### 2.26.2.1. Introduction[¶](#introduction "Permalink to this headline")

Groups developing Earth System Models generally account for the human footprint on the landscape in simulations of historical and future climates. Traditionally we have represented this footprint with natural vegetation types and particularly grasses because they resemble many common crops. Most modeling efforts have not incorporated more explicit representations of land management such as crop type, planting, harvesting, tillage, fertilization, and irrigation, because global scale datasets of these factors have lagged behind vegetation mapping. As this begins to change, we increasingly find models that will simulate the biogeophysical and biogeochemical effects not only of natural but also human-managed land cover.

AgroIBIS is a state-of-the-art land surface model with options to simulate dynamic vegetation ([Kucharik et al. 2000](https://escomp.github.io/ctsm-docs/versions/master/html/tech_note/References/CLM50_Tech_Note_References.html#kuchariketal2000)) and interactive crop management ([Kucharik and Brye 2003](https://escomp.github.io/ctsm-docs/versions/master/html/tech_note/References/CLM50_Tech_Note_References.html#kucharikbrye2003)). The interactive crop management parameterizations from AgroIBIS (March 2003 version) were coupled as a proof-of-concept to the Community Land Model version 3 \[CLM3.0, [Oleson et al. (2004)](https://escomp.github.io/ctsm-docs/versions/master/html/tech_note/References/CLM50_Tech_Note_References.html#olesonetal2004) \] (not published), then coupled to the CLM3.5 ([Levis et al. 2009](https://escomp.github.io/ctsm-docs/versions/master/html/tech_note/References/CLM50_Tech_Note_References.html#levisetal2009)) and later released to the community with CLM4CN ([Levis et al. 2012](https://escomp.github.io/ctsm-docs/versions/master/html/tech_note/References/CLM50_Tech_Note_References.html#levisetal2012)), and CLM4.5BGC. Additional updates after the release of CLM4.5 were available by request ([Levis et al. 2016](https://escomp.github.io/ctsm-docs/versions/master/html/tech_note/References/CLM50_Tech_Note_References.html#levisetal2016)), and those are now incorporated into CLM5.

With interactive crop management and, therefore, a more accurate representation of agricultural landscapes, we hope to improve the CLM’s simulated biogeophysics and biogeochemistry. These advances may improve fully coupled simulations with the Community Earth System Model (CESM), while helping human societies answer questions about changing food, energy, and water resources in response to climate, environmental, land use, and land management change (e.g., [Kucharik and Brye 2003](https://escomp.github.io/ctsm-docs/versions/master/html/tech_note/References/CLM50_Tech_Note_References.html#kucharikbrye2003); [Lobell et al. 2006](https://escomp.github.io/ctsm-docs/versions/master/html/tech_note/References/CLM50_Tech_Note_References.html#lobelletal2006)). As implemented here, the crop model uses the same physiology as the natural vegetation but with uses different crop-specific parameter values, phenology, and allocation, as well as fertilizer and irrigation management.

