Simulating forage plantain growth and defoliation in APSIM

Area of Science:

• Agricultural science
• Agronomy
• Plant science

Background:

• Plantain forage (Plantago lanceolata L.) is a valuable component of grazing systems.
• Accurate simulation models are crucial for optimizing forage management and productivity.
• Existing models may not fully capture plantain's growth dynamics under defoliation.

Purpose of the Study:

• To develop and test a crop system model for simulating plantain forage growth and defoliation management.
• To integrate this model within the Agricultural Production Systems Simulator (APSIM) framework.
• To assess the model's applicability in various regions and potential for extension to new cultivars.

Main Methods:

• Data from literature and field trials were used to parameterize the model.
• The model was developed to simulate plant growth and regrowth after defoliations.
• Validation focused on pure plantain stands in New Zealand, using biomass accumulation and nitrogen content as metrics.

Main Results:

• The model demonstrated good performance in predicting seasonal biomass accumulation and nitrogen content (Nash-Sutcliffe Efficiency > 0.8) for pure plantain stands.
• Predictions for individual defoliation events showed lower accuracy (NSE between -1.0 and 0.6).
• The model is capable of simulating both monoculture and mixed swards within APSIM.

Conclusions:

• The developed APSIM-compatible model provides a valuable tool for simulating plantain forage.
• Further data are required to enhance the model's accuracy in predicting biomass partitioning and responses to environmental factors and defoliation.
• This model supports efforts to improve grazing system management for reduced environmental impact and sustained productivity.