水稻机插双膜育秧床土培肥对秧苗素质和秧龄弹性的影响

以直立穗型粳稻品种武运粳7号为供试品种，用地力中上等的砂壤水稻田表土作基础床土进行双膜育秧试验，机插移栽人大田，观测秧苗的形态、相关形态生理指标和产量及穗、粒结构。结果表明：床土培肥量较大的处理田间发根力、苗干重等苗质指标显著或明显优于培肥量少的处理，且大田分蘖发生早，最高茎蘖数高，产量随床土培肥量的增加呈明显的提高趋势。据此提出了该品种机插中苗壮秧指标：苗高12cm，苗基粗度2．7mm，糖氮比1．0～2．0；各培肥量较大的处理秧苗地上部干重的峰值出现在播后20d、叶龄为3．8～4．1时，其后秧苗干重下降，苗质迅速变劣，而不培肥和培肥量小的处理秧苗地上部干重的峰值明显延迟，秧龄弹性增大。

Effects of Seedbed Fertilizing on Quality and Flexibility of Rice Seedlings Nursed with Tow-layer Plastic Film for Mechanical Transplanting

Wuyunjing 7, a semi-erect panicle variety,was used and 5 levels of seedbed soil fertilizing were designed in the experiment for nursing seedlings with tow-layer plastic film on loam soil. The seedlings were transplanted to paddy field with a transplanting machine. The morphological and related physiological traits of seedlings, yield, and yield components were investigated. The results showed that: the main indices of seedling quality such as root-developing ability and dry weight of seedlings nursed in high levels of fertilizing were significantly higher than those in low fertilizing levels. Furthermore, tillers in seedlings nursed in the high levels developed earlier, and peak number of tillers was greater. Yield was raised with the increase in fertilizer levels. The appropriate indices for vigorous seedlings of Wuyunjing 7 were as follows: 12 cm for seedling height, 2- 7 mm for thickness of fake-stem, 1. 0 - 2. 0 for ratio of sugar to nitrogen. The proper peak value of shoot dry weight should be 20 days after sowing, with leaf-age 3. 8 - 4. 1. After that stage,seedling dry weight decline, and seedling quality worsened. For seedlings nursed with low levels of fertilizing or with no fertilizing, the time of peak value of seedling dry weight (i. e. over-aged seedlings) was delayed, and the flexibility of fitting leaf-age of seedlings for transplanting increased. This suggests that seedbed fertilizing has significant effects on regulation of seedling flexibility.