耕作对黄土高原和北美大草原三种典型农业土壤有机碳的影响  

Influence of cultivation on organic carbon in three typical soils of China Loess Plateau and Canada Prairies

作　　者：武天云[1] Jeff J.Schoenau 李凤民[1] 钱佩源 Sukhadev S.Malhi 

机构地区：[1]兰州大学干旱农业生态国家重点实验室 [2]Department of Soil Science [3]Nutrient Cycling Research Station

出　　处：《应用生态学报》2003年第12期2213-2218,共6页Chinese Journal of Applied Ecology

基　　金：国家重点基础研究发展规划项目(G2 0 0 0 0 1860 3 );教育部留学基金项目(990 0 0 5);SaskatchewanAgricultureDevelopmentFundStrategicResearch(R2 5 2B);InternationalFoundationforSciences(C/3313 1)

摘　　要：耕作对黄绵土 (CalcaricCambisols,FAO)、灰褐土 (HaplicGreyxems,FAO)和典型褐灰钙土 (OrthicBrownChernozem)的土壤有机碳 (SOC)动态的影响存在明显差异 .黄绵土在开垦 5年内 0～ 2 0cm土壤有机碳损失了 77% ,损失速率为 2 .15t·hm-2 ·yr-1,其主要原因为水蚀和耕作侵蚀 .灰褐土在开垦后的 4 2年里耕层土壤的有机碳损失了 70 % ,损失速率为 0 .96～ 1.0 6t·hm-2 ·yr-1,主要为水蚀和有机碳的矿化分解 .196 0以后开垦的典型褐灰钙土 0～ 2 0cm耕层土壤有机碳损失了 11% ,损失速率为 0 .17t·hm-2 ·yr-1.192 0年开垦的典型褐灰钙土有机碳损失了 4 4 % ,损失速率为 0 .4 5t·hm-2 ·yr-1.造成这一差异的主要原因是耕作和轮作体制的改善有效地阻止了风蚀的危害 ,并增加了进入土壤系统的有机物的量 .3种土壤轻组有机碳 (LFOC)的变化趋势与总有机碳的变化趋势相似 :黄绵土和灰褐土在相应的时间内LFOC损失了 73%和 90 % ,192 0年和 196 0年开垦的典型褐灰钙土LFOC分别损失了 74 %和 70 % .3种土壤间LFOC和HFOC的分配比例不同也可能是造成黄绵土和灰褐土有机碳下降快的原因 .The dynamics of organic carbon in 3 soils of China Loess Plateau and Canada Prairies was significantly different: in China,the Huangmian soil (Calcaric Cambisols,FAO) lost 77% of total organic carbon (0～20 cm) within 5 years of cultivation,with a decrease rate of 2.11 tons C·hm -2 ·yr -1 ,which was mainly caused by water erosion and tillage erosion; and the Huihe soil (haplic greyxems,FAO) lost 70% of total organic carbon (0～20 cm layer) at the rate of 0.961.06 tons C·hm -2 ·yr -1 ,because of water erosion and decomposition over 42 years. However,the orthic brown chernozem in Canada lost 11% and 44% of the total soil organic carbon (0～20 cm layer) after 40 and 80 years of cultivation,respectively,with a corresponding rate of 0.17 tons C hm -2 ·yr -1 and 0.45 tons C hm -2 ·yr -1 . The improvement in tillage and rotation system,which prevented soil from wind erosion and increased current residues into soil,was responsible for the decrease of the loss rate. The dynamics of soil light fraction organic carbon (LFOC) was similar to that of total organic carbon:Huangmian and Heilu soil lost 73% and 90% of LFOC,while orthic brown chernozem lost 74% and 70% of LFOC after breaked in 1920 and 1960,respectively. Among the test soils,Huangmian and Huihe soil had the fast SOC depletion due to the difference in the allocation of organic carbon between LFOC and HFOC.

关 键 词：有机碳 轻组有机碳 重组有机碳 黄土高原 土壤侵蚀 

分 类 号：S158[农业科学—土壤学]