Water Quality Effects of Economically Viable Land Use Change in the Mississippi River Basin under the Renewable Fuel Standard
Water Quality Effects of Economically Viable Land Use Change in the Mississippi River Basin under the Renewable Fuel Standard
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DOI：
10.1021/acs.est.0c04358
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发表时间：
2021-01-12
影响因子：
11.4
通讯作者：
VanLoocke, Andy
中科院分区：
文献类型：
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作者：
Ferin, Kelsie M.;Chen, Luoye;VanLoocke, Andy
可再生燃料标准（RFS 2）推动的生物燃料生产需求与玉米生产土地的增加和墨西哥湾氮（N）损失的增加相吻合。种植多年生能源作物（芒草和柳枝稷）可以减少氮的流失，改善水质。然而，这些好处的程度取决于生物质原料（玉米秸秆，多年生植物）的混合激励RFS 2和能源作物取代氮密集型中耕作物的程度。我们开发了一个综合的经济-生物物理模型来量化三种潜在政策情景对水质的影响，这些政策情景提供了RFS 2（RFS 1基线）之前的玉米乙醇水平; 150亿加仑的玉米乙醇（仅玉米乙醇）;或160亿加仑的纤维素乙醇（玉米+纤维素乙醇）。我们的研究结果表明，多年生能源作物生产的经济最佳位置分布在闲置农田比活跃农田具有较低的内在氮损失。我们发现秸秆清除激励的RFS 2抵消N损失的好处多年生能源作物。这一发现表明，有针对性的激励措施，减少氮素损失的补充RFS 2诱导氮密集型行作物与能源作物的位移，以减少氮素损失。
Demand for biofuel production driven by the Renewable Fuel Standard (RFS2) has coincided with increased land in corn production and increasing nitrogen (N) loss to the Gulf of Mexico. Diversifying cropland with perennial energy crops (miscanthus and switchgrass) may reduce N loss and improve water quality. However, the extent of these benefits depends on the mix of biomass feedstocks (corn stover, perennials) incentivized by the RFS2 and the extent to which energy crops displace N-intensive row crops. We developed an integrated economic-biophysical model to quantify the water quality impacts of three potential policy scenarios that provided corn ethanol at levels before the RFS2 (RFS1 baseline); 15 billion gallons of corn ethanol (corn ethanol only); or 16 billion gallons of cellulosic ethanol in addition to corn ethanol (corn + cellulosic ethanol). Our results showed that economically optimal locations for perennial energy crop production were distributed across idle cropland with lower intrinsic N loss than active cropland. We found stover removal incentivized by the RFS2 offset N loss benefits of perennial energy crops. This finding suggests that targeted incentives for N loss reduction are needed to supplement the RFS2 to induce displacement of N-intensive row crops with energy crops to reduce N losses.