Reliably mapping clay content coregionalized with electrical conductivity

Javier Reyes, Ole Wendroth, Christopher Matocha, Junfeng Zhu, Wei Ren, A. D. Karathanasis

Research output: Contribution to journalArticlepeer-review

10 Scopus citations


Understanding the spatial variability of soil texture within field soils is important due to its influence on a large number of soil and plant related processes and for site-specific application of inputs that are crucial to crop production. It remains a problem to obtain a reliable clay content map based on a limited number of sampling locations. The objective of this study was to identify spatial variability of soil clay content and the behavior of the estimation result for different spatial resolutions of measured clay content (0–20 cm depth) in combination with a coregionalization approach using apparent electrical conductivity (eCa). In a silty loam soil, soil clay content was measured at 96 points in a 50-m by 50-m grid within an agricultural field. eCa was measured using a contact sensor Veris 3150. Data were analyzed with ordinary kriging and cokriging while using eCa at a shallow depth. We analyzed different sampling scenarios based on clay subsamples of 48, 24, and 12 data points distributed over the 27-ha field. In all scenarios investigated here, the RMSe stayed in the range of 3 to 4% by using different validations, with cokriging performing constantly better than ordinary kriging. Clay content maps estimated with cokriging maintained a satisfactory precision when the sampling density was reduced to one sample per two hectares, a result that leads to the conclusion that electrical conductivity in combination with spatial coregionalization demonstrated to be a promising tool to estimate the spatial variation of clay content even at a low clay sampling density.

Original languageEnglish
Pages (from-to)578-592
Number of pages15
JournalSoil Science Society of America Journal
Issue number3
StatePublished - May 1 2018

Bibliographical note

Funding Information:
The authors gratefully acknowledge funding of this research by the Kentucky Small Grain Growers’ Association, the Kentucky Corn Growers’ Association, the Kentucky Soybean Board, the Southern Soybean Research Program, the SFB 271 Water Quality Program through the College of Agriculture, Food and the Environment, and the Department of Plant & Soil Sciences. The authors very much appreciate the technical support of Mr. Riley Jason Walton and Mr. James Dollarhide. The authors are very thankful to Trevor Gilkey, Hillview Farms, Princeton, KY for allowing the research to be conducted on his farm. This is publication No. 18-06-030 of the Kentucky Agricultural Experiment Station which is published with the approval of the Director. This work is supported by the USDA National Institute of Food and Agriculture, Multistate Project KY006093.

Publisher Copyright:
© Soil Science Society of America.

ASJC Scopus subject areas

  • Soil Science


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