Validating Top-dressed K Fertilizer Recommendations in an Alfalfa-Corn Rotation

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Start Date: 2008

Principal Investigator: Michael Russelle

Organization: USDA Agricultural Research Service

Status: Complete

Background Information:

Soil fertility affects alfalfa yield and quality. Potassium (K) plays a critical role in yield by moving sugars from shoots to roots, and then back again during regrowth. Additionally, K availability is crucial for optimum stress tolerance, including winter survival.

However, because K fertilizer is expensive and forage with excessive K can cause problems as dry cow feed, it’s imperative that producers apply the most economic rate in order to maximize profit. As corn grain and cellulosic biomass production become more important in Minnesota, growers must be educated as to what minimum rates of fertilizer inputs will support maximum economic yields. Considering that corn stover likely will become a significant source of cellulosic biofuel, do the same fertilizer N and K recommendations apply as for corn grain?

Key Findings:

©2017 Agricultural Fertilizer Research and Education Council of Minnesota