Citation: Vaca, R.; Del Águila, P.; Yañez-Ocampo, G.; Lugo, J.A.; De la Portilla-López, N. Soil Quality Assessment in Response to Water Erosion and Mining Activity. Agriculture 2023, 13, 1380. https://doi.org/10.3390/ agriculture13071380 Academic Editors: Ilyusya M. Gabbasova and Mikhail Komissarov Received: 31 May 2023 Revised: 8 July 2023 Accepted: 10 July 2023 Published: 12 July 2023 Copyright: © 2023 by the authors. 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/). agriculture Article Soil Quality Assessment in Response to Water Erosion and Mining Activity Rocio Vaca 1 , Pedro Del Águila 1 , Gustavo Yañez-Ocampo 2 , Jorge A. Lugo 1 and Nadia De la Portilla-López 1, * 1 Laboratorio de Edafología y Ambiente, Facultad de Ciencias, Instituto Literario No. 100, Universidad Autónoma del Estado de México, Toluca 50000, Mexico; rociovpaulin@gmail.com (R.V.); delaguila.1959@gmail.com (P.D.Á.); jorgelug@gmail.com (J.A.L.) 2 Centro de Investigación en Recursos Bióticos (CIRB), Instituto Literario No. 100, Universidad Autónoma del Estado de México, Toluca 50000, Mexico; yanezg0206@gmail.com * Correspondence: naomenpl@hotmail.com; Tel.: +52-72-229-6555-6162 Abstract: Erosion significantly decreases the depth of a soil, the nutrients available for plants, the organic matter and, consequently, the productivity of the edaphic environment. Due to the above considerations, the objective of this study was to evaluate, through various properties, the quality of two eroded soils, one eroded by water and the other by mining activity, amended with biosolids. The quality for both soils was estimated through the selection of a minimum set of data by means of principal component analysis (PCA) and the subsequent realization of correlations, multiple regressions and finally calculations of normalized values (Vn) of those properties considered as indicators of soil quality. According to the results, inorganic nitrogen (NI) and respiratory activity (RA) were the properties selected as indicators to assess quality. For soil eroded by water and by mining activity, NI presented a low and very low quality, respectively (class 4 and 5 of quality according to the calculation of Vn). The quality of RA in soil eroded by mining extraction was very high (quality class 1 according to Vn), and thus it can be considered an ideal indicator for the evaluation of soil quality due to its sensitivity to anthropogenic changes (mining) in soil. Keywords: biosolids; erosion; inorganic nitrogen; quality index; normalized value (Vn); respiratory activity 1. Introduction Erosion refers to the removal of the upper layer of the soil due to the effect of external agents such as wind and water; however, the erosive phenomenon is increased by human activities. The state of Mexico (Central Mexico) ranks fourth nationwide for water erosion (81.19%), with degrees ranging from moderate to extreme [1,2]. Water erosion is the most common form of soil degradation. The process consists of the detachment, transport and deposit of soil particles caused by rain; the process begins with the impact of the raindrops and once the infiltration and surface storage capacity is saturated, the runoff begins, dragging the loose particles and those that its own force detaches; the mechanism ends when the eroded material, also called sediment, is deposited. As a result of the erosive phenomenon, there is a loss of the superficial layer of the soil, which has become a growing concern throughout the world and has been identified as one of the key elements of soil degradation. Soil degradation via erosion involves (a) physical changes, among which are: formation of crusts, loss of structure, compaction and anoxia; (b) chemicals that include salinization and alkalization and (c) biochemicals, presenting a decrease in the diversity and microbial function of the soil. Soil erosion also contributes to climate change, as soil degradation processes caused by erosion often result in the release of soil organic carbon into the air, increasing carbon dioxide in the atmosphere. This, in turn, exacerbates climate change through increased greenhouse gas (GHG) emissions [3–6]. Agriculture 2023, 13, 1380. https://doi.org/10.3390/agriculture13071380 https://www.mdpi.com/journal/agriculture