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Post-Harvest Update on K Fertilizer Recommendations and Cover Crops

By Nathan Drewitz
Harvest appears to be fully underway for most of the area.  With many of the corn silage and soybean fields harvested, attention will soon turn to nutrient applications and cover crop planting.  As we start planning for the next year, emphasis should be made on using the most up-to-date research and information surrounding these two topics.  Recently, UMN Extension has made updates to Potassium fertilizer recommendations for Corn and Soybeans and collaborated with the Midwest Cover Crop Council (MCCC) to create two different cover crop scenarios.  Both have full articles with more information on the Minnesota Crop News page of the Extension website. 
For Potassium requirements, primarily changes were made to the critical level for both corn and soybean with an increase to 200 PPM from 160 PPM for both crops.  Application rates were left unchanged for corn and increased for the Medium and High soil test classifications for soybean.  K removal values for both corn and soybean were adjusted to 0.19 and 1.10 lbs. of K2O per bushel respectively.  All these changes are based off of research done through the UMN Extension.  There is more research planned around exploring K fertilizer questions in the state.  This new research needs more on-farm sites across Minnesota.  If you are interested in hosting field trials, please contact Extension specialist Dan Kaiser at or call 612-624-3482.
For cover crop management sheets, often time finding information on cover crop management can be difficult.  To help remedy this, Extension and the MCCC created two separate low-risk cover crop management sheets on planting cover crops post corn and soybean harvest.  These step by step guides were designed to help give growers the tools to start incorporating oat and winter rye cover crops on their farms.  Both guides start with a planning and preparation section which is followed by a fall management section and finished with spring management.  Inside each section are considerations and recommendations for management of those two cover crops.  The recipes can be found on the MCCC website (, which also includes detailed information about many common cover crop species and links to other resources.
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