Verified FBN Member (SK, CAN)

What is the % of nutrient loss associated with fall floating fertilizer?

Has anyone done or know of a company that has done multiple soil samples to calculate the nutrient loss from fall float to seeding? I know that there's lots of variables to consider but surely someone has some data.

We have fall floated fertilizer for the last several years. The cost to have it custom applied is easily justified by the spring logistics and limits of our equipment. We are considering purchasing a pull type boom floater or spin spreader to recapture the cost of custom work. We know that there is some product loss over winter. Not much, but enough. We have tried to get soil testing done to put a number to it but haven't been able to get samples when needed for various reasons.

I want to know if there is a place to find a % loss for each product applied as it sits in the field over winter. Currently we don't use Nitrain or agritain to reduce gas-off and will be considering that aswell. Thanks in advance

Verified FBN Member

It is all over the place. I am assuming you are referring to urea. Generally if you have moist soil but drying, warm-hot temperatures, and surface trash you are in trouble...could be 30% loss. If you get >1/2" rain right after spreading, you are golden, should be zero loss. Products like Agrotain and other urease inhibitor products work as advertised, buying you a window of time proportional to the rate you apply.

Verified FBN Member (IN)

I am also interested in this information on N, P, and K.

Verified FBN Member

P and K don't move other than in very high P or K environments (such as repeated manure applications on coarse textured soil). With that, you may want to use your fall application to 'top up' P and K if your soil tests are low, then add some P and K with the seed to get pop up effect going.

Note to corn belt growers: this is a Western Canadian generalized recommendation. You have a whole different history and deal down south.

Verified FBN Member (SK, CAN)

We use to put nh3 down in the fall. And assume 15-20% loss. The price difference between spring and fall is so little now. I don't think it justifies to fall apply N unless you really don't have the equipment. In the long run cheaper to upgrade equipment.

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