Test your soil!
· Optimize economic returns.
· Optimize crop production.
· Maintain levels of plant available nutrients.
· Improve the nutritional balance of the growing media.
· Avoid pollution and environmental degradation.
· Understand nutrient deficiencies, pH imbalances, and excess soluble salts.
How do I take a soil sample?
Soil testing can be done any time your soil isn’t frozen or overly wet. You will want to take 10 random soil cores from the specific area you are wanting to test (e.g., field or pasture unit, lawn, garden bed) if the area is small (under 2 acres) and 20 to 25 samples for a larger field.
· Container (0.25 cup is ideal)
· Insert the spade or trowel to the desired depth in soil, making an opening.
· Create a soil slice about ½ inch thick by reinserting the spade next to the initial opening.
· Remove your tool and leave the slice intact. Take a 1 inch wide strip from the centre down the entire length.
· Remove grass, stems, thatch, and stones from the sample.
· Use the container to measure out your sample size. Once measured, put the sample in your bucket. Repeat at the other testing holes.
· Mix all the samples thoroughly to get one uniform sample.
· Label your sample bag (date, pasture, number of samples [# combined], your name), fill your sample bag with the tested soil.
· Field corners or turnarounds
· Livestock watering areas
Where do I send the soil to be tested?
You will need to include a submission form with your soil sample. Submission forms can generally be found on the website, or by calling the testing lab directly.
What does a soil test look like and how do I read it?
Here is a soil test that was sent to Interior Seed and Fertilizer, and analyzed in Edmonton AB. The managers goal is to build nutrients in his East Kootenay soils to a level to maintain soil health. He operates a grazing operation on dryland pasture.
This lab uses nutrient extraction and analytical methods specifically developed for western Canadian soils. These use standards methods for testing soil in Western Canada.
Take a look at an example…
Interpreting this soil test:
Nitrate nitrogen is what is called plant available nitrogen. For this soil sample, nitrate nitrogen is very low. This is normal for a fall sample, because soils cool down, microbial activity decreases and soil microbes use available nitrogen.
Phosphorus levels are very low. Phosphorus is important during the seeding year, and for optimum production.
In the Kootenays, over time applied phosphorus can become unavailable to plants. Soils generally have high pH, high calcium and high magnesium. Plant available phosphorus is not stockpiled in the soil, particularly for soils with these properties.
Potassium levels are high in the soil test (over 190 ppm or 380 lbs/acre). Potassium is an inexpensive fertilizer nutrient. Potassium deficiencies are easy to visually see on the plants.
Sulfur is listed as marginal, or near deficient. When sulfur is low, other plant nutrients are not utilized effectively. Sulfur, applied in elemental form is not available to plants immediately. Elemental sulfur must be modified to sulfate form by soil microorganisms, which takes about 1 growing season.
Ammonium sulfate fertilizer (21-0-0-24S) delivers sulfur in sulphate form and is available to plants immediately.
Recommendations Given for this Soil Test
· Apply a blend of fertilizer that will give the following nutrients for the current year
· If you do not wish to fertilize next year
o Increase N and P205 in the current year to save costs in Y2 and Y3
o **This is only applicable for dryland sites
How Often Should I Test my Soils?
· Every 2 to 3 years until results stabilize.
· Every 3 to 4 years for maintenance.
Current Value of Common Plant Nutrients
Cost per pound of Nutrient (2021)· N: $0.72/lb· P205: $0.74/lb· K20: $0.51/lb· S04: $0.42/lb· S(ele): $0.28/lb· B: $9.41/lb
Soil Test Phosphorus and Potassium Guideline
KBFA Soil Resources
Alberta Agriculture, Food and Rural Development. (2004). Alberta Fertilizer Guide. Agri-Facts. Agdex 541-1.
Alberta Agriculture, Food and Rural Development. (1998). Crop Nutrition and Fertilizer Requirements. Agri-Facts. Adex 540-1.
Alberta Agriculture, Food and Rural Development. (2005). Fertilizing Grass for Hay and Pasture. Agri-Facts. Agdex 127/541-1.
Alberta Agriculture, Food and Rural Development. (2001). Fertilizer Requirements of Irrigated Alfalfa. Agri-Facts. Agdex 561-18.
Alberta Agriculture, Food and Rural Development. (2013). Phosphorus Fertilizer Application in Crop Production. Agri-Facts. Agdex 542-3.
Weil, R.R., Brady, N.C. (1990). The Nature and Properties of Soils (10th Edition). Chapters 11, 12, 16. Maxwell MacMillan International.