耕作措施对东北黑土微生物呼吸的影响  

Effect of Conservation Tillage on Microbial Respiration of Black Soil

作　　者：贾淑霞[1] 孙冰洁[1] 梁爱珍[1] 陈学文[1] 张士秀[1] 魏守才[1] 刘四义 陈升龙 张晓平[1] 

机构地区：[1]中国科学院东北地理与农业生态研究所/中国科学院黑土区农业生态重点实验室,长春130102

出　　处：《中国农业科学》2015年第9期1764-1773,共10页Scientia Agricultura Sinica

基　　金：国家自然科学基金(41101241;41201217);中国科学院黑土区农业生态重点实验室开放基金(2012ZKHT-02)

摘　　要：【目的】利用东北黑土13年保护性耕作定位试验,研究耕作措施(免耕和秋翻处理)对土壤微生物的影响,从土壤微生物角度分析免耕是否有利于土壤有机碳(SOC)的固定,为合理评价农田黑土碳"源"与"汇"功能提供科学依据。【方法】以连作玉米为研究对象,采用单因素随机区组设计,耕作处理包括免耕和秋翻。免耕除播种外不扰动土壤,秸秆覆盖地表。秋翻处理的田间管理包括人工除草、中耕起垄和秋翻,秋翻时将秸秆翻于地表之下。土壤微生物呼吸速率通过PVC环在野外采用动态气室法(Li-Cor8100)直接测定(去除植物根系),定期监测土壤微生物呼吸速率的季节变化,并在土壤微生物呼吸速率最高的季节取样分析不同处理土壤微生物量碳和数量特征。【结果】生长季节内免耕和秋翻处理下土壤微生物呼吸速率分别为0.42—3.35和0.48—3.24μmol CO2·m-2·s-1,两处理平均值差异不显著(8.8%),但土壤累积CO2-C释放量免耕比秋翻高10.0%(2012)和4.3%(2013)(P<0.05)。免耕显著地增加0—5 cm表层土壤细菌、真菌和放线菌的数量,分别比秋翻高125.7%、112.4%和53.3%;还显著地增加了其他土层的真菌数量,分别为105.3%(5—10 cm),159.4%(10—20 cm)和114.7%(20—30 cm)。耕作处理影响土壤温度,主要体现在春季,秋翻(0—5 cm,5—10 cm)春季(6月)土壤温度比免耕分别高2.8%和5.8%。土壤微生物呼吸速率表现出显著的季节变化规律,与土壤温度具有相似的动态变化,夏季(7、8月份)最高,秋季较低。尽管耕作处理没有明显地影响土壤微生物呼吸速率的季节动态格局,但秋翻的土壤微生物呼吸最高值比免耕晚半个月。土壤微生物呼吸速率随土壤温度(5 cm和10 cm)呈指数型增长,10 cm处的回归模型明显好于5 cm。耕作处理只改变了5 cm的Q10值,免耕比秋翻高10.8%。土壤微生物呼吸速率与土壤温度、水分混合回归模型能更好地反应其变化�Objective] In this study, soil microbial activity and biomass carbon under 13-year conservation tillage （no-till） were assessed in a black soil agro-ecosystem in northeast China in order to determine the effect of tillage treatment on soil organic carbon and soil microbial biomass, which would provide a theoretical basis for valuing the ‘sink’ or ‘source’ function of soil carbon pool.[Method] The present study was conducted as part of a long term tillage experiment on the continuous maize （Zea mays L.）, tillage treatments consisted of no-tillage （NT）, and mouldboard plough （MP）. The NT treatment had no soil disturbance except planting, crop residues were left on soil surface after harvest. The MP treatment included one fall mouldboard plough （about 15 cm in depth） after maize harvest, one disking （7.5 to 10 cm in depth） in spring and field cultivation （ridging in June）. Soil respiration without roots represented soil microbial respiration, which was measured biweekly from 14 June 2012 to 25 September 2013 using LI-8100 automated soil CO2 flux system （LI-COR Inc., Lincoln, NE, USA）, soil microbial biomass and the number of colony forming units of bacteria （cfub）, fungi （cfuf）, and actinomyces （cfua） were measured during the soil microbial respiration was the highest.[Result] It was found that the range of soil microbial respiration was 0.42-3.35μmolCO2·m-2·s-1under NT and 0.48-3.24μmolCO2·m-2·s-1under MP during growing season, the average soil microbial respiration was similar between NT and MP （8.8%）, while the total soil CO2 emission during the growing season under NT was 10.0% （2012） and 4.3% （2013） higher than MP （P〈0.05）. The cfub, cfuf and cfua at 0-5 cm under NT were significantly higher by 125.7%, 112.4%, and 53.3% than MP, respectively, and cfuf at 5-10 cm, 10-20 cm and 20-30 cm under NT was 105.3%, 159.4% and 114.7% higher than MP, and. Soil temperature at 0-5 cm and 5-10 cm under NT were 2.8% and 5.8% higher than MP in June, res

关 键 词：土壤微生物呼吸 土壤微生物数量 免耕 黑土 

分 类 号：S154.3[农业科学—土壤学]