Agronomic Potential of Avocado-Seed Biochar in Comparison with Other Locally Available Biochar Types: A First-Hand Report from Ethiopia

Biochar is a promising option for improving soil fertility and agricultural productivity. The potential of biochar for specific purposes depends on its physical and chemical characteristics. The avocado seed is widely available as a leftover after the fleshy part is used for food and as a byproduct of avocado-oil producing agro-industries in Ethiopia. Its potential as a biochar for an agronomic purpose has not been studied. The objective of this study was to compare the agronomic potential of avocado-seed biochar (ASB) type in comparison to other biochar types produced from locally available feedstocks at two selected pyrolysis temperatures (450 and 550 degrees C). It was identified that on a mass-base, the produced biochar yields were in a range of 29.68 to 47.45%, higher for ASB pyrolyzed at 450 degrees C. The scanned images of the biochar types showed a remarkable surface morphology for bamboo biochar (BB) and ASB. The bulk density of the biochars were in the range of 0.21 to 0.49 g/mL. The highest volatile matter was measured for BB-450 degrees C, fixed carbon for BB-550 degrees C, and ash content for BB-450 degrees C. The mean pH values were in the range of 9.1 to 11.3. The ASB-450 and 550 degrees C exhibited higher nutrient content. The highest cation exchange capacity (CEC) was recorded for ASB-450 degrees C; organic carbon (OC) for corncob biochar (CCB) was followed by ASB-450 and 550 degrees C. The calcium carbonate (CaCO3) content of ASB-550 degrees C was the second-highest value next to coffee husk biochar (CHB). In this study, ASB and BB were found to have important qualities for improving degraded agricultural soils in terms of soil acidity, nutrient content, and soil fertility. Therefore, ASB-450 degrees C and BB-450 degrees C can be suggested to be promising candidates for reclaiming acid-soils and for improving nutrient-depleted infertile soils into agriculturally productive soils.

Automated summary

Biochar, derived from avocado seeds and bamboo, has shown promising qualities for improving soil acidity, nutrient content, and fertility. This study compared the agronomic potential of different biochar types at different pyrolysis temperatures and identified avocado seed biochar and bamboo biochar as potential candidates for reclaiming acid-soils and improving nutrient-depleted infertile soils.