Selection of Indicator Species of the Tembotrione Sorption in Soils with Different Attributes

Seleção de Espécie Indicadora da Sorção do Tembotrione em Solos com Diferentes Atributos

ABSTRACT:

Studies on herbicide behavior in soils may be performed using biological and chemical methods. The efficiency of the biological method depends on the indicator species sensitivity to low herbicide concentrations in the soil solution. Among the herbicides commonly used in Brazil for corn cultivation, tembotrione stands out. In the last agricultural seasons, the intoxication of some crops when cultivated in succession to corn has been reported, which may be attributed to tembotrione recommendations without the knowledge of their interactions with colloids of tropical soils. In this research, we selected an indicator plant species of tembotrione residues in the soil after sorting 12 species. The sorption of this herbicide was estimated in two Oxisols (Latossolo Amarelo and Latossolo Vermelho-Amarelo, Brazilian Soil Classification) and in a Histosol (Organossolo, Brazilian Soil Classification) with different attributes. Initially, after sorting the 12 plant species, the two most efficient in detecting tembotrione in the soil were selected. In the second stage, the most sensitive species was selected. In the third stage, tembotrione sorption was assessed in the three soils by using the selected species. Among the 12 species, Beta vulgaris and Brassica oleracea var. capitata were the most efficient in detecting tembotrione at low concentrations in the soil, being B. vulgaris (beet) the most sensitive. Thus, due to its ease of cultivation, high sensitivity, and fast initial growth, beet can be used as an indicator species of tembotrione presence in the soil solution. The sorption of this herbicide was higher in the Histosol and it is directly related to the organic matter content.

Keywords:
bioassay; environmental impact; herbicides; technical efficiency