By Greg LaBarge, Ohio State University Extension, Field Specialist, Agronomic Systems
The Tri-State Fertilizer Recommendations is the foundation of fertility management in Ohio. The build, maintenance, and drawdown approach of this bulletin rely on managing the soil test level around a critical level that provides enough nutrient to meet the immediate needs of the crop. This philosophy of management is used for two of our three macronutrients needed in crop production, phosphorus and potassium. The scheme works due to the immobile nature of these two nutrients in the soil and the method of uptake exhibited by plants.
It is important to fully understand how the bulletin co-editors defined the terms used in the Tri-State Recommendations as we put the principals into practice. The key term is “Critical Level.” Other parts of the recommendations hinge on defining this term.
As defined, the Critical Level is “…the soil test above which the soil can supply adequate quantities of nutrient to support optimum economic growth.”… Continue readingRead More »