Tucker et al. (2025) Modeling soil water dynamics to optimize blueberry irrigation in sandy soils

Identification

• Journal: Frontiers in Agronomy
• Year: 2025
• Date: 2025-11-07
• Authors: Stevens P. Tucker, Najme Yazdanpanah, Apurva Rai, Josh Vander Weide, Younsuk Dong
• DOI: 10.3389/fagro.2025.1686668

Research Groups

• Department of Biosystems and Agricultural Engineering, Michigan State University, East Lansing, MI, United States
• Department of Horticulture, Michigan State University, East Lansing, MI, United States

Short Summary

This study optimized drip irrigation system design and management for blueberry plants in sandy soils using the HYDRUS-2D model, finding that a single drip line with 0.45 m or 0.60 m emitter spacing, 1800 seconds (0.5 hour) irrigation duration, and a flow rate of 5.250 x 10⁻⁷ m³/s (1.89 L/h) maximized water use efficiency and minimized leaching.

Objective

• To optimize drip irrigation system design and management practices for blueberry plants grown in sandy soils by monitoring field soil water dynamics, calibrating the HYDRUS-2D model with field data, and simulating various irrigation approaches under different climate conditions to maintain optimal soil moisture levels.

Study Configuration

• Spatial Scale: Field experiment in a commercial 'Duke' blueberry field in West Olive, Michigan, USA. Soil moisture was monitored at nine depths (0, 0.15, 0.30, 0.45, 0.60, 0.75, 0.90, 1.05, and 1.20 m). The blueberry root zone was considered to be approximately 0.30 m in radius.
• Temporal Scale: Field data collected hourly during the 2024 growing season (May 1st – October 31st). Weather data (precipitation and reference evapotranspiration) analyzed for 10 years (2014–2024) to identify average (2016), wet (2018), and dry (2021) growing seasons for simulations. Irrigation durations evaluated included 900 seconds (0.25 hour), 1800 seconds (0.5 hour), and 3600 seconds (1 hour).

Methodology and Data

• Models used: HYDRUS 2D (V.5) for simulating two-dimensional water flow in soil, governed by the 2D Richards equation and van Genuchten-Mualem constitutive relationships.
• Data sources:
  • Field soil moisture and environmental conditions: Sentek Drill & Drop soil moisture sensor system installed at nine depths, calibrated against gravimetric soil moisture content.
  • Weather data: Michigan State University Enviroweather station in Grand Junction, Michigan, for hourly precipitation and reference evapotranspiration.
  • Drip system parameters: Emitter flow rate measured using catch cans (average 5.250 x 10⁻⁷ m³/s or 1.89 L/h).
  • Wetting region: Blue dye test to evaluate the affected area from a single emitter.
  • Soil hydraulic parameters: Optimized using inverse modeling in HYDRUS-2D, calibrated against field soil moisture data.

Main Results

• The HYDRUS-2D model was successfully calibrated and validated with high statistical performance (Nash–Sutcliffe efficiency (NSE) > 0.93, index of agreement (IA) > 0.98, and root mean square error (RMSE) < 0.03 cm³/cm³).
• Optimal irrigation design for blueberry plants in sandy soil with a flow rate of 5.250 x 10⁻⁷ m³/s (1.89 L/h) was identified as a single drip line, emitter spacing of 0.45 m or 0.60 m, and an irrigation duration of 1800 seconds (0.5 hour). This combination optimized application efficiency and minimized leaching below the root zone.
• Higher emitter flow rates (5.250 x 10⁻⁷ m³/s or 1.89 L/h) enhanced soil moisture availability within the root zone for both single and double drip line systems.
• Longer irrigation durations (e.g., 3600 seconds or 1 hour) significantly increased the risk of water percolating beyond the effective root depth (0.30 m), particularly in sandy soils. Shorter durations (900 seconds or 0.25 hour) may not provide sufficient penetration.
• A single drip line with 5.250 x 10⁻⁷ m³/s (1.89 L/h) for 1800 seconds (0.5 hour) caused minimal leaching below the effective root zone, while double drip lines, though providing more even wetting, increased water loss from the root zone.
• Emitter spacing of 0.45 m and 0.60 m minimized water leaching past 0.30 m, whereas closer spacing (0.15 m and 0.30 m) led to oversaturation and deep percolation.
• Daily irrigation for 1800 seconds (0.5 hour) with 0.60 m emitter spacing and 5.250 x 10⁻⁷ m³/s (1.89 L/h) flow rate offered the most consistent performance across average, wet, and dry growing seasons, maintaining soil moisture within the optimal range (permanent wilting point (PWP) of 0.034 m, field capacity (FC) of 0.072 m, and recommended irrigation trigger of 0.053 m for the top 0.60 m of soil).

Contributions

• This study provides a unique application of the HYDRUS-2D model for site-specific drip irrigation management in commercial blueberry fields, a high-value crop with sensitive water requirements, by integrating field data and simulating varying climate conditions.
• It offers optimized design parameters (drip line configuration, emitter spacing, flow rate, duration) and management strategies for drip irrigation systems in sandy soils, enhancing water use efficiency and reducing nutrient leaching.
• The research demonstrates the HYDRUS-2D model as a reliable and effective tool for precision irrigation decision-making, contributing to the resilience of crop production against climate variability.

Funding

• Project GREEEN (project award number GR25-013) from AgBioResearch and MSU Extension at Michigan State University, in partnership with the Michigan Department of Agriculture and Rural Development.
• Michigan Blueberry Commission.
• College of Agriculture and Natural Resources Undergraduate Research Program.

Citation

@article{Tucker2025Modeling,
  author = {Tucker, Stevens P. and Yazdanpanah, Najme and Rai, Apurva and Weide, Josh Vander and Dong, Younsuk},
  title = {Modeling soil water dynamics to optimize blueberry irrigation in sandy soils},
  journal = {Frontiers in Agronomy},
  year = {2025},
  doi = {10.3389/fagro.2025.1686668},
  url = {https://doi.org/10.3389/fagro.2025.1686668}
}

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