黄土旱塬区麦田土壤碳排放特征及其与休闲裸地的差异  

Soil CO_2 Efflux of Rain-fed Wheat Field and the Discrepancy With Fallow Bare Land in Dryland of Loess Plateau

作　　者：郭强[1] 

机构地区：[1]河北省唐山市农业科学研究院,河北唐山063000

出　　处：《河北科技师范学院学报》2015年第1期45-52,共8页Journal of Hebei Normal University of Science & Technology

基　　金：国家自然科学基金项目(项目编号:31171506)

摘　　要：利用Li-8100开路式土壤碳通量系统,于2014-03～2014-06研究了黄土旱塬区麦田（RT）土壤CO2排放特征及其与休闲裸地（ck）的差异。结果表明：（1）RT和ck等2个处理土壤CO2排放速率的日、季节变化趋势均呈单峰曲线;在小麦返青至拔节期土壤CO2排放速率日变化峰值出现在13∶00前后,而在开花至成熟期土壤CO2排放速率日变化峰值出现在11∶00前后;土壤CO2排放速率季节变化的最大值出现在小麦拔节中期,最小值出现在小麦灌浆后期;观测日麦田土壤CO2排放速率平均值为221 mg·（m^2·h）^-1,比休闲裸地的201 mg·（m^2·h）^-1约高出9.05%。（2）回归分析表明,土壤CO2排放速率与土壤水分和温度均成二次函数关系（P〈0.05）。随着土层深度的增加,相关性逐渐降低。在同一土层深度下,RT处理土壤CO2排放速率与土壤中水的质量分数和温度的相关性均高于ck处理。（3）相关分析表明,土壤CO2排放速率与土壤细菌数量和过氧化氢酶活性呈显著正相关关系（P〈0.05）。综合分析表明,黄土高原种植小麦能增加土壤碳排放,并且土壤中水的质量分数对土壤CO2排放速率的影响大于土壤温度对土壤CO2排放速率的影响,土壤细菌数量和过氧化氢酶活性能够显著影响土壤CO2排放速率。In order to accurate assessment comprehensive benefit of rain fed Wheatland ecosystem,we used bare land treatment as control. During March to June in 2014,we used LI-8100 automated soil CO2 flux system to determine the characteristic of wheat field soil（ RT） CO2 emission rate and the discrepancy with leisure bare land soil（ck） every 7-10d. Meanwhile Soil samples were collected from 0-15 cm soil depth to determine soil enzyme and microorganism at about every 20 d. The results showed that：（1） the daily and seasonal change of soil CO2 emission rate under RT and ck treatments were unimodal curves; From green up to jointing stage,the peak value of diurnal variation of soil CO2 emission appeared at about 13： 00,but from booting stage to harvest stage,the peak value of diurnal variation of soil CO2 emission rate appeared at about 11： 00; The maximum value of seasonal variation of soil CO2 emission rate was in the middle of wheat jointing stage,the minimum value of seasonal variation of soil CO2 emission rate was in wheat filling later; The average wheat field soil CO2 emission rate was 221 mg·（ m^2·h）^-1 in observational days,which was about 9. 05% higher than leisure bare land（ 201 mg·（ m^2·h）^-1）.（ 2） Regression analysis showed that the relationship between soil CO2 emission rate and soil moisture,temperature was fitted to an quadratic equation（ P〈0. 05）,with the soil depth increasing,the correlation reduced gradually. Under the same soil layer depth,the correlation between soil CO2 emission rate and soil moisture was higher than soil temperature,the correlation between soil CO2 emission rate and soil moisture,temperature under RT treatment was higher than ck treatment.（3） Correlation analysis showed that the correlation between soil CO2 emission rate and soil enzyme,microorganism exhibited a positive correlation in the 0 cm to 15 cm soil layer,even if the number of soil bacteria,the activity of hydrogen peroxide reached significant positive correlation（ P〈0. 05） u

关 键 词：旱作麦田 CO2排放速率 土壤水分 土壤温度 土壤酶 土壤微生物 

分 类 号：S154.1[农业科学—土壤学]