Comparison of Irrigation Allocation Models for Estimating Agricultural Water Requirements in Florida Considering the Influence of Precipitation Data Type

Collaborators Conrado de Leon(Graduate student), Kati W. Migliaccio, Michael Dukes, Henry Hochmair, Kelly Morgan
Time frame August 2014 to May 2016

Summary
Irrigation models in Florida use different climate data to estimate the amount of water needed by plants to satisfy crop water requirements. Crop water requirements refer to the amount of water needed to satisfy the loss of water due to evapotranspiration, considering precipitation and irrigated water required for an optimal crop yield and an efficient use of water resources. Hence, rainfall variability and quality of rainfall data are influential factors to be considered in the estimation of irrigation requirements in Florida. An evaluation of different rainfall data sets and their effects on irrigation requirements will be performed with two of the irrigation models used by the Florida Water Management Districts.

Irrigation requirement models in Florida use different climate data to estimate the amount of water needed by plants to satisfy the loss of water due to evapotranspiration. To satisfy these water requirements, irrigation models consider precipitation and irrigated water required for an optimal crop yield and an efficient use of water resources. Hence, rainfall variability and quality of rainfall data are influential factors to be considered in the estimation of irrigation requirements in Florida. An evaluation of different rainfall data sets and their effects on irrigation requirements will be performed with two of the irrigation models used by the Florida Water Management Districts.

Research Objectives
The overall goal of this study is to compare the estimation of irrigation requirements for agricultural farms in Florida with the use of two commonly used models using different sources of rainfall data as inputs in farms with varying distance from measured precipitation data sources (i.e., weather station). The specific objectives are as follows:

  1. Apply the AFSIRS and AGMOD models to compare differences in predicted irrigation requirements using input data from a gridded weather data source and a weather station network.
  2. If time permits, we will develop and calibrate a soil water balance model with a GIS interface for estimation of irrigation requirements.

Methods
We will use the Agricultural Field Scale Irrigation Requirement Simulation (AFSIRS) model, and the Agricultural Water Use Model (AGMOD) to estimate crop water requirements in agricultural farms in Florida. We will modify model input rainfall data sets with historical data of the Florida Automated Weather Network and with multi-sensor radar and rain gauge estimates from the National Weather Service and the National Oceanic and Atmospheric Administration to compare output estimations of water requirements from the two models. The results of this study will evaluate the effects of rainfall distribution and source of rainfall data and the potential differences on irrigation requirements and water allocation according to the two different models.


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