套种可争取季节,提高光、热、水的利用率。在华北复杂多变的自然条件下,套种可以趋利避害,产量较稳。但由此也产生了一系列种内和种间竞争,例如边行优势与减少播种行的矛盾、群体与个体的矛盾、共生期作物之间的矛盾等。这就需要从作物搭配、田间结构和水肥管理等方面予以调整。麦后复播便于机械化,同时不存在两种作物共生,没有种间竞争,易做到匀苗密植,保证播种面积。但复播作物对六、七月份光、热、水不能充分利用,同时华北地区遇旱涝、低温、病害等自然灾害机率较大。种植方式,决定于多种因素,故应强调综合研究,因地制宜、合理搭配,还要使机械化与种植方式相互适应。 Intercropping can win the season, improve light, heat, water utilization. Under the complex and ever-changing natural conditions in North China, intercropping can be advantageous and avoidable with relatively stable output. However, a series of intraspecific and interspecific competitions have also emerged, for example, the contradictions between advantages and reduction of sowing lines, the contradictions between groups and individuals, and the contradictions between crops during the symbiotic period. This needs to be adjusted from crop collocation, field structure and water and fertilizer management. After the wheat replay to facilitate mechanization, while there is no symbiotic two crops, there is no interspecific competition, easy to make uniform seedlings dense, to ensure sown area. However, the seeding crop will not fully utilize the light, heat and water in June and July, meanwhile the natural disasters such as drought and flood, low temperature and diseases in North China are more likely to occur. Planting methods, depending on many factors, should emphasize comprehensive research, suit one’s measures to local conditions, reasonably match, but also to mechanization and planting methods to adapt to each other.