Models in Irrigation andWater Management - Practices of Irrigation and On-farm Water Management - page 379

Chapter 10
Models in Irrigation and Water Management

Contents

10.1 Background/Need of a Model ........................ 380
10.2 Basics of Model: General Concepts, Types, Formulation and Evaluation System . 380
10.2.1 General Concepts .......................... 380
10.2.2 Different Types of Model ...................... 381
10.2.3 Some related terminologies ..................... 386
10.2.4 Basic Considerations in Model Development and Formulation of
Model Structure ........................... 389
10.2.5 Model Calibration, Validation and Evaluation ............. 390
10.2.6 Statistical Indicators for Model Performance Evaluation ......... 391
10.3 Overview of Some of the Commonly Used Models ............... 393
10.3.1 Model for Reference Evapotranspiration (ET 0 Models) ......... 393
10.3.2 Model for Upward Flux Estimation .................. 397
10.3.3 Model for Flow Estimation in Cracking Clay Soil ........... 397
10.3.4 Model for Irrigation Planning and Decision Support System ....... 402
10.3.5 Decision Support Model ....................... 405
10.4 Crop Production Function/Yield Model .................... 406
10.4.1 Definition of Production Function ................... 406
10.4.2 Importance of Production Function .................. 406
10.4.3 Basic Considerations in Crop Production Function ........... 407
10.4.4 Pattern of Crop Production Function ................. 407
10.4.5 Development of Crop Production Function ............... 408
10.4.6 Some Existing Yield Functions/Models ................ 408
10.4.7 Limitations/Drawbacks of Crop Production Function .......... 411
10.5 Regression-Based Empirical Models for Predicting Crop Yield from
Weather Variables ............................. 411
10.5.1 Need of Weather-Based Prediction Model ............... 411
10.5.2 Existing Models/Past Efforts ..................... 412
10.5.3 Methods of Formulation of Weather-Based Prediction Model ...... 413
10.5.4 Discussion ............................. 415
10.5.5 Sample Example of Formulating Weather-Based Yield-Prediction Model

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