基于最小限制水分范围评价不同耕作方式对土壤有机碳的影响  

Evaluating tillage practices impacts on soil organic carbon based on least limiting water range

作　　者：陈学文[1] 王农 时秀焕[1,3] 张晓平[1] 梁爱珍[1] 贾淑霞[1] 范如芹[1,3] 魏守才[1,3] 

机构地区：[1]中国科学院东北地理与农业生态研究所,长春130102 [2]吉林省国土规划研究室,长春130051 [3]中国科学院研究生院,北京100049

出　　处：《生态学报》2013年第9期2676-2683,共8页Acta Ecologica Sinica

基　　金：国家自然科学基金项目(41201217;31170483;41101241);中国科学院知识创新工程重要方向项目(KZCX2-EW-QN307)

摘　　要：以2009年吉林省德惠市中层黑土上进行了8a的田间定位试验小区土壤为研究对象,对免耕和秋翻两种耕作方式及玉米-大豆轮作和玉米连作两种种植方式下耕层有机碳进行分析,分别采用加权平均和分层两种方法计算最小限制水分范围(LLWR),用其评价不同耕作方式对土壤有机碳的影响。结果表明,免耕在玉米-大豆轮作和玉米连作下0—5 cm土壤有机碳含量分别比秋翻增加了15.2%和11.5%(P<0.05)。采用加权平均法计算的LLWR值为0.148—0.166 cm3/cm3,不同耕作方式下玉米-大豆轮作的LLWR高于玉米连作且在两种种植方式下均表现出免耕小于秋翻的特点;利用分层法计算得到的LLWR值介于0.130—0.173 cm3/cm3之间,玉米-大豆轮作和玉米连作下免耕0—5 cm LLWR均显著小于秋翻,而5—30 cm LLWR数值免耕大于秋翻(P>0.05);玉米-大豆轮作下0—30 cm各层LLWR均高于玉米连作。由于LLWR可以评价不同耕作方式对土壤有机碳的影响,因此采用加权平均法计算的LLWR可以客观的反映不同耕作处理尤其是种植方式对土壤有机碳的影响;而采用分层法计算的LLWR则更清晰的刻画了土壤表层与亚表层固碳能力的差异。The least limiting water range(LLWR) is the range in soil water content within which limitations to plant growth associated with water potential,aeration and mechanical resistance to root penetration are minimal.It has been proposed as an index of the structural quality of soils for crop growth.In many studies,soil CO2 evolution rates are well explained by changes in soil temperature and moisture using a Q10 equation.Even though soil temperature is one of the most important factors influencing soil respiration,tillage-based differences in soil CO2 evolution are not fully explained by changes in soil temperature because differences in soil temperature under different tillage practices are generally small and not significant compared with much larger seasonal temperature fluctuations.Conversely,differences in soil moisture content under different tillage systems are more often reported to be large enough to influence soil CO2 evolution rates.This is probably related to the fact that soil structure,which is changed by tillage practices,partially determines soil moisture content.Even though bulk density and penetration resistance are commonly used measures of soil structure,they do not describe its interactions with moisture.A multi-factor parameter might better represent the complex relationships that exist between soil structure and moisture.The LLWR,which integrates several soil physical parameters,has been proposed as an index of soil structural quality.The LLWR is the range of volumetric soil water contents(cm3 / cm3) within a soil where biological processes are not limited by soil water or O2 availability.Although the concepts of LLWR have been applied to processes in plants,they have rarely been applied to microbial processes such as C mineralization and soil organic carbon(SOC).The purpose of this study is to evaluate the effect of tillage on SOC based on the least limiting water range.Soil samples were collected from a tillage trial established in Dehui County,Jilin Province,Northeast China,in fall 2001.Unde

关 键 词：最小限制水分范围 加权平均 分层 土壤有机碳 免耕 

分 类 号：S153.6[农业科学—土壤学]