Idiomas disponibles
Idiomas disponibles
Forest sedimentation analysis according to KRUEDENER
2.12 Determination of soil type (sedimentation analysis)
Procedure:
A soil sample is crumbled with the fingers in the screen and
coarse contents (stones, etc.) are removed.The crushed sample
is placed in the test glass (22) and compressed a little with the
glass stamper (10) There must be sufficient soil in the test glass
to reach the E mark. If necessary, the test glass must be knocked
several times in the flat of the hand. The glass is then filled with
water up to the F mark below the top of the glass. The addition of
10 drops of pyrophosphate solution (32) prevents flocculation of
the clay particles.
22
The glass is closed with the screw cap and shaken thoroughly
until soil and water are evenly dispersed. When very loamy soils
are involved, the samples are first of all "softened" and then shak-
en thoroughly. Shaking is then stopped suddenly and the test
glass is positioned vertically.
After 18 s, the sand particles have sedimented; the height of the
sand fraction will have reached one of the lower 4 marks after
these 18 s. Read off the identification letter and refer to the table
above to establish the soil type.
The closed test glasses can be checked again after a few days
(particularly when heavy soils are involved), when the clay frac-
tions have also settled. The separation of all the fractions in the
glass is then to be seen very clearly. In this case, the volume
ratio of the fractions "sand" and "elutriatable matter" can also be
determined more accurately.
Example: Filling height = E
Evaluation:
Classification of soil types according to the German soil es-
timation regulation [ 3 ] [ 6 ]
Mark
Sand ( %)
Soil type
E
100–91
Sand
D
90–87
Slightly loamy sand
C
86–82
Loamy Sand
81–77
Very loamy sand
B
76–71
Sandy loam
70–54
Loam
A
55–40
Heavy loam
40– 0
Clay
Manual VISOCOLOR
Manual VISOCOLOR
Pyrophosphatlösung
PyrophosphateSolution
Solutiondepyrophosphate
Solucióndepirofosfato
10
32
after 18 s = A mark
Sand:
< 40 %
Elutriatable matter:
> 60 %
Soil type:
Clay
®
reagent case for soil analysis 02.19
®
reagent case for soil analysis
3. Procedure for photometric soil analysis
®
The VISOCOLOR
reagent case fully satisfies the requirements
for rapid determination of nutrient supply and fertilizer require-
ment. Together with the VISOCOLOR
case with PF-3 provides with quick and user-independent in-
formation on soil samples. For more extensive investigations,
there is the possibility to use the PF-3 in combination with the
®
NANOCOLOR
system.
The following chapters describe the preparation of soil extracts
and the determination of ammonium, nitrate, potassium and
phosphate with the PF-3. Further they give information about the
use of other NANOCOLOR
test kits*.
3.1 Preparation of soil extract AF
Soil extract AF, which is prepared with extraction solution A (cal-
cium chloride solution, 0.0125 mol/dm
used to analyze pH value, ammonium, nitrite and nitrate. The
composition of this soil extract differs from soil extract A.
Procedure:
Soil extract AF is produced from the non-dried soil sample, but
it should not be too wet and it should, if possible, be screened.
Remove all coarse and untypical constituents. Weigh out 100 g of
the soil sample prepared in this manner in a shaking bottle. Add
200 mL of the extraction solution A with the aid of the measuring
cylinder. Close shaking bottle. Shake bottle vigorously for 5 min,
allow solid matter to settle briefly. Place plastic funnel in a mea-
suring cylinder 100 mL, insert an MN 616 ¼ folded filter. Filter
suspension. If the solution is initially cloudy, pour it back into the
folded filter.
Filtrate = soil extract AF
3.2 Determination of pH value
The pH value is determined in soil extract AF using colorimetry
or pH indicator strips, a photometric determination of the soil pH
is not possible.
Procedure:
Insert the pH 4.0–10.0 color disc in the VISOCOLOR
parator block. Fill both measuring glasses up to the ring mark
with soil extract AF and place them in the comparator (if the soil
extract is colorless, the glass on the left can be filled with clear
water). Add 4 drops of pH 4–10 to the right glass, close and mix.
Look through the glasses from above, compare the colors of the
two glasses and turn the color disc until the colors match. Read
off the result from the marking on the front side of the compara-
tor block. Intermediate values can be estimated. After use, rinse
both round glasses thoroughly and close.
When pH values of less than 4.5 are measured, an additional
measurement is carried out with pH-Fix 2.0–9.0 test strips.
Fill a test tube with ring mark with soil extract AF to a height of ap-
prox. 3 cm, insert pH test strip in the sample. After 5 min, remove
the test strip and compare with the color scale, read off pH value.
* The preprogrammed submethods (mg/kg and mg/100 g) for soil analysis in our NANOCOLOR
photometers account for all steps and dilutions in the sample preparation during the calculation of
the measurement result and therefore only give reliable results using the methods and prepara-
tion steps described in this handbook. The amendments CAL (calcium acetate lactate) and AF
(Soil extract AF) in the submethod names refer to the extraction solutions to be used. In case of
changing the procedure, we recommend to use the submethod with the unit mg/L and a conver-
sion to the desired unit for soil analysis by accounting for dilutions manually.
®
test kits the reagent
®
photometers and NANOCOLOR
3
, see 2.5, page 24) is
®
®
HE com-
®
27
Capítulos
