Additional comments on"Synthetic nitrogen fertilizers deplete soil nitrogen: a global dilemma for sustainable cereal production," by R.L. Mulvaney, S.A. Khan, and T.R. Ellsworth in the Journal of Environmental Quality 2009 38:2295-2314
J Environ Qual. 2010 Jul-Aug;39(4):1526-7; author reply 1528-32.
doi: 10.2134/jeq2010.0003le.