[Regulation of fertilizer application on yield and root growth of spring wheat-faba bean intercropping system]

The effects of N and P fertilizer application on the multiple population yield and root growth of spring wheat (Triticum aestivum)--spring faba bean(Vicia sativa)intercropping system were studied by two field experiments with 0, 150 and 225 kgN.hm-2, three pot and pool experiments with 2 N applications (0, 100 mg N.kg-1 soil) and 3 P applications (0, 100 and 200 mg P.kg-1 soil). The results showed that this intercropping system had a significant advantage of yield and beneficial effects. Compared to Po supply, P fertilization increased the seed yield by 48.39% for intercropped spring wheat and 16.69% for intercropped faba bean in field experiment. Furthermore, the total seed yield of both crops was increased by 20.07% to 43.14% in pool culture, and the grain yield of intercropped faba bean was increased by 58.46% to 78.78%. In the intercropping system, the growth peak of root density of both crops was appeared alternately, the peak of wheat root growth being earlier than that of faba bean. The maximum root weight of intercropped wheat was in its early heading periods, whereas that of faba bean appeared at its maturity periods, which reduced the competition for water and nutrients between the crops, and resulted in yield increase. The weight, length and surface area of wheat roots in P supply were increased by 54.33%, 48.88% and 47.00%, and in N supply, they were increased by 15.25%, 11.61% and 11.46%, respectively. About 57.61% of wheat root weight and 69.20% of faba bean root weight were distributed at 0-30 cm soil depths in the treatments of receiving P fertilizer at various rates, which indicated that P supply increased root weight and length of both crops in the intercropping system.