TY  - JOUR
AV  - public
TI  - Hydraulic resistance of soil surface seals in irrigated furrows
VL  - 55
ID  - nwisrl557
JF  - Soil Science Society of America Journal
A1  - Segeren, Antonius G.
A1  - Trout, Thomas J.
EP  - 646
UR  - https://eprints.nwisrl.ars.usda.gov/id/eprint/557/
Y1  - 1991///
SP  - 640
N2  - Soil surface seals resulting from overland flow in irrigation furrows
reduce infiltration rates. A method was developed to quantify the
hydraulic resistance of furrow seals. Infiltration was measured with
a recirculating infiltrometer on two southern Idaho soils, Portneuf
silt loam (coarse-silty, mixed, mesic Durixerollic Calciorthid) and
Bahem loam (coarse-silty, mixed, mesic Xerollic Calciorthids). Surface
sealing was prevented on half the furrow test sections with
cheesecloth laid on the furrow perimeter. Subseal soil-water potential
was measured with a recording tensiometer. A two-dimensional finite-difference
infiltration model with measured flux as the wetted
perimeter boundary condition calculated matric potential directly
beneath the seal. Seal resistance was then calculated by Darcy's law
from the measured flux and calculated potential. Surface sealing on
the bare furrows decreased infiltration by an average of 46% compared
with the cloth-covered furrows. The seal conductivity values,
based on a constant seal thickness, decreased rapidly during the
initial 100 min and reached 0.1 to 8% of the conductivity of the soil
underlying the seal after 300 min. Potential gradients across the seal
were inversely related to infiltration rate and the conductivity of the
seal. The procedure successfully calculated seal conductivity changes
with time and can be used to evaluate the effects of management
practices on seal formation.
ER  -