关键词: 玉米, 大豆, 套作, 磷, 竞争, 互惠

Abstract: [Objective] The aim of this study was to clarify the mechanism of P uptake under a maize/soybean intercropping system. The results may provide some theoretical basis for optimal P management in intercropping system. [Method] A pot experiment, which included three cropping patterns such as maize/soybean relay intercropping (M/S), maize monoculture (MM)and soy-bean monoculture (SS)under three fertilizer treatments (no fertilizer CK;nitrogen and potassi-um, NK; nitrogen, phosphorus and potassium, NPK)was carried out to compare crop aboveground biomass, grain yield, crop P uptake, and soil available P content. [Results] The yield of intercropped maize and soybean were significantly higher than that of mono maize and soy-bean, respectively, in the same fertilization treatment. Under the same cropping pattern, P appli-cation significantly increased maize aboveground biomass but no significant effect was observed in soybean. In the same fertilization treatment, P uptake by maize per plant was significantly higher in intercropping than in monoculture. In the same cropping pattern, P uptake of maize were in the order of NPK > NK > CK. In the same fertilization treatment, P uptake by soybean per plant was significantly higher under intercropping than under monoculture. In the same cropping pat-tern, P uptake of soybean was the lowest in NK treatment. In the same cropping pattern, P appli-cation significantly improved the rhizosphere available phosphorus of maize and soybean. The bulk soil available phosphorus was the highest in the treatment of maize monoculture and P fertili-zation. The rhizosphere available P was the greatest in the intercropped soybean with P applica-tion. However, the bulk soil available P was the highest in the mono soybean with P fertilization. [Conclusion] In the same land area, intercropped maize and soybean can significantly improve the grain yield and P uptake of maize and soybean per plant compared with mono maize and soybean.

Key words: maize, soybean, relay intercropping, phosphorus, competition, facilitation