Tuesday, November 14, 2006

Look Ma! No Hands! (or Flags or Stakes or Row Markers).

Robert Nielsen1, Eric White2, Jacky Payne2, and Norman Larson3. (1) Purdue Univ.-Agronomy Dept., 915 W State St, West Lafayette, IN 47907-2054, (2) Case-IH, 700 State St., Racine, WI 53404, (3) Elburn Cooperative Co., 2915 Wedgewood Dr, Dekalb, IL 60115-4932

Field-scale research, whether in collaboration with farmers or “on-farm” at university research stations, presents logistical challenges to planting randomized treatment plots of even simply designed field experiments. Accurately flagging or otherwise marking treatment plots to identify their location prior to planting and to facilitate accurate planting of the same requires time and labor during a time of the year when both resources are limited. Farmer collaborators, in particular, often resist the notion of treatment randomization because of their concern for these logistical “headaches”. These logistical challenges associated with marking field plots are compounded with fields that are odd-shaped or have undulating topography. We will share our experiences using a commercial tractor + 8-row planter equipped with a commercially-available after-market GPS-enabled assisted steering system that facilitates the planting of randomized treatment plots with little to no field marking (plot flags, plot stakes, or planter row markers). Field plot layouts are designed with GIS software based on previously acquired georeferenced field boundaries. Swath identification numbers are assigned to plots before planting that will correspond to those that result from setting the lightbar’s “AB” line in the first plot of the trial. The plot list (including Swath IDs) is sorted by treatment and printed prior to planting. Armed with this printed plot list, one simply navigates manually by the lightbar to the appropriate Swath ID for any given plot, turns into the plot, and engages the assisted steering system. The tractor/planter “follows” the lightbar swath along a straight course toward the other end of the field, whereupon the assisted steering system is manually disengaged and the tractor/planter manually navigated to the next randomly located plot. This system simplifies the logistics of planting field-scale research trials and has proven to be acceptably accurate in pass-to-pass accuracies of the “guess rows” between plots.