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Potassium Fertilization of Corn and Soybean

Start Date: 2011
Principal Investigator: Jeffrey Vetsch
Organization: University of Minnesota, Department of Soil, Water, and Climate
Status: Ongoing

Background Info

Research on potassium (K) fertilization of corn and soybean in Minnesota has not received a great deal of attention in recent years. Generally, resources have focused on nitrogen and phosphorus, because of greater potential economic return and environmental concerns related to these nutrients. During the last 10 years agriculture has experienced tremendous volatility of input and commodity prices, including fertilizer K (potash 0-0-60). Price volatility of inputs and commodities increases financial risk for growers. These financial risks include the risk of yield loss from inadequate fertilizer K application and risk of applying expensive fertilizer that may not be needed, especially on short-term rental farmland. These experiences have raised questions about K fertilization of agronomic crops.


Determine the effects of STK level and K fertilizer rate on crop yield, profitability, and K removal in corn and soybean

To measure STK incline/decline rates as affected by K fertilization rate and document temporal STK variability as affected by crop removal and K fertilization

To evaluate the field moist soil test as a predictor of crop response to STK levels and fertilizer K additions

Key Findings

Potassium fertilization research continued at two locations: Waseca and Rochester in 2018. This study measured the effects of fertilizer K rate at different STK levels on crop yield, K removal in grain and economic return to K fertilizer application. These data are currently being used to modify K fertilizer guidelines for corn and soybean. New guidelines are planned to be released in 2019.

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