In-Situ Differentiation of Acidic and Non-Acidic Tundra via Portable X-ray Fluorescence (PXRF) Spectrometry

作     者：Somsubhra CHAKRABORTY David C. WEINDORF GARY J. MICHAELSON Chien Lu PING Ashok CHOUDHURY Tarek KANDAKJI Autumn ACREE Akriti SHARMA WANG Dandan 

作者机构：Uttar Banga Krishi Viswavidyalaya Cooch Behar 736165 Department of Plant and Soil Science Texas Tech University Lubbock TX 79409 University of Alaska Fairbanks Palmer Research Center Palmer AK 99645 Louisiana State University Agricultural Center Baton Rouge LA 70803 College of Geography and Remote Sensing Nanjing University of Information Science and Technology Nanjing 210044 

出 版 物：《Pedosphere》 (土壤圈（英文版）)

年 卷 期：2016年第26卷第4期

页      面：549-560页

核心收录：

学科分类：09[农学] 0903[农学-农业资源与环境] 090301[农学-土壤学] 

主　　题：frozen soil Gelisols Geochem Mode proximal sensing Soil Mode soil pH determination 

摘      要：Frozen soils or those with permafrost cover large areas of the earth s surface and support unique vegetative ecosystems. Plants growing in such harsh conditions have adapted to small niches, which allow them to survive. In northern Alaska, USA, both moist acidic and non-acidic tundra occur, yet determination of frozen soil p Hs currently requires thawing of the soil so that electrometric pH methods can be utilized. Contrariwise, a portable X-ray fluorescence(PXRF) spectrometer was used in this study to assess elemental abundances and relate those characteristics to soil pH through predictive multiple linear regressions. Two operational modes, Soil Mode and Geochem Mode, were utilized to scan frozen soils in-situ and under laboratory conditions, respectively, after soil samples were dried and ground. Results showed that lab scanning produced optimal results with adjusted coefficient of determination(R^2) of 0.88 and 0.33 and root mean squared errors(RMSEs) of 0.87 and 0.34 between elemental data and lab-determined pH for Soil Mode and Geochem Mode, respectively. Even though the presence of ice attenuated fluoresced radiation under field conditions, adjusted R^2 and RMSEs between the datasets still provided reasonable model generalization(e.g., 0.73 and 0.49 for field Geochem Mode). Principal component analysis qualitatively separated multiple sampling sites based on elemental data provided by PXRF, reflecting differences in the chemical composition of the soils studied. Summarily, PXRF can be used for in-situ determination of soil pH in arctic environments without the need for sample modification and thawing. Furthermore, use of PXRF for determination of soil pH may provide higher sample throughput than traditional eletrometric-based methods, while generating elemental data useful for the prediction of multiple soil parameters.