Effects of sowing density, fertilizer amount in seedbed and seedling age on seedling quality and grain yield in paddy field for mechanical transplanting rice

中国人. 以迟熟中粳武育粳3号为材料，塑料软盘育秧，进行落谷密度和施肥量二因素试验，并将各处理秧苗分3期插人大田，实收产量，测定其构成。主要结果如下：（1）3试验因素对苗质和产量的影响为秧龄〉施肥量〉落谷密度。（2）秧龄由16d延至21d，即使较密的落谷密度、少量施肥（处理编码M1、M2）或较稀的落谷密度、多量施肥（编码）X3），均表现减产趋势，故适龄早栽至关重要。（3）秧龄21d秧苗的发根力和茎鞘淀粉含量等指标均优于秧龄16d的（差异显著），但因大田苗数和穗数减少，稻谷产量显著下降。可见机插秧的壮苗指标因秧龄而异。（4）各产量构成因素对产量效应的通径分析表明，在本试验条件下，穗数对产量的影响最大（通径系数为1．1112），每穗粒数次之（通径系数为0．6517）。说明机插稻以争穗数为第一要务。

英语. An experiment of two factors（sowing density and fertilizer amount in seedbed） was conducted in plastic film seedling nursery using a late maturity japonica cultivar Wuyunjing 3. The seedlings of three different ages were transplanted into paddy field, and yield and yield components were tested. The main results were as follows ： （ 1 ） The effect of seedling age on seedling quality and yield was predominant, and followed by fertilizer amount and sowing density. （2） The trend of grain yield reduction was obvious when seedling age was extended from 16 d to 21 d after sowing, although under dense sowing with less fertilizer application （treatments code M1 and M2）, or thin sowing with more fertilizing （code X3）. Therefore, transplanting at optimum seedling age is very important for mechanical transplanting. （3） The seedling quality indices, such as mot-developing ability and sugar content in stem and sheath at seedling age of 21 d were superior to that at seedling age of 16 d （ significantly different）, but the grain yield in paddy field of 21 d seedling age was decreased because of plant and panicle number reduction. So the indices of vigorous seedling would be varied with seedling age. （4） Path analysis of yield components on yield showed that panicle number was the most effective （path coefficient 1.1112） followed by grains per panicle （path coefficient 0.6517） for mechanical transplanting rice.