An Overview of Phytosanitary Risk Aspects of Composting by Organic Farmers

Summary

Usage of compost in agriculture always brings about the risk of introducing plant pathogens. By proper composting, resulting in high temperatures during the thermophilic phase, compost can be applied safely. Organic farmers often prefer to compost organic residues themselves. The advantage of such an approach is that no material of foreign origin is introduced, but a drawback is the smaller scale of composting, which brings about greater phytosanitary risks. These risks can be dealt with by increasing the composting duration and by proper turning of the compost heap. If only organic residues from farms are composted, this usually results in low-quality composts because of the low lignin contents. Therefore, addition of materials that are high in lignin, such as wood chips, is advisable. In conclusion, on-farm composting is well possible from a phytosanitary point of view, but the farmer has to be aware of the factors that affect the phytosanitation of organic waste and the quality of the compost.