Development of a Soil Quality Index for Soils under Different Agricultural Management Conditions in the Central Lowlands of Mexico: Physicochemical, Biological and Ecophysiological Indicators

Héctor Iván Bedolla-Rivera,Midory Samaniego-Hernández,Dioselina Álvarez-Bernal,María De La Luz Xochilt Negrete-Rodríguez,Eloy Conde-Barajas,Francisco Paúl Gámez-Vázquez,Alfredo Josué Gámez-Vázquez,Miriam Del Rocío Medina-Herrera

doi:10.3390/su12229754

Abstract

The Bajío—Mexico’s central lowlands—is a region of economic importance because of its agricultural industry. Over time, agricultural practices have led to soil deterioration, loss of fertility, and abandonment. In this study, six agricultural soils were analyzed: AGQ, CTH, CTJ, JRM, CRC, and CYI, and used to develop a soil quality index (SQI) that includes the use of physicochemical, biological, and ecophysiological indicators to differentiate soil quality. Principal component analysis (PCA) was used, reducing the indicators from 46 to 4, which represents 80.4% of data variability. It was implemented the equation of additive weights using the variance of the principal components as a weight factor for the SQI. The developed SQI was according to the indicators WHC, SLT, N-NO3−, and qCO2, differentiating the quality of soils from the agricultural management in low quality (JRM < CYI < AGQ) and moderate quality (CTJ < CRC < CTH). The use of biological and ecophysiological indicators added to the PCA and the equation of additive weights allowed establishing an SQI with a minimum of indicators, sensitive to agricultural management, facilitating its interpretation and implementation for the Mexican Bajío region and soils in similar conditions around the world.

Highlights

In recent years, the growth of urban and rural populations worldwide has increased the use of natural resources at a rapid pace
The soil quality index (SQI) model developed from the different principal components (PCs) made it possible to differentiate the quality of the analyzed soils, according to the indicators that the SQI comprises, and classify them into two categories: low quality (JRM < CYI < AGQ), and moderate quality (CTJ < CRC < CTH)
The Principal component analysis (PCA) methodology reduced the number of indicators analyzed, making it possible to establish—from a minimum data set—the indicators that have a direct influence on soil quality

Summary

Introduction

The growth of urban and rural populations worldwide has increased the use of natural resources at a rapid pace. This situation has compelled governments—at the international, national, and local levels—to create policies and strategies to meet the shelter, health, education, and food needs of their citizens, resulting in constant environmental stress and imbalances [1]. Since 2003, the Mexican Ministry of Environment and Natural Resources (SEMARNAT), in conjunction with the College of Postgraduates in Agricultural Sciences (COLPOS), has reported that 44.9% of the national territory presented some type of soil deterioration. In Mexico, almost 1.5 million hectares of agricultural land are lost each year, which results in a decrease of 11 billion dollars in agricultural production [8]. In regard to soil degradation, chemical degradation has prevailed in the form of lost fertility, affecting 29% of the state’s territory, equivalent to more than 856,000 hectares [9,10]

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