Soil Testing

I recently got two calls about interpreting soil tests that had been done by labs outside the state - Massachusetts and Wisconsin.  They aren't bad labs, but the results have problems. The problem is that these labs typically run analysis on acid soils and use different extraction procedures than are used on our calcareous soils. The numbers, other than pH, were funny, odd.  So I suggested using one of the California labs listed below. 

The analysis for pH in the results is probably good.  pH is probably the most important chemical property of the soil and knowing that and managing it will solve most nutritional problems found in many California soils.  Nitrogen and potassium would be handled with leaf analysis. 

 

The other thing to note before jumping to the results of a soils report is how the trees look.  Do they look healthy: http://ipm.ucanr.edu/PMG/C107/m107bpleaftwigdis.html

 

And is the irrigation system being managed correctly.  Suspect irrigation problems before nutrient deficiency problems

 

Allan Fulton in Tehama County has put together some good soil testing guidelines: