Four-year field study: Increased yields in soils amended with biochar from sugarcane residues

Authors: Lima, Isabel; White Jr, Paul; Webber Iii, Charles

Submitted to: Biochar Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/9/2025
Publication Date: 6/23/2025
Citation: Lima, I.M., White Jr, P.M., Webber Iii, C.L. 2025. Four-year field study: Increased yields in soils amended with biochar from sugarcane residues. Biochar Journal. 24. pg 970-991. https://doi.org/10.1007/s12355-025-01600-7.
DOI: https://doi.org/10.1007/s12355-025-01600-7

Interpretive Summary: Surplus bagasse from sugarcane mills and leaf residue left in the field remain untapped resources associated with the harvesting and processing of sugarcane. Pyrolysis of these two organic feedstocks produces biochar which can be land applied to increase soil health and crop performance. Biochar produced from field residue (LRB) and sugarcane bagasse (BGB) was applied once at either 0.80 t ha-1 (LRB1, BGB1) or 1.60 t ha-1 (LRB2, BGB2) to sugarcane, as a single amendment or in combination with fly ash (FA) at 0.63 or 1.26 t ha-1. HoCP 96-540 cane yield, theoretical recoverable sucrose (TRS), and sugar yield were measured and compared across treatments during four harvest years. Biochars were characterized; through its high content in organic matter (68.8% and 71.1% for BGB and LRB, respectively) and H:C ratio (0.48 and 0.46 for BGB and LRB, respectively), biochar contributed carbon to the soil and helped build soil organic carbon. Fixed carbon made up 64% and 60% of the carbon found in the biochar, giving it a long-term permanence in the soil. The effects of biochar addition to the sugarcane growth were also investigated. All biochar treatments led to improvements to crop performance, albeit some were not significantly different than the control. No reductions in sugar yield were observed for FA additions. Best results were determined for field application of LRB at 0.8 t ha-1 followed by BGB at 1.6 t ha-1, specifically with 0.90 and 0.88 kg/stalk, cane yield of 85.8 and 83.3 Mg ha-1, sucrose yield of 8,647 and 8,210 Kg ha-1, respectively for LRB1 and BGB2, when compared to control at 0.78 kg/stalk, 68.3 Mg ha-1 and 6,566 Kg ha-1 sucrose yield. Considering the cumulative sugar yield over four years, additional income can be realized from amending soil with biochar. Best outcome for this study resulted in estimated sugar profits up to additional $1,418 ha-1 for LRB1 (raw sugar priced at $0.17 Kg-1).

Technical Abstract: Surplus bagasse from sugarcane mills and leaf residue left in the field remain untapped resources associated with the harvesting and processing of sugarcane. Pyrolysis of these two organic feedstocks produces biochar which can be land applied to increase soil health and crop performance. Biochar produced from field residue (LRB) and sugarcane bagasse (BGB) was applied once at either 0.80 t ha-1 (LRB1, BGB1) or 1.60 t ha-1 (LRB2, BGB2) to sugarcane, as a single amendment or in combination with fly ash (FA) at 0.63 or 1.26 t ha-1. HoCP 96-540 cane yield, theoretical recoverable sucrose (TRS), and sugar yield were measured and compared across treatments during four harvest years. Biochars were characterized; through its high content in organic matter (68.8% and 71.1% for BGB and LRB, respectively) and H:C ratio (0.48 and 0.46 for BGB and LRB, respectively), biochar contributed carbon to the soil and helped build soil organic carbon. Fixed carbon made up 64% and 60% of the carbon found in the biochar, giving it a long-term permanence in the soil. The effects of biochar addition to the sugarcane growth were also investigated. All biochar treatments led to improvements to crop performance, albeit some were not significantly different than the control. No reductions in sugar yield were observed for FA additions. Best results were determined for field application of LRB at 0.8 t ha-1 followed by BGB at 1.6 t ha-1, specifically with 0.90 and 0.88 kg/stalk, cane yield of 85.8 and 83.3 Mg ha-1, sucrose yield of 8,647 and 8,210 Kg ha-1, respectively for LRB1 and BGB2, when compared to control at 0.78 kg/stalk, 68.3 Mg ha-1 and 6,566 Kg ha-1 sucrose yield. Considering the cumulative sugar yield over four years, additional income can be realized from amending soil with biochar. Best outcome for this study resulted in estimated sugar profits up to additional $1,418 ha-1 for LRB1 (raw sugar priced at $0.17 Kg-1).