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一、适宜播期的确定:用积温法,计算播种适期。从播种到出现预期分蘖和叶片数所需积温:强冬性小麦为650℃左右;冬性600℃左右;弱冬性55℃左右;春性499℃左右。因此,用积温法掌握适宜播期的标准,根据实践经验,应该是:当平均气温稳定在17℃时,播种强冬性品种(中苏68、清涧白小麦、农大139、榆田2号);稳定在16℃时播种冬性品种;稳定和15℃时播种半冬性品种;稳定在14℃时播种春性品种。
First, the sowing date to determine: with temperature method, calculate the sowing period. From sowing to expected tillering and leaf number required for accumulated temperature: strong winter wheat is about 650 ℃; winter about 600 ℃; weak winter about 55 ℃; spring about 499 ℃. Therefore, using the accumulated temperature method to grasp the appropriate sowing criteria, based on practical experience, should be: when the average temperature stable at 17 ℃, the sowing of strong winter varieties (Zhong Su 68, Qingjian wheat, Nongda 139, Yutian 2 ); Sowing winter varieties stable at 16 ℃; sowing semi-winter varieties at 15 ℃ and sowing spring varieties at 14 ℃.