The wetted areas in the A horizon on the delving line, off-line, and in the undelved soil were greater than those shown in Fig.
A representative area of the delved profile was selected and a transect was made perpendicular across the delving fines with a delving fine at the centre.
Delving significantly increased the average steady-state infiltration rate at the soil surface (on the delving line) at site C, and increased this rate at site A but not by a statistically significant amount; there was no apparent effect of delving on infiltration at site B (Table 4).
In the delved soil, the dye staining was consistent with the infiltration results shown in Table 4 in which greater depths of infiltration corresponded with greater infiltration rates along the delving lines.
The 'dry' condition experiments (Figs 5a, 6 a and Tables 5, 6) showed a considerable effect of clay delving on water penetration and redistribution; the difference in the proportion of wet (stained) profile between treatments was highly significant (P< 0.
By contrast, the A-B boundary on the delving line was broken and this allowed water to penetrate deeper into the soil with no ponding.
Clay delving uses two, three or four wide tines (typically 0.
2013) at random locations over the delving lines, off the delving lines, and in undelved soil.
The scientific literature on the effects of delving on soil hydraulic properties is sparse, so this study was designed to quantify and evaluate the changes in infiltration brought about by delving at three different sites in South Australia.
Delving can increase crop yields (Cann 2000; May et al.
At all three sites in South Australia, clay delving significantly increased the proportion of the A1 horizon that wetted up during infiltration into dry soil, and the penetration of water below the A-B horizon boundary.
Most of the increase in soil wetting from delving occurred in the area of maximum soil disturbance directly on the delving line, especially
This outcome suggests that more uniform wetting of the soil profile could be achieved by narrowing the spacing of delving tines or through cross-delving and thereby reducing the extent of the off-line region, where finger flow still occurs.
Under dry conditions, clay delving significantly reduced preferential water (finger) flow, especially where water repellence at the soil surface was severe.
Nevertheless, in the A horizon the delved profiles showed significantly larger wetted areas, particularly along the delving lines, which can be crucial for plant root growth in semi-arid and Mediterranean areas (Lampurlanes et al.