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Sampling Designs for Validating Digital Soil Maps: A Review

Pedosphere 2018年第1期28卷 1-15页

作者： asim biswas Yakun ZHANG School of Environmental Sciences University of Guelph Department of Natural Resource Sciences McGill University University of Wisconsin-Madison Department of Soil Science FD Hole Soils Lab

Sampling design(SD) plays a crucial role in providing reliable input for digital soil mapping(DSM) and increasing its *** design, with a predetermined sample size and consideration of budget and spatial variability, is a selection procedure for identifying a set of sample locations spread over a geographical space or with a good feature space coverage. A good feature space coverage ensures accurate estimation of regression parameters, while spatial coverage contributes to effective spatial ***, we review several statistical and geometric SDs that mainly optimize the sampling pattern in a geographical space and illustrate the strengths and weaknesses of these SDs by considering spatial coverage, simplicity, accuracy, and efficiency. Furthermore, Latin hypercube sampling, which obtains a full representation of multivariate distribution in geographical space, is described in detail for its development, improvement, and application. In addition, we discuss the fuzzy k-means sampling, response surface sampling, and Kennard-Stone sampling, which optimize sampling patterns in a feature space. We then discuss some practical applications that are mainly addressed by the conditioned Latin hypercube sampling with the flexibility and feasibility of adding multiple optimization criteria. We also discuss different methods of validation, an important stage of DSM, and conclude that an independent dataset selected from the probability sampling is superior for its free model assumptions. For future work, we recommend: 1) exploring SDs with both good spatial coverage and feature space coverage; 2) uncovering the real impacts of an SD on the integral DSM procedure;and 3) testing the feasibility and contribution of SDs in three-dimensional(3 D) DSM with variability for multiple layers.

关键词： calibration geographical space Latin hypercube sampling model-based design spatial coverage three-dimensional(3D) digital soil mapping

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Leaf stoichiometry of Leontopodium lentopodioides at high altitudes on the northeastern Qinghai-Tibetan Plateau,China

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Journal of Arid Land 2022年第10期14卷 1124-1137页

作者： WANG Hairu SU Haohai asim biswas CAO Jianjun College of Geography and Environmental Science Northwest Normal UniversityLanzhou 730070China School of Environmental Sciences University of Guelph50 Stone Road EastGuelphOntario N1G 2W1Canada Key Laboratory of Eco-Functional Polymer Materials of the Ministry of Education Northwest Normal UniversityLanzhou 730070China Key Laboratory of Resource Environment and Sustainable Development of Oasis College of Geography and Environmental ScienceNorthwest Normal UniversityLanzhou 730070China

Altitude affects leaf stoichiometry by regulating temperature and precipitation,and influencing soil properties in mountain *** carbon concentration(C),leaf nitrogen concentration(N),leaf phosphorous concentration(P),and their stoichiometric ratios of Leontopodium lentopodioides(Willd.)Beauv.,a widespread species in degraded grasslands,were investigated to explore its response and adaptation strategy to environmental changes along four altitude gradients(2500,3000,3500,and 3800 m a.s.l.)on the northeastern Qinghai-Tibetan Plateau(QTP),*** leaf C significantly varied but without any clear trend with increasing *** N showed an increasing trend,and leaf P showed a little change with increasing altitude,with a lower value of leaf P at 3500 m than those at other ***,leaf C:P and N:P exhibited a little change with increasing altitude,which both had greater values at 3500 m than those at other ***,leaf C:N exhibited a decreasing trend with increasing *** NH^(+)_(4)-N,soil pH,soil total phosphorus(STP),mean annual temperature(MAT),and mean annual precipitation(MAP)were identified as the main factors driving the variations in leaf stoichiometry of *** across all altitudes,with NH^(+)_(4)-N alone accounting for 50.8%of its total ***,leaf C and N were mainly controlled by MAT,soil pH,and NH^(+)_(4)-N,while leaf P by MAP and *** the study area,it seems that the growth of *** may be mainly limited by *** results could help to strengthen our understanding of the plasticity of plant growth to environmental changes and provide new information on global grassland management and restoration.

关键词： alpine area environmental changes leaf elements nutrient limitation Qilian Mountains

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Comparison of sampling designs for calibrating digital soil maps at multiple depths

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Pedosphere 2022年第4期32卷 588-601页

作者： Yakun ZHANG Daniel D.SAURETTE Tahmid Huq EASHER Wenjun JI Viacheslav I.ADAMCHUK asim biswas University of Wisconsin-Madison Department of Soil ScienceFD Hole Soils Lab1525 Observatory DriveMadison WI 53706USA School of Environmental Sciences University of Guelph50 Stone Road EastGuelph ON N1G 2W1Canada College of Land Science and Technology China Agricultural UniversityBeijing 100083China Department of Bioresource Engineering McGill University21111 Lakeshore RoadSte-Anne-de-Bellevue QC H9X 3V9Canada

Digital soil mapping (DSM) aims to produce detailed maps of soil properties or soil classes to improve agricultural management and soil quality assessment. Optimized sampling design can reduce the substantial costs and efforts associated with sampling, profile description, and laboratory analysis. The purpose of this study was to compare common sampling designs for DSM, including grid sampling (GS), grid random sampling (GRS), stratified random sampling (StRS), and conditioned Latin hypercube sampling (cLHS). In an agricultural field (11 ha) in Quebec, Canada, a total of unique 118 locations were selected using each of the four sampling designs (45 locations each), and additional 30 sample locations were selected as an independent testing dataset (evaluation dataset). Soil visible near-infrared (Vis-NIR) spectra were collected in situ at the 148 locations (1 m depth), and soil cores were collected from a subset of 32 locations and subdivided at 10-cm depth intervals, totaling 251 samples. The Cubist model was used to elucidate the relationship between Vis-NIR spectra and soil properties (soil organic matter (SOM) and clay), which was then used to predict the soil properties at all 148 sample locations. Digital maps of soil properties at multiple depths for the entire field (148 sample locations) were prepared using a quantile random forest model to obtain complete model maps (CM-maps). Soil properties were also mapped using the samples from each of the 45 locations for each sampling design to obtain sampling design maps (SD-maps). The SD-maps were evaluated using the independent testing dataset (30 sample locations), and the spatial distribution and model uncertainty of each SD-map were compared with those of the corresponding CM-map. The spatial and feature space coverage were compared across the four sampling designs. The results showed that GS resulted in the most even spatial coverage, cLHS resulted in the best coverage of the feature space, and GS and cLHS resu

关键词： 3D digital soil mapping conditioned Latin hypercube sampling grid sampling quantile random forest model stratified random sampling

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Determining minimum sample size for the conditioned Latin hypercube sampling algorithm

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Pedosphere 2024年第3期34卷 530-539页

作者： Daniel D.SAURETTE asim biswas Richard J.HECK Adam W.GILLESPIE Aaron A.BERG School of Environmental Sciences University of Guelph50 Stone Rd EastGuelph ON N1G 2W1(Canada) Ontario Ministry of Agriculture Food and Rural Affairs1 Stone Rd WestGuelph ON N1G 2Y4(Canada) Geography Environment&GeomaticsUniversity of Guelph50 Stone Rd EastGuelph ON N1G 2W1(Canada)

In digital soil mapping(DSM),a fundamental assumption is that the spatial variability of the target variable can be explained by the predictors or environmental *** to adequately sample the predictors have been well documented,with the conditioned Latin hypercube sampling(cLHS)algorithm receiving the most attention in the DSM *** advances in sampling design,a critical gap remains in determining the number of samples required for DSM *** propose a simple workflow and function coded in R language to determine the minimum sample size for the cLHS algorithm based on histograms of the predictor variables using the Freedman-Diaconis rule for determining optimal bin *** preprocessing was included to correct for multimodal and non-normally distributed data,as these can affect sample size determination from the *** on a user-selected quantile range(QR)for the sample plan,the densities of the histogram bins at the upper and lower bounds of the QR were used as a scaling factor to determine minimum sample *** technique was applied to a field-scale set of environmental covariates for a well-sampled agricultural study site near Guelph,Ontario,Canada,and tested across a range of *** results showed increasing minimum sample size with an increase in the QR *** sample size increased from 44 to 83 when the QR increased from 50% to 95% and then increased exponentially to 194 for the 99%*** technique provides an estimate of minimum sample size that can be used as an input to the cLHS algorithm.

关键词： bin width digital soil mapping normal distribution quantile range sampling design

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祁连山植物共有种沿海拔梯度的叶片化学计量特征

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Journal of Plant Ecology 2024年第1期17卷 78-93页

作者： Shuyan Hong Jie Chen asim biswas Jianjun Cao Xiaogang Dong College of Geography and Environmental Science Northwest Normal UniversityLanzhou 730070China School of Environmental Sciences University of GuelphGuelphON N1G 2W1Canada Key Laboratory of Eco-functional Polymer Materials of the Ministry of Education Northwest Normal UniversityLanzhou 730070China

研究不同海拔地区植物共有种叶片化学计量的变化及其影响因素和适应策略,对于理解全球环境变化中的生物地球化学循环具有重要意义。在本研究中,我们测量了中国西北部祁连山5个海拔高度(海拔2400-3200 m,间隔200 m)的土壤有机碳和养分浓... 详细信息

研究不同海拔地区植物共有种叶片化学计量的变化及其影响因素和适应策略,对于理解全球环境变化中的生物地球化学循环具有重要意义。在本研究中,我们测量了中国西北部祁连山5个海拔高度(海拔2400-3200 m,间隔200 m)的土壤有机碳和养分浓度,以及植物共有种的叶片化学计量,以期能更好地了解山区植物共有种如何对海拔变化表现出适应性反应及未来潜在的环境变化如何影响其叶片功能。研究结果表明,随海拔高度的增加,植物共有种叶片C:N:P化学计量的变化不同。在不同的海拔梯度上,年平均气温(MAT)、土壤全磷(STP)、年平均降水量(MAP)、土壤含水量(SWC)和土壤硝态氮(NO3-N)是影响植物共有种叶片元素浓度的主要因素。而叶片化学计量比主要由MAT、MAP和土壤全氮(STN)决定。MAT和MAP对植物共有种叶片元素浓度和叶化学计量比均有显著影响。研究区植物生长主要受到磷的限制。研究结果不仅凸显了植物的可塑性生存策略,还有助于加深我们对植物叶片化学计量学的理解,建立单个植物物种和植物群落与共有种之间的联系。

关键词：地形因子海拔梯度常见植物种类叶片化学计量祁连山

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Interactions between invasive plants and heavy metal stresses:a review

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Journal of Plant Ecology 2022年第3期15卷 429-436页

作者： Jian Li Zhanrui Leng Yueming Wu Yizhou Du Zhicong Dai asim biswas Xiaojun Zheng Guanlin Li Esawy Kasem Mahmoud Hui Jia Daolin Du Institute of Environment and Ecology Institute of Environmental Health and Ecological SecuritySchool of the Environment and Safety EngineeringJiangsu UniversityZhenjiang 212013China Key Laboratory of Original Agro-Environmental Pollution Prevention and Control Ministry of Agriculture and Rural Affairs/Tianjin Key Laboratory of Agro-Environment and Agro-Product SafetyAgro-Environment Protection InstitutionMinistry of Agriculture and Rural AffairsTianjin 300191China Faculty of Engineering School of Computer ScienceUniversity of SydneyDarlingtonNSW 2008Australia School of Environmental Sciences University of GuelphGuelphON N1G 2W1Canada Department of Soil and Water Science Faculty of AgricultureTanta UniversityTantaEgypt

Global changes have altered the distribution pattern of the plant communities,including invasive *** contamination may reduce native plant resistance to the invasive ***,the focus of the current review is on the contaminant biogeochemical behavior among native plants,invasive species and the soil within the plant-soil ecosystem to improve our understanding of the interactions between invasive plants and environmental *** studies together with synthesis of the literature showed that(i)the impacts of invasive species on environmental stress were heterogeneous,(ii)the size of the impact was variable and(iii)the influence types were multidirectional even within the same impact ***,invasive plants showed self-protective mechanisms when exposed to heavy metals(HMs)and provided either positive or negative influence on the bioavailability and toxicity of *** the other hand,HMs may favor plant invasion due to the widespread higher tolerance of invasive plants to HMs together with the‘escape behavior’of native plants when exposed to toxic HM ***,there has been no consensus on whether elemental compositions of invasive plants are different from the natives in the polluted regions.A quantitative research comparing plant,litter and soil contaminant contents between native plants and the invaders in a global context is an indispensable research focus in the future.

关键词： environmental stresses heavy metals plant invasion biogeochemical cycle mechanisms

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The impact of alpha-fetoprotein(AFP),child-turcotte-pugh(CTP)score and disease staging on the survival of hepatocellular carcinoma(HCC)patients:a retrospective cohort from single oncology center

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Oncology Research 2025年第1期33卷 149-160页

作者： NASSER MULLA YOUSEF KATIB asim M.ALMUGHAMSI DUAA S.ALKHAYAT MOHAMED MOSAAD SAMIR T.ALFOTIH RAWAN ALAOFI Department of Internal Medicine Faculty of MedicineTaibah UniversityMadinah42278Saudi Arabia Department of Radiology Faculty of MedicineTaibah UniversityMadinah42278Saudi Arabia Department of Surgery Faculty of MedicineTaibah UniversityMadinah42278Saudi Arabia Department of Endemic and Infectious Diseases Suez Canal UniversityIsmailia41522Egypt King Salman bin Abdulaziz Medical City Madinah42311Saudi Arabia Prince Mohammed Bin Abdulaziz Hospital Madinah41511Saudi Arabia

Background:Hepatocellular carcinoma(HCC)is the most common cause of cancer-related death in Saudi *** study aimed to investigate the patterns of HCC and the effect of TNM staging,Alfa-fetoprotein(AFP),and Child-Turcotte Pugh(CTP)on patients’overall survival(OS).Methods:A retrospective analysis was conducted on 43 HCC patients at a single oncology center in Saudi Arabia from 2015 to *** patients had to fulfill one of the following criteria:(a)a liver lesion reported as definitive HCC on dynamic imaging and/or(b)a biopsy-confirmed ***:The mean patient age of all HCC cases was 66.8 with a male-to-female ratio of 3.3:*** patients were stratified into two groups:viral HCC(n=22,51%)and non-viral HCC(n=21,49%).Among viral-HCC patients,55%were due to HBV and 45%due to *** was diagnosed in 79%of *** and sex did not significantly statistically differ in OS among viral and non-viral HCC patients(p-value>0.05).About 65%of patients had tumor size>5 cm during the diagnosis,with a significant statistical difference in OS(p-value=0.027).AFP was>400 ng/ml in 45%of the *** was a statistically significant difference in the OS in terms of AFP levels(p-value=0.021).A statistically significant difference was also observed between the CTP score and OS(p-value=0.02).CTP class B had the longest *** was the most common treatment provided to HCC patients followed by sorafenib *** was a significant statistical difference in OS among viral and non-viral HCC patients(p-value=0.008).Conclusions:The most common predictors for OS were the underlying cause of HCC,AFP,and tumor *** having non-viral etiology,a tumor size>5 cm,an AFP>400 ng/mL,and a CTP score class C were all negatively associated with OS.

关键词： Hepatocellular carcinoma Pattern Alpha-fetoprotein(AFP) Child-turcotte-pugh Progression free survival

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Preparation of LDPE-Acetylated/Butyrylated Starch Blend Blow Films and Characterization

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Chinese Journal of Polymer Science 2014年第3期32卷 268-279页

作者： Sangeeta Garg asim Kumar Jana Department of Chemical Engineering National Institute of TechnologyJalandhar Department of Biotechnology National Institute of TechnologyJalandhar

Development of modified plastics has been studied through the LDPE-acylated starch blend films to examine the effect of different acyl groups and degrees of substitution （DS） on properties of films. Corn starch was modified with acetyl and hutyryl groups and films were prepared by blending acylated starch with low density polyethylene （LDPE）. Systematic studies were done to observe the effect of acyl groups, DS and starch concentration on the properties and biodegradability of the blend films. It was observed that blend films containing 5% acetylated and butyrylated starches of high DS （2.5, 1.7） maintained 75% and 83% of tensile strength of LDPE films. Thermal analysis results indicated that acetylated and butyrylated starch blend films decomposed at 370℃ and 389℃ which were higher than the decomposition temperature of native starch film （349℃）. Scanning electron micrographs of blend films containing high DS acylated starch showed well dispersed starch particles due to improvement in dispersion between starch and LDPE. Water absorption capacity of high DS acetylated and butyrylated starch blend films （4.18% and 3.76%, respectively） was lower than that of native starch films （5%）. This study has an advantage because of blown films prepared can be integrated with the present manufacturing systems without any other requirement.

关键词： Acylated starch LDPE-starch blend films Mechanical properties Water absorption capacity Biodegradability.

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Generation of a long-term daily gridded precipitation dataset for the rTjSj-Upper Indus Basin(UIB)through temporal Reconstruction,Correction I sag&Informed Regionalization-“ReCIR”

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International Soil and Water Conservation Research 2021年第3期9卷 445-460页

作者： asim Jahangir Khan Manfred Koch Department of Geohydraulics and Engineering Hydrology University of Kassel34125KasselGermany

This study attempted to generate a long-term(1961-2010)daily gridded precipitation dataset for the Upper Indus Basin(UIB)with orographic adjustments so as to generate realistic precipitation estimates,enabling hydrological and water resource investigations that can close the water balance,that is difficult,if not impossible to achieve with the currently available precipitation data products for the *** procedure includes temporal reconstruction of precipitation series at points where data were not recorded prior to the mid-nineties,followed by a regionalization of the precipitation series to a smaller scale across the basin(0.125°x 0.125°),while introducing adjustments for the orographic effect and changes in glacier *** reconstruction process involves interpolation of the precipitation at virtual locations of the current(1995-)dense observational network,followed by corrections for frequency and intensity and adjustments for temporal trends at these virtual *** data generated in this way were further validated for temporal and spatial representativeness through evaluation of SWAT-modelled streamflow responses against observed flows across the *** results show that the calibrated SWAT-simulated daily discharge at the basin outlet as well as at different sub-basin outlets,when forcing the model with the reconstructed precipitation of years 1973—1996,is almost identical to that when forcing it with the reference precipitation data(1997-2008).Finally,the spatial distribution pattern of the reconstructed(1961—1996)and reference(1997—2008)precipitation were also found consistent across the UIB,reflecting well the large-scale atmospheric-circulation pattern in the region.

关键词： Precipitation Temporal reconstruction Orographic correction factor(OCF) Soil and water assessment tool(SWAT) Glacier/water mass balance Upper indus basin(UIB)

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Binding energy of the donor impurities in GaAs-Ga_(1-x)Al_xAs quantum well wires with Morse potential in the presence of electric and magnetic fields

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Chinese Physics B 2016年第10期25卷 39-44页

作者： Esra Aciksoz Orhan Bayrak asim Soylu Department of Physics Akdeniz University Department of Physics Nigde University

The behavior of a donor in the GaAs–GaAlAs quantum well wire represented by the Morse potential is examined within the framework of the effective-mass approximation. The donor binding energies are numerically calculated for with and without the electric and magnetic fields in order to show their influence on the binding energies. Moreover, how the donor binding energies change for the constant potential parameters(De, re, and a) as well as with the different values of the electric and magnetic field strengths is determined. It is found that the donor binding energy is highly dependent on the external electric and magnetic fields as well as parameters of the Morse potential.

关键词： Morse potential electric field magnetic field the donor atom quantum well wire

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