June 21, 2022
Dickinson Research Extension Center Updates

Input Efficiency



Ryan Buetow
Extension Cropping Systems Specialist
Dickinson Research Extension Center
North Dakota State University
1041 State Avenue
701 456-1106
One of the most frequent questions we receive at winter meetings is “how do I reduce inputs.” Unfortunately, the answer for most things in agriculture is “it depends.” When thinking about inputs it is always important to think about Liebigs Law of the Minimum. This concept goes back to the 1840s from German agricultural scientists and botanists including the man who popularized the idea, Justus von Liebig. The best way to describe it is to envision a barrel. If the liquid inside is the yield and each stave is a different management factor, that barrel can only hold as much liquid as the shortest stave. If you have plenty of moisture for the year, have plenty of phosphorus and nitrogen, but your sulfur levels are deficient this will limit your yield. We often are limited by water in this region but we often have multiple yield limiting factors limiting our overall yield potential. This concept should be thought in unison with the idea of Maximum Economic Yield. Our goal isn’t always maximum agronomic yield, we want to maximize our economic efficiency on our operations. If we are applying nitrogen like we are expecting a record growing season for rain, this might not be the best use of input dollars. This sometimes means applying less fertilizer with the option for coming back mid-season. When it comes to fertilizer inputs use of soil sampling and breaking fields into zones is a great way to ensure you aren’t applying more than you need and the use of nitrogen rich strips is a great way to check for in-season fertilizer needs when we have enough moisture.

Once we set our yield potential, we need to protect that from yield limiting factors. This can be adverse soil conditions such as soil salinity or soil acidity. These can include weeds, insects, and disease. Use of Integrated Pest Management (IPM) is a great way to make sure our inputs are used efficiently. There are 5 main components to IPM; pest identification, monitoring and assessing pest numbers and damage, guidelines for when management action is needed, preventing pest problems, using a combination of biological, cultural, mechanical, and chemical management tools. The first component pest identification is the most important. If you don’t know what your issue is, how can you properly manage it? Knowing what is in your field can allow you to make sure the pest is at a threshold where chemical action is necessary and will be effective. When it comes to weed control it’s important to be timely, a chemical application to weeds or insects past a certain growth stage will often times be a spite application and not actually help yield. A mindset I’ve seen too often is to wait longer for more weeds to come up, but all this means is less control because the weeds are larger and less likely to be managed. With insects we need to make sure we are at economic threshold or an early application could take out beneficial insects that could otherwise keep damage below an economic level. Years like this can be difficult with a time crunch and waiting for the wind to die down, but make sure chemical applications are as timely as possible and needed and not just going by the calendar.

The best way to reduce input costs is to approach your operation as a system. Many issues can be prevented with a well-planned crop rotation. When doing things a certain way ask if there is a better solution and make sure to use each growing season as a learning opportunity to improve your operation.

If you haven’t already make sure to make use of the NDSU Nitrogen Calculators


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