工厂化集中育秧模式下荆州市双季早稻低温冷害风险分析

利用荆州市6个国家气象站1981-2014年早稻生育期和日平均气温观测资料,统计传统露地育秧(TS)情况下早稻的生育期和积温,设定比传统方式提前10d播种于温室集中育秧(CS-10)和提前20d播种于温室集中育秧(CS-20)两种育秧模式,推算出相应的生育期,利用日平均气温观测资料和weibull分布模型,统计分析当地采用这两种育秧模式时早稻关键生育期冷积温(指早稻某生育期内冷害临界温度指标与日平均气温差值的累积值)变化及概率密度分布,比较分析3种育秧模式下早稻遭遇低温冷害的风险。结果表明,相较于TS模式,提前10d集中育秧时,移栽-分蘖始期、幼穗分化始期、抽穗开花始期、灌浆结实始期和收获始期分别提前14d、10d、8d、11d和7d;提前20d集中育秧时,各生育期则分别提前24d、15d、11d、17d、10d。其中,轻度冷害发生概率在发育前期(移栽-分蘖期、幼穗分化期)逐渐下降,发育后期(抽穗开花期、灌浆结实期)逐渐增加,而中度以上冷害的发生概率在发育前期增幅较大,其中提前10d集中育秧时,移栽-分蘖期和孕穗分化期的冷害概率分别为14.7%、49.7%;提前20d集中育秧时,冷害概率分别可达57.1%、71.7%,是传统育秧模式的数倍。因此,为降低冷害风险、保障早稻稳产,荆州市早稻集中育秧模式的适宜播种期应不早于3月25日,即比传统育秧模式提前7d左右。

Chilling Injury Risk of Early Rice in Centralized Seedling Mode in Jingzhou

According to investigations of early rice seedling modes in Jingzhou, chilling injury was usually occurred, and initiated by yield reduction. Based on the average daily temperature observations of 6 national meteorological stations, and development period observations between 1981 and 2014, the average effective accumulated temperature of each stage was counted under the traditional seedling mode(TS). Furthermore, two kinds of centralized greenhouse seedling modes, which were 10 days(CS-10) or 20 days(CS-20) earlier than TS, were set to analyze the change rules of chilling accumulative temperature(accumulated value of the difference between critical temperature of chilling injury and average daily temperature in each stage) and the chilling injury characteristics of weibull probability density distribution. The results indicated that, compared with TS mode, advanced with seedling date, the beginning date of transplanting-tillering stage, panicle differentiation, flowering, grain filling and maturation stage were respectively 14d, 10d, 8d, 11d and 7d earlier in CS-10 mode, and 24d, 15d, 11d, 17d, 10d earlier in CS-20 mode. In addition, in the early stage(transplanting-tillering stage and panicle differentiation stage), the probability of mild chilling injury(010℃·d) was increased rapidly in the transplanting-tillering stage and panicle differentiation stage, which were separately reached 14.7%, 49.7% in the CS-10 mode, and 57.1%, 71.7% in the CS-20 mode. For reducing the risk of chilling injury, the suitable sowing date of centralized seedling mode in Jingzhou should be later than March 25th, which was 7 days earlier than TS mode.