林芝河谷地区典型农田土壤主要性质及重金属状况初探

选择西藏林芝河谷地区代表性麦田及蔬菜大棚土壤,对其主要土壤肥力指标、重金属浓度及相应小麦及蔬菜样的重金属浓度进行了测定。结果发现:该区耕地土壤有机质、全氮、碱解氮处于中等及较缺乏水平,全磷、全钾、有效锌处于缺乏水平,速效磷、钾及有效铜处于较丰富水平;研究区土壤及作物铜、锌、镉浓度均未超出我国土壤环境质量标准,但农业生产活动造成了表层土壤铜、锌、镉的富集。研究区耕地应注重有机肥、化肥及微量元素的合理施用,同时注意农业生产活动造成的土壤酸化、重金属富集问题并加以监控,以促进该区农业的可持续发展。

Preliminary Study on Soil Fertility and Heavy Metal Concentrations of Croplands in Nyingchi Valley of Tibet

Nyingchi Valley is one of the most important agricultural areas on the Tibetan Plateau, and soil degradation has become more and more severe there with the development of agriculture. Fertility indexes and heavy metal concentrations of soil samples from the representative fields in Nyingchi Valley and heavy metal concentrations in corresponding wheat and vegetable samples were investigated. The results showed that soil organic matter, alkali-hydro nitrogen and total nitrogen were from moderate to low levels. The concentrations of total phosphorous, potassium and bioavailable zinc were at low level, but bioavailable phosphorous, potassium and copper were abundant. Soil organic matter played a key role in the preservation of soil fertility. The concentrations of copper, zinc and cadmium in both soil and plant were all lower than the corresponding national standards. However, the accumulation of copper, zinc and cadmium occurred in topsoil in Nyingchi Valley and could be attributed to over farming.