Simulation of year-round plant growth and nutrient uptake in Rosa hybrida over flowering cycles

Abstract

Cut flower roses grown hydroponically in greenhouses produce flowers year-round in flushes, indicating changes in the plant biomass during each flowering cycle. Due to the cyclical nature of productivity, it is difficult to optimize the supply of nutrient to the plants in hydroponic system. To address this challenge, this study was conducted to develop an integration model using three sub-models (shoot growth, root growth, and nutrient uptake), evaluate the developed models with experimental data, and predict the year-round changes in plant growth and nutrient uptake in rose plants. Parameters for the models were estimated using non-linear regression by fitting data collected from experiments. The nutrient uptake rate of six macro-nutrients (NO₃-N, NH₄-N, P, K, Ca, and Mg), and the root growth rate relying on the shoot growth from self-rooted one-year old ‘Kardinal’ roses were collected. As results of simulation, the maximum nutrient uptake potential (mM · m⁻² · d⁻¹) was predicted for macro-nutrients of 17.07 in NO₃-N, 12.67 in K, 12.22 in NH₄-N, 4.39 in Ca, 3.12 in P, and 1.57 in Mg. Simulations using the developed models were well matched with real plant responses in plant growth and nutrient uptake in short-term (one flowering cycle) and long-term (year-round).