There’s Still Time to Apply Lime

166Why waiting to correct soil pH can decrease yields

Gilmore City, IA — For growers unable to apply lime last fall, a new generation of engineered lime products are a solution that can be applied year-round. Unlike standard ag lime, advanced soil amendment products such as SuperCal 98G provide fast and complete soil pH changes because of they contain extremely small lime particles (150 microns versus 590 microns for standard ag lime.) Engineered to have high reactivity, the products change soil pH within weeks and maintains soil pH changes in subsequent years.

“This time of year, limestone quarries are either out of limestone or have frozen piles of ag lime which can’t be accessed until the spring thaw,” says Dr. Andrew Hoiberg, Director of Research and Development at Calcium Products. “In many locations, snow prevents lime applications. These are just a few complications from an unusual 2013 weather year that started with an extremely wet and late spring and ended with a late harvest. Cool fall soil temperatures caused many growers and dealers to choose anhydrous application over limestone application.”

According to Hoiberg, applying more nitrogen fertilizer (the main source for acidity) and skipping limestone application is a recipe for lower yields. Soil pH of 5.7 can cost a grower an additional $200 per acre of income at today’s prices, even more if the pH is lower. A University of Wisconsin study cites low pH as reducing yield up to 40% (1). As soil acidity is lowered, corrective measures to bring soils back to optimal conditions for crops are harder to achieve. Managing soil pH on a yearly basis is the most effective way to maintain optimal soil pH.

“Ignoring one of the most important agronomic factors like pH correction will cause yields to suffer,” says Hoiberg. “Growers have many inputs to balance, and pH is one issue that’s often pushed to the back burner. Generally speaking, growers may decide to apply lime every three to five years. If conditions are not optimal for an application of ag lime, they usually wait until the next year. No other farm input is treated in this way. Growers should take a proactive approach to managing pH, as they do all other inputs for maximum yields.”

Heading into spring planting season, ag lime application ceases as dealers transition into fertilizer applications. There is an option to help growers increase soil pH and protect yields. “With our SuperCal 98G advanced engineered lime, growers can see soil pH improvement in weeks instead of years,” says Hoiberg. “This means that even if growers cannot apply lime until spring, they can still protect yields and improve nutrient utilization.”

SuperCal 98G is a unique pH correcting material. It is made from 98% pure calcitic limestone that is finely ground to fully react in the soil. During manufacturing, the product is passed through 100-mesh screens to create extremely small lime particles. The size impacts the spread throughout the field, how quickly the lime reacts in the soil solution and how quickly and completely it moves through the soil profile. The smaller the particle, the more surface area it will cover. For example, one ton of 30 mesh standard ag lime covers one acre. One ton of 100 mesh SuperCal 98G covers five acres. SuperCal 98G is pelletized to be applied like any dry fertilizer at any time.

Producers in Iowa can try SuperCal 98G for themselves, by partnering with the Iowa Soybean Association’s On-Farm Network. The ISA On-Farm Network has agreed to conduct up to 20 replicated strip trials with Calcium Products, Inc. to evaluate SuperCal 98G to neutralize acidic soils and how corn and soybean yields are affected as a result of these applications. If you have a field with areas of low pH and would like to participate in the study, contact Pat Reeg at 515-669-9184.

1 “What Ignoring Lime can do to Corn and Soybeans.” Kelling, Myers, and Peters. UW-Madison Department of Soil Science. 2008.