CHARACTERISTICS OF NUTRIENT ELEMENTS CYCLING IN FERN COMMUNITY
芒萁群落中营养元素的循环特点

The characteristics of nutrient elements cycling in D.dichotoma community have been studied. -The cycle process of nutrient elements in this community was analysed and some dynamic models of elements N,P,K,Ca, Mg,Al and Mn were established. The results are as follow: (1) The storages Of N,P,K, and Al were the highest in live rhizomes. This shows that the rhizomes are reproduction organ and concentration organ. The storages of Ca,Mg, and Mn were the highest in pinnules because these elements are structure matters of chlorophyll. (2 ) The concentration of N, P and K decreased with time because of "dilution effecf.Al concentration increased with time because of "concentration effect". The concentrations of Ca,Mg and Mn decreased after Septemper. The concentrations of seven elements were in the following order: N>K>Al>Ca>Mg>P>Mn. (3) The community enriched Al but did not enrich Mn. (4) The total amount of the seven elements were located largely in soil and very little in community. This shows that the community has little ability to conserve and utilize the elements. (5) Cycling dynamic models of the seven elements have been established.