Abstract: Soil respiration is the most important way of carbon emission in ecosystem,and small changes in soil respiration will have a profound impact on the carbon cycle in terrestrial ecosystem. In order to explore the effects of different management styles on carbon emission during the winter wheat stage in the alfalfa-winter wheat grass-crop rotation system,a control experiment on water and fertilizer addition was carried out to dynamically measure indicators such as soil respiration rate,soil microbial biomass carbon/nitrogen content,soil temperature and soil moisture. The results showed that water addition increased soil respiration rate by 28.5%(P<0.05),but the effect of fertilizer addition on it was not significant. Water addition significantly increased soil moisture by 24.7%,but reduced soil temperature by 9.7%. Fertilizer addition significantly reduced soil temperature by 11.0%,but increased soil microbial biomass nitrogen content by 336% and 131% in the 0~10 cm and 10~20 cm soil layers respectively. This study demonstrates that water and fertilizer addition affect the growth and development of plant roots,and microbial activity by affecting soil quality indicators such as soil temperature and soil moisture,and ultimately affect soil carbon emissions in grass-field rotation system.

Key words: Alfalfa-winter wheat, Microbial biomass carbon/nitrogen content, Soil respiration rate, Water and fertilizer addition

摘要： 土壤呼吸是生态系统碳排放最重要的途径，其微小变化将对陆地生态系统碳循环产生深远的影响。为探究不同管理方式对草田轮作系统土壤碳排放的影响，本研究开展水肥添加控制试验，动态监测紫花苜蓿（Medicago sativa L.）-冬小麦（Triticum aestivum L.）草田轮作系统中冬小麦阶段的土壤呼吸速率、土壤微生物生物量碳/氮含量、土壤温度和土壤含水量等指标。结果显示水分添加使土壤呼吸速率提高28.5%（P <0.05），但肥料添加对其影响不显著。水分添加使土壤含水量提高24.7%，但使土壤温度降低9.7%；肥料添加使土壤温度降低11.0%，使0~10 cm，10~20 cm土层土壤微生物生物量氮含量提高336%，131%。本研究说明水肥添加通过影响土壤温度、土壤含水量等土壤质量指标，影响植物根系生长发育和微生物活性，最终影响草田轮作系统土壤碳排放。

关键词: 紫花苜蓿-冬小麦, 微生物生物量碳/氮含量, 土壤呼吸速率, 水肥添加