Earthworms in Agricultural Soils - Part Two

This is Tim Hammerich of the Ag Information Network with your Farm of the Future Report.

Phosphorus, an essential nutrient for crop production, is actually plentiful in a lot of agricultural soils, but is easily tied up so that it is unavailable to the plant. So, the costly and limited resource must be constantly applied to grow crops. Scientists like Jan Willem van Groenigen, however, are finding that earthworms can play an important role in making this nutrient more bioavailable.

Van Groenigen… “Phosphorus is very easily bound chemically to soil particles. We actually have an enormous amount of phosphorus in our soils from past over fertilization, but you cannot get it out. And earthworms increase the amount of dissolved organic carbon in their cast. So you have a lot of dissolved carbon, which is negatively charged just like a phosphorus. And that means that it binds to the same soil particles as phosphorous. So if you have a log of that DOC that dissolved organic carbon, it means that more of that is bound to the soil particles and less phosphorous. The phosphorous desorbed from the soil and it becomes available temporarily at least, for the plants. So the earthworm really temporarily loosens that phosphorus from those soil particles.”

Research into earthworms has also revealed benefits to chemical and physical soil properties.