Effects Of Optimized Fertilization On K, Ca And Mg Uptake Of Rice In Cold Area

In order to study the effects of optimized fertilization on K, Ca and Mg absorption and distribution in different organs and yield of rice in cold region, so as to provide a theoretical basis for rational fertilization of rice in the future, a field experiment was conducted with two rice varieties(Daohuaxiang-2 and Longdao-16) using a field comparison method with two fertilization treatments. FFP was farmer’s fertilization practice with fertilizer rates of N 113 kg? ha-1, P2O5 42 kg? ha-1, K2 O 73 kg? ha-1. OPT was optimizd fertilization with fertilizer rates of N 110 kg? ha-1, P2O5 54 kg? ha-1, K2 O 70 kg? ha-1. There were three treatments(FFP-D, OPT-D, OPT-L), each treatment replicated 4 times. K, Ca and Mg contents at different stage in various rice organs were measured, and the accumulation of K, Ca and Mg were calculated. The main results are shown as following:Optimized fertilization could promote the absorption of K in rice after heading. K content in leaves and panicles have the same trends with growth stages, each treatment were manifested as decreased. K content in stems was showed first decreased then increased with growth stages. Optimized fertilization improved K content in rice organs and accumulation in leaves and stems after heading stage, simultaneously promoted K accumulation in panicles at late seed filling stage. Optimized fertilization enhanced panicle initiation-heading K accumulation in whole plants, OPTD were higher than FFP-D by 22.6%(P<0.01). K accumulation at maturity stage in each organ of different treatments: in leaves OPT-D were higher than FFP-D by 20.4%(P<0.01), in stems OPTD were higher than FFP-D by 6.5%(P<0.05), in panicles OPT-D were higher than FFP-D by 19.1%(P<0.01). At maturity stage, K content and accumulation in OPT-L stems were higher than OPT-D by 7.4%(P<0.05) and 6.0%(P<0.05).Optimized fertilization could promote the absorption of Ca in rice after heading. Ca content in leaves were increased with growth stages, in panicles decreased gradually, in stems first decreased and then increased. Optimized fertilization improved Ca content in rice organs and accumulation in leaves and stems after heading stage, simultaneously promoted panicle initiationheading Ca accumulation in whole plants, OPT-D were higher than FFP-D by 31.9%(P<0.01). Ca accumulation at maturity stage in each organ of different treatments: in leaves OPT-D were higher than FFP-D by 11.7%(P<0.01), in stems OPT-D were higher than FFP-D by 14.6%(P<0.01), in panicles OPT-D were higher than FFP-D by 17.9%(P<0.01). At maturity stage, Ca content and accumulation in Longdao-16 different organs were higher than in Daohuaxiang-2, distribute ratio of panicles OPT-L were higher than OPT-D by 9.4%(P<0.05).Optimized fertilization could promote the absorption of Mg in rice after heading. Mg content in leaves and stems have same trends of single-peak curve with growth stages, in panicles decreased gradually. Optimized fertilization raised Mg content and accumulation in rice organs at 20 d after heading and maturity stage, meanwhile improved panicle and whole plants Mg accumulation at different growth stages. Mg accumulation at maturity stage in each organ of different treatments: in leaves OPT-D were higher than FFP-D by 8.8%(P<0.05), in stems OPT-D were higher than FFP-D by 23.2%(P<0.01), in panicles OPT-D were higher than FFP-D by 16.3%(P<0.01). Different rice varieties were different in the absorption of Mg at maturity stage. Mg content and accumulation in Daohuaxiang-2’s different organs were higher than Longdao-16, distribute ratio of panicles OPT-D were higher than OPT-L by 7.1%(P<0.05).Optimizd fertilization increased rice yield significantly. OPT-D yield was increased by 11.2%(P<0.01) than FFP-D. At maturity stage, K accumulation in panicles and whole plants were significantly correlated with yield, correlation coefficient were 0.960 and 0.902,respectively.