3.2.2. On-farm trials
Across all four on-farm trials, gravimetric soil moisture to
255 cm deep did not show marked differences between the irrigation
treatments at the harvest sampling times. Overall, when data
were averaged for the four sites,theAFItreatments had 12.8% moisture,
compared to 13.9% for EFI, a 7% decrease regardless of depth (p < 0.10; data not shown). Moreover, the 75–120 cm depth of the
AFItreatments, had 13% lower soil moisture than the EFItreatments (p < 0.01; data not shown).
Soil moisture between planting and harvest showed large differences
among fields and, in some cases, between low water (AFI)
and control (EFI) irrigation treatments. The very fine sandy loams
(i.e., Reiff-A and Reiff-B trials) had the lowest soil moisture content
at planting (i.e., average 12% for all sampled depths to 255 cm deep),
with slight variation among the depths (i.e., ranging from 13% soil
moisture at the top to 10% at the 255 cm depth)
(Fig.
2
A and B). By
harvest, soil moisture in the Reiff-A trial decreased
∼6% down to
120 cm depth for both irrigation treatments compared to planting
(6.3% and 12.7%, respectively), but lower depths showed no water
depletion. In the Reiff-B trial, the moisture depletion was deeper in
AFI (to 210 cm depth) than EFI (to 165 cm depth), with an average
soil moisture reduction from 12.2% at planting to 8.7% at harvest
across all depths.