Furrow irrigation-induced soil erosion is a serious threat to sustaina
ble irrigated agriculture globally. Recent field studies have demonstr
ated that small concentrations of polymers dissolved in irrigation wat
er appreciably reduce soil loss from irrigated furrows and increase ne
t infiltration (total inflow - total outflow). This paper summarizes p
olymer-related field studies conducted in Idaho on highly erodible sil
t loam soils (Durixerollic Calciorthids, Xerollic Haplargids, Haploxer
ollic Durargids). A range of furrow lengths (163-264 m), slopes (0.5-7
%), and inflows (15-38 L min-1) were included in the studies. A modera
te-charge-density anionic polyacrylamide (PAM), highly effective for c
ontrolling furrow sediment losses, was employed in the field trials. T
reatment efficacy depended primarily on application rate, PAM concentr
ation in irrigation water, duration of furrow exposure, and inflow rat
e. Nontreated furrow soil loss in 75% of the irrigations exceeded soil
loss tolerance (T) for these soils, whereas only 13% of the PAM-treat
ed irrigations exceeded T. Those treatments that applied at least 0.7
kg ha-1 PAM (mean, 1.3 kg ha-1) reduced furrow sediment loss by 94% (r
ange: 80-99%) and increased net infiltration by 15% (range: -8-57%). O
ne of the most effective treatments applied PAM at 10 g m-3 in irrigat
ion inflows during the furrow advance period. This initial high-load t
reatment was nearly twice as effective as a continuous 0.25 g m-3 PAM
application on these soils when slopes were 1-2%. The initial high-loa
d treatment protected furrows with slopes ranging from 0.5 to 3.5%. PA
M reduced total phosphorus (84% of control value), nitrate (83%), bioc
hemical oxygen demand (72%), and sediment (57%) in treated runoff wate
r.