再生水—土壤—蔬菜体系中Zn的迁移

2011~2013年通过小区试验种植小白菜和萝卜,以再生水灌溉和污泥施肥,采用修正的BCR法测定了再生水、污泥、土壤、蔬菜中Zn的5种形态含量,分析Zn在再生水(污泥)-土壤-蔬菜体系中的迁移和累积特征。结果表明:2011~2013年水样中Zn含量均未超出国家《农田灌溉水质标准(GB5084—2005)》中Zn的标准。水样中水溶态B0比例较大。污泥中B0含量极少,残渣态B4含量较高。土壤中Zn的本底含量较少,经过3年的蔬菜种植和灌溉,土壤中Zn含量有增高的趋势。蔬菜中5种形态均有分布,地上部分中水溶态B0和可氧化态B3含量较高,地下部分中残渣态B4含量也较高。小白菜中Zn的含量高于萝卜。灌溉水中B0的含量对Zn在土壤和蔬菜中的迁移产生了较大影响。适当的再生水灌溉和污泥施肥可以改善土壤的缺Zn状况。

Migration of Zn in Reclaimed Water-Soil-Vegetable System

Small-scale experiments were carried out on pakchoi and radish which were irrigated with reclaimed water and fertilized with sludge from 2011 to 2013. Five chemical forms of Zn in the reclaimed water, sludge, soil and vegetable were detected by use of modified BCR method. The characteristics of migration and accumulation of Zn in the reclaimed water （sludge） -soil-vegetable system was analyzed. The result showed that the content of Zn in the water samples from 2011 to 2013 did not exceed the limit regulated in the Standard for Irrigation Water Quality （GB5084-2005）. The proportion of water-soluble B0 in the water samples was higher, but extremely low in the sludge. The content of B4 in the residue form was higher. The background content of Zn in soils was less. Through 3 years of vegetable growing and irrigation, the content of Zn in the soils tended to increase. 5 chemical forms of Zn were found in the vegetables. The contents of water-soluble B0 and oxidizable B3 were higher in the above-ground portion of the vegetables, while the content of B4 in the residue form was higher in the underground portion. The content of Zn in pakchoi was higher than that in radish. The content of B0 in the irrigation water greatly affected the migration of Zn in soils and vegetables. Therefore, reclaimed water irrigation and sludge fertilization in an appropriate way could improve the Zn deficiency condition in soils.