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一、当土壤水分得到满足时,甜菜播种至出苗持续时间与平均气温的关系,近似反相关关系。平均温度为10—15℃时,影响出苗速度非常显著,出苗日数为10—20天,随着温度的升高对加速出苗的效应就相对减低了。二、甜菜播种期的农业气象指标,当土壤水分维持在21—26%,平均气温和5厘米地温达7—8℃,为最适宜的条件。在黑龙江南部地区,最早播种期为4月11—15日,最适播种期为4月16—25日,最晚播种期为4月26—30日。三、甜菜不同生长时期,要求不同的气象条件。甜菜叶片抽生速度以6月下旬至8月份最快,平均两天抽生一片,需有效积温30—40℃。需较高的温度和充足的降水有利于茎叶生长,此期的气象条件为平均气温22.4℃,土壤水分25—27%,相对湿度71%。块根膨大时期需较高的地温:20厘米深度为22.5℃,平均气温21.8℃,土壤水分在22—25%。在收获前30—40天糖分形成积累时期,需比较低的温度:平均气温10—14℃,昼夜温差大于10℃,在此时期对水分反应极为敏感,有的年分收获时的含糖率比收获前含糖率降低的原因,主要是秋雨过多,致使块根组织中水分增多含糖率降低,此时期比中期需要较低的土壤水分,土壤水分维持在20—22%,对糖分形成积累是有利的。四、甜菜在整个生育期以茎叶繁茂和块根膨大时期需水量最大,在茎叶繁茂时期生长基本?
First, when the soil moisture is satisfied, the relationship between the duration of beet seedling emergence and the average temperature is approximated by the inverse correlation. The average temperature of 10-15 ℃, the impact of the emergence rate is very significant, the number of emergence days 10-20 days, with the increase of temperature to accelerate the emergence of the emergence of relatively reduced. Second, beet seeding agrometeorological indicators, when the soil moisture is maintained at 21-26%, the average temperature and 5 cm to 7-8 ℃ temperature, the most suitable conditions. In southern Heilongjiang Province, the earliest planting period is April 11-15, the most suitable planting period is April 16-25, and the latest sowing period is April 26-30. Third, different growth stages of beets, require different weather conditions. Beet leaf pumping speed in late June to August the fastest, an average of two pumping a day, the effective accumulated temperature 30-40 ℃. The higher temperature and adequate precipitation are good for stem and leaf growth. The meteorological conditions of this period are average temperature 22.4 ℃, soil moisture 25-27% and relative humidity 71%. The root tuber enlargement period required a higher ground temperature: 20 cm depth of 22.5 ℃, the average temperature of 21.8 ℃, soil moisture at 22-25%. 30-40 days before harvest sugar formation accumulation period, the need for relatively low temperature: the average temperature of 10-14 ℃, the temperature difference between day and night is greater than 10 ℃, during this period is extremely sensitive to water reactions, and some sugar content when the harvest points The reason for the lower sugar content than before harvesting was mainly the excessive autumn rainfall, which led to the decrease of water content in root tuber. Sugar content was lower than that in the middle period, the soil water content was maintained at 20-22% Accumulation is beneficial. Fourth, beet throughout the growing period of stem and leaf lumens and bulky water demand during the period, growing in the prime of the stem and leaf?