[Profile distribution of zinc forms under calcareous purple soil under different land use]

The distribution of DTPA-Zn was influenced by other zinc forms in soil profile. In order to approach the mechanism of zinc deficiency in calcareous purple soil widely distributed in hilly regions of central Sichuan Province, four profiles(paddy field, dry land, K1c forest land and J3p forest land) under different land use were selected to study the distribution of other zinc forms. The results indicated that the distribution complication of zinc forms was in order of paddy field > dry land > forest land. The quantities of CAB-Zn(3.65%), TOM-Zn(2.81%) and COFe-Zn(22.04%) in farmland were evidently more than those (1.86%, 0.84%, 11.59%) in paddy field.