title: Cost-effective sampling of (137)Cs-derived net soil redistribution: part 2 - estimating the spatial mean change over time.
abstract: The caesium-137 ((137)Cs) technique for estimating net, time-integrated soil redistribution by the processes of wind, water and tillage is increasingly being used with repeated sampling to form a baseline to evaluate change over small (years to decades) timeframes. This interest stems from knowledge that since the 1950s soil redistribution has responded dynamically to different phases of land use change and management. Currently, there is no standard approach to detect change in (137)Cs-derived net soil redistribution and thereby identify the driving forces responsible for change. We outline recent advances in space-time sampling in the soil monitoring literature which provide a rigorous statistical and pragmatic approach to estimating the change over time in the spatial mean of environmental properties. We apply the space-time sampling framework, estimate the minimum detectable change of net soil redistribution and consider the information content and cost implications of different sampling designs for a study area in the Chinese Loess Plateau. Three phases (1954-1996, 1954-2012 and 1996-2012) of net soil erosion were detectable and attributed to well-documented historical change in land use and management practices in the study area and across the region. We recommend that the design for space-time sampling is considered carefully alongside cost-effective use of the spatial mean to detect and correctly attribute cause of change over time particularly across spatial scales of variation.
authors.affiliation: CSIRO Land & Water National Research Flagship, GPO Box 1666, Canberra ACT 2601, Australia. Electronic address: adrian.chappell@csiro.au.
authors.forename: A
authors.initials: A
authors.lastname: Chappell
authors.affiliation: Agricultural Clean Watershed Research Group, Institute of Environment and Sustainable Development in Agriculture, Chinese Academy of Agricultural Sciences (CAAS), Haidian District, 100081 Beijing, China. Electronic address: liyong@caas.cn.
authors.forename: Y
authors.initials: Y
authors.lastname: Li
authors.affiliation: Agricultural Clean Watershed Research Group, Institute of Environment and Sustainable Development in Agriculture, Chinese Academy of Agricultural Sciences (CAAS), Haidian District, 100081 Beijing, China. Electronic address: yuhanqing@caas.cn.
authors.forename: H Q
authors.initials: HQ
authors.lastname: Yu
authors.affiliation: Agricultural Clean Watershed Research Group, Institute of Environment and Sustainable Development in Agriculture, Chinese Academy of Agricultural Sciences (CAAS), Haidian District, 100081 Beijing, China. Electronic address: 0349yjy@163.com.
authors.forename: Y Z
authors.initials: YZ
authors.lastname: Zhang
authors.affiliation: College of Life Sciences, Henan Normal University, Xinxiang, Henan, China. Electronic address: yu_ping2012@yeah.net.
authors.forename: X Y
authors.initials: XY
authors.lastname: Li
mesh_terms: D002588:Cesium Radioisotopes / Q000032:analysis*; D003362:Cost-Benefit Analysis; D011834:Radiation Monitoring / Q000191:economics* / Q000379:methods*; D012990:Soil Pollutants, Radioactive / Q000032:analysis*
chemical_list: D002588:Cesium Radioisotopes; D012990:Soil Pollutants, Radioactive
keywords: Caesium-137; Deposition; Land use change; Net soil redistribution; Repeated sampling; Soil erosion