春小麦大豆间作条件下作物养分吸收积累动态的研究

采用田间小区试验和微区根系分隔试验，通过间作与相应单作养分吸收动态的比较，阐明了小麦大豆间作中养分吸收的种间竞争作用和促进作用。结果表明，小麦具有更强的养分竞争能力，在两作物共生的８０多天中，间作小麦的吸氮量、吸磷量始终高于单作小麦，是其获得高产的基础。虽然间作大豆在前期养分吸收缓慢，在两作物共生期的氮磷钾吸收量均显著地低于单作大豆，但小麦收获后有明显的恢复。种间根系分隔试验结果表明，小麦大豆根系间不分隔时，小麦的吸氮量和吸磷量有明显的边行优势；用塑料膜分隔时，边行优势消失；但用尼龙网分隔时，小麦吸磷量表现出一定的边行优势，是大豆根际效应所致。

DYNAMIC OF NITROGEN, PHOSPHORUS AND POTASSIUMUPTAKE BY INTERCROPPED SPECIES IN THESPRING WHEAT/SOYBEAN INTERCROPPING

Nitrogen, phosphorus and potassium uptake dynamic in terms of interspecific competition and facilitation were studied by comparing intercropped species with corresponding sole species through a 233 field plot experiment and a microplot experiment. The results showed that there was more competitive ability to nitrogen, phosphorus and potassium by wheat than by soybean during more than 80 days of coexistence for spring wheat and spring soybean in the intercropping. Peak of nitrogen and phosphorus uptake by intercropped soybean was delayed to some time after wheat harvesting due to intercropping, which was one of mechanism of intercropping yield advantage. The result of interspecific root partition experiment demonstrated that the border effect of nutrient uptake by wheat was largely due to interaction between wheat root and soybean root.