Study On The High-yielding Cultivation Technology Under Later Sowing In Jiangxi With Northeast Japonica Rice Varieties

To explore the feasibility of using Northeast japonica rice varieties as remedyvarieties after suffering flood disasters in the northern Jiangxi Province, a field experimentwas conducted to examine the effect of different types of japonica rice, sowing dates,seeding ages, density and nitrogen fertilizer rates on yield in2012-2013. Main results areas follows:(1) Ecological adaptability of japonica rice varieties under delayed sowing.In terms of growth duration, when the Northeast early japonica rice varieties(Longjing24, Longjing26, Longjing21,Changbai9, Songjing9, Jijing83, Liaoxing1,Yanfeng47) were grown in the south China, their growth durations were significantlyshortened relative to those at their original sites, whereas the number of leaves tended todecrease, but no significant difference was found. Accumulation of dry matter increasedwith increasing growth durations. Delayed sowing tended to increasing rice yield duemainly to the increase in the number of panicles. Owing to long growth durations,Liaoxing1and Yanfeng47did not mature at the second sowing date (July25), while allvarieties did not mature at the third sowing date (August9).(2) Effect of seedling ages on yield under delayed sowingEffect of seedling ages on yield was investigated using five japonica rice varieties(Longjing26, Longjing21,Changbai9, Songjing9, Jijing83). Results showed that theyield increased with increasing growth durations. The yield decreased with increasingseedling ages under the same fertilizer rate and density. The25-day-seedling failed tomature.(3) Effect of density on yield under delayed sowingIncreasing densities leaded to the advance of rice phenology under seedling throwing.The yield increased and reached a peak and then decreased with growing densities. Thelower yield under low densities was mainly due to the lower number of panicles, whereasthe lower percentage of filled grains also resulted in lower yield under high densities.(4) Effect of N fertilization on yield under delayed sowingThe biomass of the same variety increased with increasing N fertilization. Under thesame N fertilization, the yield increased with increasing growth durations. The yield didnot differ significantly among short-duration varieties, but had significant differenceamong long-duration varieties resulting from the higher number of panicles. The number ofpanicles and the percentage of filled grains were significantly reduced when the N rate wasover210kg/hm2.