# Modeling and Parameter Calibration of Morchella Seed Based on Discrete Element Method
## 1 Introduction
Firstly, the physical properties of Morchella seeds, including their shape, adhesiveness, and softness, differ greatly from rapeseed, making it challenging for NIRS to capture the complex interaction characteristics. Secondly, the dynamic environmental conditions required for Morchella growth cannot be adequately assessed by NIRS calibration, making it difficult to reflect its actual growth and interaction dynamics. [PERSON] et al. [12] and his team proposed the differential evolution (DE) algorithm, which improved the calibration accuracy of soil models. However, its application to Morchella seed calibration may be limited. The growth of Morchella involves complex biological traits and dynamic environmental conditions, while DE algorithms are better suited for optimizing continuous physical parameters and are less effective in handling multivariable biological systems and environmental fluctuations. On the other hand, [PERSON] et al. [13] and his team's Hertz-Mindlin with JKR model calibration method proved promising for Morchella seed calibration. This method accurately describes the adhesion and contact behavior between seeds and substrate, while optimizing substrate particle size to ensure aeration and drainage, better simulating the growth environment of Morchella. Domestic scholars have proposed a \"virtual calibration\" method using the DEM to address the challenge of timely and accurate acquisition of contact parameters for small cohesive particles with high moisture content. [PERSON] et al. and [PERSON] et al. [14; 15], among others, used DEM to study the interactions between key components of seeders and seeds, providing valuable insights for the calibration of Morchella seeds. Firstly, their research emphasized the mechanical properties during the contact process between mechanical components and seeds, offering a reference for modeling the movement and interaction behavior of Morchella seeds within the substrate. Secondly, the precise seed positioning and seeding control strategies in seeder design can help optimize the distribution and nutrient absorption of Morchella seeds in the substrate. By applying similar DEM techniques, it is possible to better simulate the complex interactions between Morchella seeds and the substrate. The JKR (Johnson-Kendall-Roberts) sphere adhesion model proposed by [PERSON] et al., [PERSON] et al. (2016); [PERSON] et al. (2017), and others has been widely applied in DEM simulations and has successfully completed material calibration experiments. This model, which accounts for the adhesive forces and contact behaviors between particles, is particularly suited for materials with high surface energy and adhesion properties. This method provides important insights for the calibration of Morchella seeds. Firstly, the JKR model can accurately describe the adhesive behavior between particles, which is similar to the adhesive interactions between Morchella seeds and the substrate during cultivation. Therefore, the application of this model can help precisely simulate the complex contact processes between Morchella seeds and the substrate. Secondly, the model allows for the study of the impact of particle surface energy on their mechanical behavior, which is crucial for optimizing the growth conditions of Morchella seeds in various substrates. By adjusting the contact parameters and surface characteristics between particles, the accuracy of Morchella seed calibration can be improved, enabling a more accurate simulation of its growth behavior in real environments. [PERSON] et al. (2018); [PERSON] et al. (2019); [PERSON] et al. (2020); [PERSON] et al. (2021); [PERSON] et al. (2022) conducted DEM parameter calibration studies on grains, soil, and organic fertilizers, providing references for the calibration of Morchella seeds. Their research methods can be used to measure the physical parameters of Morchella seeds and simulate their interactions with the substrate, particularly in terms of aeration and drainage, which are key for optimizing the growth environment of Morchella seeds.