Abstract: Diet selection is a complicated topic. This paper reviewed the multi-disciplinary research advances in the diet selection mechanisms of grazing herbivores. There were two hypotheses about the mechanisms. One assumed that the diet selection behaviors were inherited and innate, while the other supposed that they were from learning, including post-ingestive feedback, trial-and-error learning, social learning, spatial memory, visual cues, and skin-defense. Four hypotheses on diet selection strategies including RT, MVT, OFT and MTD of grazing herbivores were summarized, and the prospects of grazing herbivores diet selection study, such as spatial-scale of diet selection, physiological factors of digestion, and interactions of multiple affecting factors, were discussed.

Key words: Soil bulk density, Soil water content, Split-root, Maize, Growth, Effect