摘要
溶解性有机碳、氮在土壤全碳、全氮含量中所占的比例很小,但却是土壤有机质中最为重要和活跃的部分。研究利用土壤溶解性有机碳、氮生物降解的测定方法,分别选取沈阳农业大学试验站不同肥力及与定位试验地紧密相连的自然林地棕壤为研究对象,开展棕壤溶解性有机碳、氮的生物降解特性的研究,为了解溶解性有机碳、氮在土壤生态系统碳、氮循环中的作用,探讨棕壤溶解性有机碳、氮与土壤肥力的关系提供理论依据。研究结果表明,棕壤林地溶解性有机碳、氮的含量最高,高肥处理次之,低肥处理含量最低。棕壤溶解性有机碳、氮与全碳、全氮和微生物量碳、氮的相关性达到极显著水平,与土壤肥力紧密相关,可以作为指示土壤肥力的重要指标。不同肥力棕壤溶解性有机碳、氮的降解速率在培养初期较快,而后逐渐减慢,降解数据符合双指数衰变模型。棕壤溶解性有机碳分别由降解速率不同的两个库组成:周转时间在1d的易分解部分和周转时间大约为400d的难分解部分。棕壤溶解性有机氮是由周转速率大约为2d的易降解部分和周转速率在99～105d左右的难分解部分组成。经过42d的培养,浸提液中剩余溶解性有机质碳氮比值较培养前有所增加。
Although dissolved organic carbon（ DOC ） and nitrogen（DON） in soil have little proportion in the total carbon and nitrogen, they are the most important and active parts of soil organic matter （SOC）. They could accelerate the weathering of minerals, supply the energy to the growth of microorganism and its decomposition, but also affect the validity and fluidity of nutrient substance in ecosystem. Compared with SOC, DOC and DON were more sensitive to reflect the chemical characteristics of soil, especially for indicating the quality and fertility level of soil. In order to study the characteristics of biodegradation of DOC and DON, the contents of DOC and DON in different fertility levels of Brown earth were determined. The results showed that the highest contents of DOC and DON in Brown earth were found in the native soil, the next was in the treatment of higher fertility and the lowest was in the treatment of lower fertility. The relations among DOC, DON, SOC, SON and soil microbial biomass carbon and nitrogen results also showed that DOC and DON were closely relevant with soil fertility, were remarkably positive correlation. The and could be regarded as the important indices of soil fertility. The decomposition rates of DOC and DON were faster at the initial stage of incubation and subsequently slower gradually. The decomposition data fitted a double exponential first-order decay model, which suggests that the DOC was comprised of tow fractions： a rapidly decomposable fraction with a turnover time of 1 day and a slowly decomposable fraction with a turnover time of about 400 days. And the DON was also comprised of two fractions： a rapidly decomposable fraction with a turnover time of about 2 days, and a slowly decomposable fraction with a turnover time of about 99 --105 days. After the incubation of 42 days, the ratios of carbon to nitrogen in dissolved organic matter were enhanced.
出处
《生态学报》
CAS
CSCD
北大核心
2008年第12期6165-6171,共7页
Acta Ecologica Sinica
基金
国家重大基础研究资助项目(2005CB121108)
国家自然科学基金资助项目(40871142)~~
