Q. Are there any micronutrients in our hard Vegas water of
significant quantity? I ask because I'm
wondering if say a fertilizer I use lacks a certain nutrient (say calcium),
could it be made up for through regular waterings alone (assuming we remove
soil from the equation and all things being equal)? Can we definitively
conclude our water is calcium-rich or sulphur-rich or whatever rich?
A. Micronutrients are kind of a funny thing to try and
predict. Yes, there are lots of many nutrients (micronutrients as well as major
nutrients) present in our soils and water as well as calcium, magnesium and
other major or macro elements but not a sizable amount of nitrogen, hopefully.
The quantity of iron in many of our soils is more than
adequate for plants BUT because the soil is alkaline the plant can’t use them
efficiently. By making the water or soil more acidic these micronutrients
convert to a more available form and the plant can take them up. Thus we have
those iron fertilizers that are mixed with sulfur to help make the soil more
acidic (e.g., Ironite) and we have chelates which bind the iron in an a form available
to plants and release it in this form so the plant can take it up and use it
(EDDHA, EDTA, DTPA). Unlike Ironite, for instance, the chelates do not affect
the acidity of the soil making the iron (or any of the other micronutrients)
more available to plants.
Those are the two methods used to make micronutrients available to plants;
Those are the two methods used to make micronutrients available to plants;
- increase acidity, or
- chelate (protect) the nutrient in a form available to plants.
Just because there is a lot of something in the soil or
water does not mean the plant can get to it. Sometimes, besides the pH being a
problem, these nutrients may be “bound up” either as secondary minerals
(calcium in the form of calcium carbonate = limestone).
Calcium carbonate does not dissolve quickly. So if crops have a high demand for calcium over a fairly short period of time (March through August) they may not be able to get enough of that mineral (calcium) from the bound form (calcium carbonate or limestone). For instance, on some cultivars of pears and apples their demand for calcium can be very high over a relatively short period of time during development and the soil cannot release enough calcium to keep up with this large and quick demand. Thus the plants become calcium deficient (from this deficiency we develop disorders like cork spot on pear and bitter pit on apple; they are the same problem, a lack of calcium, but given different names on different crops).
Calcium carbonate does not dissolve quickly. So if crops have a high demand for calcium over a fairly short period of time (March through August) they may not be able to get enough of that mineral (calcium) from the bound form (calcium carbonate or limestone). For instance, on some cultivars of pears and apples their demand for calcium can be very high over a relatively short period of time during development and the soil cannot release enough calcium to keep up with this large and quick demand. Thus the plants become calcium deficient (from this deficiency we develop disorders like cork spot on pear and bitter pit on apple; they are the same problem, a lack of calcium, but given different names on different crops).
Golf course superintendents see this problem too in our arid
West. These very expensive golf course greens and tees are built totally on
sand. The grasses on these spots sometimes develop calcium deficiency even
though the water contains LOTS of calcium but the sand may not. They must apply
calcium to their greens and tees even though the soil surrounding the greens and
tees and the water they are applying is saturated in calcium in bound up forms.
Because they cannot return the clippings to these spots (interferes with play)
the nutrients are carted off these areas and dumped after mowing. If they could
return the clippings and let them decompose back into the grass it would lessen
the problem.
So a long winded answer to your question. Yes, there are
lots of these nutrients around but often times they are unavailable due to the
chemistry of the water, the soil and interactions with the plants.
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