Effect Of Nitrogen Application On The Development Of Rice Yield And Nitrogen Absorption And Utilization

Effect of nitrogen application on the development of rice yield and nitrogen absorption and utilization (agr ic. coil. Yangzhou university. Yangzhou 225009) postgraduate: Lu xiutao supervisor Professor: Zhang Hongchen A. professor: Dai Qigeng ABSTRACT The study takes early maturing late japonica variety wu 941 as test materials. Under the condition of the 1.5 X I O4hills /mu and the total applied nitrogen amount of 15 Kg/mu in the all growth stage, nitrogen applied at the earlier and middle-later stages respectively in a ratio of 2:8, 3:7 ,4:6, 5:5, 6:4, 7:3.Every treatment has 3 kinds of fertilizer applied method in the middle and late period: fertilizer applied equally in the stages of remaining leaf primordium number 5, 3, fertilizer applied equally in the stages of remaining leaf primordium number 4, 2, and fertilizer applied equally in the stages of remaining leaf primordium number 5, 4, 3, 2, I .And the treatment of fertilizer applied only at earlier stage and the treatment of no fertilization was Set. The contrast was the treatments of appling nitrogen normally at the total applied nitrogen amount of 15 Kg/mu, 20 Kg/mu (the ratio of basal and tiller fertilizer and spike fertilizer was 6:4). Effect of different nitrogen application on the development of rice yield and nitrogen absorption and utilization was studied. The main results were as follows: (1) The sequence of yield in different nitrogen proportion treatments was 4:6> 5:5> 6:4> 7:3> 3:7> 2:8.The ratio from 4:6 to 5:5 was benefit to the development of high yield. When nitrogen applied at the earlier and middle-later stages respectively in a ratio of 2:8, the sequence of yield was the treatment of applying nitrogen equally in the stages of remaining leaf primordium number 5, 4, 3, 2, 1> the treatment of applying nitrogen equally in the stages of remaining leaf primordium numberS, 3 > the treatment of applying nitrogen equally in the stages of remaining leaf primordium number 4, 2. While when nitrogen applied in other proportion, the sequence of yield was the treatment of applying fertilizer equally in the stages of remaining leaf primordium number 5, 3 > the treatment of applying fertilizer equally in the stages of remaining leaf primordium number 5, 4, 3, 2, 1> the treatment of applying fertilizer equally in the stages of remaining leaf primordium number 4, 2. (2) If nitrogen applied at the earlier and middle-later stages respectively in a ratio from 4:6 to 5:5,and if fertilizer applied at middle-later stage devided equally at the stages of remaining leaf primordium numberS and 3, the treatment could reach 19X l04-20X 104 ear - 53 - ~+Lk~ 2001 眫)F~i~ number per mu, above 150 grains per spike, above 2850 X 104 spikelets, and 700 Kg yield per mu. (3) The treatment 2:8 and treatment 3:7 had greater maximum of tillers and lower spike rate. The treatment 6:4 and the treatment 7:3 also had greater maximum of tillers and lower spike rate, but the maximum of tillers appeared earlier than that of the treatment 2:8 and treatment 3:7. The treatment 4:6 and the treatment 5:5 had smaller maximum of tillers and higher spike rate. Maximum of LAI of the treatment 2:8 appeared at heading stage. While that of the treatment 4:6 and the tr...