Soil Moisture Modeling with Minimal Data for Operational Ag Decision Support
Applied Research
Stacia Conger
Extension Irrigation Specialist
LSU AgCenter
Bossier City
Abstract
Efficient irrigation and drought management in Louisiana and the broader southern U.S. depends on accurate assessment of soil moisture (SM), which dictates plant water availability and evapotranspiration (ET) rates. Soil moisture directly influences agricultural productivity and water resource management, but continuous monitoring at multiple depths is limited due to high in-situ measurement costs and sparse field observations. We propose a soil water balance approach to estimate soil moisture dynamics to assess its predictive potential for agricultural applications. A five-layer soil moisture model was developed to simulate the vertical distribution of water within the root zone through estimations of infiltration, deep percolation, ET, and root water uptake processes. The key innovation lies in the use of Diurnal Amplitude of Near-surface Temperatures method for ET estimation, which relates diurnal contrasts of land and air temperature to fractional ET dynamics at the field scale. This helps equilibrate the model and preserve water balance in the soil hydrology model using minimal field data for calibration. The model parameters are optimized to ensure water and energy balance consistency and validated using data from 91 U.S. Climate Reference Network (USCRN) stations representing diverse soil and climate conditions. Results show strong agreement between simulated and observed soil moisture across depths and time, confirming the model’s ability to predict soil water dynamics reasonably. The approach demonstrates that a physically based, multi-layer soil water balance model can effectively estimate soil moisture from field to regional scales and the predictive approach can support irrigation scheduling, drought monitoring, and hydrologic forecasting, offering a reliable, low-cost tool for climate-smart and efficient agricultural water management in Louisiana and beyond.
Poster has NOT been presented at any previous NACAA AM/PIC
This poster is being submitted for judging. It will be displayed at the AM/PIC if not selected as a State winner. The abstract will be published in the proceedings.
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Authors: Stacia Conger, Nusrat Jahan, Vinit Sehgal
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Conger, S. Extension Irrigation Specialist, LSU AgCenter, Louisiana, 71112
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Jahan, N. Graduate Research Assistant, Louisiana State University, Louisiana, 70803
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Sehgal, V. Assistant Professor, Louisiana State University, Louisiana, 70803