Fig. 1. Effect of thymol and N-(n-butyl) thiophosphoric triamide used as amendments in swine manure pits and their effect on volatile fatty acids (VFA) production, urea, and ammonia. (A–D) Thymol addition of 1.5 g L^–1 of slurry. (E–H) Addition of 3.0 g L^–1 of slurry. Each data point represents the mean ± SE of six samples.