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Mapping Topsoil Total Nitrogen Using Random Forest and Modified Regression Kriging in Agricultural Areas of Central China

Accurate understanding of spatial distribution and variability of soil total nitrogen (TN) is critical for the site-specific nitrogen management. Based on 4337 newly obtained soil observations and 33 covariates, this study applied the random forest (RF) algorithm and modified regression kriging (RF...

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Autores principales: Zhang, Liyuan, Wu, Zhenfu, Sun, Xiaomei, Yan, Junying, Sun, Yueqi, Liu, Peijia, Chen, Jie
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2023
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10097186/
https://www.ncbi.nlm.nih.gov/pubmed/37050090
http://dx.doi.org/10.3390/plants12071464
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author Zhang, Liyuan
Wu, Zhenfu
Sun, Xiaomei
Yan, Junying
Sun, Yueqi
Liu, Peijia
Chen, Jie
author_facet Zhang, Liyuan
Wu, Zhenfu
Sun, Xiaomei
Yan, Junying
Sun, Yueqi
Liu, Peijia
Chen, Jie
author_sort Zhang, Liyuan
collection PubMed
description Accurate understanding of spatial distribution and variability of soil total nitrogen (TN) is critical for the site-specific nitrogen management. Based on 4337 newly obtained soil observations and 33 covariates, this study applied the random forest (RF) algorithm and modified regression kriging (RF combined with residual kriging: RFK, hereafter) model to spatially predict and map topsoil TN content in agricultural areas of Henan Province, central China. According to the RFK prediction, topsoil TN content ranged from 0.52 to 1.81 g kg(−1), and the farmland with the topsoil TN contents of 1.00–1.23 g kg(−1) and 0.80–1.23 g kg(−1) accounted for 48.2% and 81.2% of the total farmland area, respectively. Spatially, the topsoil TN in the study area was generally higher in the west and lower in the east. By using the Boruta variable selection algorithm, soil organic matter (SOM) and available potassium contents in topsoil, nitrogen deposition, average annual precipitation, livestock discharges, and topsoil pH were identified as the main factors driving the spatial distribution and variation of soil TN in the study area. The RF and RFK models used showed the expected performance and achieved acceptable TN prediction accuracy. In comparison, RFK performed slightly better than the RF model. The R(2) and RMSE achieved by the RFK model were improved by 4.5% and 4.5%, respectively, compared with that by the RF model. However, the results suggest that RFK was inferior to the RF model in quantifying prediction uncertainty and thus may have a slight disadvantage in model reliability.
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spelling pubmed-100971862023-04-13 Mapping Topsoil Total Nitrogen Using Random Forest and Modified Regression Kriging in Agricultural Areas of Central China Zhang, Liyuan Wu, Zhenfu Sun, Xiaomei Yan, Junying Sun, Yueqi Liu, Peijia Chen, Jie Plants (Basel) Article Accurate understanding of spatial distribution and variability of soil total nitrogen (TN) is critical for the site-specific nitrogen management. Based on 4337 newly obtained soil observations and 33 covariates, this study applied the random forest (RF) algorithm and modified regression kriging (RF combined with residual kriging: RFK, hereafter) model to spatially predict and map topsoil TN content in agricultural areas of Henan Province, central China. According to the RFK prediction, topsoil TN content ranged from 0.52 to 1.81 g kg(−1), and the farmland with the topsoil TN contents of 1.00–1.23 g kg(−1) and 0.80–1.23 g kg(−1) accounted for 48.2% and 81.2% of the total farmland area, respectively. Spatially, the topsoil TN in the study area was generally higher in the west and lower in the east. By using the Boruta variable selection algorithm, soil organic matter (SOM) and available potassium contents in topsoil, nitrogen deposition, average annual precipitation, livestock discharges, and topsoil pH were identified as the main factors driving the spatial distribution and variation of soil TN in the study area. The RF and RFK models used showed the expected performance and achieved acceptable TN prediction accuracy. In comparison, RFK performed slightly better than the RF model. The R(2) and RMSE achieved by the RFK model were improved by 4.5% and 4.5%, respectively, compared with that by the RF model. However, the results suggest that RFK was inferior to the RF model in quantifying prediction uncertainty and thus may have a slight disadvantage in model reliability. MDPI 2023-03-27 /pmc/articles/PMC10097186/ /pubmed/37050090 http://dx.doi.org/10.3390/plants12071464 Text en © 2023 by the authors. https://creativecommons.org/licenses/by/4.0/Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).
spellingShingle Article
Zhang, Liyuan
Wu, Zhenfu
Sun, Xiaomei
Yan, Junying
Sun, Yueqi
Liu, Peijia
Chen, Jie
Mapping Topsoil Total Nitrogen Using Random Forest and Modified Regression Kriging in Agricultural Areas of Central China
title Mapping Topsoil Total Nitrogen Using Random Forest and Modified Regression Kriging in Agricultural Areas of Central China
title_full Mapping Topsoil Total Nitrogen Using Random Forest and Modified Regression Kriging in Agricultural Areas of Central China
title_fullStr Mapping Topsoil Total Nitrogen Using Random Forest and Modified Regression Kriging in Agricultural Areas of Central China
title_full_unstemmed Mapping Topsoil Total Nitrogen Using Random Forest and Modified Regression Kriging in Agricultural Areas of Central China
title_short Mapping Topsoil Total Nitrogen Using Random Forest and Modified Regression Kriging in Agricultural Areas of Central China
title_sort mapping topsoil total nitrogen using random forest and modified regression kriging in agricultural areas of central china
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10097186/
https://www.ncbi.nlm.nih.gov/pubmed/37050090
http://dx.doi.org/10.3390/plants12071464
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