High tolerance of subalpine grassland to long-term ozone exposure is independent of N input and climatic drivers

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• 作者：Matthias Volk ; ^{matthias.volk@agroscope.admin.ch" class="auth_mail} ; Veronika Wolff ; Seraina Bassin ; Christof Ammann ; Jü ; rg Fuhrer
• 关键词：Air pollution ; Nitrogen ; Critical load/level ; Phytotoxic ozone dose POD ; Productivity
• 刊名：Environmental Pollution
• 出版年：June, 2014
• 年：2014
• 卷：189
• 期：Complete
• 页码：161-168
• 全文大小：999 K

文摘

In a seven-year study, we tested effects of increased N and O₃ deposition and climatic conditions on biomass of subalpine grassland. Ozone risk was assessed as exposure (AOT40) and as stomatal flux (POD_0,1). We hypothesized that productivity is higher under N- and lower under O₃ deposition, with interactions with climatic conditions.

Aboveground biomass was best correlated with growing-degree days for May (GDD_May). Nitrogen deposition increased biomass up to 60% in the highest treatment, and 30% in the lowest addition. Also belowground biomass showed a positive N-response. Ozone enrichment had no effect on biomass, and no interaction between O₃ and N was observed. Growth response to N deposition was not correlated to GDD_May or precipitation, but indicated a cumulative effect over time.

Productivity of subalpine grassland is tolerant to increasing ozone exposure, independent of N input and climatic drivers. N deposition rates at current critical loads, strongly increase the grassland yield.