Water stress due to increased intra-annual precipitation variability reduced forage yield but raised forage quality of a temperate grassland
Water stress due to increased intra-annual precipitation variability reduced forage yield but raised forage quality of a temperate grassland
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DOI：
10.1016/j.agee.2014.01.013
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发表时间：
2014-03-15
影响因子：
6.6
通讯作者：
Jentsch, Anke
中科院分区：
文献类型：
--
作者：
Grant, Kerstin;Kreyling, Juergen;Jentsch, Anke
由于气候变化，预计年内降水量变异性的增加，包括极端干旱和暴雨事件，将影响主要的生态系统进程。有证据表明，作物和饲料产量将受到气候变化的影响。由于人口的增长和对高质量饲料需求的增加，有必要确定降水变率增加对牧草产量和质量的影响，以适应或实施补偿策略来应对可能的负面影响。（低、中、高）与管理策略即施肥和改变收获日期（推迟10天）的相互作用。测定了产草量和根长，量化了粗蛋白、粗纤维、粗灰分、粗脂肪、糖、中性洗涤纤维（NDF）、酸性洗涤纤维（ADF）、体外产气量等牧草品质参数，估算了相对饲用价值、泌乳净能和代谢能。此外，我们测试了极端天气事件的季节性对牧草产量和质量对管理策略的响应的影响。此外，功能组的比例被改变对更少的草和更多的杂类草生物量与放大的降水变化。随着降水量的增加，粗蛋白含量增加，纤维含量（粗纤维，NDF，ADF）减少，提高了相对饲料价值。干旱期施肥提高了粗蛋白含量，干旱期后延迟收获降低了粗蛋白含量。施肥减少了极端降水造成的草地年产量损失。氮稀释效应（植物氮浓度随地上部生物量的增加而降低）可能会影响降水变化下草地的粗蛋白含量，并可能掩盖降水变化对植物氮的影响，从而影响草地物种的质量。然而，植物群落组成和植物衰老的变化似乎是牧草质量变化的主要驱动力。施肥在干旱期间和收获延迟干旱期间后，只有部分成功的管理策略，以维持牧草生产在更极端的降水制度的未来。需要制定进一步的战略，承认植物物种组成的变化，在面对不断变化的降水模式的饲料质量变化的主要驱动力。(c)2014爱思唯尔有限公司版权所有。
Due to climate change an increase in the intra-annual precipitation variability including extreme drought and heavy rainfall events is predicted to impact major ecosystem processes. Evidence suggests that crop and forage production will be affected by altered climate variability. Due to the growing human population and rising demand for high quality animal feed it is necessary to determine the consequence of increased precipitation variability on forage yield and quality in order to adapt or implement compensation strategies against possible negative effects.Here, we present data from a field experiment in which a temperate European grassland was subjected to altered intra-annual precipitation variability (low, medium, high) in interaction with management strategies namely fertilization and alteration of harvest date (delay by 10 days). We measured forage yield and root length, quantified parameters of forage quality (crude protein, crude fiber, crude ash, crude fat, sugar, neutral detergent fiber (NDF), acid detergent fiber (ADF), in vitro gas production) and estimated relative feed value, net energy for lactation and metabolizable energy. Additionally, we tested the influence of seasonality of extreme weather events on the responsiveness of forage yield and quality to management strategies.Increased intra-annual precipitation variability decreased forage yield of the grassland. Furthermore, the proportion of functional groups was altered toward less grass and more forb biomass with amplified precipitation variability. Increased crude protein content and reduced fiber content (crude fiber, NDF, ADF) with increasing precipitation variability improved the relative feed values. Crude protein content was enhanced by fertilization during drought but reduced by delayed harvest after the drought period. Fertilization reduced losses in grassland annual yield caused by extreme precipitation. Management strategies proved less effective if precipitation variability occurred later in the season than earlier in the season.A nitrogen dilution effect (decreased plant nitrogen concentration with increasing shoot biomass) likely influenced the grassland crude protein contents under altered precipitation regimes and might have masked possible effects of precipitation variability on plant nitrogen and therefore on quality of grassland species. Nevertheless, alterations in the plant community composition and plant senescence seem to be the main drivers of forage quality change. Fertilization during drought periods and harvest delay after drought periods were only partially successful as management strategies to sustain forage production in more extreme precipitation regimes of the future. Further strategies need to be developed that acknowledge the shift in plant species compositions as the main driver of changes in forage quality in the face of changing precipitation patterns. (c) 2014 Elsevier B.V. All rights reserved.