Agroscope, Air Pollution/Climate Group, Reckenholzstrasse 191, CH-8046 Zurich, Switzerland.
Agroscope, Air Pollution/Climate Group, Reckenholzstrasse 191, CH-8046 Zurich, Switzerland.
Environ Pollut. 2014 Jun;189:161-8. doi: 10.1016/j.envpol.2014.02.032. Epub 2014 Mar 22.
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 (POD0,1). 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 (GDDMay). 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 GDDMay 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.
在一项为期七年的研究中，我们测试了增加氮和臭氧沉积以及气候条件对亚高山草原生物量的影响。臭氧风险评估为暴露（AOT40）和气孔通量（POD0,1）。我们假设在氮沉积下生产力更高，在臭氧沉积下生产力更低，且与气候条件存在相互作用。地上生物量与 5 月生长度日（GDDMay）的相关性最好。氮沉积在最高处理中增加了 60%的生物量，在最低添加中增加了 30%。地下生物量也表现出对氮的正响应。臭氧富集对生物量没有影响，也没有观察到臭氧和氮之间的相互作用。对氮沉积的生长响应与 GDDMay 或降水无关，但表明随着时间的推移会产生累积效应。亚高山草原的生产力对增加的臭氧暴露具有耐受性，与氮输入和气候驱动因素无关。当前临界负荷下的氮沉积速率会强烈增加草原的产量。
