Agriculture Reference
In-Depth Information
have turned to deep ripping (sometimes called subsoiling), which involves no
soil inversion, and compaction under the tractor wheels is broken up by the
ripper shafts that follow. However, old roots are not brought to the surface, so
thesoilmayneedtobefumigatedtodestroynematodes(see“Preplanting”in
this chapter).
Deep ripping is often used to break up a compacted layer, either induced
or formed naturally, which restricts root development and seriously impedes
drainage. For example, large rippers drawn by crawler tractors are used to rip
shallow soils in the Napa region of California. In the Western Cape region of
South Africa, a “finger delve” plow is used to break up compacted B horizons
in duplex soils, without inverting the soil (figure 2.12). With this plow, as with
rippers, lime can be incorporated at depth to raise the pH and improve soil
structure; or in soils where acidity is not a problem, gypsum can be added to
improve structure.
In established vineyards, compaction from traffic in the mid-rows can be
serious, more so in sandy soils; but this, too, can be alleviated by ripping. South
African scientists have developed a novel cultivator for deep disturbance of the
mid-row soil to alleviate compaction (figure 2.13). This implement also prunes
the roots, which stimulates root growth and rejuvenates old vines of declining
Figure 2.12
A “finger delve” plow used
for soil preparation for vineyards in the
Western Cape region, South Africa.
The maximum depth of ripping is
approximately 1.5 m. (Courtesy of
Dr. Eduard Hoffman, Stellenbosch
University, South Africa.)
