How to Test Agricultural Soil


Agricultural soil can be tested to determine its nutrient content and levels of biological activity. Soil health improves crop production and helps protect water quality. Seventeen nutrients are essential to healthy plant growth, according the Utah State University Extension. Deficiencies can be corrected with the addition of organic soil amendments or compost. Organic amendments can be added to bring soil into balance. Soil characteristics vary from location to location. Samples should be taken in all areas that will be cultivated.

Step 1

Wash your hands and put on latex gloves for sampling.Take soil samples from five to 10 sites in the area of interest. Wipe aside any organic materials from the top of the soil where you want to sample. Using the apple corer, take a sample from near the root zone of the plant. If the root zone cannot be located, dig 3 to 4 inches down and take the core sample there.

Step 2

Dig up five to 10 soil samples. Include some root materials. Random sampling of five to 10 areas gives representation to microbial populations living in the soil. Microbiological soil test laboratories give test results that assess biological activity. Traditional soil tests give the chemical analysis of nitrogen, phosphorus and potassium content, as well as pH levels.

Step 3

Place each core soil sample in a clean bucket or bowl and mix together. Place approximately 2 cups of soil into each plastic zip-lock bag. Leave a 1/2-inch space at the top. Package immediately to send to the soil testing lab. Keep samples cool but do not freeze or store before sending to the lab. Freezing and thawing kills some bacteria.

Tips and Warnings

  • Avoid cigarette ash contamination of soil samples. Cigarette ash causes considerable change in test results, according to Ohio State University.

Things You'll Need

  • Latex gloves
  • Shovel
  • Apple corer
  • Plastic sandwich size zip-lock bag
  • Bucket or bowl


  • Utah State University Extension: Nutrients-Vitamins for the Soil
  • Ohio State University Extension: Soil Sampling, Handling and Testing
  • Soil Food Web: Sampling Instructions

Who Can Help

  • National Sustainable Agricultural Information Service: Alternative Soil Testing
  • Soil Food Web: 12-Step Approach to Understanding the Soil Foodweb
Keywords: soil testing, soil food web, nutrient testing

About this Author

Joan Norton, M.A., is a licensed psychotherapist and professional writer in the field of women's spirituality. She blogs and has two published books on the subject of Mary Magdalene; "14 Steps To Awaken The Sacred Feminine:Women in the Circle of Mary Magdalene," and "The Mary Magdalene Within."