Population Size and Nitrification Activity of Soil Ammonia-Oxidizing Bacteria in Long-Term Intensive Managed Phyllostachys praecox Stands

High rate of fertilization and heavy winter mulch have been a common practice to gain a good yield in Phyllostachys praecox stands, but the long-term impact of this intensive management on soil ammonia-oxidizing bacteria (AOB) is largely unknown. Population size of soil AOB was quantified by real-time PCR in Phyllostachys praecox stands with different intensive management history. AOB population sizes and nitrification activities in intensive managed bamboo stands were significantly higher than that of the control. However, both soil AOB abundance and activity significantly decreased after long-term intensive management, and they correlated positively with soil mineral N and available potassium but negatively with soil pH. The results indicated that, although AOB activity and growth responded strongly to high rate of mineral fertilization during the first few years of intensive management, soil pH should be a dominant factor regulating the communities on a long-term basis.