Fig. 4

Abundance (a) and principle component analysis (b) of AOA T-RFs in vegetable soils treated with control, urea, urea + nitrapyrin, urea + NBPT at different pH. Error bars indicate standard errors of three replicates. Different pH represented by different colors, red, green, purple and black color indicate treatments at pH 3.97, pH 4.82, pH 6.07 and pH 7.04, respectively