Enhanced evapotranspiration was observed during extreme drought from Miscanthus, opposite of other crops
Enhanced evapotranspiration was observed during extreme drought from Miscanthus, opposite of other crops
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在极端干旱期间观察到芒草的蒸散量增强，与其他作物相反
DOI：
10.1111/gcbb.12448
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发表时间：
2017
期刊：
影响因子：
5.6
通讯作者：
C. Bernacchi
中科院分区：
文献类型：
--
作者：
É. Joó;Marcelo Zeri;M. Z. Hussain;E. DeLucia;C. Bernacchi
作为长期实验的一部分，研究了2012年美国中西部地区发生的极端干旱和高温胁迫对3个多年生生态系统(柳枝菊、芒草、草原)和玉米/大豆农业生态系统的蒸散(ET)、净生态系统生产力(NEP)和水分利用效率(WUE)的影响。芒属植物最初的反应较慢，但随着干旱的加剧，最终会出现剧烈的ET，这导致了作物中最大的水分亏缺。干旱高峰时较高的蒸腾速率可能是由深层土壤水分提供的，但这表明芒属植物在干旱期间的气孔导度可能与其他生态系统的响应不同，这与各向异性策略一致。在干旱初期，玉米和柳枝菊/草原的耗水量存在差异，但当干旱加剧时，所有这些生态系统都遵循节水策略。当温度达到40℃时，芒属植物的总初级生产力(GPP)有所下降，但这是可逆的，但仍是生态系统中总GPP最大的。与其他年份相比，2012年芒属植物的蒸散量增加导致生态系统WUE大幅下降。在一次极端的历史性干旱中测量到的芒属的生物物理反应表明，这种物种在干旱期间可以比其他生态系统更长时间地保持高生产力，但代价是用水。虽然芒花在干旱期间保持了生产力，但由于土壤水分枯竭，恢复滞后。芒草的增强ET可能通过增加深层土壤水分向大气的供应而加剧干旱。
The impact of extreme drought and heat stress that occurred in the Midwestern U.S. in 2012 on evapotranspiration (ET), net ecosystem productivity (NEP), and water‐use efficiency (WUE) of three perennial ecosystems (switchgrass, miscanthus, prairie) and a maize/soybean agroecosystem was studied as part of a long‐term experiment. Miscanthus had a slower initial response but an eventually drastic ET as drought intensified, which resulted in the largest water deficit among the crops. The substantially higher ET at peak drought was likely supplied by access to deep soil water, but suggests that stomatal conductance of miscanthus during the drought may respond differently than the other ecosystems, consistent with an anisohydric strategy. While there was a discrepancy in the water consumption of maize and switchgrass/prairie in the early time of drought, all these ecosystems followed a water‐saving strategy when drought intensified. The gross primary production (GPP) of miscanthus dropped, but was reversible, when temperature reached 40 °C and still provided the largest total GPP among the ecosystems. Increased ET for miscanthus during 2012 resulted a large decline in ecosystem WUE compared to what was observed in other years. The biophysical responses of miscanthus measured during an extreme, historic drought suggest that this species can maintain high productivity longer than other ecosystems during a drought at the expense of water use. While miscanthus maintained productivity during drought, recovery lagged associated with depleted soil moisture. The enhanced ET of miscanthus may intensify droughts through increase supply of deep soil moisture to the atmosphere.