Keywords

Carbon and water fluxes; Grasslands; Plant traits; Pasture Simulation model; Soil variables

Location

Session B4: Environmental and Agricultural Modelling for Ecosystem Services

Start Date

13-7-2016 10:50 AM

End Date

13-7-2016 11:10 AM

Abstract

We used a functional trait-based plant classification to improve the plant module of the biogeochemical grassland model PaSim. Based on four main classes (A, B, C, D) and two derived types (b, d) covering a gradient from high to low productive/fertile grassland vegetation types, we derived new classes of model plant parameters representing an evolution of a previous parameterization obtained by calibration without considering any plant diversity. Illustrative results are presented for the French grassland site of Laqueuille, by comparing two grazing management treatments: high animal stocking rate and fertilisation “intensive” (type B) and low animal stocking rate “extensive” (type b). Model performances (reflected by root mean square error and coefficient of determination metrics) showed that accounting for plant traits may help predicting carbon-water fluxes (actual evapotranspiration, gross primary productivity, ecosystem respiration and net ecosystem exchange) and soil variables (temperature and water content). Whether the pattern of results (yet complex) generally supported the validity of the plant trait-based approach to derive model parameters, a substantiation is required by assessing model performances on a range of sites (as listed in the paper) covering a wide variety of conditions.

 
Jul 13th, 10:50 AM Jul 13th, 11:10 AM

Plant trait-based assessment of the Pasture Simulation model

Session B4: Environmental and Agricultural Modelling for Ecosystem Services

We used a functional trait-based plant classification to improve the plant module of the biogeochemical grassland model PaSim. Based on four main classes (A, B, C, D) and two derived types (b, d) covering a gradient from high to low productive/fertile grassland vegetation types, we derived new classes of model plant parameters representing an evolution of a previous parameterization obtained by calibration without considering any plant diversity. Illustrative results are presented for the French grassland site of Laqueuille, by comparing two grazing management treatments: high animal stocking rate and fertilisation “intensive” (type B) and low animal stocking rate “extensive” (type b). Model performances (reflected by root mean square error and coefficient of determination metrics) showed that accounting for plant traits may help predicting carbon-water fluxes (actual evapotranspiration, gross primary productivity, ecosystem respiration and net ecosystem exchange) and soil variables (temperature and water content). Whether the pattern of results (yet complex) generally supported the validity of the plant trait-based approach to derive model parameters, a substantiation is required by assessing model performances on a range of sites (as listed in the paper) covering a wide variety of conditions.