Field-Scale Experiments for Site-Specific Crop Management. Part I: Design Considerations M. J. PRINGLE* matthew.pringle@bbsrc.ac.uk Australian Centre for Precision Agriculture, MacMillan Building A05, University of Sydney, NSW 2006, Australia S. E. COOK CIAT, A.A. 6713, Cali, Colombia A.B. McBRATNEY Australian Centre for Precision Agriculture, MacMillan Building A05, University of Sydney, NSW 2006, Australia Abstract. This is a two-part paper concerned with the role of field-scale experiments in site-specific crop management (SSCM). Part I is a general introduction to experimental design for SSCM, while Part II focuses on applied analysis. All references are listed at the end of Part II. In Part I, we list the goals of SSCM-experimentation, in addition to the classes of valid experimental designs. Three general approaches are proposed for choosing experimental designs: approach A is for experiments concerning management classes, while approaches B and C are alternatives for continuous management. Approaches A and B are comparative and can be analysed with an appropriately modified ANOVA. Keywords: site-specific crop management, field-scale experiments Introduction Experimental techniques are an essential component of site-specific crop manage- ment (SSCM). (We use the term ‘site-specific crop management’ throughout, in preference to the more-general ‘precision agriculture’). Historically, agronomic experimentation with the controllable inputs of a cropping system (e.g., seed, tillage, fertiliser, pesticides, irrigation) has been restricted to small, representative areas. The enabling technologies of SSCM—i.e., Global Positioning Systems (GPS), yield sensors and variable-rate applicators (VRA)—however, imply that agronomic experiments can be applied on-farm, and to much larger areas than were previously possible. Such experiments generate large amounts of site-specific response data when the field is yield mapped. In this way, farmers can extend their knowledge about how to improve management. We refer to the juxtaposition of SSCM with experimental techniques as ‘SSCM-experimentation’. Although many authors have now used experimentation to aid their site-specific investigations, there have been surprisingly few attempts to describe the role of experimentation in SSCM (notable exceptions include Gotway Crawford et al., 1997; Bramley et al., 1999). How, then, does SSCM-experimentation differ from tradi- *Current address: Rothamsted Research, Harpenden, Hertfordshire, AL5 2JQ, UK. Precision Agriculture, 5, 617–624, 2004 Ó 2005 Kluwer Academic Publishers. Manufactured in The Netherlands.