有机物料中有机碳和有机氮的分解进程及分解残留率

在中国科学院沈阳生态站(埋袋法)和海伦站(砂滤管法)研究了不同有机物料中有机碳和有机氮的矿化进程、分解残留率和C/N的动态变化.结果表明:有机物料中有机碳和有机氮的分解进程可分为快、慢2个阶段;各有机物料中有机氮的矿化速率均明显低于有机碳,因而其残留率高于有机碳;有机物料C/N的下降速率也可分为快、慢2个阶段.经3～5年分解后,各种有机物料残留物的C/N趋于稳定:低C/N有机物料(猪粪)残留物的C/N值接近土壤腐殖质的C/N,约为10,已完成其腐殖化过程;高C/N有机物料残留物的C/N值处于适宜微生物活动的25左右,利于增加土壤有机质、培肥土壤.

Decomposition process and residual rate of organic materials C and N in soils

By using nylon mesh bags and sand filter tubes,this paper studied the decomposition of organic materials in the soils at Shenyang and Hailun eco-experimental stations of CAS to investigate the dynamic changes of their organic C and N during decomposition.The results showed that the decomposition process could be divided into two phases,i.e.,quick phase and slow phase.The organic N in the materials had an obviously lower decomposition rate than organic C,and thus,had a higher residual rate.The decline of C/N ratio could be also divided into quick and slow phases.After 3-5 years decomposition,the C/N ratio of all test materials tended to be stable.The C/N ratio of the residual organic materials with an initial lower C/N(such as pig manure)approached to that of soil humus,being about 10,which indicated that the humification process was completed,while that of the residual organic materials with an initial higher C/N was about 25,being available to the activities of soil microbes,which would benefit the increase of soil organic matter and the improvement of soil fertility.