Best Practices for Soil Sampling

Soil testing is an outstanding method for assessing the fertilizer needs of your soil. Given the cost of fertilizer, soil sampling is the best way to determine whether you are using the correct amount of fertilizer on your crops.

Most agricultural experts recommend testing soil every two to four years. They also caution that soil testing is not a task to be taken lightly and that to get accurate results, it must be done correctly and consistently.

What follows are some important things to keep in mind when collecting soil samples:

  1. Mind your tools. Tools that are not clean will contaminate soil samples so it is important that you never use tools that have not been thoroughly washed. Plastic tools and buckets are preferable to metal ones as metal may have small amounts of rust or zinc that can flake off and contaminate the samples. Such contamination will skew the results of the soil’s nutrients.
  2. Dig at the same depth. Experts recommend collecting samples roughly 7 inches deep. Collecting too shallow of samples will give misleading results about nutrient-supplying capacity. Likewise, going too deep down for samples will lead to diluted soil concentrations. Consistency also is important so make sure you dig down the same number of inches for all samples.
  3. Carefully collect and mix cores. It is critical to collect enough cores per sample area. This number should be anywhere between 15 and 20 cores. When you fail to collect enough cores, the soil samples will be inaccurate. Remember, the samples you are collecting represent a huge number of pounds of soil so there must be enough to get precise results. Cores also must be thoroughly mixed. This will allow the composite to contain an accurate mixture of all the soil samples.
  4. Sample in the fall. Fall is usually the best time for soil sampling because it allows you enough time to get it right. In the fall, there is more time to collect samples, run the analysis and then buy the right fertilizer. If you must do your soil sampling at another time of year, however, make sure you do it the same time each year.

Soil sampling is an outstanding method to ensure that you are making efficient use of your fertilizer. It also helps you to devise the best fertilizer management plan over the long term. Finally, when done correctly, it will go a long way toward improving yields.