Too Much 0-0-60?
As the agricultural press contains more articles about soil health and its relationship to agricultural sustainability, an article from www.dtnpf.com on December 20, 2020 was slightly confusing. The article, entitled "Watch Your Crop K Applications," discussed Purdue University and North Dakota State University research which found that a high rate of applied potassium chloride (KCI), or 0-0-60 fertilizer, reduced corn and soybean yields. Also, a university researcher from the University of Minnesota confirmed seeing problems with high rates of 0-0-60 on soybeans and speculated that the problem with 0-0-60 is the anion chloride (Cl) that is part of the compound potassium chloride (KCI), which is the majority of 0-0-60. The idea of Cl toxicity from 0-0-60 has been debated in agriculture for many years; however, the so-called need for K for plant growth has received more attention so that the Cl toxicity has been mostly ignored.
In fact, the agricultural establishment has tried to minimize the Cl- problem by suggesting that Cl is a necessary element for plant growth. Cl is used by the plant for growth; however, the volume needed for growth is significantly less than what is applied by small amounts of 0-0-60. (For example, a 30 ton per acre corn silage crop requires 6 pounds of Cl per acre while 100 pounds of 0-0-60 furnishes 40 pounds of CI per acre.)
The confusion in this article is that the agricultural experts do not understand the toxicity of Cl in the soil environment. This is especially true since many agricultural experts have started to embrace the idea of soil health with practices such as cover cropping. Growers Mineral, Corp. has questioned for years the effect of Cl on the microbiological populations present in soil. The reason for this stems from the water treatment industry using chloride products to reduce microbes in drinking water. No matter what chloride product is used for water treatment, when it enters the water, the Cl anion is the killing mechanism of the microbes in the water. Therefore, when CI enters the soil environment water, it has the capability of injuring microbes in the soil. Since the population of microbes in the soil is so large, the high rate of Clt in 0-0-60 probably will not destroy all the microbes; however, the excess Cl is counteracting the objective of using the cover crop to help improve the effect of the microbes in the soil for crop production.
The mindset of the Growers Program is not that fertilizer elements are not necessary for agricultural production, but rather the overall effect of adding all the ingredients that are associated with the given fertilizer element. If the fertilizer elements contain toxins that upset the balance of the soil's microbiological population, removing those toxins may allow more efficient utilization of the applied element so as to allow a lowering of the volume of applied element. Lowering the volume of the applied element may reduce costs, but it can surely help address environmental loss, which is an important part of sustainability.
This is an excerpt from the Spring Growers Solution (2021) written by Jim Halbeisen, Director of Research & Education.
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