Simulating Guinea Grass Production: Empirical and Mechanistic Approaches

• DOI: 10.2134/agronj2012.0245
• Publication Date: 2012-11-13T10:04:30Z
• Authors: Leandro C. Araujo; Patricia M. Santos; Daniel Rodriguez; José Ricardo M. P...; Patricia P.A. Oli...; Pedro G. Cruz
• Keywords: Panicum; Simulation Modeling; Dynamic simulation model

Tropical grasses are economically important for cattle production in Brazil, and accurate simulation models tropical pastures can benefit forage researchers farm managers by improving systems. This research calibrated validated four modeling approaches of contrasting complexity to simulate mass Mombaça Guinea grass ( Panicum maximum Jacq.). The included three empirical agro‐climatic (i.e., using cumulative degree days, photothermal units, a climatic growth index) biophysical model, Agricultural Production Systems Simulator (APSIM)‐Growth. Data sets calibration independent validation frequent records aboveground dry matter during the 2005–2006 2010–2011 growing seasons from trials. All performed well R 2 = 0.78–0.86; coefficient variation 26–32.1%). During model validation, varied between 0.69 0.78, agreement index was 0.88 0.93, 37.6 50.2%, mean bias error 6 470 kg ha −1 . Even though all were simulated observed results, APSIM‐Growth able across broader climatic, soil, management (e.g., N fertilization) conditions.