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phitong

木虫 (小有名气)

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虫号: 776643
注册: 2009-05-22
专业: 全球变化生态学

[求助] 土壤碳库测定

现在小虫做实验，欲采用Rovira and Vallejo(2002)的方法来分析土壤活性和惰性有机碳库。
Rovira and Vallejo(2002)文章简述如下：Brieﬂy, 20 mL of
5NH2SO4 was added to 500 mg soil, and the sample was hydro-
lyzed for 30 min at 105 C in sealed Pyrex tubes, after which
the hydrolysate was recovered by centrifugation and decantation.
The residue was washed with 20 mL of de-ionized water and the
washing added to the hydrolysate. This hydrolysate was taken as
labile pool I (LPI) and analyzed for labile pool I carbon (LPI-C) and
nitrogen (LPI-N). The remaining residue was hydrolyzed with 2 mL
of 26 N H2SO4 overnight at room temperature under continuous
shaking. The concentration of the acid was then brought down to
2 N by dilution with de-ionized water and the sample was hydro-
lyzed for 3 h at 105 Cwith occasional shaking. The hydrolysatewas
recovered in the same manner as for the LPI. This second hydro-
lysatewas taken as labile pool II (LPII) and analyzed for labile pool II
carbon (LPII – C) and nitrogen (LPII – N).
问题如下：1.离心速度多大合适？
2.称量土，加入2.5 M H2SO4溶液这一步可以直接放在离心管中高温水解吗？不可以的话，该用什么容器，之后如何无损失转移？

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