论文部分内容阅读
农田土壤中磷的流失与磷的积累及其吸附/释放特性等有关。为了解千岛湖库区土壤中磷素积累对农地土壤磷流失的潜在影响,本文选择了10个代表性土壤,采用等温吸附与室内加磷培养及化学提取等试验,探讨了库区代表性农地土壤对磷的固定和释放特性;同时采样评估了库区内140个农田土壤有效磷积累状况及其磷素释放的潜力。结果表明,千岛湖库区农地土壤最大磷吸附量有较大的差异,在214.5~745.2 mg kg-1之间变化,平均最大磷吸附量:红壤>石灰岩土>水稻土>紫色土。土壤最大磷吸附量主要与粘粒和游离氧化铁含量有关。加磷培养试验表明,水溶性磷水平随土壤磷的积累呈显著的增加,当土壤有效磷(Olsen P)达45 mg kg-1左右时,土壤磷的释放潜力明显增强。对库区代表性农田磷素积累研究表明,约有19.8%的样点土壤有效磷在45 mg kg-1以上,存在一定的磷流失风险。研究建议加强千岛湖库区农田土壤的测土配方施肥工作,减免因农田土壤中磷素的过度积累而增加对水体的污染。
Phosphorus loss in farmland soil is related to phosphorus accumulation and its adsorption / release characteristics. In order to understand the potential impact of phosphorus accumulation in the soil in the Qiandao Lake reservoir area on the phosphorus loss in the farmland, 10 representative soils were selected for this study. The isotherm adsorption, The fixation and release characteristics of phosphorus in farmland soil were evaluated simultaneously. Simultaneously, the accumulation of available P in 140 farmland and the potential of phosphorus release were evaluated. The results showed that the maximum phosphorus uptake in farmland of Qiandao Lake reservoir area varied greatly from 214.5 to 745.2 mg kg-1. The average maximum phosphorus uptake was red soil> limestone soil> paddy soil> purple soil. The maximum phosphorus uptake by soil is mainly related to the content of clay and free iron oxide. Phosphorus culture experiments showed that the level of water-soluble phosphorus significantly increased with the accumulation of soil phosphorus. When the soil available phosphorus (Olsen P) reached about 45 mg kg-1, the release potential of soil phosphorus was significantly enhanced. The study on phosphorus accumulation in representative farmland in the reservoir area shows that about 19.8% of the soil available phosphorus is above 45 mg kg-1, and there is a certain risk of phosphorus loss. The study suggests to strengthen soil testing and formula fertilization of farmland soil in Qiandao Lake reservoir area and reduce the pollution of water bodies due to the excessive accumulation of phosphorus in farmland soils.