Soil quality in the plains and piedmont areas of Valle del Cauca, Colombia: impact of heavy metal concentrations

Abstract

This study evaluated the quality of agricultural soils in Valle del Cauca, Colombia, through an integrated analysis of physicochemical properties and heavy metal concentrations. The research was conducted in the plains and piedmont areas of the region. The Soil Quality Index (SQI) ranges from 0 to 1, with values between 0.20–0.39 indicating low quality; 0.40–0.59, moderate; 0.60–0.79, high; and 0.80–1.00, very high. The results show that the evaluated agricultural soils exhibit moderate quality (SQI = 0.57), providing suitable conditions for agricultural productivity. Soil quality was positively influenced by saturated hydraulic conductivity, porosity, pH, and cation exchange capacity. The impact of heavy metals such as Cr, Ni, Pb, and Co on soil quality was moderate. Electrical conductivity contributed less to soil quality, mainly due to the established threshold values rather than actual salinity issues. It is recommended that agricultural practices that may alter soil properties and compromise its quality be avoided. The proposed soil quality index proved useful for monitoring soil conditions, ensuring sustainable agricultural productivity, and mitigating the effects of potentially toxic trace elements.

Keywords: heavy metals in soils, quality index, soil quality, soil properties.