【摘要】 选择已广泛使用稀土微肥的大兴县庞各庄小麦种植区内,进行稀土喷施常规量、土施常规量及3倍常规量和对照4种处理的田间实验。以各地块的耕层土壤为主体,观测、收集和测定了与之相关各项源汇物质及它们所载带稀土的通量。结果表明,未施稀土的地块中,由降雨、降雪、灌水、复合肥、尿素和降尘等主要源物质载带的稀土输入量极少,每年共计仅有19 3g·hm-2左右;而外施稀土的地块中,稀土输入量显著增高。喷施或土施常规量所输入的稀土分别为对照地块总输入量的9.7和106倍。但在对照和施用不同量稀土的4个地块中,由小麦植株的收获和雨水下渗所引起的稀土总输出量都很相近,而且均以收获期的小麦植株为主要输出物质,各部位的稀土输出量排序均为根>叶>茎>颍壳>籽粒。由计算结果得知,在对照地块的耕层土壤中稀土输出量与输入量基本平衡,不会发生稀土累积;而在外施稀土的地块中,随着外施稀土量的增加,耕层土壤中的稀土累积量有相应增高,如果多年连续土施常规量稀土,仅需159年就会使耕层土壤中稀土含量增加1倍,发生环境污染有较大的潜在危险;而采用喷施(常规量)的方法累积速度低得多,需要2008年才能使耕层土壤中稀土含量增加1倍。更多还原

【Abstract】 In order to study the biogeochemical cycle process and accumulation rate of extraneous rare earths elements （REEs） in agricultural surface soil, four groups of field experiments including REEs foliage dressing, soil dressing, triple amounts of soil dressing and control were carried out in Daxing Pangge Village, which is widely using REEs-fertilizer. All kinds of REEs flux related with input and output in soil and plants system were collected and measured by ICP-MS. The results show that contents of REEs be carried off by rain, snow, irrigation water, compound fertilizer and dust are very low in control field, which is only about 19.3 g·hm^-2 per year. The amount of REEs input is much higher in REEs-dressed field than in control. Total amounts of input REEs in foliage-dressing and soil-dressing fields are 9.7 times and 106 times higher than that of control respectively. However, total outputs of REEs from wheat plants and infiltrated water are quite similar among the four experimental fields. Wheat plant is the main output part and contents of REEs followed the descending order: root, leaf, stem, crust and seed. A result by calculating pointed out that amount of output of REEs is slightly higher than that of input in control field, which means the accumulation of REEs can hardly happened. In the REEs-dressed fields, amount of REEs in soil increases with the increase of input of REEs. If REEs-fertilizer are used continuously, contents of REEs in surface soil will be doubled in 159 years. Comparison with soil-dressing, the speed of REEs accumulation with foliage-dressing is much lower, it needs 2008 years to make the contents of REEs doubled in surface soil.更多还原