Sulfur availability
Historically, farmers have overlooked sulfur in their nutrient management practices due to its natural availability from rainfall. In fact, farmers rarely had to worry about adding sulfur to their fields. This changed when the U.S. clean air standards were established in 1970 and updated in 1990. Sulfur emissions from power plants, factories and automobiles significantly declined, decreasing the amount of sulfur available in the atmosphere.
Forms of sulfur
There are many fertilizer options on the market today, but the majority fall into one of two categories: sulfate, which is mobile in the soil. or elemental sulfur. which is immobile until it is oxidized. Ultimately, the source of sulfur you choose to apply varies depending on the time of year, precipitation pattern, soil type, and application method. For those applying sulfur with or near the seed, consider a sulfur source with a lower salt index to maintain seed safety.
The need for sulfur fertilization
Farmers now must either rely on sulfur that is already present in their fields or apply it as fertilizer. Adding sulfur to your fertilization program is much more cost-effective than correcting a sulfur deficiency once it occurs. Some states and provinces use organic matter content and soil test values in making sulfur fertilizer application rates. However, the rates of mineralization can vary widely and since sulfate is highly mobile within the soil profile. both values can be misleading to make recommendations. For this reason, the best estimate for determining sulfur application rates for a specific crop is usually based on removal rates and total uptake. As growers are reaching for higher and higher yields, the need for providing additional nutrition to the soil has evolved. This means considering sulfur as part of your fertility program…every year.
Smart Nutrition™ MAP+MST® is a great option for adding sulfur to your soil and supplying crops with some of the key nutrients they need throughout the growing season. The phosphorus to sulfur ratio was created with the grower in mind: simplifying nutrient management to suit all crops while maintaining seed safety.
