Effect Of Different Density On Development And Yield Of Machine-Transplanted Rice In The Coastal Regions

In order to supply practical basis for rice production in the coastal regions, we explored the effects of different density on rice development and yield in two different ways, one was the same variety in different spacing in between rows-and holes, and the other was two rice varieties in different transplanting seedlings. The results are as follows:In the case of the same rows spacing transplanted by machine, the treatment of the spacing of 30 x 14 cm in between rows -and holes had too much hills leading the too large rice population, was not conducive to the growth of rice, and caused lower yield. Among the remaining three treatments, with spacing increasing, the density decreasing, the seed rate and spike rate get larger, but effective panicles per unit area, grains per panicle, spikelet volume per unit area, height and the maximum number of seedlings reduced, and ultimately the yield decreased. Yanfeng 47 get the highest yields in A2 treatment (30.0×16.0 cm), it reached 10.20t/hm2, was higher than that of Al (9.56t/hm2), A3 (9.78t/hm2), A4 (9.40t/hm2) 6.69%,4.30% and 8.51% separately. The spacing of 30 × 16 cm in between rows-and holes can be applicated and used in Yanfeng 47 transplanted by machine in the coastal regions.Huajing 22 and Yanjing 1202 both had higher yield under the treatment of 4 seedlings per hole. Huajing 22 procesed the highest yield in B2 treatment, it reached 10.86t/hm2, was higher than that of B1 (9.75t/hm2), B3 (10.08t/hm2) 11.38% and 7.73% separately. And Yanjing 1202 processed the highest yield under C2 treatment, it reached 9.68t/hm2, was higher than that of C1 (8.93t/hm2), C3 (9.54t/hm2) 8.4% and 1.5%.separately. Therefore in rice yield structure, effective panicles per unit area directly affected by planting density, with the increasing of planting density, the yield and spikes in a certain range of planting density. On one hand, the Inadequate transplanting density leading postpone seedling and the high tillerings became to effective panicles, causing the neat panicle which was not conducive to high yield; On the other hand,the transplanting density get too large, leading the earlier seedling, can cause the lower tillers, increased the ineffective tillers, and made the group become too large, each individual grow weakly witch was not conducive to high yield either.