【作者】 李文学；

【导师】 张福锁； 李隆；

【作者基本信息】 中国农业大学 ， 植物营养， 2001， 博士

【摘要】 间作套种是我国传统精耕细作农业的重要组成部分,有着悠久的历史。间作具有充分利用资源和大幅度增加产量的特点,在当前对解决人口持续增长与耕地不断减少之间的矛盾具有重要地现实意义。本研究于2000 年在甘肃省武威市白云村进行,以小麦/玉米/蚕豆间作体系为研究对象,通过双裂区(主区5 个氮水平,副区2 个磷水平与6 种种植方式)田间试验,对间作作物种间促进和竞争,特别是关于氮、磷养分吸收的促进和竞争进行了较为详尽地研究,并探讨了间作条件下施肥对硝态氮在土壤剖面累积及分布的影响。获得的主要结果如下: (1)施磷肥和间作均显著提高小麦籽粒产量和生物学产量;施肥(包括氮肥和磷肥)显著提高玉米籽粒产量,而生物学产量主要取决于氮肥;蚕豆对于肥料反应不敏感;在相同的施肥水平下,与蚕豆间作的玉米籽粒产量和生物学产量要显著地高于与小麦间作的玉米,根据“线形+平台”模型,与小麦间作的玉米达到最高产量所需的施氮量要高于与蚕豆间作的玉米,然而与小麦间作的玉米能够达到的最高产量却低于与蚕豆间作的玉米; (2)间作小麦增产的主要原因在于小麦具有明显地边行产量优势,在低氮情况下尤为如此,但是随着施氮量的提高,边行优势有降低的趋势; (3)小麦籽粒和秸杆中的氮浓度与施氮量呈明显地正相关,间作小麦籽粒和秸杆中的氮浓度较单作有明显地增加,施氮肥促进小麦对氮的吸收;施氮量显著影响玉米籽粒和秸杆的氮浓度,而与磷肥和间作形式无太大的关系,但是玉米的吸氮量则与间作形式和施氮量密切相关;蚕豆籽粒、秸杆的氮浓度、吸氮量与施肥及种植形式无明显地相关性。(4)虽然施肥与种植形式对小麦秸杆、籽粒磷浓度无明显影响,但间作小麦的吸磷量却显著高于单作小麦;玉米籽粒磷浓度同样不受间作形式影响,但吸磷量与施氮量及间作形式密切相关;各处理蚕豆籽粒、秸杆磷浓度及吸磷量无明显差异。(5)与蚕豆间作的玉米无论是吸氮还是吸磷量均要显著高于与小麦间作的玉米; (6)在低氮情况下,间作小麦吸氮量的增加主要是边行贡献的结果,而在高氮情况下,边行优势不明显,吸氮量的增加主要是边行和内行共同作用的结果;而对于吸磷量来说,无论施磷肥与否,间作小麦边行吸磷优势明显; (7)无论种植方式如何,土壤剖面硝态氮的累积量随施氮量的增加而增加;麦收后,小麦带土壤中累积的硝态氮最多,其次为种植蚕豆带,种植玉米带土壤剖面累积的硝态氮量最少,同时间作明显地减少土壤剖面硝态氮的累积量;玉米收获后,种植蚕豆带土壤剖面硝态氮累积量比麦收时有明显地增加,土壤中累积硝态氮的顺序由多到少依次为单作小麦、单作蚕豆、间作小麦、间作蚕豆、与蚕豆间作的玉米、与小麦间作的玉米;有机肥与化肥的合理配施有助于降低土壤硝态氮的累积。(8)不施氮肥情况下,上层(0~60cm)土壤剖面累积的硝态氮相对较多;在N200处理中,上层土壤剖面硝态氮相对累积量比不施氮肥处理有降低的趋势;而在高氮情况下,更多还原

【Abstract】 Intercropping is a practice quite possibly as old as settled agriculture, it is becoming more important to raise crop productivity in order to meet the increasing food requirement of an increasing population all over the world. Intercropping, through more effective use of water, nutrients and solar energy, can significantly enhance crop productivity compared to sole crops. This field experiment, with split-split-plot design including N fertilizer, P fertilizer and intercropping and monocropping treatments, integrated the wheat/maize and maize/faba bean intercropping system to assess the effects of intercropping on interspecific facilitative and competitive interactions between intercropped species under various application rates of N and P fertilizers. The emphases were laid on the nutrient uptake by crops and nitrate accumulation and distribution in soil profile. The field experiment was conducted in Gansu province, northwest part of China. The results were as follows: （1） The grain yield of wheat was significantly enhanced by P fertilizer and intercropping, while the one of intercropped maize was improved by both N and P fertilizers. The grain yield of faba bean was not affected by fertilization or cropping pattern. At the same fertilization rate, the grain yield of maize intercropped with faba bean was much higher than that of intercropped with wheat. （2） The yields in the border rows of intercropped wheat were higher than in the inner rows, which was the main reason for total grain yield increase. The border row yield advantage was obvious under low N application conditions and reduced with the increase of N fertilizer. （3） Both the application of N and the intercropping could enhance the N concentration in grain and straw of wheat, the amount of N uptake by wheat was also increased by N fertilizer. The N concentration in maize was relative to N fertilizer application. Both intercropping and N fertilizer could enhance the amount of N uptake by maize. （4） Phosphorus uptake by intercropped wheat was higher than that by sole wheat, both N fertilizer and intercropping also enhanced the amount of P uptake by maize. The P concentration in grain and straw of wheat and maize was not affected by fertilization and intercropping. （5） Nitrogen and P uptake by maize intercropped with faba bean was higher than that of intercropped with wheat. （6） Under low N application, the increase of total N uptake was attributed to the border row advantages, but the increase under high N conditions was due to of both border and inner rows. As for P, the border row advantages always existed regardless of P fertilization. （7） Nitrate accumulation in soil was positively related with application rates of N fertilizer. The amounts of NO₃^-presented in soil after wheat or faba bean harvest was the greatest under sole wheat, followed by intercropped wheat, sole faba bean, intercropped faba bean, maize intercropped with faba bean, and least under maize intercropped with wheat. But the sequence of that after maize harvest was sole wheat and faba bean, intercropped wheat and faba bean, maize intercropped with faba bean and wheat. The results suggest that intercropping could decrease the accumulation of nitrate in soil profile. From long-term fertilization experiment, it could be concluded that the reasonable combination of organic matter and N fertilizer might also lower the nitrate accumulation in soil. （8） The possibility of nitrate leached to deeper soil profile was enhanced with the increase of N fertilizer.更多还原