Abstract

A spatially distributed agroecosystem biogeochemistry model, C-PIHM, has been developed by coupling a 1-D agroecosystem model Cycles with a spatially distributed land surface hydrologic model, Flux-PIHM. Flux-PIHM is a coupled physically based model, which incorporates a land-surface scheme into the Penn State Integrated Hydrologic Model (PIHM). The land surface scheme is adapted from the Noah land surface model. Flux-PIHM is able to represent the link between groundwater and the surface energy balance, as well as the land surface heterogeneities caused by topography. Cycles is a daily time-step agroecosystem model that simulates the biogeochemical processes and management practices occurring within cropping systems and other land uses. Components of the nutrient cycling algorithms evolved from the CropSyst model, and include a unique non-linear simulation of the carbon-nitrogen cycle that includes saturation theory and a robust radiation and transpiration-based growth engine. Cycles can simulate a wide range of agricultural management practices such as tillage, organic and inorganic nutrient additions, annual and perennial crops, crop harvests as grain or forages, polycultures and relay cropping, grazing, and irrigation.
In the coupled C-PIHM model, each Flux-PIHM model grid couples a 1-D Cycles model, while soil nitrogen is transported among model grids via subsurface water flow. In each grid, Flux-PIHM provides Cycles with soil moisture, soil temperature, and solar radiation information, while Cycles provides Flux-PIHM with leaf area index. The main advantage is that the transport of nutrients are landscape-driven processes (e.g. denitrification in water accumulation areas, lags in nutrient flow due to dispersion in groundwater), which emerge from the model properties and are not incorporated via calibration.

C-PIHM provides a “next generation” tool to study the interaction among water, energy, carbon, and nutrient cycles in different landscape positions, that cannot be achieved without the coupling of these model components. The features will be demonstrated with a simulation in a 40-ha watershed with mixed land use.

Citation

Yuning Shi*, Armen Kemanian, Charles White, Felipe Montes (2018): Development of a Next Generation Spatially Distributed Agroecosystem Model. Abstract B33G-2761 presented at 2018 AGU Fall Meeting, Washington, D.C., 10-14 Dec .

This Paper/Book acknowledges NSF CZO grant support.