The Impact of Crop Residue Burning on Fate and Efficacy of Herbicide Residues

Crop residue burning is applied in agricultural systems to remove extra residues before or after harvest. Although, there are some benefits of crop residue burning, but soils amended with crop residue ashes would obviously be increased herbicide persistence, and change desorption, and bioavailability of herbicides in soils crop residues have burned. It may also limit the access of microorganisms to the herbicides and therefore, prolonged carryover effect of their residues on rotational crops, resulting in cost burden for farmers due to the enhancement of sorption and the decrease of herbicides efficacy. The behavior of herbicides (persistence and movement), uptake by plants, and efficacy of herbicides in soil for control of weeds is governed by a variety of physical, chemical, and biological processes that are often complex and dynamic. The key process includes sorption–desorption, volatilization, and chemical and biological degradation, transport from soils into water, is directly controlled by these processes. Ashes arising from the burning of crop residues may be an important factor leading to changes in soil properties with contact time resulting in increased immobilization and sorption of herbicides. This paper highlights some key factors affecting the behavior of pesticides in the soil, in particular, understanding the effects of ashes on fate and efficacy of herbicides especially dealing with agronomic and crop residue burning.