Nitrogen Accumulation And Translocation Characteristics Of Direct-seeded Rice In Cold Area

A field experiment using Daohuaxiang-2 as the test material was conducted to study the effects of nutrient management on N translocation, distribution and yield of direct-seeded rice in cold area. 3 planting patterns(transplanting, ridge direct-seeding, no tillage direct-seeding) and 2 N regulation modles were set, N contents at different growth stage in rice organs were determined, the amounts of accumulated N was calculated. The main results are as follows:From heading to 15-day after heading, the N content of leaf increased in direct-seeded rice, transplanted rice leaf N content decreased; ridge direct-seeded rice stem and leaf N accumulation increased, no tillage direct-seeded rice stem and leaf N accumulation remain unchanged, and transplanted rice stem and leaf N accumulation decreased, direct-seeded rice N accumulation increasing speed was higher than that of transplanted rice significantly, which showed at heading stage, direct- seeded rice appling fertilizer enhanced the photosynthetic production capacity, provided sufficient N for grain formation, and lay a foundation for improving rice yield.At maturity stage, ridge direct-seeded rice and no tillage direct-seeded rice stem and leaf N accumulation were 4.4%(p<0.05) and 16.5%(p<0.01) higher than transplanted rice respectively. Ridge direct-seeded rice and transplanted rice N accumulation in panicle was not significant, no tillage direct-seeded rice N accumulation compare with transplanting rice was lower 9.3%, the difference was not significant. The N accumulation from 30 days after heading to maturity, ridge direct-seeded and no tillage direct-seeded rice increased by 2.17 kg/ha and 3.81kg/ha respectively. However, transplanted rice in this period has not accumulated. Panicle stage N accumulation of ridge direct-seeded rice and no tillage direct-seeded rice compared with transplanting rice was higher 94.6%(p<0.01) and 23.8%(p<0.01), respectively. That indicated direct-seeded rice roots at late stage was well, strong ability of absorb N, living under mature, stem vigor was stronger, and the stem can accumulate and transform the substances. However, transplanting rice already ageing and life activity has stopped.N assimilation of ridge direct-seeded rice and no tillage direct-seeded rice compared with transplanted rice was higher 139.9%(p<0.01) and 160.1%(p<0.01), respectively. N assimilation contribution rate of ridge direct-seeded rice and no tillage direct-seeded rice compared with transplanted rice is higher 133.3%(p<0.01) and 177.8%(p<0.01), respectively. Direct-seeded rice grain number per panicle and seed setting rate were higher than that of transplanted rice. The difference in transplanted rice and direct-seeded rice yields was not significant.