Under warmer and drier future conditions, global livestock and dairy production are threatened by impacts on the productivity and nutritional quality of pastures. However, morphological and nutritional adjustments within plants in response to warming and drought vary among species and less is known how these relate to production and forage quality. To investigate this, we grew two common pasture species, tall fescue (Festuca arundinacea: grass) and lucerne (Medicago sativa: legume), in a climate-controlled facility, under different temperatures (ambient and elevated) and watering regimes (well-watered and droughted). We found that drought had a strong negative impact on biomass production, morphology and nutritional quality while warming only significantly affected both species when response metrics were considered in concert, although to a lesser degree than the drought. Furthermore, interactions between warming and drought were only seen for lucerne, with a reduction in biomass and an increase in dead material and dry matter. In tall fescue, drought had bigger impacts on nutritional composition than morphological traits, while in lucerne, drought affected all morphological traits and most of the nutritional parameters. These findings suggest that in future climate scenarios, drought may be a stronger driver of changes in the morphology and nutritional composition of pasture grasses and legumes, compared to modest levels of warming.

中文翻译：

---

与两种常见牧草物种的变暖相比，短期干旱对植物形态和营养成分的影响更大

在未来更温暖和更干燥的条件下，全球牲畜和奶制品生产受到牧场生产力和营养质量的影响。然而，植物因气候变暖和干旱而进行的形态和营养调整因物种而异，人们对这些与生产和草料质量的关系知之甚少。为了调查这一点，我们种植了两种常见的牧草品种，高羊茅（Festuca arundinacea：草）和苜蓿（Medicago sativa：豆科植物），在气候控制的设施中，在不同的温度（室温和升高）和浇水方式（充分浇水和干旱）下。我们发现，干旱对生物量生产、形态和营养质量产生了强烈的负面影响，而在同时考虑响应指标时，变暖只会显着影响这两个物种，尽管程度低于干旱。此外，变暖和干旱之间的相互作用仅出现在苜蓿中，生物量减少，死物质和干物质增加。在高羊茅，干旱对营养成分的影响大于对形态性状的影响，而在卢塞恩，干旱影响了所有的形态性状和大部分营养参数。这些发现表明，在未来的气候情景中，