|ZHANG, LI - North Carolina State University|
|CHENG, LEI - North Carolina State University|
|WANG, YI - North Carolina State University|
|LIU, LINGLI - North Carolina State University|
|TU, CONG - North Carolina State University|
|BOWMAN, DAN - North Carolina State University|
|BIAN, XINMIN - Nanjing Agricultural University|
|ZHANG, WEIJIAN - Nanjing Agricultural University|
|HU, SHUIJIN - North Carolina State University|
Submitted to: Environmental Science and Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/17/2018
Publication Date: 5/17/2018
Citation: Zhang, L., Qiu, Cheng, L., Wang, Y., Liu, L., Tu, C., Bowman, D., Burkey, K.O., Bian, X., Zhang, W., Hu, S. 2018. Atmospheric CO2 enrichment and reactive nitrogen inputs interactively stimulate soil cation losses and acidification. Environmental Science and Technology. 52:6895-6902.
Interpretive Summary: Carbon dioxide is a well known greenhouse gas, and rising carbon dioxide in the atmosphere is expected to enhance plant growth through higher rates of photosynthesis. However, much less is understood about the indirect effects of elevated carbon dioxide on complex terrestrial ecosystems. A collaboration of North Carolina State University, USDA-ARS, and Chinese colleagues showed that elevated carbon dioxide can cause soil acidification with a concomitant loss of nutrient cations. Application of inorganic nitrogen fertilizers enhances this effect. A mechanism that links atmospheric carbon dioxide with plant and soil microbial processes is proposed to explain this phenomenon. This is, to our knowledge, the first demonstration of elevated carbon dioxide enhancement of soil acidity. These findings raise the possibility that rising carbon dioxide could inhibit future crop and forest productivity through loss of critical soil nutrients required for plant growth.
Technical Abstract: Reactive N (Nr) inputs can alleviate N-limitation of plant growth and are predicted to sustain plant responses to the rising CO2 in the atmosphere (eCO2). However, Nr and eCO2 may elicit a cascade of reactions that alter soil chemistry and availability of nutrient elements to plants, shifting the limiting factors of plant growth. Few have so far examined the interactive effects of Nr and eCO2 on the dynamics of soil nutrient cations and soil acidity. Here we show direct evidence from two independent but complementary experiments that atmospheric CO2 enrichment and N inputs, alone and in concert, increased Ca2+ and Mg2+ in soil solutions or leachates in upland systems. Elevated CO2 also caused a small, but significant decrease in soil pH, and NH4+-N inputs amplified this effect, suggesting that CO2-induced plant preference of NH4+-N and plant growth may facilitate soil acidification. This is, to our knowledge, the first demonstration of elevated CO2 enhancement of soil acidity. Together, these findings provide new insights into the dynamics of cation nutrients and soil acidity under future climatic scenarios.