High Yields, High Removal Rates

As we approach October more and more fields are getting combined, and yield reports are coming back very good. The early planted fields are showing some of the best yields we have seen in the SFG trade territory. This will require us to rethink our P & K needs for the next years crop. High yields require more nutrients, and those nutrients come from the soil. The only way to replenish them is to add more fertilizer. So yes, high yields will require more inputs, but I think that is a good problem when corn is yielding 50 bushel better than normal. 

For example, 50-bushel corn represents 16 lbs of Phosphorus and 11 lbs of potassium according to Iowa State University. This means to maintain soil test levels we need to increase our removal rates by roughly 25% if the yields are 50 bushels more than average. Soybeans are not quite as drastic on the phosphorus but potassium requirements on soybeans 15 bushel higher that average are 18-20lbs of potassium more than planned. This means in a two-year rotation you might need an extra 50lbs/ac of potash applied just for removal.

Making sure your fertility plan matches yield coming off the fields will allow you to take full advantage of the years that yields are high. We want to make sure to avoid lowering soil test levels so fields can handle the high yields we are seeing. Make sure to discuss with your SFG Agronomist about how high yield may affect your fertilizer needs this fall.