Nutrient Management Planning

Soil Testing

(2013-11-19) Soil testing should be a part of every good cropping system. The soil report shows the soil pH, the percentage of organic material, and the level of nutrients in the soil. It is important to find out if there are excessive nutrients in the soil that could be leaching into the water supply. Soil testing is the basis of any nutrient management plan. The object of nutrient management planning is to give a fertilizer recommendation that matches the requirement of the crop minus the amount of nutrients presently in the soil.

A soil test report is only as good as the sample it was taken from. Taking a poor quality sample is a waste of time and money. (Garbage in, garbage out.)

Soil Sampling Methods:

  1. Composite sampling is the most common type used by producers. In this method twenty to twenty five small sub samples are taken randomly throughout the field, then mixed together for one representative sample that is sent to the Lab for analysis. The advantage of this method is that it is quick and cheap. However problems can develop if nutrient amounts vary within the field, so mixing a number of small samples together may not accurately represent the field's fertility.
  2. Grid soil sampling is becoming more popular, especially for large fields and high value crops. This method uses computer software programs to create an accurate field map using GPS co-ordinates. The field is then subdivided into grids of approximately two acres. Composite soil samples are then taken from each grid. The results of grid sampling provide a more complete assessment of the nutrient level across the entire field. Most fields vary in nutrient levels, pH levels and soil characteristics throughout the field. Producers, then use the soil report to make recommendations which can apply different amounts of lime and fertilizer across the grids to develop more uniform nutrient and pH levels in the field. The only disadvantage is the higher cost.

Remember, Don't Guess, Soil Test!

About the Author

Harvey Cairns is the agronomist working with Kensington North and the PEI Federation of Agriculture on nutrient management with our farmers. Harvey has a long professional background with nutrient management. He has worked for the PEI Soil and Crop Improvement Association and the PEI Dept. responsible for Agriculture. He is a Certified Nutrient Planner and a Certified Crop Advisor. His many years of experience is apparent in his observations on soil and nutrient issues.

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