Tropospheric O 3 reduces growth and yield of many crop species, whereas CO 2 ameliorates the negative effects of O 3 . Thus, in a combined elevated CO 2 and O 3 atmosphere, seed yield is at least restored to that of charcoal‐filtered (CF) air at ambient CO 2 . The CO 2 ‐induced yield increase in CF air is highly variable, suggesting other potential resource limitations. To understand such variability in response, we tested tha...

A critical global climate change issue is how increasing concentrations of atmospheric CO 2 and ground‐level O 3 will affect agricultural productivity. This includes effects on decomposition of residues left in the field and availability of mineral nutrients to subsequent crops. To address questions about decomposition processes, a 2‐year experiment was conducted to determine the chemistry and decomposition rate of aboveground...