Apart from increasing the efficacy of herbicides against target weeds, application of pyroligneous acids may influence soil properties and nutrient availability that would subsequently affect plant growth and quality of products.
The post emergence herbicides were Azimsulfuron+cafenstrole (AC), Mefenacet+pyrazosulfuron-ethyl (MPE) and Betazone+cyhalofop-butyl (BCB) and the pyroligneous acids included rice vinegar (RV) and wood vinegar (WV).
At 15 DAT, the AC and MPE, granular herbicides evenly and diluted pyroligneous acids were applied to soil.
Table 1: Physical and chemical components of pyroligneous acids and soil properties before the experiments
Combined application of pyroligneous acids with lower rate of herbicides results in varying efficacies depending on the
Table 4: Effects of different mixtures of herbicides and pyroligneous acids on the yield components of rice1
Combined application of pyroligneous acids with herbicides could directly influence the herbicidal activity or indirectly alter plant- and soil-herbicide interactions.
Furthermore, the acidity and nutrient components of pyroligneous acids could modify the soil microenvironment by altering soil pH and providing source of substrates for microbial activity (Kadota and Niimi, 2004; Steiner et al., 2008).