遮阴与氮肥对冬小麦群体发育动态及产量的影响

Effects of Shading and Nitrogen Fertilizer on the Population Growth Dynamics and Yield of Winter Wheat

【目的】不同程度的遮阴条件下,研究氮肥及其互作对冬小麦群体发育动态及产量的影响,为南疆果树-小麦间作模式下小麦高产栽培技术及氮高效管理提供理论依据。【方法】采用人工模拟遮阴方法,设不遮阴(S0)、拔节期遮阴10%-抽穗期遮阴25%(S1)、拔节期遮阴20%-抽穗期遮阴50%(S2)和拔节期遮阴30%-抽穗期遮阴75%(S3)四个遮阴水平,设整个生育期不施肥(F0)、拔节期(遮阴后)追施纯氮103.5 kg/hm^2(F1)、138 kg/hm^2(F2)和172.5 kg/hm^2(F3)四个施肥水平,研究不同遮阴、氮肥及其互作对小麦群体发育动态和产量的调控效应。【结果】遮阴强度与氮肥用量的增加均推迟了小麦的生育进程。遮阴对成穗数、分蘖成穗率有显著影响(P<0.05),对最高茎数、分蘖穗比重和主茎穗比重影响不显著。同一遮阴条件下,施肥比不施肥显著提高了成穗数、最高茎数、分蘖成穗率和分蘖穗比重(P<0.05);随着施氮量的增加穗粒数先增加后降低、收获穗数增加、千粒重下降。同一施肥条件下,随着遮阴强度的增加收获穗数、穗粒数和千粒重均显著下降,进而导致产量显著降低(P<0.05)。在不遮阴(S0)条件下,产量以F2处理较高;在遮阴(S1、S2、S3)条件下,施肥处理间差异不明显。【结论】遮阴和氮肥处理对产量的影响存在显著的互作效应;氮肥对产量表现为正效应,遮阴对产量表现为负效应,并且遮阴效应大于氮肥效应,是影响产量的主导因子。遮阴与氮肥互作对穗粒数、千粒重和产量有显著影响。在不施肥条件下,适度遮阴对小麦产量形成有利,随着遮阴强度的增加,氮肥的调控效应减弱。

[Objective] This study aims to explore the effects of nitrogen fertilizer and their interaction on population dynamics and yield of winter wheat under different shading conditions in order to provide a theoretical basis for the high yield cultivation techniques and efficient management of nitrogen in the fruit wheat intercropping mode.[Method]Using artificial shading method to set up four shading levels： no shading （S0）, jointing stage 10% shading, heading stage 25% shading （S1）, jointing stage 20% shading, heading stage 50% shading （S2） and jointing stage 30% shading, heading stage 75% shading （S3）.During the whole growth period, four levels of fertilization were set up： no fertilizer （F0）, jointing stage （after shading） nitrogen 103.5 kg/ hm2 （F1）, 138 kg/hm2 （F2） and 172.5 kg/hm2 （F3） to study the regulation effect of shading, nitrogen fertilizer and their interaction on the wheat population growth dynamics and yield.[Result]The results showed that the increase of shade intensity and nitrogen fertilizer had delayed the growth process of wheat and shading had a significant influence on the spike number and spike rate of tiller （P〈0.05）, and no significant effect on the highest number of stems, tillers and panicle weight proportion was found;Under the same shading condition, fertilizing significantly increased the panicle number, maximum stem number, tillering rate and tiller percentage （P〈0.05）.With the increase of nitrogen application, the number of grains per spike increased first and then decreased and the number of harvested panicles increased.Under the same fertilization conditions, with the increase of shade intensity the spike number, grain number and grain weight were significantly decreased, which led to the significant decrease of yield.Under no shading conditions, the yield was higher in F2 treatment.Under the （S1, S2, S3） shading conditions, there were no obvious differences in fertilization treatments.[Conclusion]Analyzing the each factor effect, we knew that different shading and nitrogen treatments produced a significant interaction effect on yield.Nitrogen fertilizer on yield showed positive effects, shading on yield showed a negative effect and the shading effect was greater than the effect of nitrogen fertilizer, which was the main factor affecting yield.Shading and nitrogen interaction had a significant effect on grain number per spike, 1,000 grain weight and yield.Under the condition of not applying fertilizer, moderate shading was favorable for wheat yield and with the increase of shading intensity, the regulation effect decreased.