三江平原不同土地利用方式下土壤锰含量研究

通过对比分析三江平原典型的小叶章湿地、玉米地、水稻田、人工杨树林和岛状林土壤中锰（Mn）含量,研究了不同土地利用方式下土壤Mn分布特征及影响因素.结果表明,三江平原土壤Mn含量范围为107.73～2 798.99 mg.kg-1,平均为403.24 mg.kg-1,处于较低的水平.不同利用方式下土壤中Mn含量差异显著（F=9.272,P〈0.001）,表现出岛状林〉人工杨树林〉玉米地〉小叶章湿地〉水稻田的规律;总体上由表层至底层,各层土壤Mn含量表现为玉米地〉小叶章湿地〉水稻田,岛状林〉人工杨树林的规律,表明湿地开发为旱田后,土壤Mn将聚集,而开发为水田后,土壤Mn则流失.相关性分析表明,土壤中Mn含量与pH呈显著的负相关系（r=-0.279,P〈0.05）,Mn与S含量（r=0.383,P〈0.01）和可溶性有机碳含量（r=0.244,P〈0.05）呈显著的正相关关系,而与土壤有机质（SOM）和有效硫（Sa）含量相关性并不显著.环境因子的改变,可能是通过改变Mn的赋存状态而影响到土壤Mn含量.

Mn Content in Soil of Sanjiang Plain Under Different Land Use

Mn content and its profile distribution characteristics were investigated in soils from the typical Deyeuxia angustifolia wetland,corn filed,paddy field,poplar forest and island forest in Sanjiang Plain.Results indicated that Mn content was relatively low and was in the range of 107.73-2798.99 mg/kg with the average value of 403.24 mg/kg.Mn content significantly differed by land use (F=9.272,P<0.001) and was in the order of island forest>poplar forest>corn field> Deyeuxia angustifolia wetland> paddy field.On the whole,Mn content in each soil layer was in the order of corn filed> Deyeuxia angustifolia wetland>rice paddy in field and was in the order of island forest>poplar forest in the vertical direction.It suggested that Mn was enriched after wetlands were reclaimed in to the upland filed and Mn concentration was decreased when wetlands were changed into rice paddy.Correlation analysis showed that Mn content in soil significantly negatively related to pH (R=-0.279,P<0.05), significantly positively related to sulfur (R=0.383,P<0.01) and dissolved organic carbon (R=0.244,P<0.05),and weakly related to soil organic matter and available sulfur,respectively.Changes of environmental factors had impacts on Mn species and then resulted in soil Mn content.