Regular soil nutrient sampling and analysis is a central part of nutrient management planning and monitoring. Soil sampling can inform the right rate of nutrients for optimal growth and yield and provide a check on the efficiency of nutrient use.
There are several steps involved in getting an accurate sample and turning it into a useful fertility recommendation.
How and when a soil sample is collected matters. What you can interpret from the results will depend on the way a sample is collected. Generally, pre-plant, post harvest, or troubleshooting are the main sampling strategies to consider.
If your sample needs to provide a post-harvest nitrate test in order to determine the amount of nitrate in the soil after crop harvest, follow the specific guidance provided for post-harvest nitrate testing.
Once soil sampling has been completed, it should be sent to a soil testing laboratory for analysis. Laboratories will use different soil extractants, solutions designed to remove nutrients from soil for analysis, so be sure to record which one is used.
Soil test results provide a snapshot of the nutrient status in the soil at the time of sampling. To interpret a report, how and when the sample was taken, as well as the type of lab analysis should be considered.
Other resources available to interpret test results include: