油菜和荞麦是天水山旱地小麦收获后传统的倒茬作物，其主要栽培方式为小麦→油菜，小麦→荞麦→玉米。由于荞麦的根系分泌物对后作玉米的生长有抑制作用，因而玉米产量较低，不能起到倒茬作用。油菜冬前生长缓慢，对光能的利用率不高，以１９９７年开始，我们采用了小麦→... Rape and buckwheat are the traditional stubble crops after the harvest of dry land wheat in Tianshui Mountain. The main cultivation methods are wheat → rape, wheat → buckwheat → corn. Because the buckwheat’s root exudates have an inhibitory effect on the growth of post-made maize, the maize yield is low and can not act as a stubble. Rape slow growth before winter, the utilization of light energy is not high, beginning in 1997, we use the wheat → ...