Springtime is a busy and hectic time of year, so the fall is an ideal time to accomplish two important tasks: soil sampling and fertilizer application. 

Setting up for success 

Planning crop input decisions for the following season usually begins as harvest is wrapping up. Understanding the soil in which your crops grow is the first step to take towards implementing the 4R principles of nutrient stewardship, making soil sampling a must-add to the post-harvest task list. 

First, why should you have soil sampling done? The most valuable information from a soil test will likely come by measuring these five broad groups: 

• Organic Matter – Carbon-based compounds in the soil which often serve as a reserve for nutrients 
• Soil pH – The acidity or alkalinity of the soil, which can affect nutrient availability 
• Cation Exchange Capacity (CEC) – An inherent soil characteristic that is difficult to alter significantly and influences the soil’s ability to hold onto essential nutrients 
• Nitrate-N – The water-soluble form of nitrogen that is readily available for plant uptake 
• Extractable macro and micronutrients – The essential nutrients that are available to the plant and needed by the crop to produce maximum economic yield 

It is also imperative to sample soil consistently, in the same areas around the same time each year, to gather as much data as possible for comparison. As you and your nutrient advisors receive more information about these five areas, not only will you be able to make more informed fertility decisions, but also crop plans that can help maximize profits.  

More than just logistics 

It’s important to strike when the iron is hot when conditions are optimal for seeding, especially since earlier planting usually leads to better crop emergence and performance. This gives you a short window to assess soil conditions and make nutrient management decisions when you could already be getting seed into the ground. 

Soil sampling is best done when the soil temperature is dropping to around 5 to 7°C. In the spring, waiting for ideal soil conditions for soil sampling can take away valuable seeding time. 

In the fall, soil sampling can be done when the soil temperature has dropped, and soil conditions are more conducive to testing. Soil sampling can be accomplished over a wider window of time, allowing for further discussions with your crop advisor on any 4R adjustments that you might need to make. It’s also a good time to evaluate whether you may have under or over-fertilized based on your current season. For example, in a drought year, there may be more residual nutrients leftover in the soil. 

Fertilizing in the fall 

With the help of your Agrologist, you can review the soil sample results to see which nutrients and how much of each can be added back to the field. Certain nutrients lend well to being applied in the fall, particularly mobile nutrients such as nitrogen and sulfur. 

Typically, farmers apply large volumes of nitrogen. Applying in the fall means opening up more capacity in your seed drill. In the fall, it is key to make sure to band nitrogen at least three inches down to prevent losses or utilize nitrogen inhibitors depending on soil conditions and application method.  

Another fertilizer that can be applied in the fall is sulfur. Elemental sulfur, which comes in granules, needs time to oxidize and break down to become available to the plant, making fall an ideal application time. As it is given time to weather and be thoroughly incorporated in the soil, it will be more accessible for uptake by crops such as canola, when it needs it most, such as during flowering and pod set. 

Fertilizer pricing also tends to be more affordable in the fall. Having these cost savings up front can help alleviate some pressure on management decisions for spring, such as choice of seed, seed treatment, or the need for any additional fertilizer applications. 

Taking advantage of time 

The fall gives growers time to do what you would not be able to do otherwise in the spring. 

The best trials are ones that have been planned out quite a bit in advance. After sampling the soil and applying fertilizer in the fall, you can have more time to plan out trials and then have a higher chance of them being more successful because you have the time to review the information, change up management decisions, figure out where a new product or new practice is going to fit, and set yourself up for success the following season.  

Our trained Agrologists (P.Ag. or Tech. Ag)  are here to get you started this fall. Reach out to your local P&H today to lay the foundation for a successful growing season next year.