LaMotte Greenhouse Soil Testing Outfit GS-02 - Manual (Page 4)

SAM PLING PRO CE DURE
It is important to gather a representative soil sample to achieve
meaningful results. The following instructions will help achieve a
representative sample.
1.
Use a soil probe or similar device to collect sample.
2. Wait at least six hours after watering to sample.
3. If dry fertilizer is used, wait 5 days after application to sample. If
fertilizer is applied through a liquid injector system, wait at least 24
hours after application to sample.
4. Scrape away mulch and top c“ of soil.
5. Collect sufficient soil cores (10 - 15) to gather at least 1a pints of
soil.
WHEN TO SAM PLE
Many fertilizer problems may be avoided by sampling stockpiles of soil
mixes before adding any fertilizer. Once the fertility level of the basic soil
mix is established, a suitable soil fertility program can be implemented.
Fertilizer should be mixed with the soil according to the soil test results,
taking into account the use of a fertilizer injection system.
For all greenhouse crops, the soil should be sampled and tested prior to
seeding or planting. No additional sampling is necessary for bedding
plants and potted plants unless a problem develops. A greenhouse
operation specializing in continuous production of one or two crops will
want to sample the soil as the crop is finishing out. This will give a good
indication of the fertility level which has been maintained.
For bench crops, the soil should be sampled every three months. This will
enable greenhouse operators to maintain good soil fertility levels and
avoid nutritional problems.
For vegetables, the soil should be sampled before fertilization or planting.
This will enable the grower to use the proper kinds and amount of
fertilizer. Sampling the soil which the crop is growing will indicate
whether adequate nutrient levels are being maintained.
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PO TAS SIUM
QUAN TITY CON TENTS CODE
50 *Potassium Reagent B Tablets *5161-H
250 mL *Potassium Reagent C *5162-K
3 Test tubes, Potash “A” 0245
2 Test tubes, Potassium, glass 0232
1 Potassium Reading Stand 0946
*WARNING: Reagents marked with a * are considered hazardous substances.
Material Safety Data Sheets (MSDS) are supplied for these reagents. For your
safety, read label and accompanying MSDS before using.
PRO CE DURE
1.
Use a 1 mL pipet (0354) to add 1 mL of soil extract to the Potash “A”
tube (0245). Dilute to line with deionized water.
2. Add one *Potassium Reagent B Tablet (5161). Cap and mix until
tablet disintegrates.
NOTE:
The temperature of *Potassium Reagent C and the sample
must be kept between 20 - 27° C (68 - 80° F). On warm days, the
*Potassium Reagent C and test tube containing *Potassium Reagent
B may be cooled by placing them in cold water before mixing.
3. Slowly fill test tube to upper mark with *Potassium Reagent C
(5162), allowing *Potassium Reagent C to run down the side of the
tube. Swirl to mix. A precipitate will form if potassium is present.
4. Place an unmarked tube (0232) in the clip of the Potassium Reading
Stand (0946).
5. Use the pipet (0364) to add the reacted sample slowly, allowing it to
run down the side of the tube. Looking down through the tube, slowly
add reacted sample until the black line just disappears.
6. With the bottom of the tube resting on the plate, compare the sample
level to the scale. Read result from scale.
7. Multiply reading by 3. Record as Potassium.
NOTE:
The test result is multiplied by 3 because the original
dilution was 1:3. If a different dilution factor is used, multiply by the
appropriate factor.
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