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• Land-use types, seasons, slope position significantly affected SOC and SWC. • Revegetation increased SWS consumption and SOC accumulation. • There was a positive linear relationship between SOC and SWC. • Planting grass and shrubs is recommended in the semi-arid hilly and gully regions. Understanding the response of soil organic carbon (SOC) and moisture to different land-use types, slope positions, seasonal variations, and their interactions has great significance for land use and management. However, the coupling effects of SOC and soil moisture in typical hilly and gully regions are still elusive. Therefore, in this study, five different land-use types, including cropland, abandoned land, grassland, shrubland, and forestland were selected in a typical Chinese loess hilly-gully region, and soil samples were collected from 0 to 200 cm profiles at the upper, middle, and lower slope positions in four seasons. The results demonstrated that the distributions of SOC and soil moisture were jointly significantly affected by land-use types, seasons, and slope positions (P < 0.01). Average SOC content was found to be highest in the shrubland, followed by grassland, abandoned land, forestland, and cropland. SOC storage at the lower slope position was 10.97% higher than that at the upper slope position. SOC storage in winter was 45.47% higher than that in summer. SOC storages of abandoned land, grassland, shrubland, and forestland were 17.38%, 33.08%, 52.52% and 1.26% more than that of cropland, respectively. Soil moisture fluctuated greatly in 0–100 cm layers and was stable beneath the 100 cm layers, which was highest in autumn, and lowest in summer. Whereas, under different land-use types, the soil moisture of cropland was the highest, especially significantly higher than all revegetated treatments in the 60–200 cm soil layers. Compared with cropland, soil water storage at other land-use types was averagely 36.45 % lower in the entire 200 cm soil profile. SOC was positively correlated with soil moisture under different factors. Thus, we recommend planting shrub and grass in watersheds with serious soil erosion in the semi-arid hilly and gully region, because they can sequestrate more SOC and retain more soil water. [ABSTRACT FROM AUTHOR]

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

The socio-economic effect of the occurrence of specific forms of relief, is a significant research problem in applied geomorphology. The objective of this study was to assess the impact of permanent gullies on land cover and agriculture within the loess areas of Eastern (E.) Poland. We analyzed the relationships between an area consisting of gullies and selected environmental and socio-economic indices. We used the following statistical methods: Pearson's linear correlation, ANOVA, PCA and cluster analysis. It was found that districts with a similar gully density are characterized by the occurrence of a similar set of economic characteristics found within agriculture (cluster analysis). The most distinct impact of the occurrence of gullies on the potential of agriculture was observed when gullies covered more than 2% of the district. We identified the relationships between the area covered by gullies and present-day forest cover (Pearson correlation index 0.5), changes in the forest cover in the 20th century (0.7), the area of landscape parks and reserves (0.8) and the share of big farms (− 0.5). Weak negative correlations occurred between the gully area and the economic aspects of agriculture (indices from − 0.2 to − 0.4). The correlations between the area of gullies, area of forests and share of farms larger than 20 ha were confirmed by ANOVA. The PCA method showed a negative correlation between the area of gullies, the share of arable lands and the share of farms with good prospects. A positive correlation was found in the case of protected areas, steep slopes and forests. In the future, gullies may turn out to be a challenge to the development of efficient agriculture; they are an obstacle to land consolidation and farm enlargement. Areas characterized by a high density of gullies require special spatial management to reduce negative economic effects. [ABSTRACT FROM AUTHOR]

Abstract: The semi-arid loess hilly–gully region in China has an extremely vulnerable ecological environment. Inappropriate land use — crop farming, overgrazing, and plantation forestry - has worsened soil erosion, intensified water shortage, and hence impeded the ecological conservation and agricultural development of the entire region in the past. Optimizing land use and vegetation cover and spatial pattern is conducive to achieving both ecological and economic goals in terms of controlling soil erosion, using water resources rationally and raising agricultural productivity. Changchuan Watershed, a typical small catchment in the semi-arid loess hilly region, was selected as the case study area to analyze the impacts of land use and land cover structure and associated spatial pattern on soil erosion and water consumption in the Watershed, through field investigation and model simulation. Land use structure was optimized by multi-objective programming, using remote sensing (RS) and geographical information system (GIS) techniques, analytic hierarchical programming (AHP) and expert consultancy. The digitized optimum spatial pattern embodying rationally-proportioned land use structure was obtained through GIS-aided redistribution of land use types. The optimized land use structure re-apportioned woodlands, shrublands, grasslands, and croplands at 3.7%, 38.6%, 49.4%, and 6.3% of the land area respectively, compared to the current land use structure of 2.4%, 38.6%, 24.0%, and 12.6%, respectively, in the Changchuan Watershed. In the optimized land use spatial pattern, croplands are mainly located in the riverside plain and check-dammed valleys and grasslands are widely distributed in the lower reaches of the basin, while shrublands are appropriately established in the middle and upper reaches of the river. A comparative analysis shows that the optimized land use structure, with well-designed spatial pattern is able to reduce soil erosion, enhance the utilization of water resources and raise agricultural productivity. [Copyright &y& Elsevier]

Abstract: Due to rainfall variation and poor land cover, water erosion in the loess hilly area is severe and experiences high temporal fluctuations, which increase the difficulties of erosion quantification, prediction and control. In this study, 15 runoff plots were implemented in Dingxi, a typical loess hilly area of Gansu Province since 1986. Three typical years representing WY (wet year), NY (normal year) and DY (drought year) were firstly filtered based on the consecutive rainfall-erosion data and an aridity index. Then, water erosion dynamics involving five land uses (cropland, alfalfa, scrubland, woodland and grassland) in the three typical years were analyzed. The following results were found. Firstly, the most severe annual erosion rates did not appear in WY, but in DY. Moreover, the rates in DY were far higher than those in NY and WY. Secondly, although total rain depth and number of events were in the order of WY>NY>DY, mean maximal intensity of erosive rainfall however, was in the order of DY>NY>WY. This finding is important for erosion control. Namely, we cannot judge water erosion degree just from annual rainfall. More attention should be paid to the specific rainfall variables and distributions. Thirdly, different land uses played an important role with sea buckthorn reducing water erosion in contrast to spring wheat cultivated on steep slopes. Lastly, regardless of different drought-level years, only a few number of events with high intensities were responsible for the majority of annual soil and water loss. [Copyright &y& Elsevier]

Abstract: Key catchments of the Roztocze loess area in south-east Poland have a great potential of revealing the history of long-term soil erosion and changes in land use. The knowledge of how and when soil erosion took place in the past helps one understand the impact of land use changes on the landscapes [Bork, H.-R., 1989. Soil erosion during the past Millennium in Central Europe and its significance within the geomorphodynamics of the Holocene. Catena 15, 121–131]. The Jedliczny Dol gully system near the town Zwierzyniec in south-east Poland was investigated by using detailed field stratigraphy and radiocarbon dating of charcoal and wood. In connection with new settlements which were established between the 14th and 16th centuries, arable land was cultivated and forests were used much more intensively. As a consequence, the loess soils were strongly eroded during heavy rainfalls. Up to 4 m of colluvial sediments were deposited in the gully system during the 15th and/or 16th centuries. The thickness of the colluvial sediments indicate severe erosion which might be related to excessive timber exploitation for the local glass and iron production. With the foundation of the so-called Ordinariat Zamoyski at the end of the 16th century, some parts of the area were presumably reforested. High pressure on the land at the beginning of the 19th century enabled a second main phase of gulling before 1900. Since 1890 at the latest, almost the whole catchment is used as a forest, however, concentrated runoff on compacted forest roads can still be high after heavy rainfalls. In loess areas soil erosion caused by intensive land use, triggered by heavy rainfalls, can change the landscape drastically. These changes will continue to influence how catchments react, even if land use gets less intensive again. This knowledge should be considered regarding future, sustainable land use and recent changes in land use in the south-eastern Polish loess regions. [Copyright &y& Elsevier]

• Elaborate Sr-Nd isotopic composition of the Northeast Sandy Land were constructed. • Nd isotopic composition exhibits significant dependency on time effect. • Nd isotopic composition shows clear grain size-dependent variability. • Sr-Nd isotopic values show enrichment in the coarse-grain fraction. The Sr-Nd isotopic study of the Northeast Sandy Land (NESL), China is of great significance for a thorough understanding of the dust system in this area. The 162 bulk (<63 μm) and 86 size-fractioned samples of surface eolian sands and river sands in the NESL are very suitable to be added to the elaborate Sr-Nd isotopic composition dataset. The results are as follows. The Nenjiang River drainage system (NR) in the Songnen Sandy Land (SNSL) and the Hulun Buir Sandy Land (HLSL) are characterized by more radiogenic Nd values relative to the other areas within the NESL whereas the Onqin Daga Sandy Land (ODSL), the Horqin Sandy Land (HQSL) and the Songhua River drainage system (SR) exhibit a clear overlap of Sr-Nd isotopic composition. Nd isotopic composition (especially in the ODSL) exhibits significant dependency on time effect, indicating instability of geochemical composition in the dust source areas. Sr isotopic composition is slightly affected by grain size with very small variations of size-separated 87Sr/86Sr values, yet Nd isotopic composition exhibits clear grain size-dependent variability. The substantial proportion of Sr-Nd isotopic values show enrichment in the coarse-grained fraction, which is accounted for by source-rock control. Both the HLSL and the NR to the northwest of Harbin play very little role in contribution to eolian dust deposits in the Northeast Plain, either in the geological past or now, whereas Sr-Nd geochemical composition alone is insufficient to unequivocally distinguish exact provenance of the eolian dust deposits in this region. The integrated consideration, as expected, revealed the derivation of the eolian dust deposits. The eolian loess and the modern dust-storm deposits in Harbin share significantly different source areas: Harbin loess is the product of spring dust-storm weather and has a mixed source with the SR being the main dust contributor, whereas 2011 Harbin dust-storm deposits were derived from the ODSL and beyond which also provided minor amounts of fine dust particles to Harbin loess. [ABSTRACT FROM AUTHOR]