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How to prepare soil for the application of fertiliser
Send a sample of soil to a local cooperative extension.
Collect a sample of your soil by digging a couple of holes that are 5-6 inches (13-15 cm) deep. Then, store the soil in an airtight plastic container or sealable bag and send it to the cooperative extension for tests.
They will evaluate the soil and give you recommendations for amendments and fertilizers. Cooperative extension offices test and study agriculture and the environment and can be found at certain universities.