Are you just starting to take a look at your soil reports from this seasons soil sampling?
You may be curious how to interpret the results and specifically what’s next. We’ve started a new YouTube Educational Series to dive into those details. Head over to our Youtube channel and subscribe to be notified of our first video on soil pH and it’s affects on nutrient availability. To learn more, check out our blog below.
The soil reaction or pH is important as it affects nutrient availability, solubility of toxic substances like aluminum, the rates of microbial activities and reactions, soil structure, and more. pH measures active soil acidity or alkalinity.
Overall, the soil pH is expressed on your report ranging from 0-14. A value of seven indicates neutral, a value of 6.9 or less is acidic and higher than 7.0 is alkaline. Soils become more acidic as a result of the removal of the cations calcium, magnesium, potassium, and sodium through leaching or by growing crops.
Why is it important?
The more acidic your soil or lower your pH value, the lower the availability of nutrients for your crops. The higher the pH, or more alkaline soil, the increased likelihood nutrients are tied up in your soil. Many Agricultural soils are in the pH range 5.5-8.0. The optimum pH range for most crops is 6.0-7.5 and for leguminous and other alkaline preferring crops 6.5-8.0. A desirable pH range for mineral soils is 6.5-6.9 and organic soils is 5.5-6.0. Take a look at this map to see where pH levels often fall in your area.
Table 1.0 Soil pH across the United States
Now that you know your soil pH you may be curious about the nutrient availability in relation to your pH.
In the Midwest Labs agronomy handbook, you’ll find the below chart indicating the nutrient absorption range as it relates to a soil pH. You’ll find that most nutrients have high absorption rates around 6.2-7.3 soil pH.
Now take a look at your soil report and see what your pH levels are and how that affected the nutrients also found in your soil.
You may also find on your soil report a Buffer Index.
This is an index value use to determine the amount of lime to apply on acid soils with a pH less that 7.0. The lower the buffer index number the higher the lime requirement.
To identify the micronutrients available in your soil add on the S3 package to your Basic Soil Analysis. The S3 contains Sulfur, Zinc, Manganese, Iron, Copper, and Boron.
Tune in next time to learn about, Cation Exchange Capacity (CEC), lime recommendations, and more.
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