Tree Fruit Soils and Nutrition



Soil Sampling


Soil interpretation link


Proper soil sampling is critical in assessing the soil fertility of your site.  Soils are inherently variable and it is therefore necessary to obtain a random and representative sample.


Restrict the area sampled to a uniform soil type or condition within the orchard.


Location for sampling:

  • Normally, the samples are collected from the within the existing tree row and not row middles or grass alleyways (drive row).  Samples should also be taken from within the drip-line of the tree canopy. 

  • Sample topsoil and subsoil separately.  Scrape away the surface dirt and then collect samples from the 0-6 depth, and separate samples from the 6-18 depth. Small increments or samples below 18 may be required for diagnostic purposes.


Separately sample the following:

  • Areas where the soil texture changes (sand, loam, clay, etc.) due to variability in buffering capacity

  • Where slope of the land changes substantially or where a restrictive layer is present at depth.

  • Where differing irrigation management systems are used (sprinkler, rill or drip, etc.)


Sampling technique:

  • Zig-zag patterns are commonly used

  • The area included in one composite sample generally should not exceed about 10 acres.

  • A good rule of thumb is to take about ½ cup soil for each core and to take 20-40 cores per 10-20 acre block.

  • To avoid micronutrient contamination of samples, do not use chrome-plated or galvanized tools or containers. 

  • Thoroughly mix the 0-6 samples and collect a single composite sample.  Treat the 6-18 samples similarly. 

  • The composite sample should be air-dried for routine analysis.  Samples for nitrate analyses require special handling.  Consult with laboratory representatives before collecting samples.

  • Record sampling date, where (block), and at which depth the samples were taken and any accessory information that may be useful in interpreting the soil test results.





Updated July 9, 2004


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