The application of biochar for reduction of risk element availability for cocoa (Theobroma cacao) plants

B.Ed. Michael Frimpong

Master's thesis

Abstract:

The majority of the world's cocoa is produced in Africa, with Cote d'Ivoire and Ghana making up about three-quarters of that total. Ghana has 1.7 million hectares of cocoa plantations, contributing 17% of the world's total cocoa production, second only to Cote d'Ivoire. The objective of the study was to evaluate the effect of the ability of biochar prepared from cocoa husk to decrease the mobility of heavy metals in the soil. For the biochar preparation, air-dried and fine milled cocoa bean pods were used. Pyrolysis was performed in a laboratory fixed bed reactor. Feedstock material was pyrolyzed in an electrically heated quartz tube for 30 min at the target temperatures of 400, 500, and 600 °C, respectively (labeled B400, B500, and B600), in the presence of nitrogen (nitrogen flow 3 L per minute). For comparison, a woodchips-based biochar was applied as the reference material (labeled REF). A batch sorption experiment was performed by equilibration of 0.5 g of the biochar samples with 15 ml of Cd solutions in 0.01 mol/L solution of NaNO3 at 150 rpm at 25°C for 24 h. A model pot experiment was established, where cocoa (Theobroma cacao) seedlings were planted in the risk element polluted soil. The findings showed that the biochar prepared from cocoa husks amendments reduced the presence of cadmium in the soil. The amendments also had a significant effect on reducing the mobile concentrations of heavy metals, including Cd, Cu, Ni, Pb, and Zn, in the treated soils. The study concluded that the potential benefits of using organic amendments as a low-cost and sustainable approach to remediate heavy metal-contaminated soils.

Keywords

Biochar, Cadmium, Sorption, Cocoa husk, Risk element, Soil, Theobroma cacao

Jazyk práce: English

Datum vytvoření / odevzdání či podání práce: 23. 4. 2023

Obhajoba závěrečné práce

• Obhajoba proběhla 30. 5. 2023
• Vedúci: prof. Ing. Bohdan Lojka, Ph.D.
• Oponent: Michael Asare Opare, Ph.D.

Czech University of Life Sciences Prague

Faculty of Tropical AgriSciences

Master programme:
Tropical Crop Management and Ecology