Taking sulfur-coated slow-released fertilizer(SCU,26-12-12) and urea(46.3% N) as test fertilizers,a field experiment was conducted in 2019-2020,to study the effect of fertilization patterns of slow-released fertilizer on canopy structure and photosynthetic performance of winter wheat after rice. Six patterns were designed in the experiment:urea applied at four stages(M1); 100% SCU applied before sowing(M2); 60% SCU applied before sowing,and 40% urea applied at jointing stage(M3); 60% SCU applied before sowing,and 40% SCU applied at re-greening stage(M5); SCU and urea applied twice with 15% nitrogen reduction(M5,15% total nitrogen reduction based on M3); and SCU applied twice with 15% nitrogen reduction(M6,15% total nitrogen reduction based on M4). The results showed that,in terms of canopy structure,M4 and M6 had higher LAI at anthesis and lower decline at milking stage,which delayed the senescence of leaves and improved the interception rate of photosynthetic active radiation(PAR) of wheat canopy,especially in the middle and bottom part.Under M1,M2,M3 and M5,LAI decreased significantly at milking stage and was significantly lower than that under M4 and M6,which was not conducive to the effective utilization of light energy.In terms of photosynthetic performance,the SPAD value and net photosynthetic rate of flag leaves under M3,M4 and M6 were higher at anthesis,but the decline under M3 was greater at milking stage. M4 and M6 maintained higher SPAD values,photosynthetic electron transfer rate and net photosynthetic rate at milking stage,which were significantly higher than those under M1,M2 and M5.Compared with M1,the yield of M4 and M6 increased by 21.31% and 10.76%,respectively,and the nitrogen utilization efficiency increased by 4.36% and 7.07%,respectively.Under the conditions of this experiment,M3 was a high-yield and high efficiency fertilization pattern,which was beneficial to maintain the reasonable canopy structure and improve the photosynthetic performance of wheat after anthesis;M5 maintained high photosynthetic performance and yield,which was conducive to improve NUE. |