Lc. Brown et Ld. Norton, SURFACE RESIDUE EFFECTS ON SOIL-EROSION FROM RIDGES OF DIFFERENT SOILS AND FORMATION, Transactions of the ASAE, 37(5), 1994, pp. 1515-1524
The effect of crop residue on soil erosion by water was studied on thr
ee soils using well-defined, ridge-furrow configurations to simulate r
idge-tillage conditions. Interrill and rill erosion was studied using
rainfall simulation on freshly formed (FF) and consolidated (CON) ridg
es on somewhat poorly drained Rossmoyne silt loam in Ohio, and on fres
hly formed ridges on well-drained Chelsea fine sand and Miami silt loa
m in Indiana. Corn stalk and leaf residue were hand-applied only to ri
ll erosion plots. Average percent cover for five residue levels was 0,
4.7, 10.0, 20.0, and 45.0%. Average interrill detachment rate on cons
olidated Rossmoyne ridges was significantly smaller than that from Mia
mi and Rossmoyne freshly formed ridges. Average runoff rate for consol
idated Rossmoyne ridges was significantly greater than that on freshly
formed ridges. Average rill detachment rate decreased in the order of
Chelsea FF > Rossmoyne FF > Miami FF > Rossmoyne CON. Within each inf
low level for Chelsea freshly formed and Rossmoyne consolidated ridges
, average detachment rate decreased significantly; 51 to 83% and 88 to
92% reductions, respectively, as cover increased from 0 to about 45%.
Within each inflow level for Chelsea freshly formed ridges, detachmen
t rate decreased significantly by 40 to 72% as cover increased from 0
to about 20%. Cover levels of 20 and 45% bracket a compliance level of
30%. On Miami soil, as cover increased from 0 to about 45%, detachmen
t decreased by 65 to 82%. For Detachment = a exp (b x % residue cover)
, average coefficient b values were Chelsea freshly formed ridges, b =
-0.032; Miami freshly formed ridges, b = -0.030; Rossmoyne freshly fo
rmed ridges, b = 0.006; and Rossmoyne consolidated ridges, b = 0.061.
As residue increased from 0 to approximately 45%, average flow velocit
y decreased significantly by 55 to 71 %. Addition of 40% residue cover
decreased velocity of flow across all flow levels and soils by more t
han 50%. Reduction was greater for consolidated Rossmoyne ridges compa
red to freshly formed ridge conditions. Addition of residue at approxi
mately 45% increased the Darcy-Weisbach friction factor by 9 to 29 tim
es that of bare soil. Effect was greatest for noncohesive Chelsea sand
. For freshly formed ridge conditions, a linear relationship was found
for detachment rate versus hydraulic shear on all soils with no resid
ue cover. As residue cover increased, correlation between detachment r
ate and hydraulic shear exhibited much variability. The model fit the
data reasonably well (r(2) values of 0.6 to 0.9) for cases where there
was no, or relatively small amounts, of residue on freshly formed rid
ges. For Rossmoyne consolidated ridges, correlation between detachment
and hydraulic shear for all residue levels was very low. For freshly
formed ridge conditions, the interrill contribution was a smaller port
ion of total detachment. On consolidated Rossmoyne ridges, the interri
ll contribution was a major portion of total detachment all along enti
re range of hydraulic shear values evaluated in this study. Further re
search is needed to quantify surface residue-soil disturbance interact
ions for ridge-tillage, especially for conditions following planting,
cultivation, and harvest.