Abstract:
The effect of fertilizer application strategy on nitrogen and dry-matter accumulation, grain yield and nitrogen utilization efficiency (NUE) of the ratoon rice crop and its first cropping rice was determined through designing 3 nitrogen applied proportion between basal-tiller dressing and panicle dressing 8∶2(N
1), 7∶3(N
2), 6∶4(N
3) in the first cropping rice season with a constant nitrogen supply at 225.00 kg·hm
-2 in the experiment. The results indicate that N accumulation under N
3 treatment is 9.26% and 3.54% higher at ripening stage of the first cropping rice than that under N
1 and N
2 treatments. Transportation of N from vegetative parts to panicle during grain-filling stage of the first cropping rice under N
3 is separately 21.47% and 6.76% higher than under N
1 and N
2 treatments. For the entire growth period, net dry-matter accumulation in rice under N
3 treatment increases by 5.10% and 4.78% compared with N
1 and N
2. For grain yield of the first cropping rice, N
3 treatment produces the highest (12 431 kg·hm
-2), which is significantly higher than that produced by N
1 and N
2. N utilization efficiency of N
3 treatment is as high 46.44%, 14.81% and 5.43% higher than that under N
1 and N
2. N agronomic efficiency in N
3 treatment is 20.66 kg·kg
-1, 14.97% and 12.34% higher than in N
1 and N
2. Furthermore, the results show that different nitrogen proportion between basal-tiller dressing and panicle dressing with a constant nitrogen supply (225.00 kg·hm
-2 N fertilizer) in the first cropping rice has no significant influence on the ratoon rice crop.