Effects Of Optimized Fertilization On N And Soluble Sugar Distribution And Yield Of Soybean

The plot experiment set up three treatments: optimized fertilization (OF), farmers'fertilization practice (FFP) and high yeild fertilization (HYF). The N content and soluble sugar content in soybean leaves, stems and pods were analized in order to study the effects of OF on N, soluble sugar distribution and yield of soybean.Compared with FFP and HYF, OF increased the N content in all organs of soybean at late stages. The effect of N accumulation in the periods of R4 and R6 in different organs was particularly significant. Compared with FFP, the total N accumulation of OF from R4 to R6 increased by 25%(P<0.01). Compared with FFP, the N accumulation in leaves of OF at R4 increased by 31% (P<0.01). Compared with FFP and HYF, the N accumulation in leaves of OF at R6 increased by 33% and 37%(P<0.01).Compared with FFP, the N accumulation in stems of OF at R4 increased by 19% (P<0.05). Compared with HYF, the N accumulation in stems of OF at R6 increased by 29%(P<0.01). Compared with FFP and HYF, the N accumulation in pods of OF at R6 increased by 19%and 24%(P<0.01).Compared with FFP, OF enhanced the soluble sugar content in leaves at R2. The soluble sugar content in soybean leaves decreased as N application rate increase. Compared with FFP and HYF, OF significantly increased the soluble sugar content in soybean pods at R6 and later R6. R6 is a critical period of grain filling. The soluble sugar accumulation in soybean stems get the highest value at R6. Compared with HYF and FFP, the soluble sugar accumulation in soybean stems of OF increased 9% and 16%(P<0.05). The export percentage of the soluble sugar in stems is the highest. The soluble sugar distribution ratio in soybean pods of OF is obviously higher than HYF and FFP.OF increased the N supply at later stage appropriately. Compared with FFP and HYF, OF enhanced the dry matter accumulation of soybean leaves after R4 stage, significantly increased the dry matter accumulation of soybean pods and plant at later stage.The yield of OF, compared with HYF, increased by 26%(P<0.01); compared with FFP, increased by 10%(P<0.05).