Re: milk as fertilizer

I'm not a "soil scientist" as such, but I do know something about high-calcium
soils and water supplies from spending the first forty-five years of my life
living in SW Idaho.

The problem with the soil calcium is that most of it is in the form of Calcium
Carbonate.  Carbonates, when the lime does dissolve and ionize (which it is
reluctant to do) leaves the carbonates available to form bicarbonate radicals
which can be toxic to many plants in more than small concentrations.

Adding sulfate radicals to the soil converts a portion of the lime to gypsum,
calcium sulfate.  We always used Ammonium sulfate as the N source, for
example, and often applied sulfur in other forms as well.

In those semi-arid areas rain tended over the centuries to dissolve small
amounts calcium compounds, moving them down in the soil profile to the maximum
depth of penetration of rainfall for that season.  Calcium compound layers
gradually built up at the average depth of penetration of the low annual
rainfall, forming a hard, nearly impenetrable layer of lime and related
compounds called Caliche.

In our area of Idaho those layers typically formed between twenty to thirty
inches below the soil surface.  We found that using a huge moldboard plow
pulled by a rather large Caterpillar tractor could rip through those layers,
rotating them to near verticle.  Releveling the land and working it mixed the
rich chemicals through the soil growth zone.  Within a few years what had been
a serious problem became a source of fertility on the soils which had been
deep plowed.

An alternative, less costly and also less quickly effective was to apply large
amounts of sulfates in any form possible, which also leached downward to the
layer of accumulation.  Chemical reaction between the calcium carbonate and
any sulfate released the carbonate as carbon dioxide and water.

Any grass, and most iris, dearly love those soils once the calcium richness is
unlocked, however accomplished.  In many cases, adding additional calcium in
the already calcium-rich soil in the more available form of gypsum tended to
alter the tilth of the soil, flocculating the clays into crumbles and making
root pentration more readily accomplished.  Any organics added also added
radicals that attacked the carbonates and tended to release them.

Neil Mogensen  now in z 7, western NC, but formerly in z 6, SW Idaho irrigated
semi-arid steppe lands

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