CALIFORNIA GROWERS LABORATORY, INC.

Plant, Soil, Water, Nematode Testing & Recommendations

Soil Sampling Procedure:

0-3' Profiles- These samples are taken throughout the year, but are generally taken in the fall on established permanent crops. They are used to set up soil amendments and fertilizer programs for the upcoming year. One sample location should be taken each twenty acres. Within this location, two separate depths should be taken. A composite sample from 0-18" and another composite sample taken from 18-36" should be adequate for a 20 acre block. The two samples will allow for a comparison between the two depths, since most of the roots of permanent crops are found within three feet of the soil surface. Many significant soil variations can be found within these depths, so comparison of the two depths can aid in making proper recommendations on soil amendments. Separate samples should be taken in areas of the field with different soil textures, past cropping patterns or any other variation that may affect nutrient levels or soil chemistry.

Soil samples are to be placed in a bag and labeled as to field location, type of crop, depth and any other pertinent data that may be necessary. About 1-2 lbs of soil should be sufficient. This is usually around the size of the brown lunch bags, filled half full. Samples should be taken to the laboratory for analysis as soon as possible.

Tissue Sampling Procedure:

Tissue samples are to be placed in sample bags and labeled as to field location, date sampled, growth stage, appearance of crop and any other pertinent data. While in transport to the laboratory, the samples should be kept as cool as possible and out of the sun.

Locations of Samples:

1. Samples should be taken 20-40 acre blocks.

2. Tree & Vines-Set up sampling stations (6 rows with 10 trees or vines per row) in each block. Collect 40-60 leaves or petioles (about 1-2 leaves or petioles per plant) which represents the vineyard or orchard. Care should be taken to begin at least 60 feet from the edge of a field before you begin sampling. Cuts, fill and significantly different soil types or growth patterns of the plants should be sampled separately. Once desired location is identified, the field should be sampled in the same location at future sampling dates.

3. Different crops require different sampling dates, along with different parts of the plant. Below is a list of crops, the plant part that must be sampled, and the time of year that the sample should be taken.

Sampling Procedure- Various Crops*

CROP DATE PLANT PART
1. GRAPES FULL BLOOM (MAY 15) PETIOLE OPPOSITE CLUSTER NEAR BASE OF SHOOT
2. APPLE-PEAR-CHERRY JUNE-JULY 2-5 MO. OLD, FULLY EXPANDED SPUR LEAF
3. APRICOTS JUNE-JULY 2-5 MO. OLD, FULLY EXPANDED SPUR
4. PEACH-NECTARINE JUNE-JULY 2-5 MO. OLD, FULLY EXPANDED BASAL TO MID SHOOT LEAF
5. PLUM-PRUNE JUNE-JULY 2-5 MO. OLD, FULLY EXPANDED SPUR
6. ALMONDS JUNE-JULY 2-5 MO. OLD, FULLY EXPANDED SPUR
7. OLIVES JUNE-JULY 2-5 MO. OLD, FULLY EXPANDED BASAL TO MID SHOOT LEAF
8. POMEGRANATE JUNE 2-5 MO. OLD, FULLY EXPANDED BASAL TO MID SHOOT LEAF
9. WALNUT-PISTACHIOS AUGUST TERMINAL LEAFLET
10. AVOCADO SEPT.-OCT. 5-7 MO. OLD SPRING CYCLE TERMINAL LEAF
11. CITRUS SEPT-OCT. 5-7 MO. OLD SPRING CYCLE TERMINAL LEAF
12. COTTON 1st BLOOM (JULY 1) PETIOLE OF RECENTLY FULLY EXPANDED LEAF ON MAIN STEM
13. TOMATO EARLY BLOOM PETIOLE OF 4TH LEAF FROM GROWING TIP

* Sampling procedures presented here are those generally applied to California climates and growing conditions. Sampling dates must be modified according to each region or climate.


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