Agriculture emits 25% of the country’s greenhouse gases, but it can be produced with benefits for agroecosystems. A FAUBA study showed that cover crops, in addition to offering multiple advantages on a field scale, can remove almost 2 tons of carbon dioxide per hectare per year from the atmosphere.
Climate change has negative impacts on natural, productive ecosystems and cities around the world. Argentine agriculture contributes to a quarter of our country’s greenhouse gas (GHG) emissions. Is it possible to reduce these emissions through simple management practices that maintain yields or even improve them?
A study by the Faculty of Agronomy at UBA (FAUBA) and INTA found that the cultivation of cover crops reduces carbon dioxide in the atmosphere, which implies benefits for agroecosystems. They proved that each year one hectare of oats is capable of incorporating almost 2 tons of carbon dioxide, a value close to that emitted by a Buenos Aires-Madrid flight.
Greenhouse gas emissions
“Between the Greenhouse gas emissions of the agroforestry sector, carbon dioxide is the most relevant. Through simple agricultural management, it is possible to produce with less global impact and without negatively affecting productivity. One strategy is to incorporate more carbon from the atmosphere into the soil, which can be favored with the implantation of more crops per year in the fields.”, explains Sebastián Vangeli, professor of Soil Management and Conservation at FAUBA.
“Plants take carbon dioxide out of the atmosphere and turn it into plant material. So the carbon either stays in the tissues or passes into the soil in dead plant debris. In this context, I evaluated the use of cover crops, that is, species that are planted between two commercial crops to cover the soil and prevent erosion, among other benefits they provide to agroecosystems.”. Vangeli carried out his tests in the Pampas region, in INTA’s experimental fields and in lots of companies and producers.
GHG capture tests
“In the tests, I incorporated several cover species between corn, which is grown in the summer, and soybeans in the following summer. The best results in terms of GHG emissions were found using oats. We found that oats sequester nearly 2 tons of carbon dioxide per hectare per year without increasing other GHG emissions.”, highlighted Vangeli from a article published in scientific journal Frontiers in Soil Science.
Vangeli, who has an INTA/CONICET scholarship, clarified that, in any case, it is necessary to take into account which coverage to choose, as there are some that can increase GHG emissions. The studies are part of Vangeli’s doctorate at the FAUBA Graduate School, under the guidance of Gabriela Posse, a researcher at INTA, and co-supervision of Carlos Di Bella, a professor at FAUBA.
Potential benefits for agroecosystems
Nitrous oxide is the third most important GHG emitted by the agroforestry sector and 95% comes from agriculture. In particular, nitrous oxide is generated by biological processes that occur in the soil. “The emission is greater the more nitrogen there is in the soil. When we fertilize, we increasesaid Vangeli.
“In my study, I applied alternative fertilizers that slow or stop biological processes in the soil and encourage nitrogen to go directly to the plant. In a maize crop, these fertilizers reduced nitrogen losses by between 35 and 49% compared to urea, the most widely used fertilizer. Although my results show a slight reduction in nitrous oxide emissions, studies carried out in Australia, Europe and the United States speak of a decrease of between 31 and 44%. We need to continue researching this line.”.
Good news
Sebastián Vangeli commented that they chose and worked with practices that were relatively easy for producers to apply to obtain benefits for agroecosystems. “Simple and cheap methodss,” he commented, adding: “Cover crops have been used for years”.
“The agricultural sector is very interested in tackling climate change. When we present the results at conferences and lectures, we get good responses from agricultural producers, companies and researchers. I think that in the near future interest may increase even more, for example, in the hands of carbon markets, which bring benefits to those who reduce the impact of agriculture on climate change. Many of us who dedicate ourselves to agronomy seek to produce with the least possible impact”, he commented.
Finally, the professor stated that his work contributes to different scales. “We are working with the National Ministries of Environment and Agriculture, which estimate and analyze greenhouse gases at the local and national level. In addition, it is essential to disseminate practices such as cover crops, as they protect the soil, favor weed control without the application of chemical products and reduce emissions of this type of gas.”.