土壤供锌机制及作物锌营养的研究

STUDY ON THE MECHANISM OF ZINC SUPPLY BY SOIL AND THE ZINC NUTRITION OF DIFFERENT CROPS

Pot experiments and chemical analyses show that the purple soil exchangeable form zinc, organic combined form zinc and oxidized form zinc, belongs to the category of "easily effective zinc" which are the important sources of available zinc, whereas the carbonate combined form and residual form zinc are slightly soluble zinc, but these five forms may be transformed each other. Calcareous purple soil is highly deficient in zinc(its available concentration zinc being 0.4-0.6ppm); Neutrial purple soil is slightly deficient in zinc(0.5-0.8ppm), whereas acidic purple soil is rich in zinc(1.0-3.2ppm). Among the six tested crops, rice is the most susceptible one to zinc-deficiency and the highest yield response to zinc fetilization. Wheat and barley have a least or ineffective response in yield increase to zinc fertilization, corn, rape and broad bean are a medium type between them. Reasonable application of zinc fertilizer should be based on the degree of zinc-deficiency of soil and the susceptibility to zinc-deficiency of different calcareous purple soil and zinc-susceptible crops such as rice perferably. In case of a rice-wheat (rape) rotation system wheat or rape can exploit the residual effect of zinc fertilizer supplied to rice, it is not necessary to apply zinc fertilizers again.