Carbon
Soil carbon and sugarcane: evidence from the field
Field data from Beggio Lorenzo and bioenergy research show why management matters for sustainability.
- Mean of the six plots
- 38.7 t C/ha
- Simple arithmetic mean
- Highest reported stock
- 46.5 t C/ha
- Plot 18-D BA
- Soil layer assessed
- 0–30 cm
- Carbon stored in the soil
Sugarcane can be part of farming that conserves soil carbon and contributes to the energy transition. Assessing that potential requires looking at management, measured results and emissions across the supply chain. At Beggio Lorenzo, data from the Fazenda 10B plots provide a concrete example for this discussion.
The automatic association between sugarcane fields and soil destruction deserves scrutiny in light of this evidence. Growing a single crop does not, on its own, tell us how much carbon the soil stores or how that stock changes. The way production is managed makes a difference.
How much carbon is in the soil of the plots assessed?
The Fazenda 10B table and chart, from Projeto Cultura do Campo, report stocks of 28.7 to 46.5 tonnes of carbon per hectare in the 0–30 cm soil layer. According to the characterization supplied by Beggio, the soil is an Argissolo eutrófico under the Brazilian classification, with 16–20% clay. The arithmetic mean of the six values is 38.7 t C/ha. This describes the plots presented, not an area-weighted average for the whole farm. [1]
Plot 18-D BA records 46.5 t C/ha and plot 15-A BA, 45.8 t C/ha. These are numerically close to the approximately 50 t C/ha estimated by MapBiomas for soil under forest formations in the Amazon biome at the same depth. The highest plot value is about 7% below that reference; the mean of the six plots is about 23% below it. Compared with the approximately 40 t C/ha for Amazonian pastures, the plot mean is about 3% lower. [1, 2]
The carbon stored in soil
Stocks in tonnes of carbon per hectare, in the 0–30 cm layer. All bars use the same scale, from 0 to 60 t C/ha.
Fazenda 10B plots
Data supplied by Beggio Lorenzo
Amazonian references
MapBiomas · 2021 estimates published in 2023
Local plots and regional averages have different scopes. This descriptive comparison does not control for soil or methodological differences.
48 t C/ha is the overall biome mean. Forest formations: approximately 50 t C/ha; pastures: approximately 40 t C/ha. These figures do not represent the total carbon in a forest.
View the data table
| Plot or reference | Stock |
|---|---|
| 15-A BA | 45.8 |
| 16-B BA | 36.0 |
| 17-C BA | 28.7 |
| 18-D BA | 46.5 |
| 20-F BA | 32.5 |
| 21-G BA | 42.6 |
| Simple mean of the six plots | 38.7 |
| Amazon biome · overall mean | 48 |
| Forest formations | ≈ 50 |
| Pastures | ≈ 40 |
The pasture reference is the average for those areas across the Amazon biome. The 48 t C/ha figure is the overall biome average. None of these figures identifies exclusively untouched forest. This is a contextual comparison of local plots and regional estimates, without controlling for differences in soil or methods. Numerical proximity within this layer does not establish equivalence between a sugarcane field and an entire forest ecosystem. [2]
Sugarcane management, carbon uptake and bioenergy
Management offers ways to conserve carbon. In a 14-year experiment in Linhares, Espírito Santo, Brazil, researchers found greater soil carbon stocks under sugarcane harvested without burning, with crop residues retained, than under a burned system. Both treatments lost some carbon originating from the preceding vegetation, but unburned cane retained more. The result shows that production choices affect system performance. [3]
We also need to distinguish uptake from storage. Growing sugarcane removes CO₂ from the atmosphere, but some carbon returns through decomposition, fermentation and the use of biomass for energy. Uptake during the crop cycle does not itself amount to permanent removal. Demonstrating stable or increasing soil carbon stocks requires comparable measurements over time. The Fazenda 10B figures presented here describe reported stocks in the plots, not an annual sequestration rate.
Ethanol’s climate contribution is assessed across its life cycle. A study published in 2023, using data from 67 Brazilian mills, estimated emissions 62% lower than those of the US gasoline reference. The scenario considers ethanol produced in Brazil and used in the United States, excluding the effects of land-use change. The percentage describes that sector study, not Beggio Lorenzo’s operation. [4]
This evidence supports a well-grounded case for bioenergy: the sector has practices that can conserve more soil carbon and energy pathways that can reduce emissions relative to fossil fuels. Results depend on management, land-use history and production conditions.
Producing crops and caring for soil as a management commitment
Beggio Lorenzo’s figures bring field experience to this debate. Some sugarcane plots have stocks close to the reference for soils under Amazonian forest formations; others have lower values. Understanding that variation helps identify opportunities for improvement and track how soil responds to management decisions.
This is the kind of farming I advocate: production that measures its results and uses knowledge to improve. Carbon is a relevant indicator alongside soil structure, erosion, water and biological activity. Forest conservation remains essential, while farmland has its own contribution to make. Showing that contribution with data helps deepen understanding of sugarcane farming.
Sources
1. Projeto Cultura do Campo — Fazenda 10B. One-page soil carbon analysis and comparison chart for 0–30 cm, supplied by Beggio Lorenzo. Six plot values: 45.8; 36.0; 28.7; 46.5; 32.5; 42.6 t C/ha. Soil characterization supplied by Giuliano Beggio.