Intercropping – the agricultural practice of growing two or more crops together – could improve the amount and quality of livestock feeds while reducing environmental impact, a new study suggests.

Scientists at Nottingham Trent University, the International Centre for Agricultural Research in the Dry Areas (ICARDA) in Ethiopia and Ethiopia’s Jimma University, wanted to explore the benefits of growing oats and alfalfa together, as opposed to separately, and without irrigation or fertiliser.

The research aimed to go beyond conventional feed evaluation by considering not only the nutritional and fermentation characteristics, but also the potential contribution to animal growth and greenhouse gas production.

The research team evaluated sole oat, sole alfalfa, and oat-alfalfa seed ratios of 3:1, 1:1, and 1:3 under strict rainfed, low-input conditions with no fertilization and found that growing in equal proportions produced the best overall results, increasing forage yields and nutritional value, while also improving soil properties.

The 1:1 intercrops produced 21% more dry matter – the total weight of the crop after water is removed – than oats grown in a monoculture, the study revealed.

The 1:1 intercrop also had a more balanced nutritional profile, yielding higher levels of crude protein and metabolizable energy, alongside reduced neutral detergent fibre which is important for animal nutrition. It also produced better-quality silage with demonstrated superior sensory quality, lower gas and effluent losses, a lower final pH, and a higher dry matter recovery rate during fermentation, it was found.

Following the study, post-harvest soil analysis showed that where the 1:1 intercrop had been grown, there was an increase in organic carbon, total nitrogen, available phosphorus, and cation exchange capacity, improving its overall quality.

The team predicted that a 1:1 ratio oats and alfalfa intercrop could reduce greenhouse gas emissions per unit of potential livestock weight gain by 37- 47% compared with growing either crop alone, for both hay and silage.

Dr Ashraf Alkhtib, a Senior Research Fellow in Nottingham Trent University’s School of Animal, Rural and Environmental Sciences, said: “Growing oats and alfalfa together, particularly in equal proportions, could offer a promising way to produce more nutritious animal feed while improving soil fertility and reducing predicted emissions in low-input farming systems.”

Dr Jane Wamatu, Senior Scientist at the International Centre of Agricultural Research in Dry Areas, added: “By integrating crop management, feed quality and predicted environmental performance, the research provides a new framework for identifying sustainable livestock strategies.”

The research, which emerged from a Memorandum of Understanding between NTU and ICARDA, is published in the Journal of the Science of Food and Agriculture.