Effects Of Nutrient Management On Qualities Of Direct-seeded Rice In Cold Area

In order to compare the difference of rice qualities between direct-seeded rice and transplanted rice in cold area, provid a theoretical basis and technical measures for high yield and quality cultivation of direct-seeded rice, a field experiment with transplanting(TP), ridge directseeding(RDS) and no-tillage direct-seeding(NTDS) rice was conducted using Daohuaxiang-2 as tested rice variety. The main research results as follows:Peak viscosity, hot paste viscosity, cool paste viscosity and breakdown viscosity of directseeded rice were 15.29%-18.82%, 12.46%-14.51%, 6.89%-9.10%, 20.31%-20.92%(P<0.01) lower than that of transplanted rice, respectively, and setback viscosity was 83.9%-93.63%(P<0.01) higher than that of transplanted rice. According to hot paste viscosity, cool paste viscosity, eating qualities of direct-seeded rice are better than that of transplanted rice, but according to peak viscosity, breakdown viscosity and setback viscosity, eating qualities of direct-seeded rice are worse than that of transplanted rice.Amylose content of all treatments were less than 20%, contents of TP, RDS and NTDS were 17.10%, 17.46% and 17.30%, respectively, gel consistency of all treatments belong to middle gel consistency(41-60 mm), TP was 58.0 mm, RDS and NTDS were 51.5 mm and 51.8 mm, respectively. Head milled rice rate of RDS was 53.64%, significantly higher than that of NTDS(51.64%) and TP(52.29%). Chalkiness degree of RDS and NTDS wer e 1.04% and 1.05%, significantly lower than that of TP(1.38%), and protein content were 6.11% and 6.09%, significantly higher than that of TP(5.60%). Cooking and eating qualities of direct-seeded rice and transplanted rice are in the range of high quality rice, and processing, appearance and n utrition qualities of directed-seeded rice are better than that of transplanted rice.Soluble sugar content in different organs and accumulation in plants of direct-seeded rice were all higher than that of transplanted rice during 30 d after heading to maturity stage. At 30 d after heading stage, soluble sugar content in leaves of RDS and NTDS were 129.5% and 149.8%(P<0.01) higher than that of TP, respectively, and at maturity stage, soluble sugar accumulation in rice plants were 36.4% and 49.2%(P<0.01) higher than that of TP, respectively. Chalkiness degree and gel consistency all had significant positive correlation with soluble sugar content in rice panicles 15 d after heading, however, amylose content had significant negative correlation with it. The results show that granular fertilizer could anti-aging of direct-seeded rice, therefore photosynthetic capacity of plants was still strong at late growth stages and could accumulate more photosynthate, which could provide energy source for plant and lay a f oundation for yield and quality. The higher the soluble sugar content in rice panicles 15 d after heading, the better the cooking and eating qualities of rice, but the worse the appearance quality.P content in panicles of direct-seeded rice increased gradually during 15 d after heading to maturity stage, and P content in panicles of direct-seeded rice and transplanted rice had no obvious difference at 30 d after heading and maturity stage. P accumulation in rice plants of direct-seeded rice was lower than that of transplanted rice at all growth stages, but the accumulation of transplanted rice decreased significantly since 30 d after heading stage, however, the accumulation of direct-seeded rice was almost invariant. Therefore, the difference diminished gra dually between direct-seeded rice and transplanted rice, indicating that granular fertilizer could ensure nutrient supply of direct-seeded rice at late growth stages, and lay a foundation for rice maturity. Amylose content and pasting temperature of rice had significant negative correlation with P content in rice panicles 15 d after heading, however, gel consistency of rice had significant positive correlation with it. The results show that it could improve cooking and eating qualities of rice if ensuring sufficient P content in panicles after heading.