O3浓度升高对麦田土壤碳、氮含量和酶活性的影响

近地层O₃作为全球最重要的大气污染物之一，其对作物的生长发育、土壤酶活性、土壤碳、氮的影响机制已成为人们关注的重要问题。采用开顶式气室(OTCs)法模拟研究O₃浓度升高对冬小麦土壤碳、氮含量和酶活性的影响。结果表明，O₃浓度升高导致麦田0~10 cm和10~20 cm土层的全碳(TC)和全氮(TN)含量呈现出下降的趋势。O₃浓度升高对土壤酶活性也有影响。在冬小麦灌浆期，O₃胁迫可促进土壤脱氢酶活性提高。当O₃浓度为120 nL·L^-1时，0~10 cm、10~20 cm和20~40 cm土层的脱氢酶活性分别比对照处理提高59.4%、51.5%和22.2%。O₃胁迫对土壤转化酶活性的影响随着冬小麦生长期和土壤采样深度的不同而发生变化。在冬小麦拔节期，O₃处理对不同土层脲酶活性的影响没有达到显著差异水平，但是在灌浆期，20~40 cm土层的脲酶活性随着O₃浓度的增加而提高，在120 nL·L^-1浓度O₃处理下脲酶活性比对照处理提高24.6%。在O₃胁迫条件下土壤转化酶活性与土壤全碳含量、土壤脲酶活性与土壤全氮含量均呈现出显著的正相关关系。

Effects of Elevated Ozone on Carbon, Nitrogen Content and Soil Enzymes Activities in a Winter Wheat Field

Tropospheric O₃ as one of the world's most important atmospheric pollutants, the mechanism of O₃ stress on crop growth, soil enzyme activities and soil carbon and nitrogen content has become the important issues of concern. An ozone-OTCs(OTCs, open-top chambers)system was setup in a winter wheat field to investigate effects of elevated ozone concentration on soil dehydrogenase, invertase, urease and soil carbon and nitrogen content in different soil depths (0-10 cm, 10-20 cm, 20-40 cm) and different growth period (shooting, pustulation period) of winter wheat. The results indicated that soil total carbon (TC) and total nitrogen (TN) in 0-10 cm and 10-20 cm soil layers tended to decrease with the increase of the ozone concentration, and both of which declined significantly in high concentration treatment (120 nL·L^-1) compared to the control treatment. In addition, soil enzyme activities were impacted by elevated ozone. In the pustulation period of winter wheat, the soil dehydrogenase activity reached a maximum when ozone concentration was 120 nL·L^-1, which increased by 59.42% (0-10 cm soil layer), 51.45% (10-20 cm soil layer), 22.16% (20-40 cm layer) compared to control treatment respectively. The soil invertase activity fluctuated in different growing periods of winter wheat and different soil layers. The soil urease activity showed no significant differences in the shooting period under different concentration of ozone; but in pustulation period, the urease activity of 20-40 cm soil layer had a rising trend with elevated ozone concentration, and reached its maximum when the concentration of ozone was 120 nL·L^-1, which increased by 24.55% compared to control treatment. The soil invertase activity and soil total carbon content showed significant relationship, while the soil urease activity and soil total nitrogen content were significantly correlated.