By Blake Jackson
The adage “there’s no such thing as a free lunch” certainly applies when it comes to “free” lime. Recently, some farmers have been exploring lime sourced as a byproduct from industrial plants. While the idea of free material may seem appealing, it’s crucial to understand what’s actually in the product and whether it performs effectively as lime.
In Pennsylvania, agricultural lime is regulated under the Pennsylvania Fertilizer, Soil Conditioner, and Plant Growth Substance Law. Any lime sold or distributed for agricultural purposes must be registered with the Pennsylvania Department of Agriculture.
Certified lime products undergo laboratory testing for fineness, calcium carbonate equivalency (CCE), and potential contaminants, including heavy metals. These standards ensure the product is safe for crop production and doesn’t pose long-term risks in the food chain.
Testing is especially important for byproducts or free lime sources. A recent analysis of one such material showed it required nearly double the application rate and tractor time to match the neutralizing power of certified agricultural lime.
Before using a byproduct lime, first test its liming capacity through labs such as A&L Great Lakes (Fort Wayne, Indiana) or Spectrum Analytic (Washington Court House, Ohio). Second, screen for contaminants.
The Penn State Agricultural Analytical Services Lab offers biosolids testing for heavy metals under EPA 503 guidelines. Only if all elements, including arsenic, cadmium, mercury, chromium, lead, and molybdenum, fall within safe thresholds should the product be applied.
Molybdenum is of particular concern in ruminants as it can interfere with copper absorption, potentially causing secondary copper deficiency with signs like changes in hair color, reproductive issues, or impaired offspring health. Sulfur content should also be considered, as it can exacerbate copper deficiencies.
Free lime may appear cost-effective, but without proper testing, it could create significant soil, crop, or livestock problems. Certified lime remains the safest option. If experimenting with byproducts, always test thoroughly and ensure the product meets safety and effectiveness standards before application.
Photo Credit: istock-ligora
Categories: Pennsylvania, Crops, Livestock