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By Daniel Kaiser
Extension Soil Fertility Specialist

At times potassium (K) can be the forgotten element when determining appropriate rates of fertilizer to apply.  Nitrogen and phosphorus typically are of main concern due to the potential yield response for corn to nitrogen and many soils around the state historically being low in P but medium to high in K.  Potassium should not be a forgotten nutrient as there are situations where K fertilizer can be profitable.

By Daniel Kaiser
Extension Soil Fertility Specialist

It is important to understand where sulfur that is utilized for crops comes from in order to determine where to best target fertilizer application. In Minnesota, sulfur was not recommended for many crops grown on medium and fine textured soils. Numerous studies were conducted during the 1970's, 80's, and 90's with little to know positive benefits shown except for a limited number of studies where corn was grown on eroded soils. Over the past 10-15 years reports increased as to sulfur deficiencies and research has found that sulfur may be needed for crops most sensitive to sulfur deficiency.

Daniel Kaiser, Fabian Fernandez, and John Lamb
Extension Nutrient Management Specialists

This week of cool weather has made it clear that fall is fast approaching.  The drop in commodity prices will likely cause a few conversations among farmers, consultants, and retailers on what fertilizer to apply for the 2015 cropping year.  Many fields are currently being soil sampled for phosphorus (P), this fall is a good time to consider what is actually out in the field to best target P fertilizer applications.

Nitrogen management for 2015

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John Lamb, Fabian Fernandez, and Daniel Kaiser, Extension Soil Scientists - Nutrient Management


Labor Day has come and gone and now it is time to think about nitrogen (N) plans for next year. This news article will cover some thoughts about fall applications of N.

Soil sampling

If you plan to use a soil nitrate-N test, you need to wait until the soil temperature is below 50°F to get a soil test value that is useful for predicting fertilizer need.

Nitrogen management

The past three years have been challenging for N management for corn. The wet springs have caused larger than normal N losses. In 2014, we saw some of the largest number of acres of N deficient corn in Minnesota in years. The current University of Minnesota N guidelines for corn were based on the use of N best management practices. Fields that had N applied at UMN guidelines may have been short of N, if the fertilizer was applied in the fall. One suggestion for fields with a history of fall N applications with N deficiency problems the last three years is to strongly consider pre-plant spring applications or a split application with some side-dress N before the V8 corn development stage.

John A. Lamb
Nutrient Management Extension Specialist
University of Minnesota

Because of weather, a number of acres of the 2013 sugar beet crop will not be harvested.  It has been a number of years (PIK years) since this many acres have been left un-harvested.  At that time, SMBSC and the University of Minnesota did conduct a number of research studies to answer the main production question:  "What should I do with these fields for next year?" 

By Daniel Kaiser
Extension Soil Fertility Specialist

Management of Iron (Fe) deficiency chlorosis (IDC) in soybean is seemingly and endless topic of research in soybean growing areas with high pH, calcareous, parent materials. We are just finishing a three-year summary of a series of IDC management strip trials that began in 2010. Our main focus for this work was to study the variability in response for a tolerant and susceptible variety to an oat companion crop and a 6% EDDHA-Fe treatment applied in-furrow (we used Soygreen at a rate of 3 lbs of product per acre). The field areas were selected to have some variation in the severity of IDC.

By Daniel Kaiser

University Extension Soil Fertility Specialist

With the extreme variability in growing conditions there have been some questions regarding the variability in soil test. A project is being launched to establish a series of sentinel plots to study the monthly variation in soil test values over the next two growing season. We are looking for participants that are willing to take samples from a single point within a field and mail them off to us at Saint Paul. The goal of this study is to gain a better understanding of what is happening over the growing season for a number of different nutrients commonly measured.

Soil Testing For K

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By Daniel Kaiser
Extension Soil Fertility Specialist


With spring finally approaching it is a good time to address some questions on soil testing that came up of the winter concerning testing soils in a field moist state versus the standard dried samples that are run through soil testing labs.  First I would like to make it clear that the issue of drying of a soil sample mainly pertains to potassium.  Most other tests routinely run through the lab are not affected by drying of the sample.  The reason why potassium is different is due to its chemistry in the soil.  We currently have finished the second year of potassium studies looking at both testing methods but will be continuing this work for the foreseeable future to gain a better understanding of what is going on within the soil.
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