When it comes to fall fertilization, the early bird could miss the worm if it shows up when the soil is too warm.
Experts say fall application of fertilizer saves producers two of their most precious resources in the spring, time and money.
Also, simple equipment can be used in the fall fertilizer application versus the multi-chute seeding equipment needed in spring.
Fertilizer prices are often lower in the fall than in the spring when demand is at its peak.
But with harvest wrapping up early this year, agrologists are noting that overly eager farmers are fertilizing too soon.
Read Also
Land crash warning rejected
A technical analyst believes that Saskatchewan land values could be due for a correction, but land owners and FCC say supply/demand fundamentals drive land prices – not mathematical models
“As much as we might want to see farmers fertilizing this fall, they are getting started too early. They need to cool it for a while,” said Rigas Karamanos, of Westco Fertilizer.
Garry Hnatowich, of Saskatchewan Wheat Pool, agreed.
“We are already sending trucks out for farmers. I think it is still too early though. A fair bit of mineralization will still occur this fall and any measure at this point will not be an accurate snapshot of what is out there,” he said.
Nitrogen levels can change dramatically through the fall and over the winter if soil conditions are wet or warm. Denitrification can occur if high moisture levels are present and microbial conversion to nitrates will also occur if soil temperatures remain above 10 C into the fall.
Karamanos said an ideal soil temperature range for soil testing is 5-10 C. And Karamanos noted that air temperature has little relationship to soil temperature, so measure the soil.
What is lacking?
A soil test done after the beginning of October will give growers a strong idea of what nutrients were removed over the past season and what will be needed for the next.
“You want to soil test as late as possible, but before the soil freezes. If you are going to apply fertilizer then the later you wait the better,” said Ieuan Evans, of Alberta Agriculture.
But frozen or water-logged soils can make getting a representative sample difficult.
Any areas with soil texture changes should have their own samples. Old fence lines and manure piles, saline areas, former farmyards, ditches or low areas can seriously affect the samples and throw off the data for an entire field and make the fertilizer recommendations inaccurate.
Producers should take a sample from the surface to 15 centimetres deep at 20 sites throughout the field. They must use clean plastic pails or bags to hold samples. Metal pails can contain elements that might skew the results. Residues of the elements being tested for can be transferred from gloves, tools or anything that comes into contact with the soil samples. Even tiny amounts of zinc from a pail or sulfur from a match will contaminate the sample.
If nitrogen problems or yield failures that might be associated with a lack of nitrogen have appeared in the last season, then 15 cm core samples at the 15 to 30 cm depth and 30 to 60 cm depth should also be taken to gain a full picture of the soil area that a plant might access during the season.
Once the field samples are mixed and lumps broken, a one kilogram sample can be taken. It should be air dried at room temperature and bagged, complete with all of the field information.
