Agriculture: changing animal feed reduces consumption of natural resources

The study published on the cover of Nature Food opens up new scenarios for sustainability in agri-food systems

A study published on the cover of Nature Food, the result of a collaboration between Politecnico di Milano and the University of Milan, highlights how the increased use of by-products in the feed sector (secondary products derived from the processing of primary crops such as cereals and sugar) in a circular perspective can lead to significant savings in the use of land and water resources and thus to more sustainable agri-food systems.

Underlying the work, signed by Camilla Govoni and Maria Cristina Rulli from Politecnico di Milano, Paolo D’Odorico from University of California at Berkeley and Luciano Pinotti from University of Milan, there is a thorough analysis and a search for strategies to reduce both the competition for natural resources between animal and human food production, and the unsustainable use of natural resources.

Not only does the use of agricultural by-products in animal diets decrease competition between sectors and pressure on resources, but it would also increase the availability of calories that can be directly earmarked for the human diet (eg cereals); if the saved resources are used for other purposes, including the production of plant foods lacking in current diets, it would improve food security in several countries, with healthier as well as more sustainable food choices

Camilla Govoni, researcher at the Department of Civil and Environmental Engineering

The study shows that an 11-16% substitution of energy-intensive crops currently used as animal feed (eg cereals) with agricultural by-products (eg cereal bran, sugar beet pulp, molasses, distillery residues and citrus pulp) would save approximately between 15.4 and 27.8 million hectares of soil, between 3 and 19.6 km3 and between 74.2 and 137.8 km3 of irrigation and rainwater.

The inter-sectoral decrease in the demand for cereals is of particular relevance at a time when the supply of these crops is facing serious shortages due to the combination of the ongoing war between Russia and Ukraine, the residual effects on the food supply of the Covid-19 pandemic, and a drop in harvests caused by increasingly frequent extreme events such as floods, droughts and heat waves induced by climate change.

Maria Cristina Rulli, Professor of Hydrology and Coordinator of the Glob3ScienCE Lab

Disegno di Laura Capellini