Late to the party, but I have links to two articles that describe the effects of lack of Nickel and why it's a REQUIRED NUTRIENT.
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1064356/
abstract for the lazy
Soybeans (
Glycine max [L.] Merr.) grown in Ni-deficient nutrient solutions accumulated toxic urea concentrations which resulted in necrosis of their leaflet tips, a characteristic of Ni deficiency. Estimates of the Ni requirement of a plant were made by using seeds produced with different initial Ni contents. When compared to soybeans grown from seeds containing 2.5 nanograms Ni, plants grown from seeds containing 13 nanograms Ni had a significantly reduced incidence of leaflet tip necrosis. Plants grown from seeds containing 160 nanograms Ni produced leaves with almost no leaflet tip necrosis symptoms. Neither Al, Cd, Sn, nor V were able to substitute for Ni.
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1054342/
Nickel was established as an essential micronutrient for the growth of temperate cereal crops. Grain from barley (
Hordeum vulgare L. cv `Onda'; containing 40 to 80 nanograms of Ni per gram dry weight) grown in solution culture with negligible Ni concentrations (< 30 nanograms of Ni per liter) exhibited greatly reduced germination rates (
i.e. 50% less than grain from Ni-adequate plants) and seedling vigor of the viable grain was greatly depressed. Grain containing less than 30 nanograms per gram dry weight was inviable. Under Ni-deficient conditions, barley plants fail to produce viable grain because of a disruption of the maternal plant's normal grain-filling and maturation processes that occur following formation of the grain embryo. The observations that (a) barley plants fail to complete their life cycle in the absence of Ni and (b) addition of Ni to the growth medium completely alleviates deficiency symptoms in the maternal plants satisfies the essentiality criteria; thus, Ni should be considered a micronutrient for cereals. Because Ni is required by legumes, and is now established as essential for cereals, we conclude that Ni should be added to the list of micronutrients essential for all higher plant growth.
Therefore based on these results, Dyna-Gro is the most advanced nutrient company on the Earth for including Nickel in their formula where others are light years behind, I've known this for awhile in my own research but since I saw your comparison threads I had to post this.
I'm switching from Lucas MaxiBloom to Dyna-Gro Bloom and never looking back, the science is there, the other companies are slacking.
