K. Auerswald et al., THE INFLUENCE OF TILLAGE-INDUCED DIFFERENCES IN SURFACE MOISTURE-CONTENT ON SOIL-EROSION, Soil & tillage research, 32(1), 1994, pp. 41-50
After 7 years of conventional- and no-till for soybeans on a silt loam
soil, replicate plots were tilled alike to produce similar surface co
nditions for erosion evaluation. Three consecutive rainfall simulation
s were carried out on each plot to examine whether no-till still had b
eneficial carry-over effects in reducing soil erosion compared with pl
ots with a conventional-till history. Soil moisture, prior to the firs
t run, was 0.075 g g-1 greater on the previously untilled plots. Their
soil loss was less than 30% of that from the previously tilled plots.
To eliminate the effect of antecedent moisture content (M(a)) on soil
loss and isolate the effect of other differences induced by soil use
history, an equation between M(a) and soil loss was used. This had bee
n independently derived from another silt loam soil. Three-fifths of t
he difference in soil loss were attributed to the greater M(a). Two-fi
fths (4.5 t ha-1) of the difference were attributed to other benefits
of no-till such as greater aggregate stability and more biopores. Grea
ter soil loss from the drier conventional-till treatment was a result
of the increased breakdown of the soil surface structure before runoff
started. The smoother surface resulted in a smaller water depth durin
g runoff. Average depth on the driest conventional-till plot was only
one-third of that on the no-till plot with the greatest M(a). The redu
ced depth increased further detachment by raindrop impact and increase
d sediment transport. The initial breakdown of structure influenced so
il loss during all three consecutive runs. For both treatments, the so
il loss of the third run was still influenced by the initial moisture
content of the first run.