水保所知识产出(1956---)知识库

Biochar amendments are effective for stabilizing soil aggregates and improving the quality and fertility of soils.
Soil internal forces (SIFs), including electrostatic, hydration, and van der Waals forces, can substantially affect
aggregate stability; however, there has been relatively little focus on the effects of biochar addition on SIFs and
their relation to aggregate stability. In this work, in order to quantitatively investigate the influence of biochar on
aggregate stability, we collected soil samples with different biochar application rates (0, 2.5%, 5.5%, and 7.0%;
w/w) after a two-year field experiment, and then used Na + -saturated soil aggregates (1–5 mm) to conduct our
experiments. Our results demonstrated that after 2-year, specific surface area (SSA), soil organic carbon (SOM),
cation exchange capacity (CEC), and surface charge density ( σ 0 ) increased while soil pH slightly decreased with
biochar application from 0% to 7%. Soil aggregate stability increased with the biochar application rate. Theo-
retical calculations indicated that forces of electrostatic repulsion and van der Waals attraction both increased in
response to biochar incorporation, however the net pressure of SIFs decreased. Soil aggregate stability was well
explained by the theoretical calculations. Biochar addition reduced the net pressure of SIFs and stabilized soil
aggregates. Overall, the investigation by using the mono-cationic model system showed that SIFs played
important roles in the aggregate stability and explained well the aggregate stability of amended soils. The
findings of this work initiate the process of elucidating and quantifying the complex biochar-mineral interaction
mechanism in soil systems.