Peanut and sorghum are excellent phytoremediators of ¹⁴C-tebuthiuron in herbicide-contaminated soil

Abstract

Background

Phytoremediation is a technique used in soils contaminated with residual herbicides, such as tebuthiuron. However, the herbicide presence in the soil and plant matrices are not generally quantified.

Objective

This study aimed to select plant species to evaluate the phytoremediation of ¹⁴C-tebuthiuron by showy rattlepod (Crotalaria spectabilis), sorghum (Sorghum bicolor), radish (Raphanus sativus), peanut (Arachis hypogaea), and alfalfa (Medicago sativa) in herbicide-contaminated soil.

Methods

The selection of the five herbicide phytoremediation plants was with the application of five rates of tebuthiuron (300, 600, 1,200, 2,400, and 4,800 g a.i. ha^-1) and compared to a control. Peanuts and sorghum (herbicide-tolerant plants) were sown in soil contaminated with tebuthiuron (600 g a.i. ha^-1) applied through a working solution containing 17.47 kBq of ¹⁴C-tebuthiuron. The total of herbicide was analyzed in the soil and plant at three phenological stages.

Results

Showy rattlepod, radish, and alfalfa were sensitive to the herbicide even at the lowest application rate. Sorghum was tolerant to the herbicide up to 600 g ha^-1 with the application of 1,200 g ha^-1, there was 80% injury; peanut was tolerant even at the highest rate (4,800 g ha^-1) with only 40% injury. Peanut and sorghum were able to phytoremediate the soil, although, peanut was more efficient in decreasing tebuthiuron contamination by 76%, while sorghum reduced at by 45% at 3^rd phenological stage.

Conclusions

Thus, both plants can be recommended in succession/rotation with crops that had tebuthiuron applied from pre-emergence weed control.

Root absorption; Rhizodegradation; Radiolabeled herbicide; Decontamination; Crop