5. Conclusions
This paper provides a novel attempt atmeasuring the influence of BC
on the physical properties of soil based on separately quantified soil variables.
The results suggest broadly similar effects across eight contrasting
soil types. Goodness of fit (adjusted R2) values suggested that FC
(0.82), BD (0.66) and to a lesser extent AWC(0.46) could be reasonably
well described by the IVs considered. Of the soil attributes considered, Z
content was observed to moderate the ability of BC to enhance the hydrological
properties of the soil. However, the analysis would benefit
from the inclusion of other types of BC and a larger number of soil
types and, in particular, a wider range of textural classes, such as those
very high in C or Z.
These results add to our knowledge of where BC may contribute to
soil management, for example in response to shortages of water or
bulky organic additions. It ought to be possible to recommend to
farmers or other land use stakeholders how much BC should be added
to a given type of soil with the aim of achieving a desired outcome,
e.g. in terms of yield increase, reduced irrigation or lower fuel use
through reduced resistance to ploughing. Further quantitative modelling
of the interacting variables germane to BC amendment would advance
understanding towards this goal.