By Charlotte Ward, MSc, PAg, Agri-Environmental Specialist, Yorkton and Kim Stonehouse, MSc, PAg, Crops Extension Specialist, Tisdale
It is widely accepted that on the Canadian prairies, forage seed crops are often deficient in nitrogen and phosphorus; however, depending on location, crop, soil characteristics and environmental conditions, potassium and sulfur may also be added to the list of nutrients to be supplemented. Depending on the type of forage seed crop, an annual application of fertilizer may be required. In the case of perennial fields, there may be a need for increased loading at the establishments for certain nutrients which are less mobile or are not at risk of volatilization. One or more of these four major nutrients may be limiting for optimum forage seed production.
There is limited knowledge around nutrients that are required in smaller quantities (micronutrients) for forage seed production. But, in terms of the macronutrients (NPKS) and their role in forage seed production, the library of production information is growing. The type, rate, timing and placement of these nutrients will not only impact production potential but can also affect the overall efficiency of fertilizer application.
When developing a fertility plan for forage seed crops, soil testing is a critical piece of the puzzle to benchmark and monitor soil nutrient levels during production or as management practices change. Soil testing can help direct application rates to ensure that crops receive adequate nutrition to reach their genetic potential and can reduce fertilizer costs.
Soil testing saves money in the long term as nutrients are applied only when and where they are needed. It also ensures management decisions can be made to ensure that the crop is healthy and has all the nutrients needed to deal with moisture, disease, pests or even problems such as lodging. Therefore, soil testing is a practice that fits well into a 4R Nutrient Stewardship program.
Agronomists are including 4R Nutrient Stewardship as part of the production package for most of the major crops that are grown. 4R Nutrient Stewardship uses scientifically proven beneficial management practices (BMP) to improve crop yield and increase economic return, while minimizing any potential negative impacts of nutrient application.
4R Nutrient Stewardship addresses soil and weather concerns to minimize crops losing nutrients after application. The 4Rs stand for the Right Source at the Right Rate at the Right Time in the Right Place. All 4Rs must be addressed to achieve the most efficient use of fertilizer.
The right source is the product that is most readily available to the crop, in sufficient quantities, where and when the plants need it. The right source also refers to a product that contains the nutrients in which the plants will be deficient if nutrients were not supplied.
The right rate is the amount of nutrients the plants require to achieve an expected yield without over- or under-supply. Soil type, organic matter, precipitation, growing degree days and residual nutrients, as determined from soil tests, will all combine to determine the right rate.
Applying nutrients at the right time (i.e. close to the time when the plants will use them) and in the right place where they will resist loss (i.e. within the soil) will help ensure maximum fertilizer efficiency.
4R Nutrient Stewardship starts with soil testing. The intensity of soil testing can vary from farm to farm. More producers are working with agronomists to develop soil maps of their fields. These maps can be used with modern farming equipment to integrate variable rate applications of inputs such as fertilizer on their farms.
Within the Canadian Agricultural Partnership, the Farm Stewardship Program provides Saskatchewan producers funding to implement BMPs in three priority areas – water, climate change and biodiversity. One of the BMPs eligible for funding is the Variable Rate Mapping BMP. This assists producers to obtain zone maps for variable rate fertilizer and variable rate irrigation application.
This BMP funds one-time consulting services and the associated costs for purposes of creating zone maps for variable rate fertilizer and variable rate irrigation application at 30 per cent of the total cost to a maximum of $2,000 over the life of the Canadian Agricultural Partnership program. The maximum eligible cost for variable rate mapping is $8 per acre.
Eligible producers must have an Environmental Farm Plan Certificate or other sustainability initiative, such as Verified Beef Production Plus, 4R Nutrient Stewardship or an International Sustainability and Carbon Certificate. For more details on who is eligible, please visit our Farm Stewardship Program page.
For more information on 4R Nutrient Stewardship or the Farm Stewardship Program, please contact your nearby Saskatchewan Agriculture Regional Office; or call the Agriculture Knowledge Centre at 1-866-457-2377.