不同地区茶园土壤硝化潜势特征研究

为明确我国茶园土壤硝化潜势及其主要影响因素,本研究采集了我国亚热带地区12个省份的30份代表性茶园土壤,通过悬浮液培养法对土壤硝化潜势进行了研究,并利用多元回归和偏最小二乘回归（PLS）等统计分析方法,明确了影响其变化的主效应因子。结果显示,茶园土壤硝化潜势在0.24~5.31 mg·kg^-1·h^-1之间;土壤氨氧化古菌（AOA）与氨氧化细菌（AOB）均与土壤硝化潜势具有显著正相关性。PLS分析显示,AOA、AOB、碳氮比、硝态氮、铵态氮、全氮、有机碳含量是影响土壤硝化潜势差异的关键因子,相对重要性大小依次降低。上述结果表明酸性茶园土壤仍然具有较强的硝化潜势,AOA可能是酸性茶园土壤氨氧化过程的主导微生物,而因气候、土壤、栽培方式不同所导致的氨氧化微生物、土壤碳氮有效性高低可能是导致茶园土壤硝化潜势差异的主要原因。

Characteristics of Soil Nitrification Potential in Different Tea Gardens of China

In order to characterize the nitrification activities of tea plantation soils in different areas, totally 30 typical soil samples from 12 provinces were collected. The soil nitrification potential was determined by using the shaken-soil-slurry method. The multiple regression analysis and partial least squares regression (PLS) were carried out to characterize the main impact factors. The nitrification potential in tea plantation soils ranged from 0.24 to 5.31 mg·kg^-1·h^-1, and the abundance of AOA in soil was significantly higher than that of AOB. Both AOA and AOB showed significantly positive correlation with soil nitrification potential. Abundance of ammonia oxidation microbes, C/N, nitrate, ammonium, total nitrogen and organic carbon contents were the significant important factors influencing nitrification potential, with a descending order of importance according to PLS. These results reveal that nitrification potential is still high in tea plantation soil, since AOA dominate the ammonia oxidation process. The difference of ammonia-oxidizing microorganisms, availability of soil carbon, nitrogen caused by climate, soil conditions and fertilization regimes are likely to be the main factors for the variation of the nitrification potential in tea plantation soils.