Soil Tests and Amendments
10 | Unit 1.11
Students’ Lecture 1 Outline
Note that different soils can require different nutrient extraction techniques, e.g., some are
developed for soils with a given pH range and will give misleading results for soils outside of that
range. Also, the presence of high levels of certain compounds in the soil may distort soil tests and
require different extraction techniques.
The specific nutrient levels listed in this unit are based on the extraction techniques used at specific
laboratories. Although over 90% of U.S. agricultural testing services use the same extraction
techniques, some variation exists.
NOTE: It is critical that one confirms the specific “optimal” levels used in this unit with those used by
your local testing service. The optimal levels presented in this unit are examples of those used by
many A & L National Agricultural Laboratories.