化肥深施对干旱条件下春小麦旗叶光合特征及产量形成的影响

Effect of deep fertilizer application on flag leaf’s photosynthetic characteristics and yield formation of spring wheat under drought conditions

【目的】探明施肥深度对春小麦旗叶光合特性及产量形成的影响,以期为旱地春小麦深施肥提供理论参考。【方法】采用盆栽试验方法,选用陇春35号,设置湿润化肥浅施15 cm(W15),湿润化肥深施30 cm(W30)、干旱化肥浅施15 cm(D15)、干旱化肥深施30 cm(D30)4个处理,测定春小麦旗叶SPAD值、叶面积、光合参数、干物质积累、灌浆速率及产量。【结果】化肥深施(W_(30)、D_(30))可显著提高春小麦旗叶叶面积、干物质积累、灌浆速率和旱地春小麦旗叶SPAD值;促进干物质同化积累向籽粒转运。深施肥(W_(30)、D_(30))在挑旗期的旗叶SPAD值较浅施肥处理(W15、D15)分别增加3.1%、5.8%;旗叶叶面积分别增加19.5%、23.7%;花后20~40 d春小麦平均灌浆速率分别增加7.0%、6.7%;成熟期单株干物质积累量分别增加12.9%、11.1%。30 cm施肥Pn、Gs、Tr显著高于15 cm施肥,而Ci则相反;在干旱条件下效果更明显;深施肥(W_(30)、D_(30))较浅施肥(W15、D15)千粒质量和穗粒数分别增加14.0%、7.7%和3.8%、9.3%;产量提高13.0%和16.0%。【结论】深施肥能弥补水分亏缺,促进春小麦光合和籽粒灌浆,且保持较高的经济产量和生物产量,可在西北黄土高原旱作春小麦生产中推广应用。

【Objective】The objective of this study was to explore the impact of fertilizer application depth on the photosynthetic characteristics and yield formation of flag leaves in spring wheat,aiming to offer a theoretical basis for the deep fertilization of dryland spring wheat.【Method】A pot experiment was conducted using Longchun 35 spring wheat,implementing four treatments:wet chemical fertilizer applied shallowly at 15 cm(W15),wet chemical fertilizer applied deeply at 30 cm(W30),dry chemical fertilizer applied shallowly at 15 cm(D15),and dry chemical fertilizer applied deeply at 30 cm(D30).The SPAD value,leaf area,photosynthetic parameters,dry matter accumulation,filling rate,and yield of spring wheat flag leaves were assessed.【Result】Deep fertilizer application(W30,D30)notably enhanced the leaf area,dry matter accumulation,filling rate,and SPAD value of flag leaves in dryland spring wheat.It facilitated the transfer of assimilated dry matter to seeds.At the flag picking stage,the SPAD values of flag leaves increased by 3.1%and 5.8%in the deep fertilizer treatments(W30 and D30)compared to the shallow fertilizer treatments(W_(15)and D_(15)).The leaf area of flag leaves increased by 19.5%and 23.7%,respectively.Moreover,the average filling rate from 20 days to 40 days after flowering increased by 7.0%and 6.7%,respectively,and the dry matter accumulation per plant at maturity increased by 12.9%and 11.1%,respectively.Photosynthetic parameters Pn,Gs,and Tr were significantly higher with 30 cm fertilizer depth compared to 15 cm depth,while Ci showed the opposite trend,particularly pronounced under drought conditions.Thousand grain weight and grain number increased by 14.0%,7.7%,and 3.8%,9.3%,respectively,with deeper fertilization(W30,D30)compared to shallower fertilization(W15,D15),resulting in a yield increase of 13.0%and 16.0%.【Conclusion】Deep fertilization can mitigate water deficits,enhance photosynthesis and grain filling in spring wheat,and sustain high economic and biological yields.This approach may be recommended for adoption in dry spring wheat cultivation in the northwest Loess Plateau.