摘要
采集长期定位试验（14年）土壤（棕壤）进行盆栽试验，并应用同位素15N示踪技术研究了土壤中微生物对肥料氮的固持及其动态。结果表明，施肥后5天土壤微生物对施入化肥氮的固持达到最高，除单施氮肥处理的固持量占施入化肥氮量的5.4％外，其余各处理均在13.3％-15.4％间。施肥后土壤微生物生物量氮的增加主要来自化肥氮，后者占微生物体总氮量的64.1％—87.3％。在作物生长期间微生物固持的化肥氮逐渐释放出来，在小麦分蘖期微生物固持的化肥氮明显减少，仅占施肥量的1.72％—3.29％。在分蘖期以后微生物固持态15N的变化趋于稳定。由微生物体释放的15N量占作物吸收15N的比例除单施氮肥处理较高外，占83.7％，其它施肥处理在34.3％—54.3％间。微生物体释放的15N量与小麦吸收15N量之间存在明显的正相关（r＝0.860，n＝6）。
The immobilization of fertilizer N by soil microbes and its changes in brown soils of different fertilization treatments were studied by a 14-year field location experiment using the 15N isotope tracer technique. The results of pot experiment showed that the immobilization of fertilizer N by microbes in various treatments reached a maximum after 5 days of fertilization, making up 13.3%-15.4% of the nitrogen applied except single application of nitrogen. In single N treatment the immobilization of fertilizer N by microbes accounted for 5.4% of the nitrogen applied.The increase in microbial biomass N after fertilization originated mainly from fertilizer N. Fertilizer N in the biomass accounted for 64.1%-87.3% of the total microbial biomass N. The biomass N was gradually released during crop growth. At the tillering stage of wheat the immobilization of fertilizer N by microbes decreased markedly,making up only 1.72%-3.29% of nitrogen applied. After the tillering stage the biomass 15N tended towards stable. 15N released by biomass accounted for 34.3%-54.3% of 15N absorbed by crop in different fertilization treatments except the application of alone fertilizer N. There existed a close relationship betWeen the 15N released by biomass and the 15N absorbed by wheat (r=0.860).
出处
《土壤学报》
CAS
CSCD
北大核心
1998年第3期412-418,共7页
Acta Pedologica Sinica
关键词
^15N标记硫铵
微生物生物量氮
棕壤
^(15)N labelled ammonium sulfate, Microbial biomass N, Brown soil
