中文摘要：

以位于西南大学农业部重庆紫色土生态环境重点野外科学观测试验站内辣椒-萝卜轮作菜地为研究对象,采用静态暗箱/气相色谱法,通过1 a的田间原位观测,研究地膜覆盖对菜地生态系统土壤的水热条件、CH_4排放通量及各土层CH_4剖面浓度的影响.结果表明,地膜覆盖能显著提高春夏辣椒种植季的土壤温度（P〈0.01）,而在秋冬萝卜种植季则改变不明显（P〉0.05）;覆膜种植土壤含水率在萝卜季显著高于常规种植（P〈0.05）,而在辣椒季则差异不显著（P〉0.05）;在整个观测周期内,覆膜和常规种植条件下,土壤CH_4的排放通量均无明显变化规律,CH_4排放通量的均值分别为-7.64μg·（m~2·h）~（-1）和-9.00μg·（m~2·h）~（-1）,整个观测期CH_4净吸收量分别为0.54 kg·hm~（-2）和0.64 kg·hm~（-2）,表明地膜覆盖在一定程度上能削弱土壤作为CH_4汇的能力.在各土层CH_4浓度观测方面,发现两种种植方式在整个观测周期内各土层CH_4浓度变化趋势大致相同,表现为：10 cm〉20 cm〉30 cm,覆膜土壤CH_4浓度在20 cm、30 cm深土层显著低于常规种植（P〈0.05）,而在10 cm土层差异不显著（P〉0.05）.相关性分析结果表明,覆膜种植土壤CH_4的排放通量与5 cm地温显著正相关（P〈0.05）,与土壤含水率之间显著负相关（P〈0.05）,而在常规种植条件下,CH_4排放通量与地表温度、5 cm地温及土壤含水率均无相关性;两处理10 cm、20 cm土层CH_4浓度均与地表CH_4浓度呈显著正相关（P〈0.01）,30 cm土层CH_4浓度与地表温度及5 cm地温均呈显著正相关,各土层CH_4浓度与土壤含水率无显著相关关系.

英文摘要：

Using the static opaque chamber method and choosing a chili-radish cropping system, a field experiment, located in the Key Field Station for Monitoring of Eco-Environment of Purple Soil of the Ministry of Agriculture of China in the farm of Southwest University in Chongqing, was conducted in situ for one year. Mulching and non-mulching treatments were set in the field, and the seasonal variation of CH4 flux and CH4 concentrations in the soil profile and the seasonal changes in soil moisture and temperature were observed for different treatments to explore the effect of plastic film mulching on soil moisture and temperature. The results showed that plastic film mulching can significantly improve the surface soil temperature during the pepper growing season in spring and summer （P〈0.01）, but no significant difference was seen during the radish growing season in autumn and winter （P〉0.05）. The soil moisture of the plastic film mulching treatment was significantly higher than that of no mulching in the radish growing season （P〈0.05）, but no significant difference was observed for the pepper growing season （P〉0.05）. During the whole observation period and under the condition of plastic film mulching and conventional planting, the CH4 flux from soil had no significant seasonal variation under all treatments, and the mean CH4 fluxes were -7.64 μg·（m2·h）-1 and -9.00 μg·（m2·h）-1, respectively. The cumulative CH4 emissions for plastic film mulching and conventional planting were -0.54 kg·hm-2 and -0.64 kg·hm-2, respectively, in the whole observation period, and all the treatments showed a net absorption of CH4 for the whole observation period. The results showed that the plastic film mulching could weaken the ability of CH4 as a sink of the CH4 for the whole observation period. The CH4 concentrations in different soil profiles were in the order 10 cm〉20 cm〉30 cm, and the concentrations of CH4 change patterns in different soil layers were almost identical during the whole observat