The role of organic amendment stability in soil biosolarization efficacy
Soil biosolarization (SBS) is a pest-control technique that could come into wider use as a sustainable alternative to highly toxic soil fumigants such as 1,3-D and chloropicrin. SBS induces biohydrothermal inactivation of soil pests by covering moist soil with clear plastic tarp to promote passive solar heating. In addition, microbial activity supported by organic soil amendments can complement the heat stress by releasing biotoxic organic acids (OAs) and other chemical decomposition compounds, enhancing pest inactivation. In California, the use of SBS is still limited to organic production, mainly due to challenges related to treatment of deeper soil layers or deployment in cooler seasons or regions. However, as the release of OAs is related to the biodegradability of the organic amendments, less stable organic amendments are expected to significantly improve SBS efficacy. We have performed a wide range of studies with organic amendments of differing stability degrees on various pests. Our results have confirmed that the lower the stability of the organic amendment (indicated by the cumulative CO2 evolution rate), the greater the release of OAs and pest inactivation. These promising results promote SBS not only as a valid alternative to chemical fumigation but also as an organic waste management practice and a tool to improve soil health via addition of organic matter.
Fernández-Bayo, J.D., Stapleton, J.J., Achmon, Y., VanderGheynst, J.S. and Simmons, C.W. (2020). The role of organic amendment stability in soil biosolarization efficacy. Acta Hortic. 1270, 161-168
organic acids, Brassica nigra, soil fumigation, organic pest management, soil amendments