encroachment of a Prealpine study site in Northern Italy (Triangolo Lariano, Como) since 1954 in response to land use change and aim to assess whether this process has been accelerated by recent climate warming and atmospheric CO 2 increase. To achieve a detailed reconstruction of forest encroachment dynamics, we adopted a multidisciplinary integrated approach, involving dendrochronological and phytosociological analyses, and vegetation mapping. Available maps updated with aerial photographs allowed the delineation of the forest distribution and changes of forest boundaries. Accordingly, along nine elevational transects, 60 plots were set within different forest-grassland successional stages in order to integrate vegetation mapping with phytosociological analyses and reconstruct the recruitment rates through dendrochronological analyses. Since 1954, the forest encroachment process occurred across an elevation range of 185 m, at a mean rate of 29 m per decade, although with uneven temporal and spatial trends. The forest encroachment rates increased progressively with time, from +0.8%/y (1954–1993) to +2.4%/y (1993–2015) to +4.9%/y (2015–2018). The air warming exhibited an increasing trend too, especially in the last twenty years. Betula pendula was the most abundant species responsible for this process (the only one presenting seedlings and saplings settling along the summit areas) and showed two recruitment peaks: the first in concomitance with the abandonment of the agro-silvo-pastoral practices (1950/60s), but the largest recruitment was detected with the increased air warming since early 2000s. The correlation analysis confirmed that forest encroachment was related to air warming (in particular summer warming), land use change and increase of atmospheric CO 2 and that it was further accelerated in concomitance with further air warming in the recent decades. The forest encroachment process on semi-natural grasslands triggered by land use change on European mountains and its recent acceleration in response to climate warming represent an increasing threat to biodiversity, leading to potential habitat and species loss, especially of the most vulnerable habitats. [ABSTRACT FROM AUTHOR]

• Soils rich in rock fragments are characterised by tri-modal pore size distribution. • The new combined model captures the presence of macro-, structural, and textural pores. • SOC and coarse fragment contents are crucial for pore size distribution in shallow soils. • Rock fragment content negatively correlated with textural porosity and water retention. • Coarse fragments significantly increased the macro-porosity and soil air capacity. Rock fragments are key components of soil systems. However, the role of rock fragments is only sporadically researched and therefore it is essential to establish how they control soil physical, biological and chemical properties and to assess the impacts of land-use on soil functions. Further, rock fragments affect soil water retention and infiltration capacity, and this is relevant for the fate of soils because water determines soil biota and weathering and decomposition processes in the soil system. Herein, we investigated abandoned arable, meadow and forest soils to determine the effect of land-use on soil water retention properties in soils containing rock fragments. Results showed that forest soil had the highest content of rock fragments and that previous ploughing on shallow abandoned arable soil on dolomite bedrock ensured that this had higher rock fragment content than meadows. We then compared coarse rock fragment effects on water retention in three research plots. Measured points in the water retention curves depict the total porosity and water retention determined at 3–1000 hPa suction in the undisturbed soil samples and 1.5 MPa in disturbed samples. Two models with different macro-porosity expressions were applied to the experimental data, and their derivatives provided pore size distribution curves with maxima for textural, structural and macro-pores. However, a new combined model with six independent fitting parameters has proven more suitable to approximate tri-modal soil water retention curves. The textural porosity was highest in the meadows due to the direct effect of organic carbon content and the indirect influence of coarse fragments which reduced the volume of small pores in the soil. Organic carbon content positively affected water retention properties in these soils. This included the permanent wilting point, field capacity and plant available water capacity, but the coarse fragment content negatively correlated with these properties. In addition, the results highlighted the stones' positive effect on structural pores in forest soils and on macro-pore formation in all soils, while structural pores in all soils were mainly influenced by organic carbon content. The combined structural and macro-pores determine the soil air capacity and this is positively influenced by the increased content of coarse rock fragments. The soil air capacity was therefore highest in the forest soil. Finally, although the irreversible increase in rock fragment content in the abandoned soil has negative impact on agricultural use, the coarse fragment influence on macro-pore volume is positive and this increases soil infiltration capacity and reduces surface runoff and soil erosion, as confirmed in the literature review. [ABSTRACT FROM AUTHOR]

• Present land use patterns are insufficient to manage storm event-related erosion. • A land use distribution index is established to represent the pattern of land use. • Slope-cropland below valley shoulder line suffer the most severe soil erosion. • Cement road above valley shoulder line can greatly reduce the soil erosion below. • Circular catchment shape is linked with higher erosion modulus. Characteristics of soil erosion under extreme rainfall conditions are indicators of the ecological restoration measures as well as the rationality of land use patterns in the region. To this end, 12 dam-controlled catchments were selected for investigation after an extreme rainstorm event in the northern Shaanxi Province on 25–26 July 2017 (known as the "7.26" rainstorm). Soil erosion intensities in the 12 catchments were obtained by excavations of sedimentation profiles and sedimentation area measurements. Digital orthophoto maps and digital terrain models by unmanned aerial vehicle were generated to characterise land use types and areas, slope gradients, and the distance from the land to the boundary of dam-land along the flow accumulation path. Stepwise regression analysis was used to determine the main factors affecting catchment erosion intensity. Results showed that the average sedimentation thickness and overall soil erosion intensity across the 12 catchments ranged from 0.16 to 1.67 m and 10295–49227 t km−2, respectively. Soil erosion caused by the extreme rainstorm was 10–50 times of the soil loss tolerance on the Loess Plateau (1000 t km−2 year−1). Stepwise regression analysis revealed that the more similar the shape of a catchment to a circle, the closer the distance between the slope-cropland and dam-land, the larger the erosion modulus within the catchment. Furthermore, the presence of a cement road along the valley shoulder greatly reduced the modulus of soil erosion. These findings indicate that the existing ecological conditions in the dam-controlled catchments were not able to effectively resist erosion under the extreme rainfall conditions of this event. Thus, optimising the distribution of land use types within catchments should be a focus for soil erosion control. [ABSTRACT FROM AUTHOR]

• The number of organic phosphate-solubilizing bacteria (PSB) increased with soil TP. • The number of phosphate-solubilizing fungi (PSF) increased with soil carbon content. • The ability to solubilize phosphate was organic PSB > PSF > inorganic PSB. • The organic PSB was the best bacterial group to solubilize phosphate. Some soil bacteria and fungi are known to solubilize phosphates and play an important role in supplying phosphorus (P) to plants. In this study, we characterized the phosphate-solubilizing bacteria and fungi as well as P availability in latosols from southern China under different land use practices. Three different latosols (i.e., red soil, lateritic red soil and laterite red soil), each with four different land uses (i.e., agricultural land, grass land, forest land and orchard land), from Guangdong Province, China, were chosen to determine the amounts of phosphate-solubilizing bacteria (PSB) and phosphate-solubilizing fungi (PSF) and their phosphate solubilizing abilities. Our results show that the amount of available P (AP) increased with the amount of PSB favored in solubilizing organic P (or PSBop), while the amount of PSF increased with the content of soil organic carbon (SOC). The average rates of phosphate solubilization were 28.23% for PSBop, 6.97% for PSF, and 0.16% for PSBip (PSB favored in solubilizing inorganic P). An increase in soil pH decreased the ability of PSB to solubilize phosphate in latosols. This ability occurred in the following order: PSBop > PSF > PSBip. No significant difference in the amount of PSF was observed among the four different land uses for the lateritic red soil and laterite red soil, whereas a profound significant difference was found for the red soil, with the highest number of PSF in the grass land. Reasonable linear correlations between the PSB and the AP and between the PSF and the SOC were obtained and could provide a good reference to characterize soil PSB and PSF. Additionally, PSBop was the best bacterial species to solubilize phosphate in the latosols. [ABSTRACT FROM AUTHOR]

• Five land uses were assessed for soil organic carbon (SOC) dynamics. • Conversion of forest land to cropland declined SOC and biological activities. • Alder + large cardamom land use was a viable alternative for SOC buildup. • Alder + large cardamom land use increased the recalcitrant pool of SOC fractions. Land use management exerts a tenacious impact on soil organic carbon (SOC) dynamics; however, the impact varies with climate, soils, and management practices. Therefore, an in-depth understanding of changes in SOC pools and its fractions is necessary to reduce carbon (C) emissions and adopt efficient land use planning for sustainable soil management in the North Eastern Himalayan (NEH) region of India. The soils under five prominent land uses [e.g., alder (Alnus nepalensis) + large cardamom (Amomum subulatum), alder + turmeric (Curcuma longa), ginger (Zingiber officinale) + maize (Zea mays), ginger and undisturbed forest] were sampled down to 45 cm depth to assess the impacts of land use systems on SOC content and storage, its fractions, microbial biomass carbon (MBC) and the dehydrogenase (DHA) activities. Results demonstrated that undisturbed forest soil had the highest organic carbon (OC, 145.8 Mg ha−1), active C (AC, 73.7 Mg ha−1), passive C (PC, 72.1 Mg ha−1) pools, MBC and DHA activities followed by alder + large cardamom system (140.7 Mg OC ha−1, 70.9 Mg AC ha−1, and 69.8 Mg PC ha−1, respectively). The soils under undisturbed forest and alder + large cardamom system had a higher share of the very labile C fractions for all depths than other land uses. Conversely, soils under sole ginger and ginger + maize land uses had a greater proportion of non-labile C (NLC) fractions; however, absolute values of the NLC pool were the highest under undisturbed forest soil. Alder + large cardamom land use system had the highest AC: PC pool ratio (1.13) and C stratification (1.02–1.05) compared to the other land uses. Of the various land uses, SOC pools (0–45 cm) in six years were reduced nominally under alder + large cardamom system (4.2%), while the reduction was maximum under the ginger system (11.2%) as compared to the SOC pools of undisturbed forest. The study demonstrated that the cultivation of crops like maize and/or ginger is more degrading and will always have a negative impact on the fertility and overall health of the Himalayan soil. Hence, alder + large cardamom system may be promoted to restore the soil C in the Sikkim Himalayan region of NEH, India, and other similar regions of the world. [ABSTRACT FROM AUTHOR]