There are many factors that affect crop growth and yield production. Some of these factors cannot be controlled, such as, climate. However, factors such as soil fertility can be controlled and managed to maximize productivity. An effective way to help control soil fertility is through soil testing. Crops require large amounts of plant nutrients that must be supplied in proper balance from the soil. Managing nutrients helps to optimize productivity and profitability of crops while maximizing efficiency of nutrient use, all while keeping environmental impact at a minimum. Soil tests measure plant available nutrients and provide and index of nutrient availability in the soil. This serves as an excellent guide to profitable use of commercial liming and fertilizer. Justus von Liebig’s Law of the Minimum states that yield is proportional to the amount of the most limiting nutrient:
Every field contains a maximum of one or more and a minimum of one or more nutrients. With this minimum, be it lime, potash, phosphoric acid, magnesia, or any other nutrient, the yields stand in direct relation. It is the factor that governs and controls…yields…
In other words, crops will only produce as much as its most limiting factor allows. Routine soil testing is an outstanding tool to help identify controllable limiting factors when it comes to nutrient availability.
As humans, we are dependent upon agriculture for food, fiber, and shelter. All of which are necessary to our survival. The responsibility of producing these essentials falls on the shoulders of our farmers. However, as we depend on them for our basic needs, farmers depend on the soil for their production. Soil fertility and nutrient management are essential to the continued production of food, fiber and shelter for an ever growing world population. Proper soil fertility and nutrient management starts will soil testing. Agricultural fields should be tested every 3 years or once per crop rotation. For spring planting, soil samples should be collected between mid-October to January. For more information, such as, good sampling technique and interpreting soil test reports visit your local county Extension Office.