油菜毯状苗适宜播期研究

为探讨不同播期对油菜毯状苗生长的影响,以宁杂1818为材料,设置B1~B5共5个处理,对应播期分别为9月5日、9月15日、9月25日、10月5日和10月15日,分析了不同播期下油菜毯苗的出苗状况、植株生长形态指标和干物质积累量,以寻求最适播期。结果表明:随着播期推迟,出苗天数延长且出苗率下降,存苗数、苗高、充实度、干物质积累量均下降,其中B2、B3播期下出苗较快且存苗数、绿叶数、叶面积较高,苗高适宜、充实度好,符合毯苗机械移栽的要求。因此,扬州地区油菜毯状苗最适播种期为9月15至25日。由Logistic拟合曲线推算出油菜毯苗从播种至出苗所需要的有效积温为99.5℃,根据回归系数可知毯苗每生长一张叶片需要的有效积温为117.1℃。综上所述,可以根据移栽时需要的叶龄以及当地历史积温推算出从播种到移栽的天数,从而制定合理的播期。

Suitable sowing date of rapeseed blanket seedlings

To explore the effects of different sowing dates on growth of rapeseed blanket seedlings, and to optimize appropriate sowing date, cultivar Ningza 1818 was used as material, and 5 treatments B1 to B5 were set up.The 5 sowing dates were Sept. 5(B1), Sept. 15(B2), Sept. 25(B3), Oct. 5(B4), and Oct. 15(B5) respectively. Seed emergence, plant growth morphology indicators and dry matter accumulation were analyzed. Results showed that with the delayed sowing dates, emergence was delayed, emergence rate decreased;and survival seedlings, seedling height, seedling fullness, and dry matter accumulation were all decreased. Among them, B2 and B3 had faster emergence and higher survival seedling number, green leaf number, and leaf area, suitable seedling height and seedling fullness, which met the requirements of blanket seedlings mechanical transplanting. Therefore, the optimum sowing date for rapeseed blanket seedlings in Yangzhou would be September 15 to 25. The effective accumulated temperature required for rapeseed blanket seedlings from sowing to emergence was calculated from the logistic fit curve to be 99.5℃. According to the regression coefficient, the effective accumulated temperature required for each leaf of the rapeseed blanket seedlings was 117.1℃. In summary, the number of days from sowing to transplanting could be calculated based on the leaf age required during transplanting and the local historical accumulated temperature, so as to determine a reasonable sowing date.