Effects of Different Upland Seedling Nurturing Modes on Shed Temperature and Rice Seedling Quality

不同大小棚旱育苗方式对棚温及秧苗素质的影响（英文）

In order to compare the advantages and disadvantages of large-shed,middle-shed and small-shed upland seedling nurturing modes in japonica rice planting regions of North China, in this study, Tongyin 58, Tonghe 836 and Tonghe 835 were used as experimental materials and cultivated with large-shed, middle-shed and small-shed upland seedling nurturing modes to investigate active and effective accumulated temperature and rice seedling quality. According to the results, active and effective accumulated temperature in three different upland seedling nurturing treatments during seedling nurturing period were generally in a descending order of large shed 〉 middle shed 〉 small shed. The occurrence frequency of temperature exceeding the biological upper limit for rice growth in different upland seedling nurturing treatments demonstrated a descending order of large shed 〉 small shed 〉middle shed; the occurrence frequency of temperature below the biological lower limit demonstrated a descending order of small shed 〉 middle shed 〉 large shed.Plant height, root number, aboveground dry weight, underground dry weight and emergence rate varied significantly among different upland seedling nurturing modes,which showed a descending order of large shed 〉 middle shed 〉 small shed; leaf age and stem number in large shed was significantly higher than that in middle and small sheds, but there was no significant difference in leaf age and stem number between middle and small sheds; underground dry weight varied slightly between large and middle shed, but underground dry weight in large and middle shed was remarkably higher than that in small shed. In production, large-shed upland seedling nurturing is most appropriate technique, followed by middle-shed upland seedling nurturing. In large-shed upland seedling nurturing, ventilation and seedling hardening should be strengthened. Small-shed upland seedling nurturing technique is not recommended to be used in regions with low accumulated temperature at night. In small-shed upland seedling nurturing, the minimum temperature at night should be concerned, and heat preservation measures should be taken immediately when there is a sudden drop in temperature.

为剖析大、中、小3种棚膜旱育苗方式在吉林稻作区的孰优孰劣,以'通引58'、'通禾836'、'通禾835'为试材,采用吉林稻区目前普遍推广的大棚、中棚、小棚旱育苗方式,就活动积温和有效积温、秧苗素质方面进行调查统计分析。3种旱育苗方式不同时间段活动积温和有效积温高低均表现为:大棚旱育苗>中棚旱育苗>小棚旱育苗。不同旱育苗方式出现超过水稻生物学上限温度次数多少表现为:大棚旱育苗>小棚旱育苗>中棚旱育苗规律;出现低于生物学下限温度次数多少表现为:小棚旱育苗>中棚旱育苗>大棚旱育苗。在秧苗素质方面,不同旱育苗方式之间的株高、根数、地上干重和出苗率差异显著,其高低、多少均呈现大棚旱育苗方式>中棚旱育苗>小棚旱育苗规律;叶龄、茎数上大棚旱育苗显著高于其他2种旱育苗方式,而中棚、小棚旱育苗差异并不显著;大棚和中棚旱育苗的地下干重间无显著差异,但二者都显著大于小棚旱育苗。生产中提倡使用大棚旱育苗方式,其次是中棚旱育苗,但大棚一定要加强通风炼苗;而小棚旱育苗在吉林省夜间积温较低地区建议不用或少用,若用应留意夜间低温,进而采取保温措施。