Browsing by Subject "earthworm"

Biochar is currently being intensively studied as a soil conditioner in agriculture and as a potential carbon sink to mitigate climate change. The knowledge of the effects of biochar field application on soil fauna remains very limited. This is underlined by the absence of field experiments on the effects of biochar on earthworms, a globally common and important faunal group in arable soils. The purpose of our study was to determine the effects of biochar on arable soil earthworms under both laboratory and field conditions in a Boreal loamy sand soil. An earthworm avoidance test with Aporrectodea caliginosa was conducted for periods of 2 and 14 days with 1.6% w:w spruce chips biochar application (produced at 550-600 ° C, application rate corresponding to 30 t/ha biochar). The effect of field application of the same biochar on earthworm density and biomass was studied over one growing season in experiment growing wheat. In the avoidance test, application did not affect the habitat choice of earthworms when incubation lasted for two days, but after two weeks, a significant (P = 0.033) avoidance of biochar was observed. We suggest that the avoidance under the two-week incubation occurred due to soil desiccation caused by high water retention of biochar. In the field trial, after BC application there were no statistically significant differences in the total density and biomass of earthworms between biochar or fertilizer treatments. Due to the short duration of the field trial, our results do not allow conclusive evaluation of the treatment effects on earthworms. The time scale of the study can only be considered sufficient for unraveling immediate avoidance reactions caused by biochar application, for which we found no evidence. In order to thoroughly investigate matter further, the follow-up of the experiment should be continued.

As global temperatures rise due to anthropogenic greenhouse gas emissions, it is becoming increasingly important to mitigate climate change. Agriculture, one of the major contributors to greenhouse gas emissions, has the potential for mitigation by implementing carbon sequestration practices. Biochars, carbon-rich materials derived from biomass pyrolysis, have drawn attention for their potential to sequester carbon and enhance crop growth. However, limited yield effects have been reported in boreal agricultural soils after applying pure biochars to soils. Therefore, application of activated and nutrient enriched biochar has been proposed as an amendment for getting most use of the practice due to slow release of nutrients and carbon sequestration. However, the effects of these new activated biochars on soil biota remain unknown. The study investigates the impact of acid and slurry activated biochar on earthworm community in agricultural soil in southern Finland, focusing on their implications for soil physical properties and ecosystem health. Through a split-plot designed field experiment, with biochar (applied at rate 0 t ha-1 and 20 t ha-1) being the main factor and fertilizer level the sub-plot factor, the interaction between nutrient enriched biochar and earthworm population was examined by assessing earthworms' abundance, biomass, and mean weight. There was no significant effect of the treatments on earthworm abundance, biomass, or mean weight. However, the mean weight showed a notable response to the interaction effect of biochar x fertiliser. Biomass and mean weight were negatively correlated by temperature. Among the other variables, soil water content had positive correlation with temperature. These findings highlight a possible association influenced by soil physicochemical parameters, microbial dynamics, and environmental conditions, even though biochar had no apparent impacts on earthworm density, biomass, or mean weight. In this first-ever field experiment with a high rate of acid and slurry-activated biochar applied to agricultural soil, biochar had no adverse effect on earthworm populations. Thus, the present findings confirm that the application of large amounts of biochar treated with acid and cattle slurry in Nordic agricultural soil is a safe C sequestration method for earthworms at least for a short time period. However, the long-term effect is still a knowledge gap. Addressing this knowledge gap is crucial to apply sustainable agriculture methods that enhance soil properties and health.