近20年来宜兴市域水稻土有机碳动态及其驱动因素  

DYNAMICS OF TOPSOIL ORGANIC CARBON OF PADDY SOILS AT YIXING OVER THE LAST 20 YEARS AND THE DRIVING FACTORS

作　　者：张琪[1] 李恋卿[1] 潘根兴[1] 张旭辉[1] 蒋定安 黄洪光 

机构地区：[1]南京农业大学农业资源与生态环境研究所,南京210095 [2]江苏省宜兴市农业局土壤肥料工作站,宜兴214200

出　　处：《第四纪研究》2004年第2期236-242,共7页Quaternary Sciences

基　　金：国家自然科学基金重点项目 (批准号 :40 2 3 10 16)资助

摘　　要：中国农业土壤有机碳的变化一直是国内外农业与全球气候变化研究中十分注意的问题。一些研究提示 2 0世纪末以来我国水稻土尤其是太湖地区水稻土的有机碳储存出现了增长趋势。文章选择了 2 0 0 2年对江苏省宜兴市市域范围水稻土的 6 1个土壤监测点进行系统采样和土壤分析 ,并与该市分别于 1983年和 1994年进行的土壤肥力调查结果相对比 ,从县市区域尺度分析、评价了近 2 0年来太湖地区水稻土表土有机碳储存的变化。尽管 2 0世纪 80年代初以前土壤有机碳含量变化以下降为主 ,但 2 0年来该市域内水稻土有机碳总体上呈上升趋势。统计表明 ,4个主要土属的表土有机碳密度的增幅以下序递增 :湖白土 ( - 2 .80tC hm2 ) <白土 ( 10 .36tC hm2 ) <乌泥土 ( 13.6 5tC hm2 ) <黄泥土 ( 14 .97tC hm2 ) ,因而全市 74 .2× 10 3hm2 水稻土表土的总有机碳库从 1983年的 1.37Tg增加到 2 0 0 2年的 2 .2 0Tg。该市水稻土的平均固碳速率达到 0 .5～ 0 .8tC hm2 a ,这种快速固碳作用与 2 0世纪 80年代以来土壤中氮素的富集、秸秆还田的推广和 90年代以来该地区不断扩大的冬季休闲有关。目前该市水稻土的固碳潜力仍很大 ,太湖地区的高产高投入农业不能排除在碳固定上的积极意义。然而 ,这种快速固碳作用的土壤过程和机理值?Understanding baseline C pools and the recent change at regional scale is fundermental for approaching C sequestration agriculture with BMP practices in China. In this study, 61 sites within the framework of soil monitoring system of Yixing Municipality, a region of different paddy soils, were sampled depth at 0～5cm and 5～15cm respectively. SOC determination was carried out for all the samples. The sample number of each kind of paddy soils depends on the dominance in the area. The SOC data were compared with those collected respectively in 1983 and 1994 in same locations. It is clear that there has been prominent trend of SOC increase for the last 20 years although the degree of SOC increase varied with the species and agricultural practices. The rise of SOC density ranges from -2.80tC/hm 2 of Hubaitu, a bleached soil to 14.97 tC/hm 2 of Huangmitu, a Fe accumulated soil rich in SOC. It means that total baseline topsoil SOC pool is raised from 1.37Tg in 1983 to 2.20Tg in 2002 at an area of 74.2×10 3hm 2. The increase of SOC was found related to the clay (<0.002mm) content and N enrichment in soils. It means that paddy soil with high clay and N enrichment is favorable for SOC accumulation in these paddy soils. The high C sequestration rate found in these paddy soils could be attributed to agricultural practices such as residue re entering and manure application, shifting rice wheat rotation to rice fallow and rice rape seed rotation. The authors believe that the high input and higher yielding may not be negative to the enhanced topsoil SOC storage.

关 键 词：水稻土 有机碳 太湖地区 碳固定 

分 类 号：S511.5[农业科学—作物学] O62[理学—有机化学]