不同育秧方式和施肥水平下华南双季早稻秧苗生长特性的初步研究

本试验初步研究了华南双季早稻秧苗于不同育秧方式和施肥水平下的生长特点,结果表明:(1)旱育秧与湿润育秧秧苗在形态生长上的差异主要在于秧苗的叶片数不同,湿润育秧的出叶速度比旱育秧明显地快.(2)在有机质含量较高通气性能较优良的砂质壤土上进行旱育秧,基肥种类与施肥量在一定范围内时,具5片叶以下的旱育小苗的叶片数和株高无显著差异。(3)播后5天内的出苗率湿润育秧比旱育秧要显著地快而齐,而成秧率则各处理间有高有低,无明显规律可循,这与我们过去报道的结果趋势一致。(4)旱育秧移栽后的发根力比湿润秧要强,这种优势可维持到第9天才消失,再加上白/褐根的比例湿润秧要大,可能是导致旱育秧移栽后根系“爆发力”强、返青活棵快的重要因素。

GROWTH CHARACTERISTICS OF SEEDLINGS OF EARLY RICE TREATED BY VARIOUS SEEDLING-RAISING METHODS AND AT DIFFERENT MANURING LEVELS IN SOUTH CHINA DOUBLE CROPPING

In the early cropping season of 1996 in Guangzhou, we studied the growth characteristics of dry-raised and moist-raised seedlings under different treatments with basal fertilizers. The results were as follows: (1) The major morphological difference between moist-raised and dry-raised seedlings appeared in leaf number. The leaf emergence rate of the former was higher than that of the latter. (2) In well-aerated sandy loam soil with high content of organic matter, dry-raised seedlings with less than 5 leaves showed no significant difference in leaf number and plant height when the type of basal fertilizer and its application rate were limited within certain ranges. (3) Within 5 days after seeding, the leaf emergence of moist-raised seedlings was faster and more synchronous, but the ratio of finally formed seedlings exibited no orderly regularity. This result was consistent with our previous reports. (4) Dry-raised seedlings excelled moist-raised seedlings in rooting ability, and this advantage could be maitained until the 9th day after seeding. Besides, dry-raised seedlings had higher ratio of white/brown roots. These factors were contributed to strong growing ability of roots of dry-raised seedlings after transplanting, and quicker colour recovery of leaves and rehabilitation of plants.