Wheat has potential to absorb more carbon than it releases
Wheat can sequester more carbon than it emits into the atmosphere, potentially paving the way for the crop to be part of the carbon market, according to scientists in Brazil.Research by research organisation Embrapa and the Federal University of Santa Maria found wheat has a “decarbonising potential”, absorbing 7540kg of carbon dioxiode (CO2) per hectare from the atmosphere during trials carried out in a subtropical region of the country.
The amount neutralised emissions from fallow periods, resulting in 1850kg of CO2 absorbed per hectare over the course of a year.
In research published in the Journal of Environmental Quality, the scientists explained they installed a flux tower – a type of equipment that can quickly measure GHG emissions – in a grain field on a no-till farm in the Rio Grande do Sul state in the south of Brazil, which is one the largest grain-producing regions in the country.
Data was captured across each stage of crop production throughout the year, covering wheat cultivation, spring fallow, soybean cultivation and autumn fallow. Fallow periods are common in Brazil as the high price of soybean means most farmers decide against planting winter crops.
From the data the research team calculated annual flows of CO2 across the farm, looking at the amount retained in the system and the emissions into the atmosphere, and discounting any carbon exported in harvested grains.
A decarbonising crop
The scientists said the assessment showed wheat can remove more carbon from the atmosphere than it emits, making it a ‘decarbonising crop’ that can reduce greenhouse gases.
In the study wheat was found to incorporate 5.31 grammes of CO2/m2/day into the farming system.
Soya beans only emitted 0.02g/ m2/day – almost the same amount they absorb – while the two fallow periods emitted a combined 6.29g/ m2/day.
The researchers said the fallow land data suggested it has a negative impact on farming emissions; within just 30 days, it emitted 27% of all the carbon that wheat and soybeans accumulated across 11 months of cultivation. Planting cover crops or forage crops would help to address the issue, they added.
The team said the next step is to repeat the study across the country in different production systems to see how climate and topography impacts wheat’s ability to sequester carbon, potentially opening up avenues to link the crop into carbon credit schemes.
