Fig. 2. In vitro incubations of thymol and N-(n-butyl) thiophosphoric triamide–amended swine manure pit samples and their effect on total gas, methane, volatile fatty acids (VFA), and pH. (A–D) Thymol addition of 1.5 g L^–1 slurry. (E–H) Addition of 3.0 g L^–1 of slurry. Each data point represents the mean ± SE of six samples.