The effect of contrasting biochar structure on hydraulic properties and its stability in soil

Bc. Václav Chroustovský

Master's thesis

Abstract:

This thesis aims to examine and assess the effect of contrasting biochars on the hydraulic properties of fluvisols. Two experiments were conducted, with regards to soil hydraulic properties, in order to obtain such results that could provide more detailed information about the behavior of biochar in fluvisol collected at given site. For that, a set of boxes with amended soil was prepared. The soil was amended with biochars, which had different physico chemical properties, and were produced from different types of feedstocks and at different pyrolytic conditions. The first experiment, focusing on measurement of the saturated hydraulic conductivity of amended soil, was performed in 3 trials at 1 wt % and 2 wt % application rate. The results showed that the 1 % application of plant biochar had strongly influenced the saturated hydraulic conductivity, where the difference between values of saturated hydraulic conductivity at 1 % application of plant biochar and the control sample was statistically significant (p value=0.037), however, this results was obtained only in 3rd time step, in other two time steps the differences in measured values of treated samples compared to control samples were not statistically significant. Moreover, the increasing amount of biochar did not improve the hydraulic properties of amended soil.The second experiment focused on water holding capacity of soil amended with biochar, and was performed at 1 wt % and 2 wt % application rates. Measured data showed inconsistency of the results, where no obvious trend was observed, except the volumetric moisture content at high suction pressures, i.e. the soil amended with biochar indicates the ability to hold hygroscopic water, where the highest content of moisture was measured for samples with 1 % application of plant biochar. In all cases the water holding capacity of amended soil was increased.Thus, the results of both experiments, have partially confirmed what was hypothesized.

Keywords

biochar, retention curves, saturated hydraulic conductivity, structure, DOC leaching

Language used: English

Date on which the thesis was submitted / produced: 18. 4. 2017

Thesis defence

• Supervisor: Mgr. Lukáš Trakal, Ph.D.

Czech University of Life Sciences Prague

Faculty of Environmental Sciences

Master programme / field:
Geology / Environmental Geosciences