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以西藏拉萨国家农业科技园区温室连续种植12年的温室土壤为研究对象,随机选取9座设施园区,对比园区种植前后各项土壤数据,比较pH、有机质、大量和微量元素以及重金属的变化。结果表明:随着日光温室土壤种植年限的增加,土壤的pH明显下降(P<0.05),有酸化的趋势,而土壤有机质在种植前后并没有发生显著变化;其中全磷、速效磷和全钾含量随着种植年限的增加而增加;但全氮含量随着种植时间的增加而呈下降趋势,速效钾含量变化并不明显;铁(Fe)含量随着种植年限的增加而呈下降趋势,而镁(Mg)含量呈上升趋势,锌含量变化不明显;重金属元素铅(Pb)、砷(As)、汞(Hg)、镉(Cd)含量符合国家环境保护总局发布的温室蔬菜产地环境质量评价标准,均未超标。其中Pb、As和Hg的环境质量等级均评价为一级,为清洁;总镉的环境质量等级为二级,为尚清洁,说明该园区温室土壤的重金属含量是符合国家标准,土壤耕层没有受到重金属的污染。
Taking the greenhouse soil continuously cultivated for 12 years in Lhasa National Agricultural Science and Technology Park in Tibet as the research object, nine facilities parks were randomly selected to compare the changes of pH, organic matter, major and trace elements and heavy metals before and after planting in the park. The results showed that soil pH decreased significantly (P <0.05) and increased with the growing season of solar greenhouse, with the tendency of acidification. Soil organic matter did not change significantly before and after planting. Total phosphorus, available phosphorus and total potassium The content of total nitrogen increased with the increase of planting time, but the content of total nitrogen decreased with the increase of planting time, while the content of available potassium did not change obviously. The content of iron decreased with the increase of planting time, The contents of Pb, As, Hg and Cd in the heavy metals were in line with the environmental quality assessment of greenhouse vegetable producing areas issued by the State Environmental Protection Administration Standard, not exceeded. Among them, the environmental quality grades of Pb, As and Hg were evaluated as first class and clean, the total environmental quality class of cadmium was second class and clean, indicating that the heavy metal content of the greenhouse soil in the park was in line with national standards, Heavy metal pollution.