The only scientific studies that I've seen that support this idea relate
more to the plants' responses to insects and (possibly) disease
organisms. Apparently some of the phytochemicals that are beneficial
to us are produced to repel or otherwise thwart, repel, or otherwise
ward off parasitic organisms. In these studies, the "organically grown"
plants were more subject to direct attack than the plants that were
protected by various pesticides; the latter plants had no need to produce
some nutritionally beneficial phytochemicals. Sorry I don't have the
references readily available...

While I haven't done an extensive search, I don't know of any scientically
valid studies that show that nutrient densities are enhanced in organically
enriched soil. If someone knows of some (or studies that counter this
hypothesis), please post the references!

-frank
--[/quote]

Despite the best efforts of the fledgling pharmaceuticals and medical 'science' in general to belittle the problems, by the nineteen thirties it had become obvious to most Americans that something was seriously amiss with their soils, with their crops, and with their rapidly deteriorating personal health. During the 2nd Session of the 74th Congress in 1936, the United States Senate published Document #264, which really laid the problems facing American nutrition on the line. Verbatim extracts from Document 264 are provided at the bottom of this page, but for the specific purposes of this report, here are the three most important paragraphs.
"The alarming fact is that foods [fruits, vegetables and grains] now being raised on millions of acres of land that no longer contain enough of certain minerals are starving us - no matter how much of them we eat. No man of today can eat enough fruits and vegetables to supply his system with the minerals he requires for perfect health because his stomach isn't big enough to hold them."
"The truth is that our foods vary enormously in value, and some of them aren't worth eating as food...Our physical well-being is more directly dependent upon the minerals we take into our systems than upon calories or vitamins or upon the precise proportions of starch, protein or carbohydrates we consume."
"It is bad news to learn from our leading authorities that 99% of the American people are deficient in these minerals, and that a marked deficiency in any one of the more important minerals actually results in disease. Any upset of the balance, any considerable lack or one or another element, however microscopic the body requirement may be, and we sicken, suffer, shorten our lives."
So sixty-eight years ago, the American Government knew full well the problems facing the people, but the stuffed-shirt medical fraternity did absolutely nothing to help. In fact, driven ever onwards by the extravagant fiscal needs of pharmaceutical shareholders, medical 'science' and its subordinate doctors stood reality on its ear, and proceeded to steadily undermine what little good health the general community had left.