对华北平原高产农田生态系统2004年的土壤呼吸状况进行了分析,探讨了不同耕作方式下土壤呼吸量的季节变化规律.结果表明,土壤呼吸量的季节变化趋势与当地气候状况紧密相关,在暖温带半湿润大陆性季风气候的影响下,该地春季干旱,夏季雨热同期,土壤呼吸量春季缓慢升高,峰值出现在温度、降水均较高的7月,最大值约为20 g·m^-2·d^-1(以CO2计),之后逐步回落.不同的耕作措施能够影响土壤呼吸量,本试验研究的3种因素对土壤呼吸量有显著影响(p<0.01),播种前先翻耕30 cm、播种后覆盖麦秸、不施氮素、施磷75 kg·hm^-2·a^-1的处理土壤呼吸量最高.5 cm、10 cm地温是影响土壤呼吸的重要因素,土壤呼吸对5 cm地温的敏感性更强,指数方程的模拟较好地表明了土壤呼吸与地温的关系.
This study investigated variations in soil respiration under different cultivation practices on high yield farmland in the North China Plain during 2004. The area under study is characterized as a warm continental monsoon climate zone, arid in spring and moist and hot during the summer. The results indicated that soil respiration is closely related to local climate, rising slowly in spring until reaching a peak in July (20 g· m^-2·d^-1 based on CO2 calculations) then falling in steps thereafter. Cultivation practices also had a significant influence on soil respiration (p 〈 0.01 ) , with the highest level found on land where the top 30cm was turned over prior to seeding and then covered with wheat straw before the application of a phosphorus fertilizer (75 kg·hm^-2). The results also indicated that soil respiration was more sensitive to the 5era than the 10era soil temperature. In addition, the relationship between soll respiration and soil temperature was strongly exponential.