wow, what a great article. i had no idea that CO2 incrases would have those kind of affect. i pulled out two intriguing quotes. the first indicates that perhpas we can thwart this by making sure the microbe levels are high in the soil. the second one demonstrates clearly what a disaster modern day agriculture is. in fact, i have been looking for taht data for some time, so thank you for posting this article. i had an argument with someone who said there was no way we could ever determine that food in centuries past was more or less nutritious than food we grow now, well apparently we can!
But reduced nitrogen decreases the microbial population, which slows the rate at which the forage can be digested, which in turn slows the rate at which forage can be eaten, and ultimately the rate at which the animals grow.
A particularly disturbing study suggests that the mechanisms of CO2 nutrient depletion may already be causing a decline in the quality of our food supply. Josep Penuelas of the Center for Ecological Research and Forestry Applications in Barcelona, Spain, compared historical plant samples grown at preindustrial levels of atmospheric CO2 with modern equivalents. He found that today's plants had the lowest levels of calcium, copper, iron, potassium, magnesium, sodium, sulfur, and zinc than at any time in the last three centuries.