Fig. 3From: pH rather than nitrification and urease inhibitors determines the community of ammonia oxidizers in a vegetable soilLog number of AOA and AOB amoA copies in four different treatments (control; urea; urea + nitrapyrin; urea + NBPT) at different pH levels. Error bars indicate standard errors of three replicates, different small letters indicate the significant difference within the same treatment at different pH levels (P < 0.05)Back to article page