Soil and Leaf Sampling Procedures

From BugwoodWiki

Soil and leaf samples are required for making fertilizer recommendations. A soil or leaf analysis is no better than the procedures used to collect the sample. For samples to be representative of the area tested, follow these steps for sampling:

Soil Sampling Procedures

1. Soil samples may be conveniently taken when leaf samples are pulled. Soil sample bags are available from your county agent. They should be used for submitting samples to the laboratory. Supply all the information asked for on the soil sample bags.
2. Use a spade, trowel, soil sampling tube, auger or other tool which can take a thin vertical slice of soil to a depth of 8 - 12 inches.
3. Take at least 12 or 15 cores or thin slices at random over the area to be sampled. In general, one composite sample consisting of 12 - 15 cores should be taken for each block of trees. If possible, sample under the predominant variety. (For example: Stuart.) Place samples in a clean plastic bucket or other non-metal container and mix well. Fill the soil sample bag at least 3/4 full. Do not use a galvanized bucket if the soil is to be analyzed for zinc or other micronutrients.
4. Cores should be pulled within the drip line, not between rows. The area included in one sample should have been uniformly fertilized and limed in the past. When collecting the sample, avoid high or low spots, eroded areas, and areas along roads and fences. Sample problem areas within an orchard separately.

Leaf Sampling Procedures

1. Obtain plant analysis mailing kit from the county agent’s office. One mailing kit per sample is required.
2. Sample trees between July 7th and August 7th. (Sampling can be extended into mid-August without affecting the results.)
3. Collect 100 middle-pair of leaflets from the middle leaf of this year’s growth (see illustration). Use terminal shoots exposed to the sun. Avoid twigs from the interior of the tree. Collect leaflets from all sides of the tree. Avoid leaflets damaged by insects and diseases.
4. Abnormal trees or trees not representative of the area should be sampled and sent separately. A complete and accurate description of abnormalities should accompany such samples.
5. Sample trees of the predominant variety in a given block. If Schley is the main variety, sample Schley; if Stuart is the main variety, then sample Stuart, etc.
6. Immediately upon collection, wipe leaves (entire surface, both top and bottom) with a damp cellulose sponge or cheese cloth to remove dust and spray residue. Do not allow the leaves to come into contact with rubber or galvanized containers. Partially air dry and place in the large envelope of the mailing kit.
7. Complete the questionnaire obtained in each mailing kit. Place the completed in the smaller envelope together with a check made payable to The University of Georgia to cover any charges and mail it to the Plant Analysis Laboratory.
8. If recent soil test data is not available, it would be advisable to collect a soil sample and have it sent to the Soil Testing Laboratory.