Aplikace biocharu za účelem zlepšení celkové kvality půd s nízkým obsahem organické hmoty

Samar Seyedsadr

Disertační práce

Abstract:

Soil hydraulic properties of three low-organic matter soils from Czech Republic (Fluvisol; Regosol; Cambisol) were investigated in six experiments utilising various pot and boxed designs. The core of the experimental work was to amend the soils with biochar alone or in combination with manure, compost and co-composted biochar at 2 and 5% (w/w). Hydrogel (a synthetic soil moisture retention additive) was included by way of positive comparative control. Soil moisture sensors, soil porewater sampling devices, bulk density, porosity and derived soil water retention curves were applied to analyse the results. A consolidation (artificial manipulation of soil bulk density) experiment was also carried out to study the impact of compaction on soil hydrology in the Regosol with and without biochar amendment. In the box experiments biochar significantly decreased bulk density and increased total porosity when compared to compost in the Fluvisol, while manure affected the greatest changes in the Regosol. All of the amendments adjusted the shape or extent of the soil water retention curves, but biochar addition resulted in the greatest increase (⁓50%) in plant easily available water content in both Fluvisol and Regosol, when compared to the control. Saturated hydraulic conductivity was not changed by any of the amendments which suggests a lack of influence on infiltration. An enhancement in nutrient retention occurred in co-composted biochar at 2% dosage and 5% manure-biochar mixture, as revealed by porewater analysis. The application of biochar with and without additional compost and manure enhanced soil water retention and maintained or enhancing nutrient retention in low organic drought-prone arable soils. In the pot experiments the addition of biochar into the composting process hastened the stability of the resulting compost-char, which resulted in improved provision of available nutrients to soils and reduced potential leaching of metal(loid)s. Porewater analysis showed that nutrient leaching (e.g., NO3−, K+) from manure addition to soil was reduced when biochar was blended with manure before soil application (by ≤86% compared to manure alone). Higher doses of biochar also furthest reduced soil compaction. Compared to hydrogel biochar improved available and easily available water retention (by < 50%). The results of these experiments demonstrate that biochar addition to drought prone soils offers multi-facetted benefits of improvements in soil hydraulic conditions which, especially in the presence of other organic amendments (composts, manures etc) can significantly improve the retention of nutrient laden soil moisture. Whilst these results are encouraging, field trials over longer time periods of time, will establish the longevity of the effects observed in this study.

Keywords

Soil Water Retention curve, Soil hydraulic properties, Biochar, drought-prone soil, soil organic matter, compost / manure

Jazyk práce: angličtina

Datum vytvoření / odevzdání či podání práce: 5. 2. 2023

Obhajoba závěrečné práce

• Vedoucí: doc. Mgr. Lukáš Trakal, Ph.D.

Česká zemědělská univerzita v Praze

Fakulta životního prostředí

Doktorský studijní program / obor:
Landscape Engineering / Environmental Modelling