Earthworms in Agricultural Soils - Part Three
Most farmers love to see earthworms in their fields as they are an indicator of high quality soil with organic matter. Science is validating the benefits of earthworms in agricultural soils. Dr. Jan Willem van Groenigen and colleagues have found a significant yield difference between soils that have earthworms and those that do not.
Van Groenigen… “What is the average effective earthworms in a system on plant yield? On average, the yield increased with about 24 - 25%.”
He cautions however, that this number is an average, and the number was brought up by soils that did not receive much fertilization.
Van Groenigen… “And those studies tend to be in systems that got little or no fertilization with nitrogen, for example, and that got lots of crop residue added to the soil. So the earthworms could eat that and mineralized that. So I think on average, that number is a bit biased towards very poor systems. If you look at a better fertilized systems, for example, I think the effect of earthworms on at least a nitrogen availability, for example, is less than that. It's still significant. It's important. But I don't think that in the average farm, you would have 25% increase by just a few earthworms. It's a bit more complex than that.”
While results will vary, there is no doubt that earthworms have positive effects on agricultural soils.