Hidaspyrolyysin liiketoimintojen kehittäminen Suomessa

The impact of pesticides on soils, their biota, and functions have become a matter of considerable concern especially in agriculture. Various pesticides are known to increase mortality of non-target soil organisms, thereby hampering the decomposition rate of organic matter, impacting on soil physical quality and wood web properties. Because of the various negative effects due to pesticides, there is an increasing need to develop biological methods for pest control.

Birch tar oil (BTO) is a side-product of processing birch wood in a pyrolysis system. Accumulating evidence compiled by our research group suggests the suitability of BTOs as biocides/repellents against many weeds, harmful insects, and molluscs. Due to its novelty as a biocide/repellent/plant protection product, no comprehensive information on the effects of BTO on non-target soil organisms is available. In this study programme we examine the impact of BTO on non-target soil and aquatic organisms, and plants, using an array of laboratory toxicity tests (e.g. determination of LC50 values for the biota) and field experiments.

We have shown that the effects of BTO on soil fauna were mostly insignificant. BTO seemed to be detrimental to the growth of plants directly after application, but this effect was short-term; after a period of 2.5 months, the growth of most of the plant species recovered completely from the application. The LC50 for the erathworm A. caliginosa was 6560 mg BTO/kg dry soil and EC50 for juvenile production of F. candida was 5100 mg BTO/kg dry soil. The results indicate that the risk caused by BTOs (concentration 500-1360 L/ha) to the soil environment is insignificant and short-term as compared to the many chemical products applied for similar purposes. The study is supported by the Ministry of Agriculture and Forestry and the Finnish Funding Agency for Technology and Innovation (TEKES)