Crop Mixtures, Ecosystem Functioning, and Mechanisms

Crop mixtures, including agroforestry, hedgerow intercropping, mixed intercropping, strip (row) intercropping, and relay intercropping, have been important to agriculture in the past, and are widely practiced in modern agriculture. Here we review crop mixtures and the enhancement of agroecosystem functions in terms of biodiversity, overyielding, the stability of crop yields, resources acquisition, and soil improvement, and summarize the mechanisms behind overyielding. Overyielding is caused by combinations complementarity effects, generally more complete niche partitioning, selection effects, the inclusion of exceptionally high-performing species, and facilitation. Crop mixtures can also control crop pests and diseases, which can also cause overyielding. In summary, crop mixtures can generate both more productive and more sustainable agriculture.