Evaluation of physicochemical properties in agricultural soils on the flat and piedmont areas of Valle del Cauca, Colombia with emphasis on degradation

A study for the physicochemical properties was carried out in agricultural soils (n = 489) on the flat and piedmont areas of Valle del Cauca. The degradation level of different soils (n = 489) was studied by determining and analyzing their properties. Variability and distribution analysis, central tendency, dispersion and multivariate analysis were included. The results showed that the saturated hydraulic conductivity (Ks) and electrical conductivity (EC) were highly variable. The other properties were moderately variable, depending on the coefficient of variation (10% < CV < 100%). The principal component analysis indicated that the first component was related to compaction processes in the soil (34%), the second included nutrients available to plants (24%), and the third (13%) was the movement of cations. The more susceptible to degradation properties included apparent density (Da) and porosity (η), which had normal distribution (P > 0.150). 19% of the evaluated sites had possible soil compaction, with high Da values (> 1.6 g cm−3) and low η (< 40%). The degradation from salinity was minimal, and only 2.2% of the samples had EC values greater than 2 dS m−1. 50% of the soils had organic matter levels (MO) greater than 2%. 85.5% had cation exchange capacity values (CEC) that exceeded 15 cmol (+)  Kg−1, and 42.12% were in the pH range from 5.5 to 7.0, optimal conditions for crops. The results showed that soil compaction occurred in some agricultural crops; however, most than 80% of the soils studied had excellent physicochemical properties (MO, CEC, pH).