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The Impacts of Nitrogen Applications on Paddy Field Agriculture

Paper Reviewed
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 [6] 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