Bokashi is an organic soil amendment that makes use of microbial processes to break down agricultural waste and create a nutrient-rich fertilizer. The benefits of various types of bokashi on soil fertility and plant growth are well documented, however the changes in microbial community composition and nutrients during bokashi maturation remain poorly characterized. Here, we aimed to identify potential differences in the quality of bokashi made using different ingredients and to investigate the biochemical transformation and microbial community succession of bokashi throughout the maturation process. We compared the effects of these different types of bokashi on the growth of cucumber (Cucumis sativus) and kale (Brassica napus subsp. pabularia) seedlings, measured concentrations of NH4+ and PO43-, and characterized the bokashi bacterial and fungal communities over a 12-day maturation period. We found that cucumber and kale plants growing in all types of bokashi-amended soils exhibited increased chlorophyll levels and dry biomass. During bokashi maturation, we observed a decrease in available PO43-, and an increase in NH4+. There also appeared to be an increase in relative abundances of decomposers and beneficial microbes and a decrease in putative plant pathogens. Regardless of starting bokashi ingredients and differences in microbial composition and nutrient trends, all types of bokashi similarly improve plant growth and contain beneficial microbes.

1. Both theory and prior studies predict that climate warming should increase attack rates by herbivores and pathogens on plants. However, past work has often assumed that variation in abiotic conditions other than temperature (e.g. precipitation) do not alter warming responses of plant damage by natural enemies.Studies over short time periods span low variation in weather, and studies over long time-scales often neglect to account for fine-scale weather conditions.2. Here, we used a 20+ year warming experiment to investigate if warming affects on herbivory and pathogen disease are dependent on variation in ambient weather observed over 3 years. We studied three common grass species in a subalpine meadow in the Colorado Rocky Mountains, USA. We visually estimated herbivory and disease every 2 weeks during the growing season and evaluated weather conditions during the previous 2-or 4-week time interval(2-week average air temperature, 2-and 4-week cumulative precipitation) as predictors of the probability and amount of damage.3. Herbivore attack was 13% more likely and damage amount was 29% greater in warmed plots than controls across the focal species but warming treatment had little affect on plant disease. Herbivory presence and damage increased the most with experimental warming when preceded by wetter, rather than drier, fine-scale weather, but preceding ambient temperature did not strongly interact with elevated warming to influence herbivory. 4. Disease presence and amount increased, on average, with warmer weather and more precipitation regardless of warming.This is an open access article under the terms of the Creative Commons Attribution-NonCommercial License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposes.

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