Dr. Cristie L. Preston is an Assistant Professor of Sustainable Cropping Systems at the Kansas State University Southeast Research-Extension Center, where her work focuses on soil fertility, crop nutrition, and cropping systems research and extension across the region. Before joining KSU, Dr. Preston served as a technical agronomist in industry, with expertise spanning corn, soybeans, and wheat production systems across the Corn Belt, Central Plains, and Mid-South. She is a Certified Crop Advisor and serves on the Kansas CCA Board. Dr. Preston earned her Ph.D. from Kansas State University in Agronomy and a M.S. in Soil and Environmental Science and B.S. in Animal Science from Virginia Tech. Dr. Preston has spent the last decade helping farmers bridge the yield gap by helping them make better Nutrient Management decisions.
When it comes to nutrient management, every agronomist and farmer should be familiar with several basic concepts. From how to take the ideal soil sample to determining rates, farmers can maximize fertilizer efficiency and their profitability with these four concepts highlighted on eKonomics.
The first step is to take the best soilsample. By determining the amount of plant available nutrients in the soil, a farmer can better plan for supplemental fertilization needed to maximize yield. 4 Steps to achieving the ideal soil sample
A farmer’s maximum yield will be limited by the most limiting factor – Liebig’s Law of the Minimum – which means continually adding more nitrogen will not increase your yield if potassium has become the primary limiting factor. We have all seen the “barrel” of crop inputs and how each factor affects the water (or yield) within the barrel. However, at eKonomics, we believe a dam gives a better representation of how yield may continue to “leak” from behind the dam if all nutrient needs are not met. Why investing in only nitrogen this spring, may cost you dollars this Fall
Soil sampling is an imperfect science. It is common knowledge that nutrients, like phosphorus, have high spatial variability at the field level. When soil test levels fall below critical levels – the point at which the probability of a fertilizer response decreases – most farmers recognize they need to apply fertilizer. However, since soil sampling is an average of the area sampled, there are areas of low and high soil test levels within that area. Fertilizer management practices, such as The Maintenance Approach, assure soil test levels are built up so the chances of those nutrients being limited are reduced. Fertilization: comparing the maintenance approach vs. the sufficiency approach
By estimating the nutrients removed with grain or stover/straw harvest, farmers can at least apply the nutrients removed the previous year. The Nutrient Removal Calculator can be used to determine the amount of nutrients a crop will take up and remove at a given yield level. Nutrient Removal Calculator – Learning How to Use this Tool
There is no one-size-fits-all approach to crop production; however, by utilizing these basic agronomic concepts found on eKonomics, a farmer can better their chances of increased fertilizer efficiency and their bottom line of increased profitability.
