摘要
通过14C示踪技术模拟实验(25℃下)研究砂壤土、壤黏土、粉黏土3种质地的水稻土有机碳矿化对水分变化的响应.砂壤土和壤黏土中水稻秸秆(14C标记)的矿化率在75%田间持水量(WHC)达到最大值,160 d分别约为53%和58%,粉黏土在45%～105%WHC范围内的矿化率处于缓慢升高趋势(41.8%～49.0%);3种土壤原有有机碳的矿化率都在75%WHC最高,砂壤土为5.8%,壤黏土为8.0%,粉黏土为4.8%,但超过此含水量后,其矿化率显著下降.3种质地水稻土的添加和原有有机碳的矿化率与土壤含水量均呈二次曲线关系(p<0.01).本研究进一步澄清了淹水对水稻土有机碳矿化的抑制作用.
To understand how soil texture and water content affect the mineralization of organic C in paddy soil, 3 selected soils （ sandy loam, clay loam, and silty clay） were incubated （25℃） with ^14C-labelled rice straw （1.0 g·kg^-1 ） at water content varied from 45% to 105% of water holding capacity （WHC）. Data indicated that, in the sandy loam and clay loam, the mineralization rate of ^14C-labelled rice straw reached the maximum at 75% WHC, as 53% and 58% of the straw C mineralized in the incubation period of 160 d, whereas in the silty clay, it increased gradually （from 41.8% to 49.0% ） as water content increased up to 105% WHC. For all of the three soils, the mineralization rate of soil native organic C reached the maximum at 75 % WHC, with 5.8 % of the organic C mineralized in the same period for the sandy loam, and 8.0 % and 4.8 % for the clay loam and silty clay, respectively. As water content increased further, the mineralization rate of native organic C in the three soils significantly declined. The mineralization rate of added rice straw and native organic C in all the three soils, was well fitted with a conic curve. These results suggest that water-logging can decrease the mineralization of organic C in paddy soils.
出处
《环境科学》
EI
CAS
CSCD
北大核心
2009年第1期214-220,共7页
Environmental Science
基金
中国科学院知识创新工程重要方向项目(KZCX2-YW-423,KZCX2-YW-432-1)
国家科技支撑计划项目(2008BAD95B02)
关键词
质地
含水量
土壤有机碳
矿化
水稻秸秆
soil texture
water content
soil organic carbon
mineralization
rice straw
