Soil acidification induced by nitrogen (N) deposition has important effects on species diversity and ecosystem function. The potential role of phosphorous (P) limitation on these effects was overlooked and observed only after decades of atmospheric N deposition. Few studies have addressed the long-term effect of P addition on soil acidification resulting from N deposition. Changes in precipitation patterns could also have important effects on soil acidification in semi-arid regions. To investigate the effects of long-term...