土地整理对土壤有效态微量元素的影响

Impact of Land Consolidation on Soil Available Microelements

以重庆丰都县三坝乡土地整理项目为研究对象,研究土地整理前后的土壤有效态微量元素铁、锰、铜、锌、硼含量及分布特征,并进一步探讨其变化的原因。结果表明:(1)土地整理后土壤有效态铁、锰、铜、锌、硼的含量均下降,其中有效铁含量下降最明显,较整理前减少72.7%;土地整理改变了土壤有效态微量元素(除有效硼外)的剖面分布规律,使离散程度降低,使各土层中微量元素的含量趋于均匀。(2)土壤有机质、pH和速效养分能影响微量元素的分布。土地整理后土壤有机质含量的下降能显著降低表层(0-20cm)土壤中有效态微量元素含量,其中土壤有效铜含量受其影响最为明显,相关系数r为0.773;随着土壤pH的增加,表层(0-20cm)和亚表层(20-40cm)中有效态微量元素含量降低,其中有效铁含量受pH影响较为显著;土壤中有效磷含量的下降是造成表层和亚表层土壤有效态微量元素含量下降的另一原因,速效钾对底层(40-60cm)土壤中有效态铁和有效态锌含量有一定的影响,相关系数分别为0.494和0.510,土壤中碱解氮含量的变化对有效态微量元素含量影响不大。

Soil of Sanba of Fengdu county,Chongqing before and after land consolidation was selected in a case study,preliminarily analyzed content distribution of soil available microelements after land consolidation（Fe,Mn,Cu,Zn,B）,to further explore its change reasons.The results show：（1）Effective state Fe,Mn,Cu,Zn,B content of the soil decreased after finishing,Fe decreased most obviously,which decreased by72.7%.Land consolidation had changed profile distribution rule of soil available microelements（except B）,reducing the degree of dispersion,leading to the content of available microelements in various soil tends to be uniform.（2）Soil organic matter,pH and available nutrients could affect the distribution of available microelements.After land consolidation the decline in soil organic matter could significantly reduce the available microelements content in the soil surface layer（0-20cm）,which the Cu content was the most effective（r=0.773）.With the rise of the soil pH,available microelements reduced in the surface layer（0-20cm）and subsurface（20-40cm）,and Fe content was significantly affected by pH.Decline of phosphorus content in soil,caused available microelements content decrease on surface and subsurface,available potassium had a certain impact on Fe（r=0.494）and Zn（r=0.510）in the bottom soil（40-60cm）.Changes of nitrogen had little effect on available microelements.