Assessing the potential of biochar to restore degraded lands

MENVSC

Department of Geography and Environmental Sciences

Land degradation and climate change are interlinked processes that negatively impact sustainable development. Globally, they pose a risk to human livelihoods, but their effects are even more prominent in developing nations, especially in sub-Saharan Africa. Even with land degradation and climate change currently happening, communities, especially in developing countries, still need to adapt to the changes. This may be due to the high adaptation costs and the need for more knowledge. Biochar is the product of the thermochemical conversion of biomass through pyrolysis. Using biochar as a soil ameliorant has been increasingly advocated because of its effects on soil properties, crop productivity, and carbon sequestration. Biochar has been reported to improve soil quality, crop yield, and soil carbon sequestration potential. Despite this, little is known about the effects of biochar on soil physical properties, making it difficult to recommend biochar to improve soil quality in agriculture. Thus, this study aims to assess the potential of biochar to restore severely degraded land by improving soil properties and crop productivity and mitigating climate change through carbon sequestration at the Lapalala Wilderness Reserve, Waterberg District, Limpopo Province, South Africa. For this purpose, four treatments (biochar, biochar with fertilizer, biochar without fertilizer, and control) were applied to four plots, each replicated five times. A 14-species grass mixture was sown in each of the 20 plots. Soil physical and chemical properties, plant biomass, carbon stock, species richness, and species composition were then measured. None of the four treatments had a significant effect on soil bulk density while only biochar had a significant effect on soil chemical properties of soil Total C, Na and soil pH. No treatment had a significant effect on plant biomass. The analysis of similarity showed no significant difference in species composition for all treatments at month three and month six. The species composition for both treatments and sites for months three and six was mostly similar. The effects of biochar were not significant on soil chemical and physical properties as well as plant growth and biomass. Longer-term studies with higher rates of biochar application are required to confirm the effects of biochar on soil properties, plant growth, and species composition. The biochar feedstock (e.g., agricultural residues, forestry residues, and grassland cutting), biochar properties (such as porosity, bulk density, carbon content) and soil types need to be taken into consideration before application of biochar into the soil to enhance soil properties and plant growth.

NRF