Computers and Electronics in Agriculture 30 (2001) 9–29 Site-specific management: the application of information technology to crop production Richard E. Plant * Departments of Agronomy and Range Science and Biological and Agricultural Engineering, Uniersity of California, One Shields Aenue, Dais, CA 95616 -8515, USA Abstract Site-specific management (SSM; also called, precision agriculture) is the management of agricultural crops at a spatial scale smaller than that of the whole field. Widespread farmer adoption of SSM practices is contingent on its economic advantage. Three criteria that must be satisfied in order for SSM to be justified are, (1) that significant within-field spatial variability exists in factors that influence crop yield, (2) that, causes of this variability can be identified and measured, and (3) that, the information from these measurements can be used to modify crop management practices to increase profit or decrease environmental impact. The objective of this paper is to review the state of SSM at the turn of the millennium and to offer some speculation as to its future course. The review is organized around the essential components of SSM listed above, i.e. measuring spatial variability, analyzing the data obtained from these measurements, using information gained from this analysis to effect changes in management practices, and determining whether the resulting benefits are worth the costs. The discussion section considers some potential effects of large-scale adoption of SSM, should this adoption occur. © 2001 Elsevier Science B.V. All rights reserved. Keywords: Agriculture; Crop yield; Crop management www.elsevier.com/locate/compag 1. Introduction Site-specific management (SSM) is the management of agricultural crops at a spatial scale smaller than that of the whole field. It is perhaps unfortunate that the Abbreiations: SSM, site-specific management. * Corresponding author. Tel.: +1-916-7521705; fax: +1-916-7524361. E-mail address: replant@ucdavis.edu (R.E. Plant). 0168-1699/01/$ - see front matter © 2001 Elsevier Science B.V. All rights reserved. PII:S0168-1699(00)00152-6