Agriculture Reference
In-Depth Information
Provided that you have a sufficient amount of low-salt irrigation water
available, you can sometimes reclaim an orchard site that has excessively
salty soils by applying large amounts of water to leach the salts from the soil.
You will need a sprinkler irrigation system that provides 100 percent cover-
age of the orchard blocks. Reclaiming a site this way works well when the
excess salts accumulate because of applying too much fertilizer or manure,
or if frequent, shallow irrigation concentrated the salts near the soil surface.
Depending on calcium, sulfur, and magnesium levels (discussed below), you
can help displace some of the unwanted salts from the soil particles by ap-
plying gypsum to the soil before leaching.
Unfortunately, some saline soils in arid regions of North America are as-
sociated with irrigation water that is also high in salts and, therefore, un-
suitable for leaching purposes. On sites with extreme soil salinity, producing
orchard crops can be difficult or impossible.
Mineral Nutrients
Soil tests provide a starting point for amending your orchard soils before
centrations and application rates for selected nutrients).
Our goal at this stage is to make sure ample supplies of nutrients will
be available to the fruit trees, particularly those nutrients that move slowly
in the soil. Once your trees are planted, it can be difficult to amend the soil
with certain nutrients. On low-pH (strongly acidic) soils rich in aluminum
and iron, for example, phosphorus is very immobile, and applying it after the
trees are planted is rather ineffective. When phosphorus is applied to the
surface of such soils, it tends to become tied up near the soil surface and
remains unavailable to the plant roots. Calcium, potassium, and sometimes
boron can also be relatively immobile in soil and are best applied before you
plant your orchard. Most other amendments can be applied to the soil up to
the time of planting the trees.
Bear in mind that soil tests do not necessarily show the actual amount
of nutrients in the soil. Instead, they show the approximate amounts that
