Abstract：
The 2015 \"Paris Agreement\" aims to limit the global average temperature rise to significantly less than 2 °C, preferably within 1.5 °C above pre-industrial levels. A multitude of studies have focused on evaluating how different sectors respond to such levels of warming. Nonetheless, most of these studies fail to provide a clear roadmap to mitigate these impacts. A case in point is the anticipated decline in corn and soybean yields and increased phosphorus (P) and nitrogen (N) discharge into water bodies, a trend linked to past agricultural practices and climate change. In this research, we employ a novel assessment of how existing management practices under 1.5 °C and 2 °C global warming (GW) scenarios can affect nutrient availability in time and space as well as crop yield in a typical agricultural watershed in the Mid-Atlantic Region, specifically the Upper Maurice River Watershed (UMRW) in New Jersey. Using the Soil and Water Assessment Tool (SWAT) with multiple Global Climate Model (GCM) projections, we found that compared to 1.5 °C, a 2 °C GW scenario would exacerbate runoff, leading to amplified nutrient leaching. These losses decrease nutrient availability during the crop growing season. Moreover, a mismatch between the timing of fertilizer application and crop nutrient absorption caused nutrient-related stress. This nutrient and anticipated temperature stress resulted in a more significant decrease in crop yields under the 2 °C GW scenario than the 1.5 °C scenario. We have designed a management scenario to reduce future nutrient losses while increasing crop yields. The strategy involves altering the timing of planting/harvesting and the fertilizer application rate in response to a warming climate. This approach is projected to increase corn and soybean yields by +39 % (+21 %) and +2 % (+17 %), respectively, under the 1.5 °C (2.0 °C) GW scenario for the RCP-4.5 pathway. Simultaneously, it is expected to decrease the N and P loads at 1.5 °C (2.0 °C) GW. Comparable projections are also observed under the RCP-8.5 pathway.
摘要：
2015年“巴黎协定”旨在将全球平均气温上升限制在明显<2°C，优选在高于工业化前水平的1.5°C内。许多研究都集中在评估不同部门如何应对这种变暖水平。尽管如此，这些研究中的大多数未能提供明确的路线图来减轻这些影响。一个恰当的例子是玉米和大豆产量的预期下降以及向水体排放的磷（P）和氮（N）的增加，与过去的农业实践和气候变化有关的趋势。在这项研究中,我们采用了新的评估，评估了在1.5°C和2°C的全球变暖（GW）情景下现有的管理实践如何影响大西洋中部地区典型农业分水岭中的时间和空间养分可用性以及作物产量。特别是新泽西州的上莫里斯河流域（UMRW）。使用土壤和水评估工具（SWAT）和多个全球气候模型（GCM）预测，我们发现，与1.5°C相比，2°CGW的情况会加剧径流，导致营养浸出放大。这些损失降低了作物生长季节期间的养分利用率。此外，施肥时间与作物养分吸收之间的不匹配导致了与养分相关的压力。这种养分和预期的温度胁迫导致2°CGW情景下的作物产量比1.5°C情景下的作物产量显着下降。我们设计了一个管理方案，以减少未来的养分损失，同时增加作物产量。该策略涉及改变种植/收获的时间和肥料施用率，以应对气候变暖。这种方法预计将使玉米和大豆产量增加+39%(+21%)和+2%(+17%)，分别,在RCP-4.5途径的1.5°C(2.0°C)GW情景下。同时,预计在1.5°C(2.0°C)GW时降低N和P负荷。在RCP-8.5途径下也观察到相当的预测。
