Using SO4 pelletized gypsum and 98G pelletized limestone in your fertility program allows flexibility when weather limits application season in the fall and spring. Using SO4 pelletized gypsum and 98G pelletized limestone in your fertility program allows flexibility when weather limits application season in the fall and spring.
Considerations for applying 98G
Ideally, 98G would be applied in the fall to initiate pH correction before spring planting occurs, but its rapid reactivity allows flexibility for spring application as well. Regardless of the season of application, one should consider how 98G is applied with respect to other field work. To maximize the efficiency of 98G, the pellets should be applied and allowed to begin breakdown via water (rain, dew, contact with soil) before being worked into the soil with a field cultivator or other tillage equipment in order to target the zone of active acidification — the top 4 inches of the soil profile.
If 98G is being applied for pH maintenance, it can be blended with other flat-rate, broadcast fertilizers to limit trips across the field, or placed into a split bin variable rate application. When the rate exceeds 200-400 lbs/A, it should be a standalone application.
Considerations for applying SO4
SO4 has several options from an application standpoint. Our general recommendation is that it be applied in spring with other soluble fertilizers, however, it can also be applied in the fall and remain available for crop sulfur needs come spring. SO4 can also be used as a rescue application in the spring where visual sulfur deficiency is present. SO4 can be applied any time after emergence and with the right amount of precipitation, will result in plant green up in less than a week. Because SO4 has a very low salt index relative to other fertilizers, it will not injure/burn young crops after broadcast application.
Regardless of application scenario, SO4 works best when it is left on the soil surface. Since sulfate is an anion (negatively charged), it has potential to leach, and letting the product work from the surface downward will result in the best sulfate uptake efficiency.
As with 98G, SO4 can also be blended with other fertilizers to maximize application efficiency. Oftentimes, SO4 is blended with a nitrogen source for sidedress application in the spring, and with phosphorus and potassium applications in the fall.
It should be noted that anytime SO4 or 98G are blended with other fertilizers, particularly those that attract moisture, the blend should go directly from the blending equipment to the spreader to minimize the amount of product degradation from added moisture. It is not recommended that liquid products be added to these blends because it can result in product breakdown and difficulty in the spreading operation.