AHC: An integrated numerical model for simulating agroecosystem processes-Model description and application

This article introduces the AHC model as a new tool for modeling and assessing the agroecosystem processes. The AHC, as a one-dimensional numerical physical model, simulates the soil water and salt/nitrogen dynamics, heat transport, and crop growth and yield in various soil-crop environments. The key features of the AHC include that it provides the optional function for simulating the fate of salt or nitrogen; it has an efficient global method for sensitivity analysis and parameter estimation; and it is useful in a wide range of field conditions, especially for those in northern China. A menu-driven program is developed as a user-friendly interface for efficient data manipulation. This paper primarily describes the main structures and algorithms of the AHC and presents its field applicability. Model testing and application was conducted with two cases: (1) a salinity case with maize growing in salt-affected fields under arid and shallow groundwater environments (Hetao, upper Yellow River basin, northwest China); and (2) a nitrogen case with a wheat-maize rotation system in the semihumid monsoon region (Tai'an, North China Plain). Good agreement was obtained between the simulated and observed data, including the soil water contents, salt/nitrogen contents, and crop growth indicators. The soil water and salt/nitrogen dynamics, crop growth processes, and their complex interactive effects were also well interpreted using the AHC. Rational simulation proves the good applicability of the AHC for practical field use.