Effects of annual combination of organic fertilizer and nitrogen fertilizer on growth and yield of re-sowing soybean in wheat-bean rotation

The aim of this study was to examine the effects of different annual fertilization combinations on the growth and yield of soybean,and screen out better annual fertilization combination for high-yield of soybean after winter wheat harvest in Ili Valley,Xinjiang.Following a split-plot design,four fertilization treatments,including no fertilizer(CK),nitrogen fertilizer(A),organic fertilizer(B),and organic fertilizer+nitrogen fertilizer(C)during wheat growing season were assigned to the main plots and a nitrogen application rate of 150 kg·hm-2 and no fertilization during the soybean growing season to the subplots on the basis of the three treatments(A,B and C)in the main plots.The results showed that SAPD value,leaf area index(LAI),transpiration rate(E),stomatal conductance(Gs),and net photosynthetic rate(Pn)of soybean under different annual fertilization combinations all had the best performance under treatment C1 with organic fertilizer and nitrogen fertilizer applied during wheat growing season and no topdressing nitrogen fertilizer during the soybean growing season.The intercellular CO2 concentration(Ci)under treatment C1 was the lowest in C1 treatment.The LAI under C1 treatment significantly differed with other treatments at 40-60 days after the seeding.The photosynthesis characters of treatment C1 were significantly different with other treatments in the flowering and pod stages(P<0.05).Under treatment C1,the total duration of dry matter accumulation was the shortest,the maximum growth rate appeared earlier,the average rate of dry matter accumulation was the largest,and the characteristic value of rapid dry matter accumulation was the highest.The yield of treatment C1 was 18.71%and 11.25%higher than that of single application of nitrogen fertilizer and single application of organic fertilizer in the wheat growing season,respectively.Our results suggest that,in the wheat-soybean rotation system,it is beneficial to soybean yield enhancement and nitrogen fertilizer reduction under the annual fertilization combin