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过量施用氮肥造成的环境问题日益严重,氮肥合理使用已成为人们研究的热点.本文研究了西南玉米两种主要套作模式下氮肥运筹对玉米氮素利用和土壤硝态氮残留的影响.结果表明:连续分带轮作种植玉/豆模式后,玉米收获期植株中的氮素积累较玉/薯模式平均提高了6.1%,氮收获指数增加了5.4%,最终使氮肥利用效率提高4.3%,氮素同化量提高了15.1%,氮肥偏生产力提高了22.6%;玉米收获后硝态氮淋溶损失减少,60~120 cm土层中硝态氮残留玉/豆模式较玉/薯模式降低了10.3%,而0~60 cm土层中平均提高了12.9%,有利于培肥地力,两年产量平均较玉/薯模式高1249 kg·hm-2,增产22%;增加施氮量提高了植株氮素积累,降低了氮肥利用率,显著提高了表层土壤中硝态氮的累积,60~100 cm土层中硝态氮的累积量在0~270 kg·hm-2处理间差异不显著,继续增加施氮量会显著增加土壤硝态氮的淋溶;氮肥后移显著提高了土壤0~60 cm土层硝态氮的积累.两种模式下施氮量和底追比对玉米氮素吸收和硝态氮残留的影响结果不一致,玉/豆模式以施氮180~270 kg·hm-2、按底肥∶拔节肥∶穗肥=3∶2∶5的施肥方式有利于提高玉米植株后期氮素积累、氮收获指数和氮肥利用效率,减少了氮肥损失,两年最高产量平均可达7757 kg·hm-2;而玉/薯模式在180 kg·hm-2、按底肥∶穗肥=5∶5的施肥方式下,氮素积累利用及产量均优于其他处理,两年平均产量为6572 kg·hm-2,可实现两种模式下玉米高产、高效、安全的氮肥管理体系.
The environmental problems caused by excessive application of nitrogen fertilizer have become more and more serious, and the rational use of nitrogen fertilizers has become a hot research area.This paper studied the effects of nitrogenous fertilizer application on nitrogen utilization and soil nitrate residual in two main intercropping modes of southwest corn.The results showed : Compared with jade / potato model, the nitrogen accumulation in maize harvesting stage increased by 6.1% on average and the nitrogen harvest index increased by 5.4% after continuous split-belt rotation for planting jade / bean mode, which eventually increased nitrogen use efficiency by 4.3% and nitrogen The assimilation amount increased by 15.1% and the partial productivity of nitrogen fertilizers increased by 22.6%. The leaching losses of nitrate nitrogen decreased after maize harvesting, and decreased by 10.3% compared with jade / potato model in 60-120 cm soil layer %, While it increased by 12.9% in 0 ~ 60 cm soil layer, which was beneficial to fertility improvement. The average yield of two years was 1249 kg · hm-2 higher than that of jade / potato model, increasing by 22% Nitrogen accumulation decreased nitrogen use efficiency and significantly increased the accumulation of nitrate nitrogen in topsoil. The accumulation of nitrate nitrogen in 60-100 cm soil layer was not significantly different between 0 and 270 kg · hm-2 treatment, Continued to increase the amount of nitrogen application will significantly increase the leaching of nitrate nitrogen in soil; Which increased nitrate accumulation in 0 ~ 60 cm soil layer.The results showed that the effects of nitrogen application rate and bottom chase ratio on nitrogen absorption and nitrate nitrogen residual in maize were inconsistent with the two modes, 270 kg · hm-2. The application of 3: 2: 5 fertilizer at base fertilizer: jointing fertilizer: panicle fertilizer = 3: 2: 5 could improve nitrogen accumulation, nitrogen harvest index and nitrogen use efficiency of maize plants at the later stage, The average yield of nitrogen and nitrogen fertilizer was 7757 kg · hm-2, while that of nitrogen and nitrogen was 180 kg · hm-2 in the mode of fertilization with 5% The average yield of two years is 6,572 kg · hm-2, which can realize the high yield, high efficiency and safe nitrogen management system of maize in two modes.