Geomorphic influences on soil development and soil organic matter dynamics in central Jackson County,Wisconsin.

详细信息   

• 作者：Gruley ; Kristine Emma.
• 学历：Doctor
• 年：2015
• 毕业院校：The University of Wisconsin
• Department：Geography.
• ISBN：9781321516623
• CBH：3673987
• Country：USA
• 语种：English
• FileSize：11063886
• Pages：158

文摘

Sandy and silty mantles in central Jackson County were investigated to characterize,identify,and document past or present geomorphic and pedogenic processes as well as soil organic matter dynamics operational in this landscape. LiDAR,particle size,and silt geochemical data suggest the sand mantle is typically 30 -- 100 cm,no more than 5 m thick,and covers much of the low-relief terrain landscape as a result of widespread eolian activity. The sand mantle acted largely as a surface of transport where saltating sands caused fine-grained material to be re-entrained to be deposited farther downwind. Eolian silt associated with deglaciation is only preserved as silty mantles in the most protected positions along the east and southeast aspects of large bedrock ridges. Silty eolian/colluvial mantles are rich in both coarse and fine silt； whereas,silt found in the sandy mantle in windward locations is dominantly fine silt. Thus,much of the fine silt was likely deposited near the end of widespread eolian activity. Without these silty additions,a continuum of podzolization processes would likely dominate the sandy soils based on drainage from Entisols in higher positions to aquic Spodosols in toeslopes. Silty soils have greater inputs of reworked loess are highly acidic and generally unproductive,however,the pedogenic pathway is pushed from podzolization to lessivage. Bisequal soils with an upper E-Bt and lower Ex-Btx are common in these settings. Comparisons of lower sequa characteristics between catena positions suggest lateral flow and translocation through both silty and sandy catenas is an important process in this landscape. Soil organic matter SOM) was compared to fresh organic matter OM),clay mineralogy and particle size data. SOM in the upper 30 cm show increasing delta 15N and delta13C values and decreasing C:N values with depth,which suggests increased decomposition with depth. In sandy profiles with impeded drainage,podzolization resulted in less decomposed OM protected by organic-mineral complexes with depth. These results point to the importance of understanding the geomorphology and sedimentology of soil parent materials in SOM research as well as the importance of using sampling protocols that are based on horizons rather than incremental depths.