Peat soils are a unique type of organic soil that is quite common in the Prairies. Like any other soil, it has advantages and challenges that growers can utilize to achieve their target yields without exceeding their budgets.
The uniqueness of this soil lies in its enormous percentage of organic matter, which results from the soil’s natural formation over time. Waterlogged conditions are the must for forming these soils. The presence of excessive moisture, whether from precipitation alone or a combination of precipitation and groundwater, creates the necessary conditions for plant residues to accumulate without rapid decomposition in the absence of oxygen.
Such layers of peat can be up to 40 feet thick. Once the excessive moisture is removed, either naturally or through human activity, oxygen helps microbiota decompose the organic matter much faster. Over many years, and depending on the use intensity, the organic matter content gradually decreases to more ‘normal’ levels. The more row crops are included in crop rotation and the fewer perennial grasses, the faster this process occurs.
Very high organic matter content (20-75% OM) creates overwhelming amounts of available nitrogen; on the other hand, other macronutrients can be at marginal or even deficient levels. Soil tests showing 700+ lbs/ac of available nitrogen in 0-24 inch are not uncommon, even in an average year. Organic matter also changes the physical soil properties, making them colder and usually ready to seed the last in the season. The lack of moisture during the growing season makes peat hydrophobic, which leads to restricted nutrient uptake by the crops. This can be a challenge in unstable moisture supply growing conditions.
Agronomists are aware of these differences and can help farmers achieve yield targets by creating a balance in macro and micronutrient supply that may differ from the rest of the mineral soil on the farm.
Having peat soil in fields with excessive nitrogen supply makes them very suitable for nitrogen-demanding crops like canola or many row crops. On the other hand, growing grain legumes can be challenging for the same reasons. Excessive nitrogen causes legumes to produce an abundance of vegetation at the expense of generative growth. Some micronutrients, such as copper (Cu), should be carefully considered to avoid possible deficiencies.
As a team of senior agronomists located across all Prairie Provinces, we encounter peat soils every season and are familiar with the common issues and specific conditions associated with peat soils, combined with grower/field-specific factors. With over 20 years of experience in creating fertilizer recommendations for such unique fields, we are the team of agronomists that can help any grower overcome any challenge. Contact us in MB, SK, and AB for help and advice in agronomy and/or precision agriculture, weather station installation and maintenance, in-season issues, or challenges in established crops.