Physical Properties of Soil-Biochar Mixtures - a Laboratory Study

Hailemelekot Teklu Kidane

Master's thesis

Abstract:

Recently, biochar´s potential use in soil management and amendment has gained a considerable interest globally. Growing evidence demonstrated that biochar results in sustainable property management when it is applied to the soil. However, biochar vary considerably in terms of physical and chemical properties and its benefits. Previous studies on biochar have been mainly focused on the chemical and nutritional effects. Little is known about the effect of biochar on the physical properties of soils. Therefore, the objective of this thesis was to determine the influence of biochar on the physical and hydrophysical properties of some soils from the Czech Republic.Three model soil types were investigated used such as; a standard fine silica sand (SA), the Suchdol silty loam Chernozem (CH), and a light Cambisol (CM). The biochar concentration treatments were a control without admixture of biochar (B0); a treatment with addition of 0.001 g/g (B1) and a treatment with addition of 0.01 g/g (B2). Each treatment was carried out in triplication.The data collected were soil porosity, bulk density and particle density measured by standard methods (drying, weighing, pycnometer). Then the saturated and unsaturated hydraulic conductivity, wettability and retention curve (up to the suction about 80 kPa) were measured with Decagon Minidisk tension infiltrometer and UMS Hyprop evaporation equipment. The experiments were carried out in the Department of Water Resources laboratory.Altogether, we can say that the effect of biochar addition on the soil physical properties is clearly perceivable but not as strong as one might expect. The identified effects of biochar addition are the decrease in sorptivity, the increase in saturated hydraulic conductivity and the increase in the water retention capacity. However, these effects are not obvious and are not always observed. This would probably happen with the higher doses of biochar above the economic limits.

Keywords

water repellency, carbonisation, water retention, hydraulic conductivity, infiltration

Language used: English

Date on which the thesis was submitted / produced: 14. 4. 2016

Thesis defence

• Supervisor: Ing. František Doležal, CSc.

Czech University of Life Sciences Prague

Faculty of Agrobiology, Food and Natural Resources

Master programme / field:
Natural Resources and Environment / Natural Resources and Environment