为明确大气CO2浓度升高和不同施氮水平对新疆棉田土壤理化性质和土壤微生物区系状况的影响,基于滴灌棉田管网系统,对背景CO2浓度(360μmol mol-1)和高CO2浓度(540μmol mol-1和720μmol mol-1)条件下不同施氮处理(0 kgN/hm2、150 kgN/hm2、300 kgN/hm2和450 kgN/hm2)的0~20 cm和20~40 cm土壤有机碳、全氮、碳酸氢根和pH值以及土壤中细菌、真菌、放线菌等指标的影响进行了评价。结果表明:在各施氮水平上,当CO2浓度升高到720μmol mol-1时,0~40 cm土壤有机碳、全氮含量趋于减少,土壤pH值趋于降低,土壤碳酸氢根及总盐含量无明显变化;在各施氮水平上,当CO2浓度升高到540μmol mol-1和720μmol mol-1时,0~40 cm土壤中细菌和0~20 cm土壤中放线菌数量均呈增加趋势,20~40 cm土壤中真菌的数量则呈减少趋势。研究表明,棉田土壤理化性质和微生物区系对大气CO2浓度升高和施氮水平有一定的响应。 In order to clarify the effects of elevated atmospheric CO2 and different nitrogen levels on soil physical and chemical properties and soil microbial flora in Xinjiang cotton field, based on the drip irrigation pipe network system, the effects of background CO2 concentration (360μmol mol-1) and high CO2 concentration (540μmol (0 kg N / hm2, 150 kg N / hm2, 300 kg N / hm2 and 450 kgN / hm2) at 0-20 cm and 20-40 cm soil organic carbon under the conditions of nitrogen, mol-1 and 720 μmol mol- Total nitrogen, bicarbonate and pH, as well as the impact of bacteria, fungi, actinomycetes and other indicators in the soil. The results showed that when CO2 concentration increased to 720 μmol mol-1, the contents of organic carbon and total nitrogen in 0-40 cm soil tended to decrease, the pH value of soil tended to decrease, and the content of bicarbonate and total nitrogen There were no significant changes in salt content at all nitrogenous fertilizers. When CO2 concentration increased to 540μmol mol-1 and 720μmol mol-1, the numbers of actinomycetes in 0-40 cm soil and 0-20 cm soil were all Increasing trend, the number of fungi in 20 ~ 40 cm soil showed a decreasing trend. The results show that the soil physical and chemical properties and microbial flora of cotton field have certain response to the increase of atmospheric CO2 concentration and nitrogen application level.