A Dynamic Research of Zinc in the Rhizosphere and Non-Rhizosphere Purple Soil in a Wheat-Rice Cropping System

Key words: 
• wheat-rice cropping system，root zone，zinc form，conversion /
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Abstract: A compartment test was adopted to study the dynamic variation in the contents of different zinc forms in the rhizosphere and non‐rhizosphere purple soil in a wheat‐rice cropping system ,so as to provide evidence for rational application of zinc fertilizer and crop zinc nutrition regulation in wheat‐rice rotation . The results showed that in the late growing period of wheat and rice in the rotation system ,the exchangea‐ble zinc content in the rhizosphere significantly increased ,by 0.83 mg/kg and 0.59 mg/kg ,respectively , compared with the control (no‐cropping) .Flooding promoted the diffusion of water‐soluble zinc to the root zone ,and the exchangeable zinc and available zinc of the non‐rhizosphere soil were significantly reduced . The transition from the wheat‐growing season to the rice‐growing season promoted the conversion of min‐eral Zn to available zinc and ,thus ,the contents of soil exchangeable Zn ,organic loose bounding Zn and carbonate Zn were higher than those of the control ,which effect was more obvious within the rhizosphere . The zinc absorbed by wheat came mainly from the root zone ,while that taken up by the rice plants might come from a wider range of soil available zinc .