Biochar soil amendments as a tool for climate change adaptation in PNW agriculture

Abstract:

Loss of snow pack, changing hydrographs, and increased temperatures and irrigation demands as a result of climate change all threaten to create transformational drought for growers in the Pacific Northwest. One approach for adapting to drought is to improve moisture retention through soil management practices. Recent efforts at the FSCRU to develop on-farm power have produced a biochar from gasification of seed mill waste that may prove useful as a tool for drought adaption. Testing of this biochar revealed that it contains no toxic elements, making it suitable as a soil amendment, and additions of 20 tonnes ha^-1 in dryland wheat system showed improved soil moisture and yield increases of 250%. Persistent but weaker impacts were observed in growing years 2 and 3 following the biochar amendments. Here we present results from a series of laboratory and field studies characterizing how grass seed screening biochar, which is produced from a regionally abundant feedstock, impacted soil hydraulic and thermal properties, soil chemistry, and plant growth. Because of the liming qualities of gasified biochar, the greatest growth benefits are likely to be realized in acidified soils, a growing problem in the PNW. Although the persistence of biochar impacts in soil is still unknown, our results indicate that gasified biochar, particularly when utilized as part of a system of on-farm power production, waste reduction, and nutrient recycling, can improve agricultural sustainability in the context of climate change.