Mapping a hydrophysical soil property through a comparative analysis of local and global scale approximations

Gustavo Alfonso Araujo-Carrillo,Leidy Yibeth Deantonio-Florido,Fabio Ernesto Martínez-Maldonado,Andrea Onelia Rodríguez-Roa,Douglas Andrés Gómez-Latorre,Viviana Marcela Varón-Ramirez,Jhon Mauricio Estupiñan-Casallas

doi:10.1590/1678-992x-2019-0126

Gustavo Alfonso Araujo-Carrillo, Leidy Yibeth Deantonio-Florido + Show 5 more

Open Access

https://doi.org/10.1590/1678-992x-2019-0126

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Abstract

Current available soil information allows building baselines to improve research, such as sustainable resource management; however, its use requires analysis of accuracy and precision that describes specific variables on local and global scales. Therefore, this study evaluated differences in the spatial distribution of water retention capacity (WRC) of the soil at a depth of 0.3 m, calculated from local general soil surveys and the global gridded soil information system (SoilGrids), using detailed or semi-detailed soil surveys as a reference, in two regions of Colombia (A and B). The qualitative and statistical analyses evaluated differences in WRC surfaces generated by the information sources. Neither information sources described WRC accurately, achieving correlations between −0.15 and 0.49 and average absolute errors between 9.65 and 19.52 mm for zones A and B, respectively. However, studies on the local scale remain within the ranges observed in the most detailed local studies. The use of products on the global scale is subject to regional analyses; nevertheless, they can be included as a covariate in digital soil mapping studies on more detailed scales.

Highlights

Soil moisture is a fundamental environmental property for physical and biological processes of terrestrial systems (Dobriyal et al, 2012; Kearney and Maino, 2018; Rodríguez-Iturbe, 2000)
This study evaluated differences in the spatial distribution of water retention capacity (WRC) of the soil at a depth of 0.3 m, calculated based on local general (1:100,000 or 100K) soil surveys and the global gridded soil information system (SoilGrids), using detailed (1:10,000, or 10K) or semi-detailed (1:25,000, or 25K) soil surveys as a reference, in two regions of Colombia
The comparison of two WRC surfaces generated from general soil surveys and digital soil mapping dates shows that the best approximations use the most similar origin scales

Summary

Introduction

Soil moisture is a fundamental environmental property for physical and biological processes of terrestrial systems (Dobriyal et al, 2012; Kearney and Maino, 2018; Rodríguez-Iturbe, 2000). Water content at FC and PWP have been poorly mapped (Wösten et al, 2001; Wösten et al, 2013) due to intensive field and laboratory work that their estimation requires Global initiatives, such as GlobalSoilMap.net (Arrouays et al, 2017) and more recently SoilGrids (Hengl et al, 2017), have required identification of soil characteristics at specific depths. These characteristics provide global predictions, with a spatial resolution of 250 m on a specific number of soil properties (e.g., OC, BD, pH, and textural fraction) They are generated through remote sensors using assembled machine learning models. Both initiatives have stressed the need to develop maps based on detailed soil information in order to improve environmental and agricultural planning and monitoring (Ramos et al, 2017; Sánchez et al, 2009)

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