Modeling soil water distribution under drip fertigation in chrysanthemum across soil types using HYDRUS-2D

Efficient water management is critical for sustainable chrysanthemum production under protected cultivation was conducted at Indian Agricultural Research Institute (IARI), New Delhi, India. While HYDRUS-based models are widely used for simulating soil water dynamics under drip irrigation, their application in floriculture crops remains limited, particularly for deriving crop-specific irrigation strategies. This study integrates field experimentation (2020-2023) with HYDRUS-2D simulations to evaluate soil water distribution under drip fertigation across multiple soil types. The effects of emitter discharge, irrigation scheduling, and soil hydraulic properties were analyzed to determine optimal root-zone moisture conditions. Results showed that soil moisture remained within the optimal range for up to 48 h after irrigation under appropriate scheduling. Among soil types, moisture retention followed the order: silt ≈ silty clay loam > loam > sandy clay loam > sandy loam. Model validation demonstrated high accuracy (R² = 0.90-0.96; RMSE = 0.011-0.012; Ceff = 0.90-0.92), confirming the reliability of HYDRUS-2D. Simulation results indicated that an emitter discharge of 1.0 lph combined with a 48-hour irrigation interval maintained optimal root-zone moisture while minimizing deep percolation losses. The study highlights the potential of simulation-based approaches for optimizing irrigation design and improving water-use efficiency in greenhouse floriculture systems.