Most people will want to sample their garden or orchard area and these guidelines are for small areas

Soil Sampling Instructions.

1. Several different tools – such as an auger, a soil sampling tube, or a spade may be used in taking soil samples.

2. Scrape away surface litter. If an auger or soil sampling tube is used, obtain a small portion of soil by making a boring about 7 inches deep, or if plowing or tilling deeper, sample to tillage depth. If a tool such as a spade is used, dig a V-shaped hole to sample depth; then cut a thin slice of soil from one side of the hole.

3. Avoid areas or conditions that are different, such as areas where fertilizer or liming materials have been spilled, gate areas where livestock have congregated, poorly drained areas, dead furrows, tillage or fertilizer corners, or fertilizer band areas of last year’s crop. Only sample growing areas, not roads or other areas of activity.
4. Because of soil variations, it is necessary that each sample consist of small portions of soil obtained from approximately 6-8 locations in the soil area. After obtaining these portions of soil, mix them together for a representative sample. Dry samples and place 16 oz. (2 cups) of soil in a soil sample bag or Zip Loc bag.

5. Soil sample depth is dependent on crop type. Our vegetable garden, since shallow rooted, is sampled at 5”, berries 6” and trees 8-10” since these depths are more indicative of the root growing zone.

6. It is important to not contaminate the samples by allowing surface debris or soil to fall into the hole where samples are gathered.

Types of Sample testing can be customized to give you results in lbs per acre, lbs per 1,000 sq ft, parts per million, Kilograms per hectare. We find lbs per 1K sq ft the easiest to work with. If I were testing a 40 acre field I would use the pounds per acre.

Standard Soil Test:

This test will show Ph, major minerals, minor minerals and some trace elements, total exchange capacity and organic matter content.  Note this differs from the basic NPK test offered by some state ag colleges because of the type test we request and use.   This will show you the total content in your sample.

Paste Soil Test:

The saturated paste test shows what nutrients are immediately available in the soil’s water solution.  These are the easy access nutrients for plants, so this test better predicts what nutrients (and how many) will get into the plant.  This will show ph, major and minor minerals and their availability.

What is the real difference in the two tests?  The easiest way to think of it is the standard test as the soil’s “savings account” and the saturated paste test as the soil’s “checking account”.  Both show nutrients that are accessible, but the checking account nutrients are more easily available.

An example we have is that each spring we face iron chlorosis in strawberries. Iron chlorosis is a yellowing of plant leaves caused by iron deficiency.  It frequently occurs in soils that are alkaline (pH greater than 7.0) and that contain lime; conditions that are common in New Mexico. Even though we have plenty of iron in our soil, the high soil pH causes chemical reactions that make the iron solid and unavailable to plant roots. Such iron will be tied up indefinitely unless soil conditions change to lower the ph.

I recommend doing both tests to give a bigger picture, but if you can only do one then a Paste test will give you items to work on immediately.

These are the basic tests we use.  Of course you can go more I depth and get particulate type tests showing percent of clay, sand, loam and organic matter or individual tests for specific minerals.  Before I do those I would get a quality water test.  It stands to reason, for example, if you are trying to lower your soil ph but constantly adding high ph irrigation water that you need to calculate this into your equations.

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