Influence of biochar admixture in soil on near saturated hydraulic conductivity

Mon War War

Master's thesis

Abstract:

Hydraulic properties of soil are the basis for understanding and responsible for water flow and nutrient transport. Biochar amendment is effective for the physical and hydraulic properties of soils. Due to its adsorption capacity (AC) and high cation exchange capacity (CEC), biochar becomes not only a nutrient carrier but also habitats of microorganisms. However, the addition of biochar without activation could lead to adverse effects in either fixing of available nutrients or water in the soil. The aim of this research was to evaluate the changes of near saturated hydraulic conductivity K(h) of clay loam soil measured by Mini Disk Infiltrometer after the application of several types of activated biochar admixtures.The study was conducted in-situ in Plant Production Station Uhříněves belonging to the Department of Agroecology and Crop Production on clay loam soil during two vegetation terms of the mustard crop (Sinapis alba L.) in July and October 2019. Experimental parcels were treated by different compost and activated biochar admixtures, including bokashi fermentation and Azotobag (Farma Žiro, Ltd., CZ) preconditioning. The experiment was carried out either in field (11 treatments) and irrigated greenhouse conditions (4 treatments), both in 3 replicates, in total on 45 parcels. Unsaturated hydraulic conductivity K(h) was measured by using the Mini Disk Infiltrometer (METER Group, Inc., USA). In total, 216 infiltration tests were conducted, 84 in greenhouse and 132 in field, at set tension 2 cm. Soil water content (θ) was measured by using the 5TE soil moisture sensor both before and after infiltration. In addition, 45 undisturbed soil samples were taken in July.The results showed that several types of activated biochar admixtures are significantly different in unsaturated hydraulic conductivity. The application of compost bokashi treated biochar (KBB) had significant effect on unsaturated hydraulic conductivity, also showing improvements in dry bulk density compared with pure compost (K) in the greenhouse. For the field, 2% of Agrouhel biochar treated with bokashi (A2Bo) was statistically significant among the other treatments in July, while no statistically significant variant is observed for K(h) on different soil treatments in October. The negative correlation between unsaturated hydraulic conductivity K(h) and initial water content is also visible, indicating decreasing K(h) with increasing initial water content.

Keywords

Biochar, Compost, Unsaturated Hydraulic Conductivity, Mini Disk Infiltrometer

Jazyk práce: English

Datum vytvoření / odevzdání či podání práce: 23. 7. 2020

Obhajoba závěrečné práce

• Vedúci: Ing. Markéta Miháliková, Ph.D.

Czech University of Life Sciences Prague

Faculty of Agrobiology, Food and Natural Resources

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