A Study On The Seeding Times And Fertilizing Rate Of Direct Seeding Rice Under Zero Tillage Condition

A preliminary exploitation for the cultivation technology of direct seeding rice under zero tillage condition was studied in Shimen county in 2002-2003. The experiment with two line hybrid rice (Peiliangyou 93 in 2002 and Liangyoupeiju) was conducted by using different seeding times and by applying different fertilizer rates. The main results were summarized as follows:Seeding times showed the greater influence on the growth duration of Liangyoupeiju. The whole growth duration became shorter with the delay of seeding times. Relatively, both heading stage and maturity stage would be ahead of time. On the other hand, seeding times has no significant influence on leaf number of rice.Seeding times showed the influence on the tillering dynamics of Liangyoupeiju to some extent. The highest velocity of tillering emergence was observed on the seeding date of the 20th of May, next on the 10th and 30th of May in turn. The tiller number was different in three seeding times, of which the smallest number was found on the seeding date of the 10th of May.Seeding times obviously affected the grain yield and the yield components. The yield significantly decreased with the delay of seeding times. In 2002, the yield of seeding date on the 10th of May was up to 593.8kg/inu and the highest in three seeding times. It was 71.6 and 27.8kg/mu higher than that of the seeding date on the 20th and 30th of May respectively. The spikelets and the setting grains per panicle and effective panicle number per unit land area all decreased with the delay of seeding times.The influence of different fertilizing rate on the growth duration and the plant height was not obvious. Except for that no fertilizer treatment (FO) had less leaf number, others treatments had about 12 leaves.The different fertilizing treatments obviously affected dynamic tendency of tiller emergence. Although there were no differences of the occurrence date of maximum tiller number among different fertilizing rate treatments, but their tiller number per unit land area were much different. The smallest number of tillers at maximum tiller stage was observed in the no fertilizer plot (FO), and significantly less than those of other fertilizing rate plots. Meanwhile, the tiller number increased with the increase in fertilizing rate, of which the plot (F4) which applied 60kg/mu coated-compound fertilizer had more tiller number than those of other three fertilizing rate plots.The influence of different fertilizing rate on the yield and yield components were observed. The yield and the effective panicles increased with the increase in fertilizing rate, of which the highest yield was 473.3kg/mu in plot F4 in 2002 and 476.0kg/mu in treat F4 in 2003. This yield was significantly higher than that of other three fertilizing rate plots in 2002. but not significantly different among other three fertilizing rate plots in 2003.