Atmospheric CO2 Helps Plants Overcome Nutrient Limitations
As in the case of water, a lack of soil nutrients may sometimes pose a significant limitation to vegetative growth and development; but rising atmospheric CO2 concentrations are making it ever easier for plants to cope with this stress as well.
In Idso and Idso's (1994) analysis of soil nutrient limitations, the percentage growth enhancement due to a 300-ppm rise in the air's CO2 content actually did exhibit a slight (but statistically non-significant) decline, dropping from 51% to 45% when nutrients went from non-growth-limiting to limiting in a group of 70 experiments. But when the atmospheric CO2 enrichment was 600 ppm, this slight negative trend reversed itself, going from a CO2-induced growth stimulation of 43% when nutrients were present in abundance to a 52% enhancement when their supply was sub-optimal. And for a 1200-ppm increase in atmospheric CO2, the percentage growth enhancement jumped from 60% when the soil nutrient supply was adequate to 207% when it was less-than-adequate.
Idso, K.E. and Idso, S.B. 1994. Plant responses to atmospheric CO2 enrichment in the face of environmental constraints: A review of the past 10 years' research. Agricultural and Forest Meteorology 69: 153-203.