title: Cost-effective sampling of ¹³⁷Cs-derived net soil redistribution: part 1--estimating the spatial mean across scales of variation.
abstract: The (137)Cs technique for estimating net time-integrated soil redistribution is valuable for understanding the factors controlling soil redistribution by all processes. The literature on this technique is dominated by studies of individual fields and describes its typically time-consuming nature. We contend that the community making these studies has inappropriately assumed that many (137)Cs measurements are required and hence estimates of net soil redistribution can only be made at the field scale. Here, we support future studies of (137)Cs-derived net soil redistribution to apply their often limited resources across scales of variation (field, catchment, region etc.) without compromising the quality of the estimates at any scale. We describe a hybrid, design-based and model-based, stratified random sampling design with composites to estimate the sampling variance and a cost model for fieldwork and laboratory measurements. Geostatistical mapping of net (1954-2012) soil redistribution as a case study on the Chinese Loess Plateau is compared with estimates for several other sampling designs popular in the literature. We demonstrate the cost-effectiveness of the hybrid design for spatial estimation of net soil redistribution. To demonstrate the limitations of current sampling approaches to cut across scales of variation, we extrapolate our estimate of net soil redistribution across the region, show that for the same resources, estimates from many fields could have been provided and would elucidate the cause of differences within and between regional estimates. We recommend that future studies evaluate carefully the sampling design to consider the opportunity to investigate (137)Cs-derived net soil redistribution across scales of variation.
authors.affiliation: 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: 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: Institute of Environment and Sustainable Development in Agriculture, Chinese Academy of Agricultural Sciences (CAAS), Haidian District, 100081 Beijing, China. Electronic address: nyamdavaa012@gmail.com.
authors.forename: B
authors.initials: B
authors.lastname: Nyamdavaa
authors.affiliation: 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
authors.initials: H
authors.lastname: Yu
authors.affiliation: Institute of Environment and Sustainable Development in Agriculture, Chinese Academy of Agricultural Sciences (CAAS), Haidian District, 100081 Beijing, China. Electronic address: davaadorjd@gmail.com.
authors.forename: D
authors.initials: D
authors.lastname: Davaasuren
authors.affiliation: Institute of Environment and Sustainable Development in Agriculture, Chinese Academy of Agricultural Sciences (CAAS), Haidian District, 100081 Beijing, China. Electronic address: zoljargalk@gmail.com.
authors.forename: K
authors.initials: K
authors.lastname: Zoljargal
mesh_terms: D002588:Cesium Radioisotopes / Q000032:analysis*; D002681:China; D003362:Cost-Benefit Analysis; D011834:Radiation Monitoring / Q000191:economics / Q000379:methods*; D012990:Soil Pollutants, Radioactive / Q000032:analysis*; D062206:Spatial Analysis
chemical_list: D002588:Cesium Radioisotopes; D012990:Soil Pollutants, Radioactive
keywords: Caesium-137; China's Loess Plateau; Fallout radionuclide; Geostatistics; Model-based and design-based sampling; Soil erosion