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

Abstract

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°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°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°C, fixed carbon for BB-550°C, and ash content for BB-450°C. The mean pH values were in the range of 9.1 to 11.3. The ASB-450 and 550°C exhibited higher nutrient content. The highest cation exchange capacity (CEC) was recorded for ASB-450°C; organic carbon (OC) for corncob biochar (CCB) was followed by ASB-450 and 550°C. The calcium carbonate (CaCO3) content of ASB-550°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°C and BB-450°C can be suggested to be promising candidates for reclaiming acid-soils and for improving nutrient-depleted infertile soils into agriculturally productive soils.

Unlocking the potential of teak seed waste: carbonization for sustainable resource transformation

“…Comparing these findings with the literature for other seed‐based biochar, it is evident that teak seeds exhibit a moderate carbonization yield. Avocado seeds, carbonized at 450 °C for 1 hour, showed a slightly higher yield of 47.45% 32 . Date seeds, carbonized at 350 °C for 2 h, demonstrated a similar yield of 43.01% 33 .…”

“…Avocado seeds, carbonized at 450 °C for 1 hour, showed a slightly higher yield of 47.45%. 32 Date seeds, carbonized at 350 °C for 2 h, demonstrated a similar yield of 43.01%. 33 However, litchi seeds, carbonized at a much higher temperature of 600 °C for 2 h, exhibited a lower yield of 28.53%, 34 and tobacco seeds, carbonized at 600 °C for 10 minutes, had the lowest yield at 25.5%.…”

Prediction, mapping, and implication for better soil organic carbon management in Ethiopia

“…Applications of biochar and compost have strong potential to improve SOC, soil water content, soil acidity, and soil nutrient status in Ethiopia and elsewhere in the world (Agegnehu et al., 2015; Danso et al., 2023; Demissie et al., 2023). The SOC loss is aggravated on rice lands due to repeated cropping and nutrient depletion (Goulart et al., 2020).…”

“…Higher SOC may, however, be attributed to the use of biochar (Alves et al, 2021;Awe et al, 2021), compost, crop residues, and inorganic inputs (Agegnehu et al, 2016;Bedada et al, 2014). Applications of biochar and compost have strong potential to improve SOC, soil water content, soil acidity, and soil nutrient status in Ethiopia and elsewhere in the world (Agegnehu et al, 2015;Danso et al, 2023;Demissie et al, 2023). The SOC loss is aggravated on rice lands due to repeated cropping and nutrient depletion (Goulart et al, 2020).…”

Avocado Waste Biorefinery: Towards Sustainable Development

“…When avocado seeds are used to produce biochar, the process involves heating the waste in a kiln or oven at temperatures between 400 and 800 • C. This results in the production of a stable, carbon-rich material with a higher heating value [98]. Biochar made from avocado waste has been found to have a high content of carbon and other nutrients, such as nitrogen and phosphorus, which can help improve soil fertility and support plant growth [70]. The porous structure of biochar also can retain water and nutrients, which can help reduce nutrient runoff and soil erosion.…”