黑龙江省第3积温带地温变化及玉米播期的确定

黑龙江省第3积温带是该省早熟玉米的重要产区,为确保玉米播种质量需要了解该区4—5月地温的变化进而确定适宜的播种期。本研究选取拜泉县、富锦市、讷河市和绥棱县4个具有代表性的市(县),以2004—2013年4—5月5~10 cm土层日平均地温为基础数据,分析近10 a该积温带播种至出苗期间(4—5月)地温的变化规律,同时结合玉米种子萌发温度,确定该积温带的播种日期。结果表明,日平均地温均随着时间推进而增长,4月1—8日地温增长比较稳定,4月9—20日地温波动幅度最大,4月25日至5月1日整体呈现上升趋势;4地平均地温稳定通过6℃、7℃、8℃、9℃、10℃的日期分别为4月17日、4月17日、4月18日、4月18日、4月26日,但年际间差异较大;第3积温带的最早播种期建议为4月20日,适宜播期为4月27日至5月10日。

Changes of Earth Temperature in Third Accumulated Temperature Zone and Determination of Maize Sowing Time in Heilongjiang Province

The third accumulated temperature zone was an important early-matured maize region in Heilongjiang province. In order to ensure the maize sowing quality,we need to know the changes of earth temperature in this area and to determine the suitable sowing date from April to May. This study analyzed the changes of earth temperature of 5—10 cm soil layer of four representative cities and counties in third accumulated temperature zone in Heilongjiang province from April to May during 2004 to 2013. The sowing time in this area was defined considering maize seed germination temperature. The results showed that daily average earth temperature increased in the fluctuations over time. It increased steadily from 1st to 8 th in April,a great fluctuation from 9 th to 20 th in April,and it showed a general upward trend from April 25th to May 1st. The earth temperature steadily reached 6 ℃,7 ℃,8 ℃,9 ℃ and 10 ℃ on 17th,17th, 18th,18th and 26th in April respectively,but the date varied largely in different years. We suggested that the earliest maize sowing time was April 20 th,the suitable sowing date was from April 27 th to May 10 th.