硫包膜缓释肥施用模式对稻茬冬小麦冠层结构、光合特性和产量的影响

为研究硫包膜缓释肥施用方式对稻茬冬小麦冠层结构和光合性能的影响,于2019-2020年进行田间试验,以硫包膜掺混肥(SCU,N∶P_2O_5∶K_2O=26∶12∶12)和尿素(U,46.3%N)为供试肥料设计6种施肥模式:尿素4次分施(M_1);100%SCU一次基施(M_2);60%SCU基施+40%U拔节期追施(M_3);60%SCU基施+40%SCU返青期追施(M_4);51%SCU基施+34%U拔节期追施(M_5,在M_3基础上减氮15%);51%SCU基施+34%SCU返青期追施(M_6,在M_4基础上减氮15%),研究不同施肥模式下小麦花后叶面积、冠层光截获特征、旗叶叶绿素荧光和光合指标等的差异。结果表明,在冠层结构方面,M_4和M_6模式在开花期的LAI较高,且乳熟期降幅较低,延缓了冠层叶片的衰老,提高冠层尤其是中下部的PAR截获率;M_1、M_2、M_3和M_5模式乳熟期的LAI降幅均较大,显著低于M_4和M_6模式,不利于冠层对光能的有效利用。在小麦光合性能方面,M_3、M_4和M_6模式在开花期旗叶的SPAD值和净光合速率均较高,但在乳熟期M_3模式降幅较大;M_4和M_6模式在乳熟期维持较高的SPAD值、光合电子传递速率和净光合速率,二者的3个指标均显著高于M_1、M_2和M_5模式。M_4和M_6模式相比于M_1模式,分别增产21.31%和10.76%,氮肥利用率分别提升4.36%和7.07%。本试验条件下,硫包膜缓释肥60%基施+40%返青期追施最有利于维持小麦花后合理的冠层结构,提高了光合性能和产量,是高产高效的施肥方式;硫包膜缓释肥51%基施+34%返青期追施模式小麦的光合性能和产量仍可维持较高水平,且提升了氮肥利用率。

Effect of Application Patterns of Sulfur Coated Slow Released Fertilizer on Canopy Structure,Photosynthetic Characteristics and Yield of Winter Wheat after Rice

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.