中文摘要：

【目的】四川盆地特殊的高温寡照气候,使得作物间套作十分广泛。"麦/玉/豆"体系有利于资源循环高效利用和农业可持续发展。本项目研究了"麦/玉/豆"周年套作体系中各作物的氮素积累分配和花后氮素转运特征,旨在明确体系各作物的氮素营养吸收特性,为该体系的氮肥合理施用及高产高效提供理论依据。【方法】通过2011、2012连续两年田间定位试验,研究了"小麦/玉米/大豆"套作体系在不同氮用量下(小麦设N 0、60、120、180、240kg/hm2,分别表示为WN1、WN2、WN3、WN4、WN5;玉米设N 0、97.5、195、292.5、390 kg/hm2,分别表示为MN1、MN2、MN3、MN4、MN5;大豆不施肥,依前作的施氮处理依次记为SN1、SN2、SN3、SN4、SN5)各作物的氮素积累分配、花后氮素的转运。【结果】1)小麦各部位氮积累量都随氮用量增加而增大,籽粒、茎鞘、叶片和颖壳穗轴分别占地上部总氮积累量(平均为218.6 kg/hm2)的71.5%、12.2%、9.2%和7.1%;小麦花后从营养器官向籽粒转移的氮量及其贡献率随施氮量增加而增大,但转移率在不同氮处理下差异不显著,平均为61.5%;随氮用量增加,籽粒的氮分配比例逐渐减少,而非籽粒部分的氮分配比例则随之增大;小麦籽粒产量随施氮量增加而增大,但WN3~WN5处理间差异不显著。2)玉米各部位氮积累量随氮用量增加而增大,籽粒、叶片、茎鞘和苞叶芯分别占地上部总氮积累量(平均为108.1 kg/hm2)的67.2%、3.9%、11.8%和7.0%;玉米花后从营养器官向籽粒的氮素转移量、转移率和贡献率均随施氮量的增加呈先增加后降低的变化趋势,都以MN3处理最大;玉米各部位的氮积累比例在叶片、茎鞘中以MN1处理最大,MN2~MN5处理明显降低,在苞叶芯中不同氮处理间无明显变化,在籽粒中表现为施氮处理显著高于不施氮处理,而施氮处理间差异不显著;玉米籽粒产量随施氮量增加而增大,但MN4、MN5处理间差异不显

英文摘要：

Objectives]The Sichuan Basin is hot but short of sunlight resources, the intercropping systems are popular in this area.Wheat/maize/soybean system is a typical efficient relay intercropping for the recycling use of the natural resources and sustainable development of agriculture.In this paper, the characteristics of nitrogen accumulation, distribution and translocation after anthesis stage of crops in the relay intercropping system were studied, so providing a base for the reasonable fertilization and high yield and high profitable production.[Methods]A field experiment was carried out in 2011 and 2012, and different nitrogen application rates in wheat (0, 60, 120, 180 and 240 kg/ha, marked as WN1 ,WN2 ,WN3 ,WN4 and WN5 ) , maize (0, 97.5, 195, 292.5 and 390 kg/ha, marked as MN1 ,MN2 ,MN3 ,MN4 and MN5 ) and soybean ( non-fertilized, marked as SN1 , SN2 , SN3 , SN4 and SN5 according to the previouse crop N rates ) were designed.[Results]1 ) The nitrogen accumulation in different parts of wheat are all increased with the increase of nitrogen fertilizer application.Of the averaged 218.6 kg/ha of total N accumulation, 71.5%in grains, 12.2% in stems and sheaths, 9.2%in leaves and 7.1%in spike axes and kernel husks.Since anthesis, more nitrogen transfers from vegetative organs to grains with an average transform of 61.5%, but there is no significant difference among the N rate treatments.With the increase of nitrogen use, the proportions of N in wheat grains are reduced gradually, increased in other parts.The N application improves the yield of wheat, but there is no significant difference among WN3-WN5.2) The amounts of nitrogen accumulation in different parts of maize are all increased with the increase of nitrogen fertilizer application.Of the average total N accumulation of 108.1 kg/ha, 67.2%is in grains, 3.9%in leaves, 11.8%in stems and sheaths, and 7.0%in husks and cobs.The largest nitrogen translocation from vegetative organs to grains and the most rapidly transfering rate are in treatment MN3 , the highest