Preparing or Upgrading Your Orchard Site - Growing Organic Orchard Fruits - page 98

Hardpans can be detected by digging test pits in your planting site (see
chapter 2 ➔ ) . Puddles that remain more than a few hours after a heavy rain
or snow melt are also indications of hardpans. In many cases, impermeable
layers result from poor soil management practices, such as excessive tilling
(see box on page 81 ➔ ) or compaction from equipment and livestock.
Hardpans also occur naturally due to clay layers (sometimes called
lenses) or mineral deposits (caliche). The mineral deposits are usually some
form of carbonate (lime) and occur most often in arid regions. Frequent,
shallow irrigation that draws soil minerals to the surface and deposits them
when the water evaporates can also create drainage problems. Less frequent
and deeper irrigation will help flush excess mineral salts out of the root zone.
FIGURE 4.1
ABOVE: In this soil profile, a clay or caliche layer impedes water drain-
age and root growth. Deep-ripping the soil can sometimes break up the
impermeable layers and improve drainage.
If a hardpan is not too deep, you can often break it up using a long, narrow
chisel plow or shank in a process called “deep ripping.” Shallow tiller- or
plow-pans can usually be broken up by ripping using a medium-sized tract-
or. Deeper and harder pans usually require a large tractor or bulldozer, of-