不同种植作物对污灌区土壤铜形态的影响

为弄清在污灌区农田种植玉米、大豆、高粱、向日葵、菊花5种作物对土壤中铜形态的影响,采用Tessier五步连续提取法对种植前后不同形态铜含量进行测定。结果表明:种植5种作物后土壤可交换态铜的含量均有增加,玉米土壤增加率最高,达到25.67%;碳酸盐结合态铜、有机结合态铜含量大致都呈降低趋势,菊花土壤降低率最高,分别达到57.95%和58.6%;铁锰氧化物结合态铜的含量在种植玉米、大豆、向日葵后均有所增加,而种植高粱和菊花后有所降低;残留态铜的含量总体呈降低的趋势。在垂直深度上,可交换态铜的含量在不同土层均表现为增加,其中种植玉米后增加最明显;碳酸盐结合态铜和残留态铜在种植作物后均表现为降低,降低率随土层加深而增加;铁锰氧化物结合态铜和有机结合态铜的变化率在不同土层没有明显的规律性。

Effect of Different Crops on Speciation of Sewage Irrigated Soil Copper

In order to clarify the effect of five different crops(corn,soybeans,sorghum,sunflower,chrysanthemum) on the morphology of copper in sewage irrigating farmland soil,different forms of copper were determined with five-step Tessier sequential extraction method before and after the planting.The results showed that the soil exchangeable copper content increased after planting the five crops,the rate of increase was the highest in corn soil,reaching 25.67%.Carbonate-bound copper,organic matter fraction copper generally tended to decrease,the reducing rate was the highest after planting chrysanthemums,reducing 57.95% and 58.6% respectively.Fe-Mn oxide bound copper content increased after planting corn,soybean,and sunflower,but decreased after planting sorghum and chrysanthemum.The content of residual state copper all decreased.In the vertical depth,exchangeable copper content increased in different soil layer,and the increase was most significant after planting corn.Carbonate-bound copper and residual state copper both decreased and the rate of decrease increased with soil deepening.The changes of Fe-Mn oxides and organic bound copper were not obvious in different soil layer.