Glyphosate use in riparian forest restoration: potential of soil and water pollution and silvicultural aspects

Abstract

Riparian areas currently concentrate most of the efforts of forest restoration in Brazil. Since there are no laws regulating the use of pesticides in these areas, the dilemma to use or not herbicides in riparian forest restoration is present in most projects, especially in those based on Payments for Ecosystem Services schemes regarding the recovery of native vegetation in watersheds of importance for drinking water supply. If on one hand the use of glyphosate - the most used herbicide in forest restoration - on these projects increases operational efficiency and reduces costs in weed control, on the other hand there is a risk of soil and water contamination, which opposes to the principles of ecological restoration. The objective of this study is to evaluate silvicultural aspects and pollution potential of soil and water associated with the use of glyphosate in riparian forest restoration. The experiment will be conducted in a Permanent Preservation Area at the Centro de Experimentos Florestais da SOS Mata Atlântica in Itu-SP, where plots of 20 x 30 m will be established, where 100 seedlings of 35 native species will be planted in each plot. Weed control strategies (treatments) will consist of mowing or glyphosate spraying. We will evaluate economic (maintenance costs), silvicultural (growth of seedlings planted in height, canopy cover and stem diameter) and pollution potential aspects (analysis of glyphosate and its major metabolite, aminomethylphosphonic acid, in the soil and in the runoff water by chromatography). (AU)