Productivity Zones Based on Bulk Soil Electrical Conductivity - Agricultural Geophysics - page 265

WYOMING

Farm-Scale Intensive Cropping Study
Sterling, CO

NEBRASKA

Central
Great Plains

COLORADO

KANSAS

fIGURe 18.2 Site map for the Farm-Scale Intensive Cropping Study in northeast Colorado, located in the
heart of the Central Great Plains.

C W

dS/m

0.55
0.50
0.45
0.40
0.35
0.30
0.25
0.20
0.15
0.10
0.05
0.00

F

C

M

F

W M

fIGURe 18.3 Farm-Scale Intensive Cropping Study: experimental layout and electrical conductivity map.
W = winter wheat, C = corn, M = millet, and F = fallow.

In 1999, it was converted to an intensified no-till winter wheat to corn ( Zea Mays L.) to proso mil-
let ( Panicum miliaceum L.) to fallow rotation. Crop treatments were assigned to each of the eight
≈31 ha fields within the site (Figure 18.3) so that each phase of the 4-year rotation was present in
two replicates each year.
In 1999, the experimental site was EC a mapped (0 to 30 and 0 to 90 cm depths) by direct contact,
using a Veris 3100 Sensor Cart (Veris Technologies, a division of Geoprobe Systems, Salina, KS)
(Figure 18.3), and separated into four zones (ranges) of EC a : low, medium low, medium high, and
high (Figure 18.4 and Table 18.1). This was done by individually interpolating EC a field maps (0 to 30
cm) by inverse-distance weighting and spatially clustering the interpolated data into twelve classes