Chen, Z., Zhang, J., Xiong, Z., Pan, G. and Muller, C. 2016. Enhanced gross nitrogen transformation rates and nitrogen supply in paddy field under elevated atmospheric carbon dioxide and temperature. Soil Biology & Biochemistry 94: 80-87.
In describing their Free Air Carbon dioxide Enrichment and elevated Temperature (T-FACE) study of a paddy-field rice-wheat rotation that was initiated in 2011, Chen et al. (2016) write that their treatments consisted of an ambient control, CO2-enriched air (500 ppm, EC), canopy air temperature elevated by 2°C (ET) and elevated CO2 combined with elevated temperature (ECT).
This significant endeavor revealed, as the five researchers report, that (1,2) "all climate change treatments stimulated gross N transformation rates and mineralization-immobilization turnover," and as a result, they say that (3) "progressive nitrogen limitation [PNL] was alleviated," due to the fact that (4,5) "all such treatments increased internal N supply and N retention capacity through  enhanced gross N transformation rates." Chen et al. additionally write that the "elevated CO2 and temperature had counteractive effects on organic N mineralization and NO3- production." But they state that "the elevated CO2 dominated the counteractive interactions between the elevated CO2 and elevated temperature."
And so it was that the five-member group of Chinese, German and Irish researchers ultimately concluded that (7) "because we expect a concomitant increase in both CO2 and temperature, we would therefore posit that there may only be minor effects on soil N dynamics in paddy fields" and that (8) "such minor effects together with alleviated PNL in paddy fields would likely benefit rice agriculture under a changing climate." And if such is truly the case, we can chalk up another benefit of atmospheric CO2 enrichment.Posted 17 June 2016