Worms: Phosphate Producers or Consumers?
Claire Braaten
Prince of Wales Secondary
Floor Location : M 136 V

Phosphorus, a nutrient crucial for plant life, can become toxic to the environment in extensive amounts. I tested whether compost with earthworms or without earthworms created more phosphate; a form of phosphorous that is available to plants. Against my hypothesis, I found that the compost without worms created more phosphate. Phosphorous is necessary for plant life but can easily go from a helpful nutrient to a fatal pollutant. When phosphorus rich soil eventually becomes runoff and makes its way into large bodies of water, such as lakes, an environmental catastrophe may take place. More specifically: cultural eutrophication. Cultural eutrophication is the unnatural and fast aging of water due to pollutants by man. Due to this, phosphorous levels in soil must be properly balanced. My experiment focussed on phosphate. Phosphate, formula PO4-3, is the most common form of phosphorous in soil and water, and is taken in by plants. Phosphate was measured in the experiment because it can represent the amount of phosphorus available to plants, but can also represent the amount of phosphate/phosphorus negatively impacting the waterways. To ensure accurate results, ten small compost samples were tested for each variable (earthworms or no earthworms). To measure the phosphate levels of each compost soil samples were taken from different places along the bin. The soil was then baked and weighed, before being soaked in water for an hour to extract the phosphate into a liquid. After being soaked, the solution was then filtered and put into a phosphate meter to determine the phosphate amount in ppm, or parts per million. After the seven-week experiment, the results found showed Compost B, the compost without earthworms, increased in phosphate throughout the course of the project. Compost A, with earthworms, was not nearly as successful and decreased from its original reading. The results were not as I predicted they would be. These results were surprising to find because previous studies, such as one done in 2009, stated that worms in soil made a significant increase in the phosphorous levels of that soil. My experiment showed the reverse results. It could be that compost affects earthworms in different ways, and also that phosphate may be harder for worms to increase compared to phosphorus or the form of phosphate the worms were producing wasn’t soluble. The information that was found in my experiment was a very small part of a big picture. However, considering every small detail, could eventually lead to new great discoveries. Knowing whether to add or not to add worms and what impact that makes in compost, and then making that small adjustment can make a big difference.