作 者 ：陈晓辉 徐开未 唐义琴 刘静 陈新平 张朝春 陈远学
期 刊 ：植物营养与肥料学报 2014年 20卷 5期 页码：1127-1138
关键词：小麦/玉米/大豆套作体系；氮积累；氮分配；氮转运；
Keywords:wheat/maize/soybean relay intercropping system, nitrogen accumulation, nitrogen allocation, nitrogen translocation,
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、 240 kg/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，MN2MN5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处理间差异不显著。3）大豆收获期茎秆、 荚皮、 籽粒的氮积累量都有随施氮量增加而逐渐增大的趋势，以SN4和SN5两个处理显著高于另外三个处理，而在SN1~SN3、SN4与SN5间无显著性差异；籽粒、 茎秆、 荚皮的氮积累比例在5个处理间无显著变化，平均分别为82.2%、5.2%、12.6%；大豆花后从营养器官向籽粒转移的氮量从SN1SN5处理有先显著降低后又逐渐升高的变化趋势，而氮素转移率和转移氮素的贡献率在各处理之间无显著差异，平均分别为80.8%和26.6%；大豆籽粒产量以SN4和SN5两个处理显著高于另外三个处理，而在SN1~SN3、 SN4与SN5间无显著性差异。【结论】低氮处理显著影响套作小麦、玉米、大豆3种作物的产量及氮素的积累，高氮投入会促使氮素滞留在营养器官中，阻碍其花后向籽粒中转移；体系全年施氮量在255~382.5 kg/hm2为宜，其中小麦120～180 kg/hm2，玉米195～292.5 kg/hm2，大豆不施或依苗情适当追施氮肥。
Abstract:【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 nitrogen accumulation proportion in leaves, stems and sheaths are in treatment MN1. Significantly high proportion of N accumulates in maize grain are showed in the nitrogen treatments than in control, but there are no significant differences among the nitrogen treatments. The N application improves the yield of maize, and there is no significant difference between MN4 and MN5. 3) With the increase of nitrogen application, more N accumulates in the grains, stems and hulls of soybean in the harvest stage, and those of SN4 and SN5 are significantly higher than those of the other three treatments, and there are no significant differences among SN1-SN3 and between SN4 and SN5. The nitrogen accumulation rates in seeds, stems and hulls of soybean are not significantly different among all the treatments, with the averages of 82.2%, 5.2% and 12.6% respectively. The nitrogen transfer rates from vegetative organs to grains after the flowering is significantly reduced first and then increased in SN1-SN5, and the contribution rates and the transfer rates are not significantly different in all treatments, with the averages of 80.8% and 26.6% respectively. The soybean yields of SN4 and SN5 are significantly higher than those of the other three treatments, and there are no significant differences among SN1-SN3 and between SN4 and SN5.【Conclusions】Low nitrogen supply influences yields and nitrogen accumulations of wheat, maize and soybean in relay intercropping system, high nitrogen input hinder the shift of accumulated N from vegetative organs to grains. The suitable N rates for the annual wheat/maize/soybean relay intercropping system is 255-382.5 kg/ha, 120-180 kg/ha for wheat, 195-292.5 kg/ha for maize and no fertilizer for soybean.