A high-resolution map of soil pH in China made by hybrid modelling of sparse soil data and environmental covariates and its implications for pollution

Chen, Songchao; Liang, Zhao; Webster, R.; Zhang, Gan‐Lin; Zhou, Yin; Teng, Hongfen; Hu, Bifeng; Arrouays, Dominique; Shi, Zhou

doi:10.1016/j.scitotenv.2018.11.230

Cited by 146 publications

(72 citation statements)

References 34 publications

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“…Consequently, WMA exhibited the best competence for capturing the spatial variation of soil TN and reducing prediction uncertainty as well. The results from many other studies have been similar, with researchers concluding that the results were better from an ensemble of different DSM models than from a single model [22,23]. Hence, we suggest that it is often useful to combine the predictions of several models because the large variance can be balanced through averaging.…”

Section: Quality Of the Predictionsupporting

confidence: 77%

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Fine-Resolution Mapping of Soil Total Nitrogen across China Based on Weighted Model Averaging

et al. 2019

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Accurate estimates of the spatial distribution of total nitrogen (TN) in soil are fundamental for soil quality assessment, decision making in land management, and global nitrogen cycle modeling. In China, current maps are limited to individual regions or are of coarse resolution. In this study, we compiled a new 90-m resolution map of soil TN in China by the weighted summation of random forest and extreme gradient boosting. After harmonizing soil data from 4022 soil profiles into a fixed soil depth (0–20 cm) by equal area spline, 18 environmental covariates were employed to characterize the spatial pattern of soil TN in topsoil across China. The accuracy assessments from independent validation data showed that the weighted model averaging gave the best predictions with an acceptable R2 (0.41). The prediction map showed that high-value areas of soil TN were mainly distributed in the eastern Tibetan Plateau, central Qilian Mountains and the north of the Greater Khingan Range. Climate factors had a considerable influence on the variation of the soil TN, and land-use types played a pivotal part in each climate zone. This high-resolution and high-quality soil TN data set in China can be very useful for future inventories of soil nitrogen, assessments of soil nutrient status, and management of arable land.

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Section: Quality Of the Predictionsupporting

confidence: 77%

“…In recent years, weighted model averaging has proved its superior predictive capacity comparing to the single DSM model [22,23]. Weighted average is a simple realization of ensemble modeling, a process of training multiple models and then synthesizing the predictions of these base learners into a single prediction value [24].…”

Section: Introductionmentioning

confidence: 99%

Fine-Resolution Mapping of Soil Total Nitrogen across China Based on Weighted Model Averaging

et al. 2019

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“…Burak et al (2010) obtained results very close to those obtained in this study. Chen et al (2018) also used MSE and RMSSE in a work aiming to map the spatial variability of soil chemical and physical attributes.…”

Section: Analysis Of Spatial Variabilitymentioning

confidence: 99%

Using multivariate analysis to design management zones

et al. 2020

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Soil chemical and physical attributes are important in any agricultural cropping system, but in precision agriculture they are more relevant due to the possibility of application using different management practices along a production field. However, the correlation between these attributes has been little explored in the delineation of management zones. This work aims to maximize the use of joint spatial variability for soil attributes. Its secondary objectives were 1) reduction of spatial variability dimensionality among all attributes and 2) assessment of agreement between univariate and multivariate management zones. The management zones resulting from the interpolation of attribute values, as well as from the scores of each of the three main components, were delineated using the Fuzzy c-means algorithm. The fuzzy performance and modified partition entropy indexes were used to determine the optimal number of management zones. The Kappa index was used to evaluate the agreement of management zones obtained from attributes with those obtained from principal components. By using principal component analysis, it was possible to reduce the dimensionality of the number of variables that contribute to the joint spatial variability existing in the study area. There was no complete agreement between the uni-and multivariate management zones outlined, which is why further studies on the subject are needed.

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“…Various assessments for natural resources include processes such as grinding of rock and metals, recovery of selected element and disposal of the wastes, often as slurry, to a tailing or preservation pond. Finally, almost all the original material may become tailings when low-quality ores are utilized [8][9][10].…”

Section: Introductionmentioning

confidence: 99%

“…Metals and radioactive elements are also abundant in soils and sediments derive from both natural and anthropogenic sources. Pathways include inheritance from the parental rocks, application of water and fluvial and/or marine deposition of discharges from dust and mining [10,17,18]. At the end, most of metal trace elements, at low values have a crucial role as nutrients for flora, animals, and human health.…”

Section: Introductionmentioning

confidence: 99%

Mine Waste and Heavy Metal Pollution in Betare-Oya Mining Area (Eastern Cameroon)

Tehna¹,

Sababa²,

Bessa³

et al. 2019

EESRJ

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This study includes soils and tailings from the gold mine of four stations (Mari, Mbigala, Mboufa and, Bedobo) in Betare-Oya, eastern Cameroon. These stations have been utilized by Cameroonians and later on by some companies. Soils and tailings were sampled and heavy metal (Cr, V, Ni, Cu, Zn, Hg and, Pb) and radioactive element (Th and U) contents have been determined using ICP-MS techniques. This work deals with the heavy metaldistribution in mining waste and surrounding soils and tailings.The study area is exposed to artisanal gold mining activities. Field observations revealed the soildestructionas well as the environment.All metal values fall below the average shale, except Cr who's the content is higher than the shale value in soils and tailings. Lead and Th values are above the average shale in tailings. Heavy metal pollution was performed using pollution indices such as enrichment factor (EF), geo-accumulation index (I-geo) and pollution load index (PLI). The overall results reveal that the soils and tailing from Betare-Oya mining area, Eastern Cameroon are only polluted by Cr. These sediments have minor to moderate enrichment; they are unpolluted to moderately polluted with a low contamination level for other metals. Only two stations can be considered as slightly polluted, with minor enrichment and moderate contamination by metals.

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A high-resolution map of soil pH in China made by hybrid modelling of sparse soil data and environmental covariates and its implications for pollution

Cited by 146 publications

References 34 publications

Fine-Resolution Mapping of Soil Total Nitrogen across China Based on Weighted Model Averaging

Fine-Resolution Mapping of Soil Total Nitrogen across China Based on Weighted Model Averaging

Using multivariate analysis to design management zones

Mine Waste and Heavy Metal Pollution in Betare-Oya Mining Area (Eastern Cameroon)

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