

Modeling representation of the coupled biogeochemical and hydrological cycling with real-world practices
Apply modeling approach as a decision-support tool to identify optimized nutrient and water management options for reducing air and water pollution, mitigating climate warming, and maintaining food production.
Current Sponsor: USDA NIFA
Selected Publications:
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Lu, C., Yu, Z., Hennessy, D.A., Feng, H., Tian, H. and Hui, D., 2022. Emerging weed resistance increases tillage intensity and greenhouse gas emissions in the US corn–soybean cropping system. Nature Food, 3(4), pp.266-274.
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Yu, Z., C. Lu, D.A. Hennessy, H. Feng, H. Tian. 2020. Impacts of tillage practices on soil carbon stocks in the US corn-soybean cropping system during 1998 to 2016. Environmental Research Letters doi: 10.1088/1748-9326/ab6393
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Yu, Z., C. Lu, P. Cao, H. Tian. 2018. Long-term terrestrial carbon dynamics in the Midwestern United States during 1850-2015: Roles of land cover and land use change and agricultural management. Global Change Biology DOI: 10.1111/gcb.14074
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Tian, H., C. Lu, J. Melillo, W. Ren, Y. Huang, X. Xu, M. Liu, C. Zhang, G. Chen, S. Pan, J. Liu, and J. Reilly. 2012. Food benefit and climate warming potential of nitrogen fertilizer uses in China. Environmental Research Letters 7, doi:10.1088/1748-9326/7/4/044020

Quantification of land-to-atmosphere greenhouse gas fluxes
Quantify net biogenic fluxes of CO2, CH4, and N2O in the terrestrial ecosystems in response to natural and anthropogenic disturbances, and assess the consequences of management practices to three gas together.
Current Sponsor: USDA NIFA
Selected Publications:
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Lu, C., Yu, Z., Zhang, J., Cao, P., Tian, H., and Nevison, C., 2021. Century‐long changes and drivers of soil nitrous oxide (N2O) emissions across the contiguous United States. Global Change Biology. https://doi.org/10.1111/gcb.16061
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Tian, H., C. Lu, P. Ciais, A.M. Michalak, J.G. Canadell, E. Saikawa, D.N. Huntzinger, K. Gurney, S. Sitch, B. Zhang, J. Yang, P. Bousquet, L. Bruhwiler, G. Chen, E. Dlugokencky, P. Friedlingstein, J. Melillo, S. Pan, B. Poulter, R. Prinn, M. Saunois, C.R. Schwalm, and S.C. Wofsy. 2016. The terrestrial biosphere as a net source of greenhouse gases to the atmosphere, Nature https://doi.org/10.1038/nature16946
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Lu, C., and Tian, H. 2013. Net Greenhouse Gas Balance in Response to Nitrogen Enrichment: Perspectives from a Coupled Biogeochemical Model. Global Change Biology 19, 571-588. DOI: 10.1111/gcb.12049.

Quantification of land-to-aquatic mass flow
Investigate how environmental changes taken place on land would affect river discharge and C and N export, and thus affect coastal productivity and water quality.
Current sponsor: Iowa Nutrient Research Center, NSF CAREER, NSF INFEWS
Selected Publications:
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Zhang, J., Lu, C., Crumpton, W., Jones, C., Tian, H., Villarini, G., Schilling, K., and Green, D., 2022. Heavy Precipitation Impacts on Nitrogen Loading to the Gulf of Mexico in the 21st Century: Model projections under future climate scenarios. Earth's Future, https://doi.org/10.1029/2021EF002141
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Lu, C., J. Zhang, H. Tian, W. Crumpton, M. Helmers, W. Cai, C. Hopkinson, S. Lohrenz. 2020. Increased extreme precipitation challenges nitrogen load management to the Gulf of Mexico. Communications Earth & Environment https://doi.org/10.1038/s43247-020-00020-7

Agroecosystem modeling and sustainable agriculture assessment
Through modeling approach, we comprehensively assess the potential of agroecosystems in increasing crop yields, while maximizing resource use efficiency, and reducing GHG emissions and land-to-water nutrient loads
Current Sponsor: NSF CNH (Dynamics of Coupled Natural and Human Systems), USDA NIFA
Selected Publications:
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Zhang, J., Cao, P. and Lu, C. 2021. Half‐Century History of Crop Nitrogen Budget in the Conterminous United States: Variations Over Time, Space and Crop Types. Global Biogeochemical Cycles, https://doi.org/10.1029/2020GB006876
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Lu, C., J. Zhang, P. Cao, J. Hatfield. 2019. Are we getting better in using nitrogen? — Variations in nitrogen use efficiency of two cereal crops across the United States. Earth’s Future, DOI: 10.1029/2019EF001155
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Lu, C., Z. Yu, H. Tian, D. Hennessy, H. Feng, M. Al-Kaisi, Y. Zhou, R. Arritt. 2018. Increasing carbon footprint of grain crop production in the U.S. Western Corn Belt. Environmental Research Letters, https://doi.org/10.1088/1748-9326/aae9fe
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Cao, P., C. Lu, and Z. Yu. 2018. Historical Nitrogen Fertilizer Use in Agricultural Ecosystem of the Continental United States during 1850–2015: Application rate, Timing, and Fertilizer Types. Earth System Science Data, 969-984. DOI:10.5194/essd-10-969-2018
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Yu, Z., and C. Lu. 2018. Historical cropland expansion and abandonment in the continental U.S. during 1850 to 2016. Global Ecology and Biogeography https://doi.org/10.1111/geb.12697.

Ecosystem model development and improvement
Use modeling approach to scale up plot-level field observations to watershed-, regional, and global levels, improve model representation of key biogeochemical and hydrological processes through data-model fusion.
Current Sponsor: NSF MacroSystems Biology and Early NEON Science
Selected Publications:
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Lu, C., H. Tian, J. Zhang, Z. Yu, S. Pan, S. Dangal, B. Zhang, J. Yang, N. Pederson, A. Hessl. 2019. Severe long-lasting drought accelerated carbon depletion in the Mongolian Plateau. Geophysical Research Letters doi: 10.1029/2018GL081418
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Yu, Z. , C. Lu, H. Tian, J. Canadell. 2019. Largely underestimated carbon emission from land use and cover change in the conterminous U.S. Global Change Biology https://doi.org/10.1111/gcb.14768
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Tian, H., J. Yang, C. Lu, R. Xu, J. Canadell, R. Jackson, A. Arneth, and 18 others. 2018. The global N2O Model Intercomparison Project (NMIP): objectives, simulation protocol and expected products. Bulletin of American Meteorological Society https://doi.org/10.1175/BAMS-D-17-0212.1