土壤有机碳和外源添加碳对水稻土土体呼吸的影响  

Effects of soil inherent and exogenous organic carbon on carbon dioxide flux of paddy soil

作　　者：张蕾[1] 尹力初[1] 易亚男[1] 高德才[1] 付薇薇[1] 

机构地区：[1]湖南农业大学资源环境学院,长沙410128

出　　处：《生态学杂志》2013年第7期1717-1722,共6页Chinese Journal of Ecology

基　　金：湖南省研究生科研创新项目(CX2012B287)资助

摘　　要：土体呼吸输出碳来源于土壤固有有机碳和外源添加碳,而以往关于不同施肥措施对水稻土碳排放的研究少有区分碳的来源。本试验利用一个长达30年的水稻土定位试验,在保证原有定位试验继续正常开展的前提下变更部分施肥处理,得到继续施用高量有机肥(HOM)、施用常量有机肥30年后改施高量有机肥(N-H)、继续施用常量有机肥(NOM)、施用化肥30年后改施常量有机肥(C-N)、施用高量有机肥30年后改施化肥(H-C)、施用常量有机肥30年后改施化肥(N-C)、继续施用化肥(CF)等7种施肥处理。通过观测早稻生长期间原有施肥和改施肥处理土体CO2排放通量(FCO2),研究不同后续施肥对水稻土FCO2的影响,以期探讨土壤原始有机碳和外源添加碳对土壤FCO2的影响。结果表明:7种不同施肥处理土体CO2平均排放通量(F珔CO2)分别为85.34、69.10、51.27、49.15、14.89、12.92和11.59 mg C.m-2.h-1;对施用无机肥料和常量有机肥料的土体而言,土壤本身有机碳含量对F珔CO2无显著影响,但对施用高量有机肥的土体而言,土壤本身的高有机碳含量会增强F珔CO2;CO2排放通量(Y)与添加外源碳量(x)之间符合指数方程:Y=13.33e1.719 x(R2=0.967,n=21),施入的外源有机碳对土体FCO2产生极显著影响;当季外源添加碳以CO2-C矿化分解释放的碳占其总碳量的14%左右,且该分解率受土壤有机碳含量和有机物料添加量的影响较小。Soil inherent and exogenous organic carbon are the carbon sources of soil respiration, but rarely distinguished in the previous studies about the effects of different fertilization modes on the carbon emission from paddy soils. In this study, three original treatments in a 30-year fertilization experiment of paddy soil were adjusted to seven treatments, i.e., original high organic material treatment （HOM）, high organic material treatment changed from original normal organic material treatment （N-H）, original normal organic material treatment （NOM）, normal organic material treatment changed from chemical fertilizer （C-N）, chemical fertilizer treatment changed from high organic material treatment （H-C）, chemical fertilizer treatment changed from normal organic material treatment （N-C）, and original chemical fertilizer treatment （CF）. The CO2 fluxes of the three original and four changed treatments were measured to study the effects of different fertilization modes on the CO2 emission and to illuminate the effects of soil inherent and exogenous organic carbon on the CO2 fluxes. The average CO2 fluxes of the seven different fertilization treatments were 85.34, 69.10, 51.27, 49.15, 14.89, 12.92, and 11.59 mg C·m^-2·h^-1, respectively. In the treatments of inorganic fertilization and normal organic fertilization, the level of soil inherent organic carbon had no significant effects on the average CO2 flux; while in the treatments of high organic fertilization, high level of soil inherent organic carbon promoted the average CO2 flux. The relationship between the CO2 flux （Y） and the exogenous carbon content （x） met the exponential equation Y=13.33e1.719x （R2=0.967, n=21）, indicating that the exogenous organic carbon had significant effects on the soil CO2 flux. About 14% of the exogenous organic carbon was decomposed and released as CO2-C during rice growth season, and this decomposition rate was less affected by soil or

关 键 词：土壤有机碳 外源添加碳 CO2排放通量 水稻土 

分 类 号：S154[农业科学—土壤学]