关键词: 牛体外胚胎、子宫内膜细胞、体外共培养, 牛体外胚胎、子宫内膜细胞、体外共培养

Abstract: Soil temperature is a major environmental factor limiting maize production, in order to seek the reasonable sowing time, the growth and development of maize in soil appropriate temperature environment, so as to ensure the formation of dry matter accumulation and yield. The representative of Wuwei inland river basin area of different sowing dates were tested in field mulched spring maize, the change of soil temperature in the whole growth period of continuous observation of spring maize growth period, yield structure and 20 cm, 40 cm two depth, analyzed the effect of different sowing dates on spring maize biomass and soil temperature. The results showed that: the vegetative growth stage of different sowing date treatment at various levels of temperature with the advance of growth and development was gradually increased trend, after the jointing stage to enter the reproductive growth stage, the temperature decrease. Sowing good second growth, dry matter accumulation was high, especially between the milky stage and mature stage significantly (P<0.05). Second yield was better than third period and the first period. The second sowing date, could obtain higher temperature at seedling stage, soil warming was obvious, but in the jointing stage and then ensures a proper low temperature, so as to ensure the formation of dry matter accumulation and yield structure, was the most appropriate mulched spring sowing. The first sowing date biomass was the worst performance, indicated that the crop under normal circumstances appropriate early sowing date, prolong the growth period was the practice of a certain risk in maize production.