On rain-fed plots in Jimma, Ethiopia, equal parts oats and alfalfa produced 21% more dry matter than oats grown alone, without fertilizer or irrigation. The result points to a practical way to get more from crops used as animal feed while also improving the soil beneath them.
The study, led by researchers from Nottingham Trent University, the International Centre for Agricultural Research in the Dry Areas (ICARDA) and Jimma University, compared oats and alfalfa grown separately with the crops grown together. The team tested seed ratios of 3:1, 1:1 and 1:3 under low-input conditions: the plots depended on rain and received no fertilizer. The findings were published in the Journal of the Science of Food and Agriculture.
The researchers looked beyond how much feed the crops produced. They assessed nutritional value, how well the plants fermented into silage, and the feed’s predicted contribution to animal growth and greenhouse gas emissions. Of the combinations tested, the 1:1 mix delivered the best overall results.
That equal blend produced more forage and a more balanced feed profile. It contained higher levels of crude protein and metabolizable energy, which animals can use, and less neutral detergent fiber, a measure of less digestible plant material. The mixed crop also made better-quality silage. During fermentation, it had lower gas and liquid losses, a lower final pH and a higher rate of dry matter recovery than the alternatives.
The benefits extended beyond the harvest. Soil tested after the crops were gathered showed higher organic carbon, total nitrogen and available phosphorus where the 1:1 mixture had grown. The plots also had greater cation exchange capacity, a measure of how well soil can hold nutrients that plants use. Together, these changes point to improved soil quality.
The environmental findings are promising, though they are predictions rather than measured emissions from livestock. The team estimated that feeding animals with the equal oat-alfalfa mix could cut greenhouse gas emissions per unit of potential animal weight gain by 37% to 47% compared with either crop grown alone. The estimate applied to both hay and silage.
Dr. Ashraf Alkhtib, a senior research fellow at Nottingham Trent University, said the approach could help farms produce more nutritious feed while improving soil fertility and lowering predicted emissions in low-input systems. Dr. Jane Wamatu, a senior scientist at ICARDA, said the work links crop management, feed quality and environmental performance to help identify more sustainable livestock strategies.
The results offer a clear lead for farmers working with limited inputs: in the conditions tested, growing oats and alfalfa in equal proportions outperformed the crops grown alone on several measures. Further research will be needed to see how reliably the approach works in other settings, but this study suggests that a change in how forage is planted could benefit both livestock feed and the land that grows it.