THE INTERACTION BETWEEN CO2 AND PLANT NUTRITION - COMMENTS

Effects of CO2 on plants are often confounded with effects of nutritio n. Coleman et al. (1993) showed that nitrogen concentrations in plants grown under different CO2 levels did not differ if plants of equal si zes were compared but varied at equal times and equal sizes for differ ent levels of nitrogen additions. I will suggest why this must occur u nder the conditions of the experiment. I will also suggest why nitroge n productivity should be used to interpret experimental results rather than the dubious nitrogen use efficiency.