Growing a variety of crops, including legumes such as beans or pigeon peas, and adding plant residues or manure to soils, according to an international team of experts, may increase food crop yields in regions such as rural Africa, where small-scale farmers cannot apply much nitrogen fertilizer. The study, published in the science journal Nature Sustainability, is the first to compare farm practices that work with nature to increase yields and explore how they interact with fertilizer use and tillage. It examined data from 30 long-running field experiments involving staple crops - wheat, maize, oats, barley, sugar beet, or potato - in Europe and Africa. Recognizing that humanity must intensify production on existing arable land to feed its growing population, the paper advances the concept of "ecological intensification," which refers to farming methods that improve ecosystem services and supplement or substitute for man-made inputs such as chemical fertilizer to maintain or increase yields.