Impact of biochar and industrial ash amendments on soil properties, growth and nutrition of black and white spruce seedlings in a sandy loam soil

Abstract

The purpose of this study was to establish and examine a controlled field experiment near Thunder Bay, Ontario using industrially produced ash and biochar as a soil amendment. This study monitors the change in physical, chemical, and biological properties to the field soil, as well as, the growth of black and white spruce seedlings. Biochar and ash were applied to split plots (black spruce on one half and white spruce on the other) at the levels of 0, 1, and 10 tonnes ha-1. Ash application at 10 tonnes ha-1 caused the most significant changes to the soil's chemical properties including: increasing pH, electrical conductivity, Ca, K, Na, estimated cation exchange capacity, S, and Zn; while decreasing Mg, and available/mineralizable NH4. The only significant change to the soil from biochar application was a decrease in extractable Cu concentrations after the application of 10 tonnes ha-1. There were no significant differences between treatments in tree growth after two growing seasons. However, seedling foliage nutrient concentrations increased significantly for some nutrients with the application of ash. Black spruce and white spruce both increased in foliage nutrients B, K, and S. However, only black spruce seedling increased in foliar Ca, and Mg, which was likely due to a difference in rooting patterns. It is possible that since the plots were located on an old nursery site that most nutrient deficiencies have been amended in the past and the effects of the treatment on the soil were not as great as they could be on poorer soil. The increase in foliage nutrient concentrations in black and white spruce points to possible changes to seedling growth in the future. Therefore, a more long term study must be done to determine if seedling performance will be affected by these treatments.