LY/T 1231-1999 PDF English
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| LY/T 1231-1999 | English | 70 |
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Determination of ammonium nitrogen in forest soil
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LY/T 1231-1999: PDF in English (LYT 1231-1999) LY/T 1231-1999 (Adjusted from GB 7851-1987)
GB
FORESTRY INDUSTRY STANDARD
OF THE PEOPLE’S REPUBLIC OF CHINA
(Adjusted from GB 7851-1987)
Determination of ammonium nitrogen in forest soil
APPROVED ON. JULY 15, 1999
IMPLEMENTED ON. NOVEMBER 1, 1999
Issued by. State Forestry Authority
Table of Contents
Foreword ... 3
1 Scope ... 4
2 Normative references ... 4
3 Methods and key points ... 4
4 Reagent ... 4
5 Main instruments ... 4
6 Determination procedures ... 4
7 Results calculation ... 5
8 Allowable deviation ... 5
Foreword
This standard is a revision of GB/T 7851-1987 “Determination of ammonium
nitrogen in forest soil”. In this revision, the unit that does not conform to the
national legal metrological unit AND the terms that do not conform to the soil
science’s terms as published by the National Scientific Terminology Review
Committee are modified; In the compilation, it is compiled in accordance with
the requirements of GB/T 1.1-1993.
As for the determination of ammonium nitrogen in the soil, there are mainly
direct distillation method, post-extraction determination method, and ammonia
electrode method. This standard adopts the magnesium oxide extraction -
diffusion method, which is easy to operate and easy to control conditions, AND
applicable to the determination of large amount of soil samples. AND it is
featured by fast analysis speed and good result reproducibility.
From the date of implementation of this standard, the original GB/T 7851-1987
is abandoned.
This standard shall be under the jurisdiction of the Forestry Research Institute
of China Academy of Forestry.
The drafting organizations of this standard. Forestry Soil Research Institute,
Forestry Research Institute, Chinese Academy of Forestry.
The main drafters of this standard. Zhang Wanru, Yang Guangying, Tu Xingnan,
Zhang Ping.
Determination of ammonium nitrogen in forest soil
1 Scope
This standard specifies the method for the determination of ammonium nitrogen
in forest soil by the magnesium oxide extraction - diffusion method.
This standard is applicable to the determination of ammonium nitrogen in forest
soil.
2 Normative references
The provisions in following documents become the provisions of this Standard
through reference in this Standard. The versions indicated at the time of
publication of this standard are valid. All standards are subjected to revision,
AND parties who reach an agreement based on this Standard are encouraged
to study if the latest versions of these documents are applicable.
LY/T 1229-1999 Determination of hydrolyzable nitrogen in forest soil
3 Methods and key points
PLACE the soil samples directly on the outer chamber of the diffusion dish; USE
the weak alkaline magnesium oxide aqueous suspension to exchange the
ammonium nitrogen attached to the soil colloid; MAINTAIN the temperature at
40 °C for 5 ~ 6 hours to release the ammonium, which is absorbed by the boric
acid in the inner chamber. USE the standard diluted acid to titrate it;
DETERMINE ammonium nitrogen content.
4 Reagent
4.1 170 g/L magnesium oxide solution. WEIGH 17.0 g of magnesium oxide
which had been burnt at 500 ~ 600 °C; ADD 100 mL of water; SHAKE it
uniformly before use.
4.2 The other reagents are the same as those in clause 4.3 of LY/T 1229-1999.
5 Main instruments
Diffusion dish (outer chamber 10 cm), dropper (5 mL).
6 Determination procedures
6.1 WEIGH 1.00 ~ 2.00 g of dried soil sample which had passed the 2 mm sieve;
SPREAD in the outer chamber of the diffusion dish; PIPETTE 3 mL of 20 g/L
......
Source: Above contents are excerpted from the PDF -- translated/reviewed by: www.chinesestandard.net / Wayne Zheng et al.
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