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Journal of Arid Land 2014年第5期6卷 540-549页

作者： JuYing JIAO ZhiJie WANG GuangJu ZHAO WanZhong WANG XingMin MU institute of soil and water conservation Northwest A&F University institute of soil and water conservation Chinese Academy of Sciences and Ministry of Water Resources

The well-documented decrease in the discharge of sediment into the Yellow River has attracted considerable attention in recent years. The present study analyzed the spatial and temporal variation of sediment yield based on data from 46 hydrological stations in the sediment-rich region of the Yellow River from 1955 to 2010. The results showed that since 1970 sediment yield in the region has clearly decreased at different rates in the 45 sub-areas controlled by hydrological stations. The decrease in sediment yield was closely related to the intensity and extent of soil erosion control measures and rainstorms that occurred in different periods and sub-areas. The average sediment delivery modulus（SDM） in the study area decreased from 7,767.4 t/（km^2·a） in 1951–1969 to 980.5 t/（km^2·a） in 2000–2010. Our study suggested that 65.5% of the study area with the SDM below 1,000 t/（km^2·a） is still necessary to control soil deterioration caused by erosion, and soil erosion control measures should be further strengthened in the areas with the SDM above 1,000 t/（km^2·a）.

关键词： sediment delivery modulus(SDM) Yellow River hydrological station(s)-controlled sub-area soil and water conservation

Interpretable Machine Learning Method for Compressive Strength Prediction and Analysis of Pure Fly Ash-based Geopolymer Concrete

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Journal of Wuhan University of Technology(Materials Science) 2025年第1期40卷 65-78页

作者： SHI Yuqiong LI Jingyi ZHANG Yang LI Li Key Laboratory of Agricultural soil and water Engineering in Arid and Semiarid Areas of Ministry of Education Northwest A&F Uni-versityYangling 712100China College of water Resources and Architectural Engineering Northwest A&F UniversityYangling 712100China Chongqing Key Laboratory of Public Big Data Security Technology Chongqing 401420China Chongqing College of Mobile Communication Chongqing 401520China Department of Civil and Environmental Engineering The Hong Kong Polytechnic UniversityHung HomKowloonHong KongChina National Rail Transit Electrification and Automation Engineering Technology Research Center(Hong Kong Branch) The Hong Kong Polytechnic UniversityKowloonHung HomHong KongChina

In order to study the characteristics of pure fly ash-based geopolymer concrete(PFGC)conveniently,we used a machine learning method that can quantify the perception of characteristics to predict its compressive *** this study,505 groups of data were collected,and a new database of compressive strength of PFGC was *** order to establish an accurate prediction model of compressive strength,five different types of machine learning networks were used for comparative *** five machine learning models all showed good compressive strength prediction performance on *** them,R2,MSE,RMSE and MAE of decision tree model(DT)are 0.99,1.58,1.25,and 0.25,*** R2,MSE,RMSE and MAE of random forest model(RF)are 0.97,5.17,2.27 and 1.38,*** two models have high prediction accuracy and outstanding generalization *** order to enhance the interpretability of model decision-making,we used importance ranking to obtain the perception of machine learning model to 13 *** 13 variables include chemical composition of fly ash(SiO_(2)/Al_(2)O_(3),Si/Al),the ratio of alkaline liquid to the binder,curing temperature,curing durations inside oven,fly ash dosage,fine aggregate dosage,coarse aggregate dosage,extra water dosage and sodium hydroxide *** temperature,specimen ages and curing durations inside oven have the greatest influence on the prediction results,indicating that curing conditions have more prominent influence on the compressive strength of PFGC than ordinary Portland cement *** importance of curing conditions of PFGC even exceeds that of the concrete mix proportion,due to the low reactivity of pure fly ash.

关键词： machine learning pure fly ash geopolymer compressive strength feature perception

Effects of land-use types on the vertical distribution of fractions of oxidizable organic carbon on the Loess Plateau, China

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Journal of Arid Land 2016年第2期8卷 221-231页

作者： SUN Caili XUE Sha CHAI Zongzheng ZHANG Chao LIU Guobin institute of soil and water conservation Northwest A&F University institute of soil and water conservation Chinese Academy of Sciences and Ministry of Water Resources College of Forestry Northwest A&F University

The oxidizability of soil organic carbon （SOC） influences soil quality and carbon sequestration. Four fractions of oxidizable organic carbon （very labile （C1）, labile （C2）, less labile （C3） and non-labile （C4）） reflect the status and composition of SOC and have implications for the change and retention of SOC. Studies of the fractions of oxidizable organic carbon （OC） have been limited to shallow soil depths and agroecosystems. How these fractions respond at deep soil depths and in other types of land-use is not clear. In this study, we evaluated the vertical distributions of the fractions of oxidizable organic carbon to a soil depth of 5.0 m in 10 land-use types in the Zhifanggou watershed on the Loess Plateau, China. Along the soil profile, C1 contents were highly variable in the natural grassland and shrubland I （Caragana microphylla）, C2 and C4 contents were highly variable in the natural grassland and two terraced croplands, respectively, and C3 contents varied little. Among the land-use types, natural grassland had the highest C1 and C2 contents in the 0-0.4 m layers, followed by shrubland I in the 0-0.1 m layer. Natural grassland had the highest C4 contents in the 1.0-4.5 m layers. Natural grassland and shrubland I thus contributed to improve the oxidizability of SOC in shallow soil, and the deep soil of natural grassland has a large potential to sequester SOC on the Loess Plateau.

关键词： Iand-use types deep soil oxidizable organic-carbon fractions Loess Plateau

Flow regime and head loss in a drip emitter equipped with a labyrinth channel

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Journal of Hydrodynamics 2016年第4期28卷 610-616页

作者：张林吴普特朱德兰郑超 institute of soil and water conservation Northwest A&F University College of water Resources and Architectural Engineering Northwest A&F University

Labyrinth channels are widely adopted in emitter designs to regulate the water *** flow regime and the head loss of labyrinth channels have significant impacts on the hydraulic performance of *** this study,the flow behavior of water passing through an emitter channel is observed using the micro particle image velocimetry（PIV）,and the head loss during the flow is analyzed for an emitter with a triangular labyrinth *** results show that the flow regime is consistent with the classical theory of hydraulics governing straight channels,even when the cross-sectional area is very small（as small as 0.5 mm×0.5 mm）.The critical Reynolds number from laminar to turbulent flows in a labyrinth channel is approximately in a range between 43 and *** local head loss factor decreases as the Reynolds number increases for labyrinth channels with smaller cross-sectional areas,such as 0.5 mm×0.5 mm and 1.0 mm×1.0 *** local head loss factor is not related to the Reynolds number and is only a function of the boundary conditions of the labyrinth channel when the Reynolds number exceeds approximately 1 000（for cross-sectional areas of 1.5 mm×1.5 mm and 2.0 mm×2.0 mm）.The ratio of the local head loss to the total head loss total（ /）j fh h first increases and then remains nearly constant as the Reynolds number increases in the labyrinth *** head loss in the labyrinth channel is almost equal to the local head loss,and total（ h_j/h_（ftctal））is approximately 0.95 for cross-sectional areas of greater than 1.0 mm×1.0 *** results can be used for optimizing the design of emitter channels.

关键词： Reynolds emitter turbulent laminar straight sectional regime hydraulic passing beads

Coupling between the Grain for Green Program and a household level-based agricultural eco-economic system in Ansai,Shaanxi Province of China

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Journal of Arid Land 2020年第2期12卷 199-214页

作者： LI Yue WANG Jijun HAN Xiaojia GUO Mancai CHENG Simin QIAO Mei ZHAO Xiaocui institute of soil and water conservation Northwest A&F UniversityYangling 712100China institute of soil and water conservation Chinese Academy of Sciences and Ministry of Water ResourcesYangling 712100China

The implementation of the Grain for Green Program(GGP)has changed the development track of the agricultural eco-economic system in *** response to the results of a lag study that investigated the coupling between the GGP and the agricultural eco-economic system in a loess hilly region,we used a structural equation model to analyze the survey data from 494 households in Ansai,a district of Yan’an City in Shaanxi Province of China in *** model clarified the direction and intensity of the coupling between the GGP and the agricultural eco-economic *** coupling benefits were derived through linkages between the program and various chains in the agricultural eco-economic *** GGP,the agroecosystem of Ansai and their potential coupling effects were in a state of general *** agroecosystem directly affected the coupling effect,with the standardized path coefficient of 0.87,indicating that the agroecosystem in Ansai at this stage provided basic material support for the coupling between the GGP and the agricultural eco-economic *** direct path coefficient of agroeconomic system impacted on the coupling effect was-0.76,indicating that partial contradictions occurred between the agroeconomic system and the coupling ***,although the current agroecosystem in Ansai should be provided sufficient agroecological resources for the benign coupling between the program and the agricultural eco-economic system,agricultural development failed to effectively transform agroecological resources into agricultural economic advantages in this region,which resulted in a relative lag in the development of the agricultural economic ***,the coupling between the GGP and the agricultural eco-economic system was *** improve the coupling and the sustainable development of the agricultural eco-economic system in cropland retirement areas,the industrial structure needs to be diversified,the agricultural resources(including agroecological r

关键词： Grain for Green Program agroecosystem agroeconomic system agrosocial system coupling effect household structural equation model

Interactions between wind and water erosion change sediment yield and particle distribution under simulated conditions

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Journal of Arid Land 2015年第5期7卷 590-598页

作者： TUO Dengfeng XU Mingxiang ZHAO Yunge GAO Liqian State Key Laboratory of soil Erosion and Dryland Farming on the Loess Plateau Institute of Soil and Water ConservationNorthwest A&F University institute of soil and water conservation Chinese Academy of Sciences and Ministry of Water Resources

Wind and water erosion are among the most important causes of soil loss, and understanding their interactions is important for estimating soil quality and environmental impacts in regions where both types of erosion occur. We used a wind tunnel and simulated rainfall to study sediment yield, particle-size distribution and the fractal dimension of the sediment particles under wind and water erosion. The experiment was conducted with wind ero- sion firstly and water erosion thereafter, under three wind speeds （0, 11 and 14 m/s） and three rainfall intensities （60, 80 and 100 ram/h）. The results showed that the sediment yield was positively correlated with wind speed and rain- fall intensity （P〈0.01）. Wind erosion exacerbated water erosion and increased sediment yield by 7.25%-38.97% relative to the absence of wind erosion. Wind erosion changed the sediment particle distribution by influencing the micro-topography of the sloping land surface. The clay, silt and sand contents of eroded sediment were also posi- tively correlated with wind speed and rainfall intensity （P〈0.01）. Wind erosion increased clay and silt contents by 0.35%-19.60% and 5.80%-21.10%, respectively, and decreased sand content by 2.40%-8.33%, relative to the absence of wind erosion. The effect of wind erosion on sediment particles became weaker with increasing rainfall intensities, which was consistent with the variation in sediment yield. However, particle-size distribution was not closely correlated with sediment yield （P〉0.05）. The fractal dimension of the sediment particles was significantly different under different intensities of water erosion （P〈0.05）, but no significant difference was found under wind and water erosion. The findings reported in this study implicated that both water and wind erosion should be controlled to reduce their intensifying effects, and the controlling of wind erosion could significantly reduce water erosion in this wind-water erosion crisscross region.

关键词： sediment yield particle-size distribution fractal dimension wind and water erosion

soil Microbial Community Composition During Natural Recovery in the Loess Plateau, China

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Journal of Integrative Agriculture 2013年第10期12卷 1872-1883页

作者： XIAO Lie LIU Guo-bin XUE Sha ZHANG Chao State Key Laboratory of soil Erosion and Dryland Farming on the Loess Plateau Institute of Soil and Water ConservationNorthwest A&F University institute of soil and water conservation Chinese Academy of Sciences and Ministry of Water Resource

This study aimed to determine the characteristics of soil microbial community composition and its relationship with soil chemical properties during natural recovery in the Loess *** soil microbial community composition was analyzed by comparing the soil microbial phospholipid fatty acids（PLFAs） of eight croplands abandoned for 1,3,5,10,13,15,20,and 30 yr in the Dunshan watershed,northern Loess Plateau,*** results showed that soil organic carbon,total nitrogen,soil microbial biomass carbon,and soil microbial biomass nitrogen significantly increased with the abandonment duration,whereas the metabolic quotient significantly *** Shannon richness and Shannon evenness of PLFAs significantly increased after 10 yr of ***-negative,Gram-positive,bacterial,fungal,and total PLFAs linearly increased with increased abandonment *** analysis showed that the abandonment duration was the most important environmental factor in determining the PLFA microbial community *** soil microbial PLFAs changed from anteiso-to iso-,unsaturated to saturated,and short-to long-chain during natural ***,in the Loess Plateau,cropland abandonment for natural recovery resulted in the increase of the soil microbial PLFA biomass and microbial PLFA species and changed the microbial from chemolithotrophic to a more heterotrophic community.

关键词： abandoned cropland microbial diversity phospholipid fatty acid(PLFA) redundancy analysis(RDA) Loess Plateau

Fractal features of soil profiles under different land use patterns on the Loess Plateau, China

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Journal of Arid Land 2014年第5期6卷 550-560页

作者： Lie XIAO Sha XUE GuoBin LIU Chao ZHANG State Key Laboratory of soil Erosion and Dryland Farming on the Loess Plateau Institute of Soil and Water ConservationNorthwest A&F University institute of soil and water conservation Chinese Academy of Sciences and Ministry of Water Resources

Fractal theory is becoming an increasingly useful tool to describe soil structure dynamics for a better understanding of the performance of soil systems. Changes in land use patterns significantly affect soil physical, chemical and biological properties. However, limited information is available on the fractal characteristics of deep soil layers under different land use patterns. In this study, the fractal dimensions of particle size distribution（PSD） and micro-aggregates in the 0–500 cm soil profile and soil anti-erodibility in the 0–10 cm soil profile for 10 typical land use patterns were investigated in the Zhifanggou watershed on the Loess Plateau, China. The 10 typical land use patterns were： slope cropland, two terraced croplands, check-dam cropland, woodland, two shrublands, orchard, artificial and natural grasslands. The results showed that the fractal dimensions of PSD and micro-aggregates were all significantly influenced by soil depths, land use patterns and their interaction. The plantations of shrubland, woodland and natural grassland increased the amount of larger micro-aggregates, and decreased the fractal dimensions of micro-aggregates in the 0–40 cm soil profile. And they also improved the aggregate state and aggregate degree and decreased dispersion rate in the 0–10 cm soil profile. The results indicated that fractal theory can be used to characterize soil structure under different land use patterns and fractal dimensions of micro-aggregates were more effective in this regard. The natural grassland may be the best choice for improving soil structure in the study area.

关键词： fractal dimension anti-erodibility soil profile land use pattern Loess Plateau

Diurnal and seasonal variations of soil respiration rate under different row-spacing in a Panicum virgatum L. field on semi-arid Loess Plateau of China

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Journal of Arid Land 2016年第3期8卷 341-349页

作者： HUANG Jin GAO Zhijuan CHEN Ji ZHANG He XU Bingcheng institute of soil and water conservation Northwest A&F University State Key Laboratory of soil Erosion and Dryland Farming on the Loess Plateau Institute of Soil and Water ConservationChinese Academy of Sciences and Ministry of Water Resources

soil respiration（SR） in crop field is affected by environmental factors, agronomic practices and crop types. To clarify how planting density affects the SR dynamics in switchgrass（Panicum virgatum L.） field on the semi-arid Loess Plateau, this research investigated diurnal and seasonal changes of soil respiration rate（RS） under three different row-spacing treatments（20, 40 and 60 cm） in the fourth growing year of switchgrass. Results showed that RS presented a pronounced seasonality under all row-spacing treatments. The highest daily average RS values appeared in August, while the lowest（P〉 0.05） among the row-spacing treatments, and similar results were found for soil temperature in 0–15 cm soil depth. soil respiration temperature sensitivity（Q_（10）） values were 1.0–3.7 during the growing months, which were strongly correlated with air temperature in May and June and the soil temperature at 15 cm depth in August. Higher aboveground biomass production and lower RS in most growth months indicated that 20 cm row-spacing treatment was beneficial for increasing the carbon fixation in switchgrass field. Results also implied that it is necessary to take into account the influence of phenology and root growth of switchgrass on soil respiration for accurately evaluating the carbon cycle in the region.

关键词： switchgrass row-spacing soil temperature soil water Q_(10) value

Effect of Root Architecture on Structural Stability and Erodibility of Topsoils during Concentrated Flow in Hilly Loess Plateau

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Chinese Geographical Science 2015年第6期25卷 757-764页

作者： LI Qiang LIU Guobin ZHANG Zheng TUO Dengfeng XU Mingxiang State Key Laboratory of soil Erosion and Dry Land Farming Institute of Soil and Water Conservation Chinese Academy of Sciences and Ministry of Water Resources University of Chinese Academy of Sciences institute of soil and water conservation Northwest A?F University

Traditional vegetation techniques for the control of concentrated flow erosion are widely recognized, whereas only a few studies have experimentally investigated the impacts of belowground roots on the erodibility of topsoils in semi-arid areas. To quantify the effects of root architectures on soil erodibility and its relevant structural properties, simulated flow experiments were conducted at six-week intervals from 18 July to 20 October in 2012 in the hilly Loess Plateau. Five treatments were: 1) bare(control), 2) purple alfalfa(Medicago sativa), representing tap roots(T), 3) switchgrass(Panicum virgatum), representing fibrous roots(F), 4) purple alfalfa and switchgrass, representing both tap and fibrous roots(T + F), and 5) natural recovery(N). For each treatment, soil structural properties and root characteristics were measured at an interval of six weeks. soil anti-scouribility was calculated. Results showed that grass planting slightly reduced soil bulk density, but increased soil aggregate content by 19.1%, 10.6%, 28.5%, and 41.2% in the treatments T, F, T + F, and N, respectively. soil shear strength(cohesion and angle of internal friction(φ)) significantly increased after the grass was planted. As roots grew, soil cohesion increased by 115.2%–135.5%, while soil disintegration rate decreased by 39.0%–58.1% in the 21 th week compared with the recorded value in the 9th week. Meanwhile, root density and root surface area density increased by 64.0%–104.7% and 75.9%–157.1%, respectively. No significant differences in soil anti-scouribility were observed between the treatments of T and F or of T + F and N, but the treatments of T + F and N performed more effectively than T or F treatment alone in retarding concentrated flow. soil aggregation and root surface-area density explained the observed soil anti-scouribility during concentrated flow well for the different treatments. This result proved that the restoration of natural vegetation might be the most appropriat

关键词： fibrous roots tap roots root density soil structural properties soil anti-scouribility hilly Loess Plateau China