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Driven piles are used in many geological environments as a practical and convenient structural component. Hence, the determination of the drivability of piles is actually of great importance in complex geotechnical applications. Conventional methods of predicting pile drivability often rely on simplified physical models or empirical formulas, which may lack accuracy or applicability in complex geological conditions. Therefore, this study presents a practical machine learning approach, namely a Random Forest (RF) optimized by Bayesian Optimization (BO) and Particle Swarm Optimization (PSO), which not only enhances prediction accuracy but also better adapts to varying geological environments to predict the drivability parameters of piles (i.e. maximum compressive stress, maximum tensile stress, and blow per foot). In addition, support vector regression, extreme gradient boosting, k nearest neighbor, and decision tree are also used and applied for comparison purposes. In order to train and test these models, among the 4072 datasets collected with 17 model inputs, 3258 datasets were randomly selected for training, and the remaining 814 datasets were used for model testing. Lastly, the results of these models were compared and evaluated using two performance indices, i.e. the root mean square error (RMSE) and the coefficient of determination (R). The results indicate that the optimized RF model achieved lower RMSE than other prediction models in predicting the three parameters, specifically 0.044, 0.438, and 0.146; and higher R² values than other implemented techniques, specifically 0.966, 0.884, and 0.977. In addition, the sensitivity and uncertainty of the optimized RF model were analyzed using Sobol sensitivity analysis and Monte Carlo (MC) simulation. It can be concluded that the optimized RF model could be used to predict the performance of the pile, and it may provide a useful reference for solving some problems under similar engineering conditions. Graphic Abstract [ABSTRACT FROM AUTHOR]

This paper studied the characteristics of the carbon emission of an industrial wastewater treatment plant (IWWTP) and a domestic WWTP (DWWTP) located in a high-tech industrial park of Shaanxi Province, China. The results showed that the total carbon emissions of the IWWTP and DWWTP were 10.13 kg/t and 1.84 kg/t in 2020, respectively. Indirect carbon emissions play a dominant role in the total carbon emission of the IWWTP, which accounts for about 97.6% of the total amount. The direct carbon emissions of greenhouse gases (e.g., CH4, N2O) account for about 62% of the total carbon emissions in the DWWTP, followed by the indirect carbon emissions generated by electricity consumption (31.06%) and chemical consumption (6.94%). Additionally, the centralized recycling and re-utilization of the wastewater could achieve 1.06 kg/t and 1.16 kg/t of carbon emission reduction in the IWWTP and DWWTP, respectively, while the carbon emissions of the DWWTP are inversely proportional to the treatment capacity. Therefore, it is of great value to collect and utilize intensively the recycled water to achieve the goal of regional carbon emission reduction and carbon neutralization of WWTPs in industrial parks. [ABSTRACT FROM AUTHOR]

To analyze the operation risk of check dams under extreme precipitation conditions, taking Ningxia area as an example, this paper carried out a risk assessment of check dams under extreme precipitation conditions in Ningxia through data collection, hydrological statistics, numerical simulation, and other methods. The conclusions are the following: (1) By the end of 2020, about 40% of the silt reservoir capacity of check dams in various water and soil conservation zones in Ningxia has been accumulated. During 1966–2020, the extreme precipitation and frequency of extreme precipitation in Ningxia increased while the intensity of extreme precipitation decreased. The extreme precipitation in Ningxia increased year by year and lasted longer. (2) Under two future scenarios of RCP4.5 (the full name of RCP is Representative Concentration Pathway) and RCP8.5, the extreme precipitation threshold in Ningxia is gradually decreasing from south to north. Extreme precipitation in the future will bring high risk to the operation of check dams in Ningxia. The results of this paper can provide a scientific basis for the operation and management of check dams in Ningxia. [ABSTRACT FROM AUTHOR]

Prefabricated building holds promise for quality, efficiency, and sustainability when compared to traditional techniques. However, realizing prefabricated building work hinges on strengthening supply chain resilience. This research assesses interdependent risks undermining prefab network continuity during disruption. Questionnaire data from industry experts informed a structural equation model quantifying pathways between component production, construction, information, and other uncertainties. Findings confirm that project delays can be traced to manufacturing and on-site risks, with information gaps broadly propagating impacts. Meanwhile, organizational risks have an insignificant influence, suggesting partnership networks readily reconfigure around operational contingencies. Robust information infrastructures and coordination, therefore, offer crucial leverage. Accordingly, a multidimensional resilience enhancement strategy is formulated, prioritizing supply chain transparency, digital integration, inventory buffering, contingencies planning, and transportation flexibility. Our mixed-methods approach advances the construction literature by demonstrating the applicability of structural equation modeling for diagnostic resilience analytics. Industry leaders also gain actionable, evidence-based guidance on strategic investments to stabilize project flows. This dual theoretical and practical contribution underscores the versatility of tailored statistical assessments in furthering construction innovation objectives within complex, uncertain environments. [ABSTRACT FROM AUTHOR]

Sewage treatment carbon emissions are one of the notable sources of total carbon emission in industrial parks. In order to explore the evolutionary characteristics of sewage treatment carbon emission in industrial parks and its coupling relationship with industrial economic development, based on the quarterly sewage quality monitoring data and regional economic development data of an energy and chemical industry park in Northern Shaanxi from 2016 to 2020, this paper analyzes the evolutionary characteristics of sewage treatment carbon emissions and the coupling relationship between economic development in the industrial parks by using the Intergovernmental Panel on Climate Change carbon emission accounting method and the coupling coordination degree model. The results show that the total carbon emission of sewage treatment in the industrial parks is increasing year by year, and the indirect carbon emissions occupy the dominant position. In 2020, the direct and indirect carbon emissions in the sewage treatment process accounted for 2.4% and 97.6% of the total carbon emission, respectively. It was found that the coupling and coordination relationship between sewage treatment carbon emissions and the economy has experienced the transformation process of serious imbalance—lagging economic development, lagging carbon emission and lagging economic development. In the past five years, the coordinated development degree of the two systems has increased year by year, and the benign mutual feedback mechanism between the two systems has gradually formed. However, regional economic development has lagged due to the impact of the COVID-19 epidemic, so speeding up regional economic development while protecting the environment is recommended. [ABSTRACT FROM AUTHOR]

Vegetation cover is an important indicator reflecting changes in terrestrial ecosystems and plays an important role in regulating and maintaining ecosystem stability. To investigate the spatial and temporal variations in the NDVI (normalized difference vegetation index) and their intrinsic driving influences, this paper uses trend analysis and a barycentric model to study the temporal and spatial variation characteristics of vegetation in the Jialing River Basin from 2000 to 2020, constructs PLS-SEMs (partial least squares structural equation models), analyzes the indirect and direct effects of latent and observable variables of surface, human activities, and climate on vegetation growth, and explores the driving processes of different levels of NDVI. The vegetation center gradually migrates northwards. The impact of surface factors on the NDVI is mainly direct and positive. The impact of human activities on the NDVI is mainly direct and negative. The impact of climate factors on the NDVI is mainly positive. The driving mechanisms of low and medium NDVI are relatively similar but tend to be opposite to those of high NDVI. Medium and high NDVI values are more influenced by observable variables. The research on vegetation change and its driving factors, through indirect and direct paths, illustrates the driving processes of different latent and observable variables of the NDVI in more detail and provides a theoretical basis for the implementation of ecological restoration projects and construction of ecological civilizations in the future. [ABSTRACT FROM AUTHOR]

Hongjiannao is the largest inland lake in China's deserts. In recent years, the water quality and area of the Hongjiannao Lake have continued to decline, which is closely associated with the economic development in the Hongjiannao basin. To explore the coupling relationship between the water quality and economic development in the Hongjiannao basin, the water quality and economic development index of the basin has been analyzed in terms of the monthly water quality and socio-economic development from 2013 to 2020. The coupling relationship and interaction mechanism between water quality and regional economic development has been studied by coupling coordination degree model. The results show that the water pollution increased and then decreased with the seasons, while the water quality was the worst in the summer. The coordinated degree between the water quality and economic development in Hongjiannao shows an upward trend from 2013 to 2020, which has transformed from the process of lagging economic development to the process of primary coordination, finally to the process of lagging water environment. The coupling relationship between water quality and economic development changed from a state of nearly un-coordination to primary coordination from 2013 to 2016, with economic development lagging behind. The coupling relationship between the two systems changed from barely coordinated to the primary coordinated from 2017 to 2018, with the rapid development of economy and slight decline in water quality. After 2018, those two systems gradually stepped into a virtuous cycle during 2019–2020, but the phenomenon of lagging water quality still existed. Therefore, in order to maintain the stable economic development of resource-based cities, it is necessary to keep improving the current situation of water environment and water shortage in Hongjiannao, which will promote the coordinated and sustainable development of water environment and economy. [ABSTRACT FROM AUTHOR]

A reliable sediment transport capacity function provides response against challenges of soil erosion prediction on the Loess Plateau of China. The popular sediment transport capacity functions are questionable on loess slopes because the experimental conditions from which they were derived, like bed materials, gentle slopes, and surface roughness, are different from soil erosion processes on the loess slopes. Due to the foregoing uncertainty, a suitable sediment transport capacity function was developed based on a flume experiment investigation. The erodible bed experiment was implemented for five unit width discharges (1.3 × 10−4–3.3 × 10−4 m2/s) and ten slopes (5.2%–57.7%). The selected sediment transport capacity equations were tested in an applicability evaluation. The results of this evaluation found that the Govers (1990) function had the best performance (P.O. 0.5-2.0 = 76%, R 2 = 0.93, RMSE = 0.03 kg/(m·s)), followed by the Yalin (1963) function (P.O. 0.5-2.0 = 80%, R 2 = 0.81, RMSE = 0.05 kg/(m·s)), and finally by the Low (1989) function (P.O. 0.5-2.0 = 72%, R 2 = 0.79, RMSE = 0.04 kg/(m·s)), where P.O. 0.5-2.0 is the percentage of estimated values with logarithmic discrepancies with the measured value between 0.5 and 2.0; R 2 is the coefficient of determination and RMSE is the roof mean squares error. The cohesive sediment incipient motion velocity is introduced into the Govers (1990) function, and the sediment particle parameter is determined from measured experimental data. The developed sediment transport capacity equation has good performance with predicted values corresponding to measured values (P.O. 0.5-2.0 = 98%, R 2 = 0.98, RMSE = 0.006 kg/(m·s)). The research results provide an improved sediment transport capacity function on the basis of experiments for steep loessal slopes. • The cohesion sediment incipient motion velocity is introduced into the Govers (1990) function. • The sediment transport capacity was established for steep loessal slopes. • The developed sediment transport capacity has a good performance for prediction. [ABSTRACT FROM AUTHOR]

The construction industry plays a pivotal role in energy conservation and emission reduction. Therefore, it is of great significance to conduct research on quantifying carbon emissions in this industry to accelerate the establishment of a standardized carbon emission accounting system and achieve the goals of carbon peak and carbon neutrality. In this study, the focus is on the building materialization stage, and a carbon emission accounting system is established using the carbon emission factor method. This system is applied to calculate the carbon emissions of 15 residential buildings in Shaanxi Province. Results indicate that the carbon concentration during the materialization stage ranges from 372.43 kgCO2/m2 to 525.88 kgCO2/m2, and the building material production stage accounts for 94.27% of the total emissions. Additionally, by analyzing the carbon emission composition of the sample buildings, the primary factors that influence carbon emissions during the residential building materialization stage are identified, and corresponding carbon reduction strategies are proposed. The sensitivity coefficients of carbon reduction strategies vary significantly across different stages, with the building material production stage exhibiting the highest sensitivity coefficient. Thus, it is imperative to prioritize carbon reduction strategies that target the building material production stage. [ABSTRACT FROM AUTHOR]

As the primary ecological construction measure on the Loess Plateau, check dams play an essential role in developing agricultural production, improving people's production and life, and replenishing groundwater. Soil water infiltration is the most important way to replenish groundwater in the dam land. In order to investigate the water infiltration process of check dams, an empirical model suitable for the simulation of the dam land infiltration process was selected. The soil water infiltration process of the check dam was studied by a field test and a model simulation. The results showed that there were few macropores in the dam, and the water mainly moved downwards in the form of matrix flow. Moreover, the stable infiltration rate of the dam site was low, and its infiltration process could be divided into three stages: rapid infiltration, fluctuating infiltration, and stable infiltration. In addition, the infiltration rate of a non-silted dense layer was 2.4~5 times that of a silted dense layer. The Horton model had a good fitting effect on the water infiltration process of the check dam and thus was suitable for the simulation and prediction of the water infiltration process of the dam. The results can provide a theoretical basis for efficient soil water utilization and infiltration simulation of check dam land. [ABSTRACT FROM AUTHOR]

In order to study quantitative indexes and characteristics of soil erosion on the Loess Plateau, degree of complexity and stability of erosion patterns are discussed. The fractal characteristics of soil erosion spatial patterns in the Dalihe River basin were evaluated by combining them with measurements extracted from the soil erosion database of the Loess Plateau, illustrated using GIS. Results demonstrate that fractal characteristics of spatial patterns of soil erosion intensity are obvious in the Dalihe River basin. Indeed, the results show that fractal dimension reflects the degree of soil erosion complexity at certain scales of observation, is indirectly related to soil erosion degree of complexity at certain scales of observation, which indirectly corresponds to the level of difficulty to implement soil-water erosion management. In addition, the fractal characteristics of soil erosion spatial patterns in the Dalihe River basin show that patch shapes correspond with size. In other words, when the patch size is about 0.2 km², scale conversion is observed in spatial patterns of soil erosion intensity and complexity of patch shape also changes. However, at patch sizes greater than 0.2 km², the two dimensional feature was gradually enhanced for a single patch, while with the patch size less than 0.2 km², the point feature was gradually enhanced. Thus, the order of complexity in spatial patterns of soil erosion intensities in the Dalihe River basin is drastic erosion > extreme erosion > serious erosion > moderate erosion, and thus the order of priorities for the implementation of management controls on soil erosion should be moderate erosion > serious erosion > extreme erosion > drastic erosion. [ABSTRACT FROM AUTHOR]

Highlights • STN concentration of sloping cropland was lower than any other land use. • Principal factors influencing soil nitrogen are clay content and slope. • STN concentrations generally decreased as soil depth increased. • Ecological construction reduces the effects of topographic factors on STN. Abstract The construction of check dams and terraces, and the ‘Grain-for-Green’ project are major soil and water conservation measures on the Loess Plateau, China. The sediment load of the Yellow River has decreased by approximately 90% over the past 60 years and its average annual runoff has reduced from 55.9 billion m3 to 45.6 billion m3. However, whether watersheds act as sources or sinks of soil nitrogen following ecological construction measures is unknown. To understand the impacts of check dams combined with forests, grasslands, and terraces on soil nitrogen content, soil samples were collected at 20-cm intervals down to a depth of 60 cm across a small watershed of the Loess Plateau. The probability density function of the Weibull distribution was used to analyze the nitrogen sources in dammed farmland. The results indicated the mean soil total nitrogen (STN) concentrations at soil depths of 0–20, 20–40 and 40–60 cm in the watershed were 0.45, 0.32 and 0.29 g/kg, respectively. The STN concentrations among the three soil layers showed significant differences (p < 0.01). The mean STN concentration decreased as follows: dammed farmland > grassland > forestland > terrace > sloping cropland. Slope and soil texture had a significant impact on STN concentration across the watershed. The STN density of terrace, grassland, forestland, sloping cropland and dam farmland at a soil depth of 0–60 cm were 0.271, 0.289, 0.279, 0.264, and 0.288 kg/m2, respectively. The source percentages of STN deposited in dam farmland were 51% (grassland), 34% (forestland) and 15% (sloping cropland). Thus, check dam constructions have made the role of gully in the small watershed as a sink for soil nitrogen. [ABSTRACT FROM AUTHOR]

Ren, Z.; Feng Z.; Li, P.; Wang, D.; Cheng, S., and Gong J., 2017. Response of runoff and sediment yield from climate change in the Yanhe watershed, China. In: Zhi, Y. and Guido Aldana, P.A. (eds.), Sustainability of Water Resources and the Development of Coastal Environments: Select Proceedings from the 2016 International Conference on Water Resource and Environment (WRE2016). Journal of Coastal Research, Special Issue No. 80, pp. 30-35. Coconut Creek (Florida), ISSN 0749-0208. Changes in temperature and precipitation in the Loess Plateau, China have been studied for many years. The runoff and sediment yield in the Loess Plateau are sensitive to global climate change. Understanding the characteristics of runoff and sediment will be of great importance in the future. The Soil and Water Assessment Tool (SWAT) was used to simulate the runoff and the sediment yield in the Yanhe watershed, a typical water basin with soil erosion in the Loess Plateau. The resulting statistics of the SWAT simulation of the runoff and sediment yield were acceptable. The rainfall for the period from 2010 to 2099, as predicted by the Statistical Down Scaling Model (SDSM), was used to simulate the runoff and sediment yield in the future, using SWAT. Compared with the period from the 1980 to 2000, the annual precipitation increased by 9.2% to 16.4%. Under simulated future climate change, the annual runoff of the Yanhe watershed changes averaged −2.6% to 52.7%, compared with the baseline period. In the context of future climate change, in general, the runoff distribution was more even within the year when it increased significantly from March to May and decreased from July to August. The variations of the sediment yield for the watershed were −31.3% to 62.5% compare with the period from the 1980 to 2000. Overall, the trends of the sediment yield for the watershed were consistent with the runoff. [ABSTRACT FROM AUTHOR]

Soil salinization is currently a constraint on agriculture development in irrigated areas throughout the world. This study was conducted to examine the temporal stability and periodicity of groundwater electrical conductivity (EC) in irrigation districts. To accomplish this, 51 observation wells were selected for analysis of groundwater EC. Relative difference analysis and the non-parametric Spearman rank correlation test were used to check EC temporal stability, while the Morlet wavelet analysis was applied to measure the periodic variation of groundwater EC and groundwater level of high and low salinity wells. The mean groundwater EC of the 51 wells did not show an increasing trend over the entire measurement period, but demonstrated a moderate spatial variability, with coefficient of variation values ranging from 61 to 72%. The groundwater EC exhibited a strong temporal stability with Spearman correlation coefficients ranging from 0.81 to 0.98. The mean EC representative location in the study area was well 2, showing a good relationship between groundwater EC and groundwater level. Changes in groundwater EC were mainly affected by lateral groundwater recharge sources in small time scales. However, the groundwater EC and groundwater level always showed an obviously inverse phase with a large time scale due to precipitation effects. In conclusion, the groundwater EC, lateral recharge sources, and irrigation time should be fully considered in irrigation to avoid soil salinization. [ABSTRACT FROM AUTHOR]

Soil phosphorus is a major determinant and indicator of soil fertility and quality, and is also a source of nonpoint-source pollution. In order to control soil and water loss in the Loess Plateau, a series of soil and water conservation measures have been taken, resulting in changes in land use and differences in spatial distribution. It is necessary to study soil available phosphorus (SAP) to evaluate land productivity and environmental quality. In this study, the spatial distribution of SAP in different land uses was investigated in a small catchment area of Loess Plateau, and the field-influencing factors were determined on five layers with soil depth of 20 cm. The results show the minimum and maximum SAP content occurred at 20–40 cm and 80–100 cm soil depth and reach a value of 27.26 mg/kg and 29.37 mg/kg at catchment scale, respectively. There is significant difference among the SAP of the five soil layers (p < 0.01). The SAP of different land uses is, in order: forestland < slope farmland < dam farmland < terrace < grassland. Different land uses' topographies make a difference to the spatial distribution of SAP. Slope and soil texture are the domain factors influencing the SAP concentration at the catchment. [ABSTRACT FROM AUTHOR]

Soil properties are influenced by freeze-thaw, which in turn influences soil erosion. Despite this, only a few studies have investigated the impacts on soil hydrodynamic processes. The objective of this study was to evaluate the impact of soil freezing conditions on runoff, its energy consumption, and soil erosion. A total of 27 laboratory-concentrated meltwater flow experiments were performed to investigate the soil erosion rate, the runoff energy consumption, and the relationship between the soil erosion rate and runoff energy consumption by concentrated flow under combinations of three flow rates (1, 2, and 4 L/min) and three soil conditions (unfrozen, shallow-thawed, and frozen). The individual and combined effects of soil condition, flow rate, and runoff energy consumption on the soil erosion rate were analyzed. For the same flow rate, the shallow-thawed and frozen slope produced mean values of 3.08 and 4.53 times the average soil erosion rates compared to the unfrozen slope, respectively. The number of rills in the unfrozen soil slope were 4, 3, and 2 under the flow rate of 1, 2, and 4 L/min, respectively. The number of rills in the thawed-shallow and frozen soil slope were all 1 under the flow rate of 1, 2, and 4 L/min. The rill displayed disconnected distribution patterns on the unfrozen slope, but a connected rill occurred on the shallow-thawed and frozen slopes. The average rill width on unfrozen, thawed-shallow, and frozen soil slopes increased by 1.87 cm, 4.38 cm, and 1.68 cm as the flow rate increased from 1 L/min to 4 L/min. There was no significant difference in the rill length on the frozen slope under different flow rates (p > 0.05). The runoff energy consumption ranged from unfrozen > shallow-thawed > frozen slopes at the same flow rate. The soil erosion rate had a linear relationship with runoff energy consumption. The spatial distribution of the runoff energy implied that soil erosion was mainly sourced from the unfrozen down slope, shallow-thawed upper slope, and frozen full slope. [ABSTRACT FROM AUTHOR]

Abstract Vegetation restoration, terrace and check dam construction are the major measures for soil and water conservation on the Loess Plateau. These effective measures of stabilizing soils have significant impacts on soil organic carbon (SOC) distribution. However, following ecological construction, whether the hilly watershed acts as a source or a sink of soil carbon is still unknown. To understand the impact of land-use changes combined with check dam construction on SOC distribution, 1060 soil samples were collected from a 100 cm soil profile across a watershed on the Loess Plateau. The soils in the 0–20 cm layer had a higher SOC concentration than those of the 20–40, 40–60, 60–80 and 80–100 cm layers. Forestland, shrubland and terrace had significant higher SOC concentrations in the 0–20 cm soil layer than that of sloping cropland and dammed farmland (p < 0.05). SOC densities (0–100 cm) in terrace, forestland, shrubland, grassland, sloping cropland and dammed farmland were 12.09, 11.99, 11.89, 11.77, 11.41 and 10.11 kg m−2, respectively. These estimations suggested that SOC was redistributed in the watershed through land-use changes. Topographical factors, including altitude, aspect and slope had impacts on SOC concentrations. The application of hydrological controls to hillslopes and along river channels should be considered when assessing carbon sequestration within the soil erosion subsystem. Graphical abstract Unlabelled Image Highlights • The revegetation and terrace on the slope increased SOC. • SOC distribution was effected by land use changes and check dam. • Topographical factors had impacts on SOC concentrations. [ABSTRACT FROM AUTHOR]

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

The effects of soil water content (SWC) and erodibility on available nutrient losses, as well as the influence of freeze-thaw on available nitrogen (AN) and phosphorus (AP) losses from loess soils have rarely been considered. We report on a series of laboratory simulation experiments conducted to determine SWC and soil erodibility effects on AN and AP losses under freeze-thaw conditions. Effect of freeze/thaw compared to unfrozen, two treatments were set (LS: Loess that unfrozen; FTS: Freeze-thawed a loess), and we studied five SWCs, between 10% and 30%, and we divided SWCs into two groups: lower water content areas (10% and 15%), higher water content areas (20%, 25%, and 30%). Overall, significant differences in runoff/sediment associated AN and AP concentrations of different SWCs for two treatments (p < 0.05) were noted, while the relationship between SWC and AN and AP loss show a quadratic function change trend (R 2  > 0.8). Largest runoff-associated AN and AP losses were found when the SWC was 30% and the largest sediment-associated AN and AP losses were found when the SWC was 10% in the two treatments. The soil erodibility factor ( K ) of the LS was less than that of the FTS when the SWC was low, and greater in a high water content area. The influence of runoff on sediment was positively linear. The absolute slope of the regression line between runoff rate and sediment yield rate is shown to be suitable as a soil erodibility indicator, while runoff-associated AN losses are mainly controlled by runoff rate, and are weakly affected by soil erodibility (p > 0.05). However, soil erodibility significantly influenced sediment-associated AP losses (p < 0.01), best described by a positive logarithmic relationship. Since the sediment-associated AP losses dominated the total AP losses for the two treatments, soil erodibility also exhibited a significant influence on total AP losses (p < 0.01). The freeze-thaw effect increased the total AN loss when the SWC was 15%, 20%, and 30%, and increased the total AP loss when it was 10% and 15%. The results of this study provide a better understanding of soil and available nutrient loss mechanisms under freeze-thaw conditions. [ABSTRACT FROM AUTHOR]

Soil water content (SWC) plays a significant role in land surface hydrological processes (e.g., evapotranspiration, infiltration and runoff) and the spatial and temporal distribution of vegetation in arid and semi-arid regions. The aim of this study was to analyze the temporal stability of the SWC distribution pattern and to examine the primary factors that influence SWC temporal stability over a year and during the rainy season at different soil depths in terraces. The SWCs in eight soil depths at intervals of 0.2 m down to a depth of 1.6 m were measured at 21 locations in terraces containing jujube trees ( Ziziphus jujuba Mill. ) over two periods (over a year and during the rainy season). The results showed that the mean SWC over a year was larger than that for the rainy season in the corresponding layers. The mean SWC was highest in the lower slope. Soil depth significantly affected the SWC distribution over time and space. Water uptake mainly occurred between 1.0 and 1.2 m soil depth in both the rainy season and over the whole season. Moreover, the SWC demonstrated moderate spatial variability and was normally distributed at each depth. The temporal stabilities of SWC spatial patterns were strong for both the year period and the rainy season. The number of SWC representative locations varied depending on the soil depth. The SWCs measured at the best representative locations correctly represented the mean SWCs. Soil particles were the primary influencing factor affecting the mean relative difference, and root density was the primary influencing factor affecting the standard deviation of the relative differences. In conclusion, the SWC in the terraces showed stronger temporal stability during the rainy season compared to the year period. [ABSTRACT FROM AUTHOR]

The scarcity of irrigation water has now become the main constraint for crop production globally. Potato growth in arid and semiarid regions is facing increasing challenges due to water deficit. Potato productivity is generally influenced by water and fertilizer, and the requirements for these factors vary depending on the soil type and potato variety. Field experiments were conducted during 2019–2020 to select the suitable potato varieties with the best combination of irrigation and fertilization levels. The three irrigation amounts were W1 (100% crop evapotranspiration (ET C)), W2 (80% ET C) and W3 (60% ET C). The three fertilizer rates were F1 (N–P 2 O 5 –K 2 O, 240–120–300 kg ha−1), F2 (180–90–225 kg ha−1) and F3 (120–60–150 kg ha−1). The three locally cultivated potato varieties were V1 (Feiurita), V2 (Xiapoti), and V3 (Yushu 4). The results showed that irrigation amount, fertilizer amount and potato variety had significant effects on potato growth, yield, quality and water and fertilizer productivity. The average potato yield and irrigation water use efficiency (IWUE) in Feiurita were 12.5% (11.9%) and 14.2% (13.3%) higher than those in Xiapoti in 2019 (2020), respectively. On average, the tuber yield and partial factor productivity (PFP) in W1 were 27.8% (35%) and 26.8% (34.7%) higher than those in W3 in 2019 (2020), respectively. Tuber yield, IWUE and polyphenol oxidase activity (POA) were most subject to irrigation amount, followed by potato variety and fertilizer rate. Potato tuber yield was significantly correlated with soil available potassium, soil actinomycete quantity, soil catalase activity, and soil sucrase activity (SSA). The W2F3V1 treatment had the highest PFP, starch content, reducing sugar content, and vitamin C content (VC), and the tuber yield and crude protein content were relatively high. The W3F2V1 treatment had the highest IWUE and vitamin C, and the starch content and POA were relatively high. Among them, the soil actinomycete quantity, soil cellulose decomposition bacteria quantity (SCDBQ), soil catalase activity, soil urease activity (SUA), and SSA in the W2F3V1 and W3F2V1 treatments were moderate. The W2F3V1 and W3F2V1 treatments are recommended as the best water and fertilizer management in sandy loam soils in Northwest China. • Tuber yield was most subject to irrigation, followed by variety and fertilizer • Soil pH and soil conductivity significantly affected vitamin C content • Increasing irrigation amount can reduce soil actinomyces and increase sucrase • Soil cellulose decomposition bacteria significantly affected reducing sugar [ABSTRACT FROM AUTHOR]

• Difference erosion process of unfrozen, shallow-thawed and frozen soils under different meltwater flow. • The sediment yield capacity is not a constant value for the two kinds of soil structures. • Runoff energy consumption can well predict soil erosion rate. The processes of rill erosion and overland flow are significantly affected by freeze-thaw cycles. Meltwater concentrated flow laboratory experiments were carried out to assess the soil erosion of different frozen conditions based on the runoff energy consumption process which own to runoff energy against the sediment transportation and terrain evolution. The experiments were performed over frozen, shallow-thawed, and unfrozen soil-filled flumes under 1, 2, and 4 L/min flow rates with the temperature around 5 °C. The results imply that soil erosion became more severe with increasing flow rate. Variation rate of the soil erosion rate of frozen slope was highest under 1 and 2 L/min flow rates due to lower infiltration of water into soil. Variation in runoff energy consumption variation with flow time presented significant differences under unfrozen, shallow-thawed, and frozen slopes at equal runoff rate (p < 0.05). Compared with shallow-thawed and unfrozen slopes, frozen slope displayed the highest runoff energy consumption and sediment yield capacity at the equal flow rate. Sediment yield capacity was constant regardless of soil condition except in shallow-thawed soil. The sediment yield capacity under 4 L/min flow rate was different from that under 1 and 2 L/min flow rates for shallow-thawed slopes. Soil erosion rates were predictable using runoff energy consumption under one soil condition. The results of this research would provide specific implications about meltwater erosion process and hydrodynamic conditions for improving the erosion model. [ABSTRACT FROM AUTHOR]