APPLICATIONS OF APPARENT SOIL ELECTRICAL CONDUCTIVITY IN PRECISION AGRICULTURE

Authors: Corwin, Dennis; PLANT, RICHARD - UC DAVIS, CA

Submitted to: Computers and Electronics in Agriculture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/25/2004
Publication Date: 3/1/2005
Citation: Corwin, D.L., Plant, R.E. 2005. Applications of apparent soil electrical conductivity in precision agriculture. Computers and Electronics in Agriculture. 46:1-10.

Interpretive Summary: To meet the world's increasing food demands because of increasing population, a means of increasing crop production while minimizing degradation to the environment, assuring economic sustainability, and optimizing the use of resources such as water, fertilizer, and pesticides is needed. Precision agriculture has been proposed as one means of achieving these goals because it seeks to apply only those resources that are needed, when they are needed, where they are needed, and in the amount they are needed. Maps of apparent soil electrical conductivity (ECa) are able to characterize the spatial distribution of soil properties that influence crop yield; consequently, they can provide answers concerning what and where to apply resources to crops. A collection of papers were organized into a Special Issue of Computers and Electronics in Agriculture to provide a review of the current technology and understanding of ECa and current approaches for their application in precision agriculture. This preface serves as an introduction which provides an overview of the significant points of each paper and how they fit into the big picture. The future of precision agriculture depends upon continued development and integration of information and electronic technologies that can identify and characterize, both over time and space, not only soil-related properties but also topographical, biological, meteorological, and man-caused factors influencing non-uniform crop growth within a field. The use of variable-rate equipment for precision agriculture will need spatial information to effectively determine where and what to apply to increase yield. Because of their reliability, ease of measurement, and flexibility, maps of ECa will undoubtedly contribute a significant portion of the spatial soils-related information needed to direct variable-rate equipment.

Technical Abstract: Sustainable agriculture is considered the most viable means of meeting future food needs for the world's increasing population. Precision agriculture is a proposed approach for achieving sustainable agriculture. Precision agriculture utilizes rapidly evolving information and electronic technologies to modify the management of soils, pests, and crops in a site-specific manner as conditions within a field change spatially and temporarily. Geospatial measurements of apparent soil electrical conductivity (ECa) are the most reliable and frequently used measurements to characterize within-field variability of edaphic properties for application to precision agriculture. The collection of papers that comprises this Special Issue of Computers and Electronics in Agriculture provides a review of the current technology and understanding of geospatial measurements of ECa and current approaches for their application in precision agriculture. The objective of this preface is to run a thread through the papers to show their interrelationship and to identify significant points. The spectrum of topics covered by the papers include (i) a review of the use of ECa measurements in agriculture, (ii) multi-dimensional ECa modeling and inversion, (iii) theory and principles elucidating the edaphic properties that influence the ECa measurement, (iv) ECa survey protocols for characterizing spatial variability, (v) ECa-directed response surface sampling design, (vi) designing and evaluating field-scale experiments using geospatial ECa measurements, (vii) mapping of soil properties with ECa, (viii) spatially characterizing ECa and water content with time domain reflectometry (TDR), (ix) delineating productivity and site-specific management zones, and (x) site-specific management methods for reclaiming salt-affected soils. The greatest potential for the application of geospatial measurements of ECa in precision agriculture is to provide reliable spatial information for directing soil sampling to identify and characterize the spatial variability of edaphic properties influencing crop yield. This in turn can be used to delineate site-specific management units, which are key components of precision agriculture.