It's a good idea to start planning for this spring’s fertilizer applications, and it’s important to know some of the key factors to consider before making nutrient management decisions. First and foremost, a soil analysis will give you the best and most accurate information on what nutrients are available for plant uptake from the soil. There are different methods of soil sampling, and any of them are a worthwhile investment:
· Composite samples are collected throughout the field, representing the full field and its soil makeup.
· Grid sampling breaks the field into squares to determine if sections of the field have higher nutrient levels than others.
· Zone sampling combines similar areas in a field, such as high spots, slopes or wet areas, so that nutrients can be managed according to the specifics of that particular zone.
Aside from soil testing, another key consideration is the history of the field. Did it yield well last year? Were there any disease outbreaks? Are the soil analyses showing that fertilizer application rates are helping restore what is being removed from the soil? Once the full scope of nutritional needs is known, determining the benefits of liquid or granular fertilizer is another important decision.
Granular fertilizer offers higher concentrations of macro- and micronutrients. If large amounts of fertilizer are required, granular is often more efficient, because more nutrients are available per pound of product. Lower nutrient requirements can be addressed with liquid fertilizers.
The specific nutrient being addressed may also impact the fertilizer decision. For example, macronutrients such as phosphorus and potassium are typically applied early in the season while nutrients prone to leaching or that may not be available throughout the entire growing season may require a side-dress application. Micronutrients are most effective when distributed uniformly across a field. For this reason, granular fertilizers, such as MicroEssentials®, are a good choice to ensure each plant has access to those nutrients.
Emphasis should be placed on taking a proactive approach to developing a crop nutrition strategy. Making sure that crops have the needed nutrients to maximize yields is an efficient use of time and inputs. Once visual signs of nutrient deficiency are recognized in a field, yield potential has already been decreased. While a rescue application may correct some of the problem, there is no way to rebound completely. This makes aggressive fertilizer management a key to higher yields.
Dr. Kyle Freeman is manager of new product development for The Mosaic Company. He is responsible for oversight and management of all research and product development efforts worldwide. Dr. Freeman and his team manage more than 600 small-plot research trials around the world and initiated a commercial trial program with more than 200 locations in 2012.