|LU, CHAOQUN - Iowa State University|
|YU, ZHEN - Iowa State University|
|TIAN, HANQIN - Auburn University|
|HENNESSY, DAVID - Michigan State University|
|FENG, HONGLI - Michigan State University|
|AL-KAISI, MAHDI - Iowa State University|
|ZHOU, YUYU - Iowa State University|
|Sauer, Thomas - Tom|
|ARRITT, RAYMOND - Iowa State University|
Submitted to: Environmental Research Letters
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/18/2018
Publication Date: 11/27/2018
Citation: Lu, C., Yu, Z., Tian, H., Hennessy, D.A, Feng, H., Al-Kaisi, M., Zhou, Y., Sauer, T.J., Arritt, R. 2018. Increasing carbon footprint of grain crop production in the U.S. Western Corn Belt. Environmental Research Letters. 13(12). https://doi.org/10.1088/1748-9326/aae9fe.
Interpretive Summary: The choice of which crop to plant is a decision farmers make based on expected prices for the crop. When prices for certain crops increase, farmers plant more of their land to those crops. High prices for corn and soybean in the mid-2000's led to many additional acres of new land being converted from grasslands and wetlands to corn and soybean. The tillage associated with corn and soybean production resulted in the increased loss of soil organic matter. This study followed the trends in crop production in the Western Corn Belt from 1980 to 2016 to determine how the amount of land growing different crops changed and to predict the effect on soil organic matter. The results indicated that bringing new land into crop production resulted in a significant loss of soil organic matter. The findings of this study are of interest to scientists, agency personnel, and policymakers interested in how crop prices effect land use and the impact on soil organic matter.
Technical Abstract: Global agriculture is challenged to increase soil carbon sequestration and reduce greenhouse gas emissions while providing products for an increasing population. New concerns about the impacts of extensive farming have been raised for the US Corn Belt, as cropland has rapidly expanded westward into wetlands and grasslands in recent years. We found that cropland expansion more than tripled in the most recent decade (2006-2016), compared to the preceding period (1980-2005), becoming a significant factor contributing to growing grain production. However, land use change in this period led to a soil carbon loss of 90.8±15.6 Tg (1 Tg = 1012 g). As a result, grain production in the Western Corn Belt shifted from carbon neutral to a carbon loss of 2.3 kg C kg-1 grain produced. The enlarging negative carbon footprint ('C/ 'P) indicates the major role that cropland expansion has had on the carbon cost of grain production in this region.