播期、密度和施氮量对南粳44产量及其构成因素的影响

Effects of Different Sowing Time,Planting Density and Nitrogen Fertilizing on Yield and Its Components of Nanjing 44

通过不同播期、移栽密度和施氮量试验,研究了南粳44产量及其构成因素的表现,结果表明:①南粳44作为直播稻,随着直播期的推迟,产量显著下降,全生育期缩短,适宜播种期以5月下旬到6月上旬为宜,最迟播期为6月17日,过迟播种则不能正常成熟。②南粳44作为机插稻,在设置每667m2插0.63万穴(40.0 cm×26.7 cm)时,以3.8万基本苗时产量最高;在每667m2插1.9万穴(26.7cm×13.3cm)时,以5.7万基本苗时产量最高;南粳44超高产栽培的关键是在适宜的基本苗的基础上,通过少穴扩行栽培,主攻大穗以获得足够的颖花量,并保持稳定的结实率与千粒重。③施氮量对南粳44产量及产量构成因素有显著影响,随着施氮量的增加,南粳44的产量呈现先上升后下降的趋势,全生育期以每667m2施18～20 kg氮素为宜,基肥、蘖肥、穗肥比例以2.4∶3.6∶4.0为宜,最佳的穗肥施用时期是倒3叶,既保证了一定的穗数,又增加了每穗粒数。

The effects of different sowing time, planting density and nitrogen fertilizing on yield and its components of Nanjing 44 were studied. The results showed that（ i）The yield was significantly decreased and the whole period of growth and development shortened along with the delayed sowing date. To attain high yidd, Nanjing 44 should be sowed as early as the time from the view point of security. The proper sowing time was from the late May to early June and the latest sowing time was June 17. （ii） As machine-transplanted flee, the maximum yield could be obtained at the plantlng spacing of 40.0 cm × 26.7 cm by transplanting 3.8 × 104 seedlings per 667m^2 for Nanjing 44, while the yield reached the highest at the planting spacing of 26.7 cm × 13.3 cm hy transplanting 5.7 × 104 seedlings per 667m^2. For super hlgh-yidding cultivation of Nanjing 44, ample spikelets were the guarantee of super and stable high yield at the basic of proper seedlings by enlarging the planting spacing and ensuring the stable seed setting rate and 1000-grain wright. （iii） The effects of amount of nitrogen fertili- zing on yield and its components of Nanjing 44 were obvious; The yield increased firstly and the dereased with the increasing nitrogen level. The yield reached the highest when the rate of nitrogen fertilization at 18 - 20 kg/667m^2 and the ratio of basal ,tillering and panicle nitrogen fertilizer at 2.4： 3.6： 4.0. The most suitable time of panicle nitrogen applied was at the third leaf age with ample panicles and spikelets.