Identifying pathways to mitigate the negative impact of urbanization trends on croplands

美国（US）在过去三十年中，中国占全球城市面积增长的40%。在这一过程中，城市化占用了数百万公顷的耕地。该项目的总体目标是确定协调城市增长与作物生产的途径，同时尽量减少负面的环境足迹。核心假设是，目前的城市化轨迹正在促使耕地向生产力较低的边缘环境扩张，并促进现有耕地上不可持续的作物产量增长，这两种情况都导致了更大的负面环境影响。具体目标是：（一）量化土地转换的长期趋势（以前是耕地，现已改为城市用地）和新耕地（ii）估计与每种作物的转换和新耕地相关的潜在生产力和环境足迹，以及（iii）探索土地利用变化、作物生产以及城市化、集约化和气候变化的不同轨迹对环境影响的未来情景。为了实现这些目标，遥感数据将用于调查美国和中国城市化的时空趋势以及主要主要作物种植面积的相关变化，再加上作物建模以及气候和土壤数据集，以估计转换和新耕地的潜在生产力和环境足迹。该研究将评估城市化对每个国家主要主粮作物面积和产量的影响，并评估在气候变化和粮食需求增加的背景下，通过更好的土地利用规划和可持续的作物集约化，协调城市增长与作物生产的途径。该项目将有助于深入了解当前将耕地转为城市用途的具体作物动态，以及与转换的耕地和新耕地相关的生产力和环境足迹。它还将提供有关通过对现有农田进行可持续作物集约化来减轻这些影响的可用空间的见解。这项研究的结果将作为未来区域研究的基础，评估城市化，粮食生产和环境影响之间的相互作用。从更广泛的角度来看，这项研究将增加农业生态系统区域建模的科学知识，提高目前为土地使用政策提供信息的能力，并优先考虑农业研究和发展计划，以实现更可持续的城乡互动。具有不同种族和性别背景的美国和中国研究人员将在该项目的保护伞下工作。将开展几项传播活动，向公众传达研究结果，旨在提高社会对城市扩张和随之而来的保护耕地的需要的认识，这最终可以帮助美国，该奖项反映了NSF的法定使命，通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

The United States (U.S.) and China accounted for 40 percent of the global increase in urban area during the past three decades. Through this process, urbanization has appropriated millions of hectares of cropland. The overall objective of this project is to identify pathways to reconcile urban growth with crop production, while minimizing negative environmental footprint. The central hypothesis is that current trajectories in urbanization are fostering cropland expansion into less-productive marginal environments and promoting unsustainable crop yield gains on existing cropland, both leading to higher negative environmental impact. Specific aims are to (i) quantify long-term trends in converted land (that was previously cropland and has changed to urban use) and new cropland (due to expansion of cropland on acres not previously used for crops) for key staple crops in U.S. and China, (ii) estimate potential productivity and environmental footprint associated with converted and new cropland for each crop, and (iii) explore future scenarios of land-use change, crop production, and environmental impact for different trajectories of urbanization, intensification, and climate change. To accomplish these aims, remote sensing data will be used to investigate spatio-temporal trends in urbanization and associated changes in planted area for key staple crops in the U.S. and China, coupled with crop modeling and climate and soil datasets to estimate the potential productivity and environmental footprint of the converted and new cropland. The research will provide an assessment of urbanization impact on area and production of key staple crops in each country and evaluate pathways to reconcile urban growth with crop production via better land-use planning and sustainable crop intensification in a context of changing climate and increasing food demand.Through an approach that combines use of remote sensing, crop modeling, and spatial analysis, the project will contribute in-depth understanding of current crop-specific dynamics in cropland conversion for urban uses and the productivity and environmental footprint associated with the converted and new cropland. It will also provide insights on the available room to mitigate these impacts via sustainable crop intensification on existing cropland. Findings from this study will serve as a foundation for future regional studies assessing interactions between urbanization, food production, and environmental impact. From a broader perspective, the research will increase the scientific knowledge for regional modeling of agro-ecosystems and improve current capability to inform land-use policy and prioritize agricultural research and development programs for more sustainable urban-rural interactions. U.S. and Chinese researchers with diverse racial and gender backgrounds will work under the umbrella of this project. Several dissemination activities will be conducted to communicate the research findings to the public, aiming to increase societal awareness about urban expansion and the concomitant need to protect croplands, which, ultimately, can help the U.S., China, and the rest of the world meet the goal of improving food security and economic development while protecting natural resources.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.