(1) freshly mounded upslope site with 2% furrow grades;
(3) freshly mounded downslope site with 1% furrow grades;
(4) `consolidated' (8-month-old) mounded upslope site with 1% furrow grades;
On the mounded areas, plots were located over a mound/furrow/inter-mound area so that one of the long boundaries of each plot was located on the centre of a mound.
Flows were applied into the furrows of mounded plots, and across the top end of remaining plots, and maintained to produce a steady runoff rate over 6 min.
For example, in the freshly mounded treatment plots, where simulated rainfall produced steady runoff rates of approximately 0.25 L/s, the selected overland flow rates simulated furrow lengths of 50, 150, and 250 m.
Runoff from mounded plots was significantly (P < 0.05) higher than runoff from the stick-raked site, which in turn was significantly higher than runoff from the undisturbed site (Table 4).
Observations of mounded plots during simulated rainfall led to the conclusion that erosion followed a consistent pattern of:
Particularly for freshly mounded plots, initial runoff was visibly enriched in dark organic matter.
Organic material was concentrated at the surface of stick-raked areas, whereas in the mounded areas, inversion of soil by tillage had reduced the surface litter of organic material.
In mounded treatments, the typical (all plots except 1 and 12) response observed for each flow rate was high initial sediment concentrations in runoff, which then decreased as supplies of readily available sediment in the furrows were exhausted (Fig.