SLU news

Doctoral thesis on sustainable plant production adapted to climate change

Published: 02 April 2024
Alessio Costa stands next to a birch log with doctoral theses nailed to it.

On Thursday, Alessio Costa will defend his doctoral thesis. He shows how crop rotation diversity, i.e. how farmers switch between different crops on their fields, can benefit food security and increase sustainability in future climates.

Diversity in crop rotation has previously shown promises to increase the yield of cereals, especially under low fertilization levels and in years of low productivity. Based on that, Alessio Costa has used data from 32 so-called long-term field experiments in Europe and North America, and shown that crop rotational diversity would enhance cereal yields over time, and would reduce cereal yield losses that could be caused by unfavorable climatic conditions. He also found that crop rotational diversity increased the productivity of the whole rotation, with benefits over time, while reducing the need for fertilizers.

We ask him three questions.

In what way is your research important?

Many cropping systems of today rely on an extensive use of inputs, and few crops being grown. Solutions are needed to reduce the negative effects of agriculture on the environment and at the same time retain food security, sustainability and diversity. Diversity in crops can promote numerous ecosystem benefits that ultimately enhance productivity, reduce wastes, and mitigate risks in crop production. We also need diversity to produce a more balanced set of human-ready carbohydrates, proteins and fats.

What was the most surprising in your work?

From reading a lot of literature about ecological diversity I had some expectations about what we would find out. I was surprised by an unexpected difference between the productivity on agricultural fields compared to grasslands. We saw that the production can start to decline under some circumstances with high diversity on agricultural fields, while on grasslands the yields reaches a plateau, without a decline. The explanation is probably the limited number of species that can be grown on agricultural fields, constrained by technical and socio-economic factors.

What are your future plans?

In the near future after the defense, I plan to continue with the same type of studies that I am doing today. Later on, I want to continue doing research on sustainable crop production, crop diversification and adaptation of agriculture to climate change, but broaden my research area to also deal with food distribution, the market, policy making and other socio-economic aspects.