Corn Cultivation and Its Relationship with Soil Quality: A Focus on Soil Quality Index Methodologies

Corn is a globally important crop, requiring extensive soils and intensive practices to meet the growing human and animal consumption demand. However, intensive agriculture has caused soil deterioration and fertility loss. In response, the Mexican government established the National Soil Strategy for Sustainable Agriculture (ENASAS, acronym in Spanish) to ensure food security and maintain soil fertility. This study develops “Soil Quality Indexes” (SQI) to monitor soil quality under corn cultivation using four methodologies (additive (SQIa), weighted (SQIw), unified weighted (SQIu), and Nemoro (SQIn)) in the Bajio region of Guanajuato, Mexico. Twenty-four physicochemical indicators were analyzed, with four (CLY, WHC, Na, and C/N) identified as key indicators of soil quality and fertility through principal component analysis. Among these, SQIa was the most sensitive and efficient (SI = 2.32, ER = 50) in assessing soil quality, showing values from very low to low (SQIa=0.13 and SQIa=0.39 respectively). Aligned with the ENASAS program, SQIa can help monitor and improve soil quality under corn cultivation, supporting food security through soil conservation. Moreover, SQIa performed similarly to the globally recognized Soil Management Assessment Framework (SMAF), making it a valuable tool for managing and improving agricultural soil quality under similar conditions in both Mexico and worldwide.