Making a Place for Science: The Field Trial - Cultivating Science, Harvesting Power - page 120

of land, labor, and materials. The level of support from the grower varies
from project to project, but the basic principle of the trial is usually the
same: to incorporate the practices of growers and demonstrate the effect
that just one change in this system of practice can have on farm produc-
tion. In this respect, fi eld-based experiments have much in common with
laboratory-based forms of science that intend to demonstrate some
phenomenon by controlling a variable or set of variables in a regulated
environment. Figure 5.2 shows one such demonstration from the early
days of extension work in California. Each photo portrays different parts
of a fi eld trial on potatoes, showing the benefi ts that fertilizer applica-
tions can have on yield. In this case, the part of the crop treated with
fertilizer, in the bottom photograph, has a much higher yield than the
unfertilized portion, in the top image. The marriage of science, place,
and practice is complete here—the experiment changes just one practice
(fertilizing) and holds all the other factors of this place constant. The
tools of this fi eld trial are not glamorous: old boxes and bags hold unre-
markable potatoes. And yet, there is a powerful symbolism in this com-
parison. It signifi es that something important and offi cial has happened
in this otherwise ordinary fi eld of potatoes—the potatoes have become
data.
At the same time, because it is in a seemingly typical fi eld, the trial
acquires a “pseudo-commercial” status, as the weed science advisor
described it:
WeedSci: [Growers] loved to see something pseudo-commercial. These
little small plots . . . they didn't have much confi dence in those. You know
because maybe [I] went out there and picked the weeds out to make sure
it looked good or something [both laugh]. But once it was out there in the
[grower's fi eld], and they saw it standing up tall . . . compared to the stand-
ard, then they'd believe it.
The weed science advisor emphasizes two things that are also evident
in the potato trial pictured in fi gure 5.2: fi eld trials capitalize on the dif-
ferences between two treatments, each within a grower's fi eld. On one hand,
this combination of the two key features of fi eld trials—their emphasis on
demonstrative comparison and their attention to the uniqueness of place—
gives them epistemic power and commercial relevance. On the other hand,
this very same combination makes trials tricky to pull off.