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Influence of soil moisture content on pullout properties of Hippophae rhamnoides Linn. roots

Journal of Mountain Science 2020年第11期17卷 2816-2826页

作者： ZHANG Chao-bo LIU Ya-ting LI Dong-rong JIANG Jing College of Water Resources Science and Engineering Taiyuan University of TechnologyTaiyuan 030024China

Plant root system plays an important role in preventing soil erosion and improving slope stability.However,its performance is significantly affected by soil moisture content,and the role of soil moisture in root reinforcement is not fully understood.In this study,the influence of soil moisture on root pullout properties was studied by experiments.Vertical in-situ pullout tests under four different levels of soil matric suction(12 kPa,18 kPa,24 kPa,30 kPa)were carried out on roots of sea buckthorn plants(Hippophae rhamnoides Linn.)which were artificially cultivated for 7 months.Diameter and length of the root system of sea buckthorn were investigated.The results showed that a very significant correlation was observed between root diameter(D)and root length(L)(Psoil depth.When soil bulk density was constant,peak pullout force(F)and friction coefficient of root-soil interface(μ)decreased with increasing gravimetric soil moisture content in power functions.soil moisture content significantly affected root pullout resistance because the increase of soil moisture content decreased the friction coefficient between the roots and soil.Root diameter at breakage point(Db)and length of root segment left in soil(Lb)were increased with soil moisture content.In addition,peak pullout force of the roots increased in a power function with root diameter at the soil surface(D0)and in a linear function with total root length(L).The results provided an experimental basis for quantifying the effects of soil moisture content on soil reinforcement by plant roots.

关键词： soil moisture content Peak pullout force Root pullout tests Root reinforcement Root morphology Hippophae rhamnoides Linn

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Changes in soil moisture content and Characteristics ofWater Movement in Citrus Orchards under Different Mulching Methods

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Asian Agricultural Research 2022年第8期14卷 49-54页

作者： Taiqing HUANG Wanzhen DENG Yanfei HUANG Agricultural Resource and Environment Research Institute Guangxi Academy of Agricultural SciencesNanning 530007China

[Objectives]The paper was to explore the effects of different mulching methods on soil moisture content and water movement in citrus orchards,and to provide the theoretical basis for improving water and weed management level in orchards.[Methods]Three ground mulching treatments including spraying herbicide(CK),grass-proof cloth cover(GPC)and natural grass mowing(NGM)were set up to analyze the soil moisture content and water flux characteristics of soil profile in the soil layers of 5,20,40 and 60 cm under different mulching methods.[Results]The GPC and NGM treatments significantly increased the soil moisture content in the soil layer of 0-60 cm at the young fruit stage and fruit expansion stage,which inhibited soil water evaporation and effectively improved soil water holding capacity,thus reducing irrigation water consumption and saving water resources.During the expansion stage of citrus fruits,the soil water flux in the soil layer of 0-60 cm in NGM and CK treatments was upward,and the upward soil water flux in NGM treatment was larger,which could mobilize more upward movement of deep soil moisture for uptake by citrus roots.However,the soil water flux in the soil layer of 0-60 cm in GPC treatment was downward,and the soil moisture conditions in the upper and middle layers were already sufficient for citrus growth.[Conclusions]Both GPC and NGM treatments can increase the overall soil moisture content.In the dry season,the soil moisture content in the upper layer treated by GPC is always relatively high,while more soil water in the lower layer move to the upper layer in NGM treatment,which has met the water requirements for citrus growth.

关键词： soil moisture content soil water flux Mulching pattern Weed management Guangxi citrus orchard

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Predicting sandy soil moisture content with hyperspectral imaging

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International Journal of Agricultural and Biological Engineering 2017年第6期10卷 175-183页

作者： Qi Haijun Jin Xiu Zhao Liu DEDO Irene Maxime Li Shaowen School of Information and Computer Anhui Agricultural UniversityHefei 230036China University of Abomey-Calavi CotonouBenin

In this study,a rapid and non-invasive technology for predicting soil moisture content(SMC)was presented based on hyperspectral imaging(HSI).Firstly,a set of HSI system was developed to collect both spectral(400-1000 nm)and spatial(1620×841 pixels)information from sandy soil samples with variable SMC levels in the laboratory.Principal component analysis(PCA)transformation,K-means clustering,and several other image processing methods were performed to obtain a region of interest(ROI)of soil sample from the original HSI data.Then,256 optimal spectral wavelengths were selected from the average reflectance of the ROI,and 28 textural features were extracted using a gray-level co-occurrence matrix(GLCM).Data dimensionality reduction was conducted on both the spectral information and textural information by using a partial least square algorithm.Six latent variables(LVs)extracted from the spectral information,four LVs extracted from the textural information and fused data were used to build regression models with a three-layer BPNN,respectively.The results showed that all of the three calibration models achieved high prediction accuracy,particularly when using spectral information with R^(2)_(C)=0.9532 and RMSEC=0.0086.However,validation models demonstrate that predicting SMC using fused data is more effective than using spectral reflectance and textural features separately,with a R^(2)_(P)=0.9350 and RMSEP=0.0141,thus proving that the HSI technique is capable of detecting SMC.

关键词： hyperspectral imaging soil moisture content image processing prediction model fused data BPNN regression

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Application of swarm intelligence algorithms to the characteristic wavelength selection of soil moisture content

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International Journal of Agricultural and Biological Engineering 2021年第6期14卷 153-161页

作者： Dongxing Zhang Jiang Liu Li Yang Tao Cui Xiantao He Tiancheng Yu Abdalla N.O.Kheiry College of Engineering China Agricultural UniversityBeijing 100083China The soil-Machine-Plant key laboratory of the Ministry of Agriculture of China Beijing 100083China Department of Agricultural Engineering College of Agricultural StudiesSudan University of Science and TechnologyKhartoum 999129Sudan

Swarm intelligence algorithms own superior performance in solving high-dimensional and multi-objective optimization problems.The application of the swarm intelligence algorithms to visible and near-infrared(VIS-NIR)spectral analysis of soil moisture can contribute to the optimization of the soil moisture prediction model and the development of the real-time soil moisture sensor.In this study,a high-resolution spectrometer was used to obtain spectral data of different levels of soil moisture which were manually configured.Isolation Forest algorithm(iForest)was used to eliminate outliers from the data.Based on the root mean square error of prediction RMSEP of Back Propagation Neural Network(BPNN)model results,a series of new swarm intelligence algorithms,including Manta Ray Foraging Optimization(MRFO),Slime Mould Algorithm(SMA),etc.,were used to select the characteristic wavelengths of soil moisture.The analysis results showed that MRFO owned the best performance if only from the predictive capability perspective and SMA had a better performance when considering the proportion of the selecting wavelengths and the results of the model prediction.By comparing and analyzing the modeling results of traditional intelligence algorithms Genetic Algorithm(GA)and Particle Swarm Optimization(PSO),it was found that the new swarm intelligence had a better performance in selecting the characteristic wavelengths of soil moisture.Integrating the results of all intelligence algorithms used,soil moisture sensitive wavelengths were selected as 490 nm,513 nm,543 nm,900 nm and 926 nm,which provide the basis for the design of real-time soil moisture sensor based on VIS-NIR.

关键词： soil moisture content swarm intelligence characteristic wavelength selection application visible and near-infrared spectroscopy

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Performance evaluation of two types of heated cables for distributedtemperature sensing-based measurement of soil moisture content

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Journal of Rock Mechanics and Geotechnical Engineering 2016年第2期8卷 212-217页

作者： Dingfeng Cao Bin Shi Honghu Zhu Kun Zhu Guangqing Wei Kai Gu School of Earth Sciences and Engineering Nanjing UniversityNanjing210023China Suzhou NanZee Sensing Technology Co. Ltd.Suzhou215123China

Distributed temperature sensing(DTS)using heated cables has been recently developed for distributed monitoring of in-situ soil moisture content.In this method,the thermal and electrical properties of heated cables have a significant influence on the measurement accuracy of soil moisture content.In this paper,the performances of two heated cables,i.***.the carbon-fiber heated cable(CFHC)and the metalnet heated cable(MNHC),are studied in the laboratory.Their structures,uniformity in the axial direction,measurement accuracy and suitability are evaluated.The test results indicate that the MNHC has a better uniformity in the axial direction than CFHC.Both CFHC and MNHC have high measurement accuracy.The CFHC is more suitable for short-distance measurement(500 m),while the MNHC can be used for longdistance measurement(>500 m).

关键词： soil moisture content Carbon-fiber heated cable(CFHC) Metal-net heated cable(MNHC) Distributed measurement Optical fiber

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Kinetic and thermodynamic effects of moisture content and temperature on the ammonia volatilization of soil fertilized with urea

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International Journal of Agricultural and Biological Engineering 2017年第6期10卷 134-143页

作者： Lei Tao Guo Xianghong Ma Juanjuan Sun Xihuan Feng Yang Wang Hongyu College of Water Science and Engineering Taiyuan University of TechnologyTaiyuan 030024China Jinzhong University Jinzhong 030600ShanxiChina

The traditional qualitative analysis of the individual factors on the kinetic and thermodynamic parameters cannot sufficiently reveal the mechanism underlying ammonia volatilization in soil.This study aimed to determine the effects of temperature,moisture content,and their interaction on the kinetic and thermodynamic parameters,which revealed the key control mechanism underlying ammonia volatilization,modified the traditional Arrhenius model,and established a quantitative prediction model of cumulative NH_(3)-N loss(CNL).Laboratory culture experiments were conducted under different temperatures(T)(15℃,20℃,25℃and 35℃)and moisture contents(θ)(60%,80%,and 100%field capacities).soil ammonia volatilization was also measured every 2 d.Results showed that the effects of individual factors and their interaction on the values of reaction rate(K_(N)),Activation free energy(ΔG),and activation entropy(ΔS)followed the descending order of T>θ>T·θ,whereas those of activation enthalpy(ΔH)and activation degree(lgN)followed the descending order ofθ>T>T·θ.The interaction showed significant effect on K_(N)value and insignificant effect on all the thermodynamic parameters.The effects of water and temperature were mainly observed during the preparatory stage and the most critical transition state stage of the chemical reaction,respectively.Given thatΔH>0,ΔG>0,andΔS>0,ammonia volatilization is found to be an endothermic reaction controlled by enthalpy.The new K_(N)(T)-2 model with the determination coefficient(R^(2))of 0.999 was more accurate than the traditional Arrhenius model with the R^(2)of 0.936.The new NH_(3)(T,θ)model with the mean absolute percentage error(MAPE)of 4.17%was more accurate than the traditional NH_(3)(T)model with the MAPE of 7.11%.These results supplemented the control mechanism underlying ammonia volatilization in soil fertilized with urea and improved the prediction accuracy of CNL.

关键词： soil ammonia volatilization kinetic parameters thermodynamic parameters soil moisture content urea fertilizer Arrhenius model NH3(T,θ)model

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Alternate freezing and thawing enhanced the sediment and nutrient runoff loss in the restored soil of the alpine mining area

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Journal of Mountain Science 2022年第6期19卷 1823-1837页

作者： LI Fa-Yong LUO Ren-jie YOU Yong-jun HU Xue-fei QIAN Xiao-yan ZHANG Peng-yan WANG Shan LI Guo-yu KAMEL Mohamed Eltohamy College of Water Resources and Architectural Engineering Tarim UniversityAral City 843300China State Key Laboratory of Frozen soil Engineering Northwest Institute of Eco-Environment and ResourcesChinese Academy of SciencesLanzhou 730000China Water Relations and Field Irrigation Department Agricultural and Biological Research DivisionNational Research CentreCairo 12622Egypt

This study highlights the influence of freezing-thawing processes on soil erosion in an alpine mine restoration area. Accordingly, a series of simulation experiments were conducted to investigate runoff, sediment, and nutrient losses, and potential influencing factors under freeze-thaw(FT) conditions. Three FT treatments(i.e., 0, 3, and 5 FT cycles), and two soil moisture contents(SMCs;i.e., 10% and 20% SMC on a gravimetric basis) were assessed. The runoff, sediment yield, ammonia nitrogen(AN), nitrate nitrogen(NN), total phosphorus(TP), and dissolved phosphorus(DP) losses from runoff were characterized under different rainfall durations. The fitting results indicated that the runoff rate and sediment rate, AN, NN, TP, and DP concentrations in runoff could be described by exponential functions. FT action increased the total runoff volume and sediment yield by 14.6%–26.0% and 8.8%–35.2%, respectively. The runoff rate and sediment rate increased rapidly with the increment of FT cycles before stabilizing. At 20% SMC, the total runoff volume and sediment yield were significantly higher than those at 10% SMC. The loss curves of AN and NN concentrations varied due to differences in their chemical properties. FT action and high SMC promoted AN and NN losses, whereas the FT cycles had little effect. FT action increased TP and DP losses by 60.2%–220.1% and 48.4%–129.8%, respectively, compared to cases with no FT action;the highest TP and DP losses were recorded at 20% SMC. This study provides a deep understanding of freezing-thawing mechanisms in the soils of alpine mine restoration areas and the influencing factors of these mechanisms on soil erosion, thereby supporting the development of erosion prevention and control measures in alpine mine restoration areas.

关键词： Freezing and thawing Mine restoration area nitrogen loss Phosphorus loss Rainfall simulation soil moisture content

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Heterogeneity of Surface Heat Exchange of Slopes and Potential Drivers of the Initiation of Thaw Slump,Qinghai‑Tibet Plateau

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International Journal of Disaster Risk Science 2023年第4期14卷 549-565页

作者： Xingwen Fan Wenjiao Li Xuyang Wu Miaomiao Yao Fujun Niu Zhanju Lin State Key Laboratory of Frozen soil Engineering Northwest Institute of Eco-Environment and ResourcesChinese Academy of SciencesLanzhou 730000China University of Chinese Academy of Sciences Beijing 100049China

In the mountainous permafrost area,most thaw slumps are distributed in north or northeast-facing shady slope areas.It is commonly known that there is a heterogeneity in permafrost between diferent slope aspects,but there has been a lack of detailed measured data to quantitatively evaluate their relationships,and in-depth understandings on how the slope aspects are linked to the distribution of thaw slumps.This study examined the heterogenous thermal regime,soil moisture content,and surface radiation at two slope sites with opposing aspects in a warming permafrost region on the Qinghai-Tibet Plateau(QTP).The results indicate that similar air temperatures(T_(a))were monitored on the two slopes,but there were signifcant diferences in ground temperature and moisture content in the active layer from 2016 to 2021.The sunny slope exhibited a higher mean annual ground surface temperature(T_(s)),and over the fve years the mean annual temperature at the top of permafrost was 1.3–1.4℃warmer on the sunny slope than the shady slope.On the contrary,the near-surface soil moisture content was about 10–13%lower on the sunny slope(~22–27%)than the shady slope(~35–38%)during the thawing season(June–September).Radiation data indicate that signifcantly higher shortwave downward radiation(DR)appeared at the sunny slope site.However,due to the greater surface albedo,the net radiation(Rn)was lower on the sunny slope.Slope aspect also afects the ground ice content due to its infuence on ground temperature,freeze-thaw cycles,and soil moisture.Shady slopes have a shallower burial of ice-rich permafrost compared to sunny slopes.The results highlight greatly diferent near-surface ground thermal conditions at the two slope sites with diferent aspects in a mountainous permafrost region.This helps identify the slope-related causes of increasing thaw slumps and provides a basis for predicting their future development.

关键词： Mountainous permafrost Slope aspect soil moisture content Surface heat exchange Thaw slumps

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Effects of mulch and planting methods on Medicago ruthenica seed yield and soil physical-chemical properties

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Journal of Arid Land 2022年第8期14卷 894-909页

作者： WANG Yuxia ZHANG Jing YU Xiaojun College of Grassland Science Gansu Agricultural UniversityLanzhou 730070China

Medicago ruthenica (L.) Trautv., a wild grass species, is commonly grown as a forage crop in arid and semi-arid areas of China. Herein, we explored mulch patterns and planting methods for optimizing M. ruthenica seed production in the loess plateau of the Gansu Province, China from 2017 to 2019. The experiments comprised of six treatments including (1) flat ground without mulch (F0, control);(2) flat ground with a transparent white 0.008 mm thick plastic film mulch (FP);(3) flat ground with 4500 kg/hm2 straw mulch (FS);(4) furrow with 10 cm ridges (R0);(5) furrow with plastic film mulch (RP);and (6) furrow with straw mulch (RS). Results showed that the harvested seed yield of M. ruthenica was the highest under RP treatment, followed by FP and FS treatments. soil moisture content from mid-May to mid-August in 2017 was the highest under RP and FP treatments, followed by RS and FS treatments. In 2018, soil moisture content was the highest under RS and FS treatments. In 2017 and 2018, soil temperature was the highest under FP and RP treatments, followed by F0 and R0 treatments. Total and available nitrogen, phosphorus, and potassium contents were the highest under RS and FS treatments, followed by RP and FP treatments. Comprehensive analysis result showed that surface mulch improved soil microenvironment and increased seed yield of M. ruthenica. Straw mulch also effectively recycled excess crop straw, thereby encouraging the sustainable development of agriculture in this area. In conclusion, FS treatment was considered the best mode for M. ruthenica seed production in this area.

关键词： arid area plastic film straw mulch soil moisture content soil temperature soil chemistry

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Improvement in winter wheat productivity through regulating PSⅡ photochemistry,photosynthesis and chlorophyll fluorescence under deficit irrigation conditions

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Journal of Integrative Agriculture 2022年第3期21卷 654-665页

作者： Shahzad ALI XU Yue-yue MA Xiang-cheng JIA Qian-min JIA Zhi-kuan College of Pastoral Agriculture Science and Technology Lanzhou UniversityLanzhou 730000P.R.China Institute of Water Saving Agriculture in Arid Areas Yangling 712100P.R.China

Deficit irrigation is critical to global food production,particularly in arid and semi-arid regions with low precipitation.Given water shortage has threatened agricultural sustainability under the dry-land farming system in China,there is an urgent need to develop effective water-saving technologies.We carried out a field study under two cultivation techniques:(1) the ridge and furrow cultivation model(R);and(2) the conventional flat farming model(F),and three simulated precipitation levels(1,275 mm;2,200 mm;3,125 mm) with two deficit irrigation levels(150 and 75 mm).We demonstrated that under the ridge furrow(R) model,rainfall harvesting planting under 150 mm deficit irrigation combined with 200 mm simulated precipitation can considerably increase net photosynthesis rate(P_(n)),quantum yield of PSII(ΦPSⅡ),electron transport rate(ETR),performance index of photosynthetic PSII(F_(v)/F_(m)′),and transformation energy potential of PSII(F_(v)/F_(o)).In addition,during the jointing,anthesis and grain-filling stages,the grain and biomass yield in the R model are 18.9 and 11.1% higher than those in the flat cultivation model,respectively,primarily due to improved soil water contents.The winter wheat fluorescence parameters were significantly positively associated with the photosynthesis,biomass and wheat production.The result suggests that the R cultivation model with irrigation of 150 mm and simulated precipitation of 200 mm is an effective planting method for enhancing P_(n),biomass,wheat production,and chlorophyll fluorescence parameters in dry-land farming areas.

关键词： chlorophyll fluorescence deficit irrigation photosynthesis production planting models soil moisture content

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