Soil tests are an essential part of farming and gardening because they can help determine plant nutrient needs and plant selection decisions thus helping to keep money in your pocket. Testing soil has often been compared to visiting a doctor for a health check-up. Physicians use tests to help them prescribe medications and the same should be done for our soil. Having too much of one nutrient can affect our crops badly and affect the productivity, on the other hand not having enough nutrients to sustain plants can be detrimental to the crop. Whether you are a wanting to grow a small vegetable garden or a thousand acres of corn; soil testing is a good thing to give you a basis on where to start.
Testing soil helps to keep the soil healthy by measuring what is exactly in the soil. Soil labs then give recommendations on what to apply to ensure excess nutrients are not available to escape into groundwater, streams and lakes where they contribute to environmental problems (i.e. algal blooms, hypoxia, etc.). A big water quality issue in the State of Ohio that is affecting not only lake Erie but inland lakes such as Buckeye Lake, Grand Lake St. Marys and even Caesar Creek is excess phosphorus. It is important that phosphorus is not added if the soil does not need it. In many parts of the country fertilizer companies are not including phosphorus in their mixes to ensure phosphorus is not over applied.
Soil sampling can be done any time of the year but it is best not to take samples in high rain events. One test can be taken for an area if there are no major topography changes or the area has not been treated differently in the past (I.e. pasture in one area of the field and crops in the other area). It is recommended that a separate test be taken in that area that was managed differently so that results are not skewed. It is also recommended to lump no more than 20 acres together in one test.
The field should be walked in a zig-zag pattern, with a subsample taken every few feet. For small areas such as vegetable garden, 5-10 subsamples are sufficient and 10-15 subsamples for larger areas such as lawns and fields. Subsample depths should be taken at the following:
Warren County SWCD Staff Blog
A blog to keep you informed on all the latest news at Warren County SWCD and in the conservation world.