Understanding the behavior of sulfometuron-methyl in soils using multivariate analysis

Abstract

The environmental fate of herbicides in soils depends on the interactions between them. Pinpointing groups of soils with a high and low potential risk of leaching can provide a better herbicide use. The objectives were: i) Identify the physical–chemical attributes that contribute to greater variance between soils through principal component analysis; ii) Group the soils according to their physical–chemical attributes; iii) Evaluate the sorption and desorption capacity among the groups of soils created. The sorption and desorption coefficients of sulfometuron-methyl in soils were calculated by the Freundlich equation. Fifteen soils were divided into five groups by factorial analysis, and the groups were validated by discriminant analysis with a hit equal to 100%. The LTOC-LCEC group consisted of low total organic carbon and cation exchange capacity, HpH, high pH, LpH-HTOC low pH and high total organic carbon, HpH-HCEC, high pH and cation exchange capacity and LTOC-Lclay, low total organic carbon and clay. The sorption of sulfometuron-methyl in the groups was LpH-HTOC (3.6 ± 0.6) > HpH (2.7 ± 0.1) > LTOC-LCEC (2.2 ± 0.2) > LTOC-Lclay (1.8 ± 0.3) > HpH-HCEC (1.3 ± 0.3). The desorption was LpH-HTOC (7.0 ± 1.0) < LTOC-Lclay (4.4 ± 0.4) < HpH-HCEC (3.4 ± 1.8) < HpH (0.9 ± 0.4) < LTOC-LCEC (0.5 ± 0.2). The group with the lowest risk of contamination of water resources has low pH and high TOC content. Multivariate analysis can support studies on herbicides' behavior in the soil to interpret better the properties that affect herbicides' mobility.