Mechanistic and Empirical Models Simulating Nutrient Absorption and Response to Saline Irrigation Water in Floriculture Crops

Models in the plant sciences can be classified as being either mechanistic (also called "process-based") or empirical.  In considering which approach to use one must be cognizant of the intended use (decision support, scientific knowledge) and intended plasticity of the model.  Several complex factors interact to affect ion absorption by roots including root surface area, ion availability, organ sink strength, nutrient storage, remobilization, and nutrient antagonisms.  A mechanistic model attempting to integrate these factors to simulate N, P, and K absorption demonstrated that remobilization of phloem mobile nutrients plays an important role in growth of flush-harvest cut flower roses.  Empirical models are often used to describe a discrete plant response under fairly specific growth conditions.  This approach was taken to describe growth response of several bedding plants in response to fertilizer concentration or saline irrigation water with the goal of aiding production management.  In another case, an empirical model helped elucidate that one of the detrimental effects of high NaCl in irrigation water is that chloride acts antagonistically to inhibit nitrate absorption.