Abstract
Biochar has been shown to improve soil quality and crop yields. Furthermore, thanks to its high carbon content (C) and stable chemical structure, biochar can sequester C in the soil for a long time, mitigating climate change. However, the variability in published biochar stability in the soil makes verifying this trait under different environmental and agricultural conditions necessary. Moreover, most of the published literature refers to short-term incubation experiments, which are considered to not adequately represent long-term dynamics under field conditions. This article reports the results of a field experiment carried out in a vineyard near Merano, northern Italy, where the stability of woodchips biochar in soil, its impact on the total soil C stocks as well as on the original soil organic C (priming effect) were studied over two years. Vineyard soil (Dystric Eutrochrept) was amended with biochar (25 and 50 t ha−1) alone or together with compost (45 t ha−1) and compared with unamended control soil. Two methods assessed the stability of biochar in soil: the isotopic mass balance approach and the quantification of Benzene PolyCarboxylic Acids (BPCAs), molecular markers of biochar. The amount of C in the soil organic matter (SOM-C) was determined in the amended plots by subtracting the amount of biochar-C from the total soil organic C stock, and the occurrence of priming effect was verified by comparing SOM-C values at the beginning and at the end of the experiment. Results did not show any significant biochar degradation for both application rates, but results were characterized by a high variation. The application of 50 t ha−1 of biochar significantly increased soil C stock while no effect of biochar on the degradation of SOM-C was observed. Results were confirmed in the case of biochar application together with compost. It can be concluded that the use of woodchips biochar as a soil amendment can increase soil C content in the medium term. However, further analyses are recommended to evaluate the impact of biochar on climate change mitigation in the long term.
Highlights
Biochar has been studied by the scientific community for the past 20 years, owing to its potential use as a soil conditioner in agriculture [1,2,3])
This paper reports the results of a two-year field experiment carried out in a vineyard, in temperate climatic conditions, where biochar was applied alone or in combination with compost
According to the isotopic mass balance three weeks after biochar application, in the B1 treatment we found, on average, 13 ± 2 t ha−1 of biochar-C corresponding to 80 ± 9% of the applied biochar-C, while in the B2 treatment we found 31 ± 6 t ha−1 corresponding to 95 ± 18% of the applied amount (Figure 1)
Summary
Biochar has been studied by the scientific community for the past 20 years, owing to its potential use as a soil conditioner in agriculture [1,2,3]). Improve its chemical [4], physical [5], and biological [6,7] characteristics, contributing to increasing agricultural yields [1,8] and reducing nutrient losses from soil Another positive impact of biochar is its potential contribution to increasing the carbon (C) sequestration capacity of the soil [2,9,10,11]. Biochar stability is affected by several factors such as the feedstock used, the production conditions, the environmental framework and the study design [12] For these reasons, previous studies on biochar stability have provided conflicting results [13]. Most of these studies have been performed in the laboratory, which are not representative of field conditions [14], and field studies often have a limited duration, even though it is well-known that the estimation of biochar stability is affected by experimental duration [11]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
