Extreme rainfall events can alter inter-annual biomass responses to water and N enrichment

• Published in: Biogeosciences Vol. 10; no. 12; pp. 8129 - 8138
• Main Authors: Kong, D. L, Lü, X. T, Jiang, L. L, Wu, H. F, Miao, Y, Kardol, P
• Format: Journal Article
• Language: English
• Published: Katlenburg-Lindau Copernicus GmbH 11.12.2013; Copernicus Publications
• Subjects: Forest Science; Precipitation variability; Rain; Skogsvetenskap; China, People's Rep
• ISSN: 1726-4189; 1726-4170; 1726-4189
• DOI: 10.5194/bg-10-8129-2013

Water availability has profound effects on plant growth and productivity in temperate and semiarid grasslands. However, it remains unclear how variation of inter-annual precipitation by extreme rainfall events will alter the aboveground and belowground responses of plants, and how these responses may be contingent on N availability. In this study, we examined the interactive effects of inter-annual precipitation variation and N addition on aboveground and live fine root biomass of a semiarid grassland in northern China for two consecutive years (2007 and 2008). Inter-annual variation in precipitation resulting mainly from the occurrence of extreme rainfall events in 2008 significantly affected above- and belowground plant biomass responses to water addition. In addition, variation of inter-annual precipitation by this extreme rainfall event suppressed plant responses to nitrogen addition and reduced the interaction effects between water and nitrogen addition. These effects of inter-annual precipitation fluctuation could be attributed to the negative influence of the extreme rainfall event on soil N and water availability, ultimately reducing plant rainfall use efficiency and nitrogen use efficiency. In conclusion, our results suggest ecosystem responses to water and N enrichment could be altered by inter-annual variation of precipitation regime caused by the naturally occurring extreme rainfall events.