Microirrigation for Crop Production

Microirrigation for Crop Production
Design, Operation, and Management

Description
Microirrigation has become the fastest growing segment of the irrigation industry worldwide and has the potential to increase the quality of food supply through improved water fertilizer efficiency. This book is meant to update the text ";Trickle Irrigation, Design, Operation and Management";. This text offers the most current understanding of the management criteria needed to obtain maximum water and fertilization efficiency.

Table of Contents
I. MICROIRRIGATION THEORY AND DESIGN PRINCIPLES
CHAPTER 1. INTRODUCTION
1.1. DEFINITION
1.2. HISTORY AND CURRENT STATUS
1.2.1. Early History Worldwide
1.2.2. Early History in United States
1.2.3. Current Irrigated Area
1.2.4. Principal Crops Utilizing Microirrigation
1.2.5. Trends
1.2.6. Economics
1.2.7. Expansion in Developing Countries
1.3. GENERAL PRINCIPLES
1.3.1. Advantages
1.3.1.1. Increased water use efficiency
1.3.1.1.1. Improved crop yields and quality
1.3.1.1.2. Reduced nonbeneficial use
1.3.1.1.3. Reduced deep percolation
1.3.1.2. Use of saline water
1.3.1.3. Improved fertilizer and other chemical application
1.3.1.4. Decreased energy requirements
1.3.1.5. Improved cultural practices
1.3.1.6. Use of biological effluent and treated wastewaters
1.3.2. Disadvantages
1.3.2.1. Extensive maintenance requirements
1.3.2.2. Salt accumulation near plants
1.3.2.3. Restricted root development
1.3.2.4. High system costs
1.3.2.5. Restricted crop rotation
1.3.3. System Considerations
1.3.3.1. Design and installation considerations
1.3.3.2. Maintenance considerations
1.3.3.3. Management considerations
1.3.3.4. Economic considerations
1.3.3.4.1. System costs
1.4. SYSTEM COMPONENTS
1.4.1. Emission Devices
1.4.2. Distribution System
1.4.3. Control and Automation
1.4.4. Filtration
1.5. SYSTEM TYPES
1.5.1. Surface Drip Irrigation
1.5.2. Subsurface Drip Irrigation
1.5.3. Bubbler Irrigation
1.5.4. Microsprinkler Irrigation
REFERENCES
CHAPTER 2. SOIL WATER CONCEPTS
2.1. INTRODUCTION
2.1.1. Soil Water Regime for High Frequency Irrigation
2.2. SOIL WATER
2.2.1. Soil Water Content
2.2.2. Soil Water Potential
2.2.3. Soil Water Characteristic Curves
2.2.4. Soil Water Measurements
2.2.4.1. Gravimetric determination of soil water content
2.2.4.2. Neutron scattering
2.2.4.3. Time domain reflectometry (TDR)
2.2.4.4. Tensiometers
2.2.4.5. Heat dissipation
2.2.4.6. Electrical resistance
2.2.4.7. Capacitance
2.3. SOIL WATER MOVEMENT
2.3.1. Darcy’s Law
2.3.1.1. Alternative forms for Darcy’s Law
2.3.2. Richards’ Equation
2.3.3. Measurements of Soil Hydraulic Parameters
2.3.3.1. Direct measurements
2.3.3.2. Indirect measurements
2.3.3.3. Inverse methods
2.3.4. Shortcuts with Pedotransfer Functions
2.4. MODELING FOR EFFECTIVE MANAGEMENT AND DESIGN
2.4.1. Simplified Hemispherical Model
2.4.2. Quasi-Linear Solutions to Richards’ Equation
2.4.2.1. Steady state solutions for point sources
2.4.2.2. Steady state solutions for surface ponding
2.4.2.3. Steady state solutions for line sources
2.4.2.4. Transient (time-dependent) solutions
2.4.3. Root Water Uptake
2.4.3.1. Transient two and three-dimensional uptake functions
2.4.4. Influence of Soil Spatial Variability on Soil Water Distribution
ACKNOWLEDGMENTS
LIST OF TERMS AND SYMBOLS
REFERENCES
CHAPTER 3. IRRIGATION SCHEDULING
3.1. INTRODUCTION
3.1.1. System Capacity
3.1.2. System Uniformity Effects on Scheduling
3.1.3. System Maintenance Effects on Scheduling
3.1.4. Scheduling Constraints
3.2. IRRIGATION SCHEDULING TECHNIQUES
3.2.1 Water Balance (Evapotranspiration Base)
3.2.1.1. Climatic factors affecting crop water use
3.2.1.2. Crop factors affecting ET
3.2.1.3. Soil factors affecting ET
3.2.1.4. A direct ET approach
3.2.1.5. Evaporation pans and atmometers
3.2.1.6. Scheduling principles using evapotranspiration
3.2.2. Soil Water Control
3.2.2.1. Soil water measurement and controls
3.2.2.2. Placement and implementation
3.2.3. Plant Water Deficit Indicators
3.2.3.1. Irrigation scheduling feedback loop using plant stress indicators
3.2.3.2. Plant water potential measurements
3.2.3.3. Plant size changes from plant-water stress
3.2.3.4. Plant stress based on plant temperature
3.2.3.5. Transpiration measurements by sap flow
3.3. SUMMARY
LIST OF TERMS AND SYMBOLS
REFERENCES
CHAPTER 4. SALINITY
4.1. INTRODUCTION
4.2. QUANTIFYING SALINITY AND SODICITY
4.2.1. Salinity
4.2.2. Sodicity
4.3. CROP TOLERANCE
4.3.1. Crop Salt Tolerance
4.3.2. Factors Modifying Salt Tolerance
4.3.3. Tolerance to Specific Solutes
4.4. LEACHING
4.4.1. Leaching Requirement
4.4.2. Impact of Rainfall
4.5. INFLUENCES OF IRRIGATION SYSTEM AND WATER SOURCE ON
SOIL SALINITY
4.5.1. Influence of Irrigation Method
4.5.2. Reuse and Conjunctive Use of Waters
4.5.2.1. Reuse
4.5.2.2. Blending
4.5.2.3. Cycling
4.5.3. Environmental Consequences
4.6. SALINITY MANAGEMENT PRACTICES
4.6.1. Soil Salinity Distribution
4.6.2. Crop Considerations
4.6.2.1. Crop selection
4.6.2.2. Other management techniques
4.6.3. Infiltration
4.6.4. Reclamation of Salt-Affected Soils
4.6.4.1. Saline soils
4.6.4.2. Sodic soils
4.6.4.3. Boron leaching
4.7. SUMMARY AND CONCLUSIONS
REFERENCES
CHAPTER 5. GENERAL SYSTEM DESIGN PRINCIPLES
5.1. OVERVIEW OF THE DESIGN PROCESS
5.1.1. Initial Assessment
5.1.2. Microirrigation Layout and Components
5.1.3. The Design Process
5.2. SOURCES OF WATER
5.2.1. Water Quantity and Quality
5.2.2. Groundwater
5.2.3. Surface Water
5.3. SYSTEM HYDRAULICS
5.3.1. Hydraulic Principles
5.3.1.1. Total head
5.3.1.2. Pump energy requirements
5.3.1.3. Total friction head
5.3.1.3.1. Pipeline friction head loss
5.3.1.3.2. Multiple outlet pipes
5.3.1.3.3. Fitting, valve and component losses
5.3.1.3.4. Emitter connection losses
5.3.2. Emitter Hydraulics
5.3.3. Microirrigation Lateral Lines
5.3.3.1. Lateral line design procedures
5.3.4. Manifolds
5.3.5. Mainline Pipe System Design
5.4. FILTRATION
5.5 SUMMARY OF THE DESIGN PROCESS
ACKNOWLEDGEMENTS
LIST OF TERMS AND SYMBOLS
REFERENCES
SUPPLEMENTAL READING
CHAPTER 6. ECONOMIC IMPLICATIONS OF MICROIRRIGATION
6.1. INTRODUCTION
6.1.1. The Farm-Level Perspective
6.1.2. The Public Perspective
6.2. FARM-LEVEL COSTS OF MICROIRRIGATION
6.2.1. Fixed and Variable Costs
6.2.2. Examples from the Literature
6.2.2.1. Irrigating vegetables in Florida
6.2.2.2. Irrigating field crops with subsurface drip irrigation systems
6.2.2.3. Other examples
6.3. FARM-LEVEL BENEFITS OF MICROIRRIGATION
6.3.1. Crop Yield Effects
6.3.1.1. Deciduous fruits and nuts
6.3.1.2. Citrus
6.3.1.3. Small fruits
6.3.1.4. Tomato
6.3.1.5. Melons
6.3.1.6. Other fruits and vegetables
6.3.1.7. Cotton
6.3.1.8. Sugarcane and sugarbeets
6.3.2. Frost and Freeze Protection with Microsprinklers
6.3.3. Fertigation
6.3.4. Chemical Application of Non-Fertilizer Materials
6.3.5. Irrigation with Saline Water and Effluent
6.4. FARM-LEVEL OBSERVATIONS
6.5. PUBLIC BENEFITS AND POLICY IMPLICATIONS
6.6. SUMMARY
ACKNOWLEDGEMENTS
REFERENCES
II. OPERATION AND MAINTENANCE PRINCIPLES
CHAPTER 7. AUTOMATION
7.1. INTRODUCTION
7.2. CONTROL THEORY
7.2.1. Control Methods
7.2.1.1. On-off control
7.2.1.2. Stepwise control
7.2.1.3. Continuous control
7.2.2. Linear Systems
7.3. AUTOMATIC CONTROL SYSTEMS
7.3.1. Soil Water Methods
7.3.1.1. Soil water potential
7.3.1.2. Soil water content
7.3.1.3. Wetting front detection
7.3.2. Plant Water Methods
7.3.2.1. Leaf water potential method
7.3.2.2. Plant canopy temperature method
7.3.2.3. Plant turgor methods
7.3.2.4. Evapotranspiration estimates
7.3.2.4.1. Evapotranspiration models
7.3.2.4.2. Direct measurement of Etc
7.4. INSTRUMENTATION AND HARDWARE
7.4.1. Controllers
7.4.2. Valves
7.4.3. Flowmeters
7.4.4. Environmental Sensors
7.4.5. Filters
7.4.6. Chemical Injectors
7.5. SUMMARY
REFERENCES
CHAPTER 8. APPLICATION OF CHEMICAL MATERIALS
8.1. INTRODUCTION
8.1.1. Definitions
8.1.2. Basic Information
8.1.3. Advantages of Chemigation
8.1.4. Disadvantages of Chemigation
8.1.5. Types of Agrochemicals
8.1.5.1. Water soluble chemicals
8.1.5.2. Wettable powders
8.1.5.3. Emulsifiable (oil soluble) chemicals
8.1.5.4. Gases
8.1.6. Safety
8.1.6.1. Following the label and other regulations
8.1.7. General Considerations
8.1.7.1. Problems with chemical mixes
8.2. CHEMICAL INJECTION METHODS
8.2.1. Injection Pumps and Systems
8.2.2. Pollution Prevention
8.2.2.1. Electrical and mechanical interlock system
8.2.2.2. Backflow prevention in the irrigation line
8.2.2.3. Injection line components
8.2.3. Chemical Supply Tanks and Secondary Containment
8.2.4. Corrosion Resistance of Surfaces
8.2.5. Maintenance
8.3. CHEMICALS AND CALCULATION OF INJECTION RATES
8.3.1. Fertigation
8.3.1.1. Calculation of plant nutrient requirements
8.3.1.2. Fertilizer selection and calculation of injection rates
8.3.2. Chemigation of Non-Fertilizer Materials
REFERENCES
CHAPTER 9. APPLICATION OF BIOLOGICAL EFFLUENT
9.1. INTRODUCTION
9.1.1. Advantages of Applying Biological Effluent
9.1.2. Disadvantages of Applying Biological Effluent
9.2. CHARACTERISTICS OF BIOLOGICAL EFFLUENTS
9.2.1. Effluent Source and Degree of Treatment
9.2.2. Composition of Effluent
9.2.3. Characteristics of Effluents Used in Some Microirrigation Studies
9.3. BIOLOGICAL EFFLUENT CONSTITUENT BEHAVIOR IN SOILS
9.3.1. Nitrogen Uptake by Plants and Potential Loss Mechanisms
9.3.2. Phosphorus Uptake by Plants and Potential Loss Mechanisms
9.3.3. Trace Element Uptake by Plants and Potential Loss Mechanisms
9.3.4. Salinity Management
9.3.5. Pathogenic Organisms
9.4. HEALTH CONSIDERATIONS
9.4.1. Typical Regulations
9.4.2. Practices to Meet the Regulations
9.5. SITE CONSIDERATIONS
9.5.1. Soils
9.5.2. Climate
9.5.3. Crops
9.5.4. Land Area
9.6. DESIGN AND MANAGEMENT CONSIDERATIONS
9.6.1. System Components
9.6.2. Filtration Requirements
9.6.3. Chemical Treatment Requirements
9.6.4. Dripline Flushing
9.6.5. Monitoring Procedures
ACKNOWLEDGEMENTS
REFERENCES
CHAPTER 10. FIELD PERFORMANCE AND EVALUATION
10.1. INTRODUCTION
10.1.1. Uniformity of Water Application
10.1.2. Order of Significance of Design Parameters
10.1.3. The Goal of Microirrigation Application
10.2. VARIATIONS OF IRRIGATION APPLICATION
10.2.1. Variations from Hydraulic Design
10.2.2. Manufacturer’s Variation
10.2.3. Effects by Grouping of Emitters
10.2.4. Possible Clogging Effects
10.2.5. Total Variation
10.3. UNIFORMITY CONSIDERATIONS
10.3.1. Uniformity Parameters
10.3.2. A Linearized Water Application Function
10.3.3. Uniformity and Total Yield
10.3.4. Uniformity and Total Economic Return
10.4. FIELD PERFORMANCE AND IRRIGATION STRATEGY
10.4.1. Significance of Irrigation Scheduling
10.4.2. Optimal Irrigation
10.4.3. Conventional Irrigation
10.4.4. A Simple Irrigation Schedule
10.4.5. Irrigation Strategy for Environmental Protection
10.4.6. Microirrigation for Water Conservation
10.4.6.1. Comparing optimal schedule with conventional irrigation schedule
10.4.6.2. Comparing simple irrigation schedule with conventional irrigation schedule
10.4.6.3. Comparing simple irrigation schedule with the optimal irrigation schedule
10.4.6.4. Comparing the irrigation schedule for environmental protection with the optimal irrigation schedule
10.4.6.5. Comparing the irrigation schedule for environmental protection with the simple irrigation schedule
10.5. FIELD EVALUATION AND ADJUSTMENT
10.5.1. Design Criteria of Microirrigation
10.5.1.1 Uniformity parameters
10.5.1.2. Determination of design criteria
10.5.1.3. Selection of design criteria
10.5.2. Field Evaluation
10.5.2.1. Significance of field evaluation
10.5.2.2. Uniformity measurement
10.5.3. Repairs and Adjustment
10.5.3.1. Repairing leaks in the system
10.5.3.2. Adjustment of irrigation time
10.5.3.3. Adjustments for changes in uniformity
LIST OF TERMS AND SYMBOLS
REFERENCES
CHAPTER 11. MAINTENANCE
11.1. EMITTER OPERATION
11.1.1. Evaluation of Emitter Clogging
11.1.1.1. Source of water
11.1.1.2. Surface water
11.1.1.3. Groundwater
11.1.1.4. Wastewater
11.1.2. Water Quality
11.1.2.1. Physical aspects
11.1.2.2. Chemical aspects
11.1.2.3. Biological aspects
11.1.3. Causes
11.1.3.1. Physical, chemical, and biological factors
11.1.3.2. Microorganisms
11.1.3.3. Macroorganisms
11.2. WATER TREATMENT
11.2.1. Filtration
11.2.1.1. Screen filters
11.2.1.2. Disk filters
11.2.1.3. Media filters
11.2.1.4. Settling basins
11.2.1.5. Cyclonic filters or centrifugal separators
11.2.1.6. Filter design and operation
11.2.2. Chemical Treatment
11.2.2.1. Chemical precipitation
11.2.2.2. Acid treatment
11.2.2.3. Chlorination
11.2.2.4. Chemical injection
11.3. MAINTENANCE OPERATION
11.3.1. Approach
11.3.1.1. Chemical water treatment research
11.3.1.2. Preventive maintenance practices
11.3.1.3. Flushing
11.3.1.4. Reclamation
11.4. GUIDELINE AND PRACTICES
REFERENCES
SUPPLEMENTAL READING
III. SYSTEM TYPE AND MANAGEMENT PRINCIPLES
CHAPTER 12. SURFACE DRIP IRRIGATION
12.1. INTRODUCTION
12.2. SURFACE DRIP IRRIGATION OF PERMANENT CROPS
12.2.1. Introduction
12.2.2. Advantages and Disadvantages of Surface Drip Irrigation for Permanent Crops
12.2.3. Suitability
12.2.3.1. Suitable tree and vine crops
12.2.3.2. Geographical considerations
12.2.3.3. Water supply and quality
12.2.3.4. Maintenance and longevity
12.2.3.5. Irrigation uniformity
12.2.4. Surface Drip Design and Application
12.2.4.1. Drip emitters
12.2.4.1.1. Physical description of drip emitters
12.2.4.1.2. Emitter hydraulic characteristics
12.2.4.1.3. Coefficient of manufacturing variation
12.2.4.2. Lateral line drip tubing
12.2.4.2.1. Lateral line spacing
12.2.4.2.2. Lateral length
12.2.4.3. Emitter spacing
12.2.4.4. Design emission uniformity
12.2.4.5. Installation issues
12.2.5. Management, Evaluation, and Maintenance of Surface Drip
Irrigation Systems
12.2.5.1. Water requirements
12.2.5.2. Crop response
12.2.5.3. Drip irrigation system application rate
12.2.5.4. Irrigation efficiency
12.2.5.5. Irrigation frequency
12.2.5.6. Special management issues
12.2.6. Evaluation of Surface Drip Irrigation Systems
12.3 SURFACE DRIP IRRIGATION FOR ROW CROPS
12.3.1. Advantages and Disadvantages of Surface Drip irrigation for Row Crops
12.3.2. Suitability
12.3.3. Drip Materials
12.3.4. Driplines
12.3.5. Manifolds
12.3.6. Emitter and Dripline Spacing
12.3.7. Installation and Extraction of Surface Driplines
12.3.8. Patterns of Soil Water Content
12.3.9. Patterns of Soil Salinity
12.3.10. Crop Response to Surface Drip Irrigation
12.3.10.1. Surface versus subsurface drip irrigation
12.3.10.2. Irrigation frequency effects
12.3.11. Managing a Drip Irrigation System of Row Crops
12.3.12. Using Plastic Mulch with Surface Drip Irrigation
LIST OF TERMS AND SYMBOLS
REFERENCES
CHAPTER 13. SUBSURFACE DRIP IRRIGATION
13.1. APPLICATION AND GENERAL SUITABILITY
13.1.1. Advantages of SDI
13.1.2. Disadvantages of SDI
13.1.3. Suitability Considerations
13.1.3.1. Suitable crops
13.1.3.2. Geographical and topographical considerations
13.1.3.3. Water supply and quality
13.1.3.4. Maintenance and longevity
13.1.3.5. System uniformity considerations
13.1.3.5.1. System uniformity considerations related to emitter clogging
13.1.3.5.2. System uniformity considerations related to root intrusion and root pinching
13.1.3.5.3. System uniformity considerations related to mechanical or pest damage
13.1.3.5.4. System uniformity considerations related to soil overburden and/or compaction
13.1.3.5.5. System uniformity considerations related to soil hydraulic
parameters
13.1.3.5.6. System uniformity and longevity
13.2. SYSTEM DESIGN AND INSTALLATION
13.2.1. Materials and Components
13.2.1.1. Emitter and dripline characteristics
13.2.1.2. Additional SDI system components
13.2.2. Dripline and Manifold Design Issues
13.2.2.1. Dripline, crop row, and emitter spacing
13.2.2.2. Emitter flowrate
13.2.2.3. Dripline length
13.2.2.4. Flushing requirements and flushline design
13.2.2.4.1. Flushing velocity
13.2.2.4.2. Dripline inlet pressure and flowrate during flushing
13.2.2.4.3. Sizing the flushline and flush valve
13.2.2.5. Dripline depth
13.2.3. Installation Issues
13.2.4. Special or Unique Design Considerations
13.2.4.1. SDI design and electrical technologies
13.2.4.2. SDI design issues for recycled waters and biological effluent
13.2.4.3. Use of SDI in fully enclosed subirrigation (FES) systems
13.3. SOIL AND CROP MANAGEMENT
13.3.1. Soil Issues
13.3.1.1. Soil physical characteristics and soil water redistribution
13.3.1.2. Salinity aspects
13.3.1.3. Soil water redistribution problems caused by backpressure
13.3.1.4. Soil compaction
13.3.1.5. Managing the soil water budget components
13.3.1.6. Special or unique soil issues
13.3.1.6.1. Weed control
13.3.1.6.2. Application of insecticides for crop protection
13.3.1.6.3. Application of biological effluent
13.3.1.6.4. Soil profile injection of gases
13.3.2. Crop Issues
13.3.2.1. Crop water uptake and crop growth
13.3.2.2. Frequency of irrigation
13.3.2.3. Crop response to conjunctive water and nutrient management
13.4. SUMMARY
ACKNOWLEDGMENTS
LIST OF TERMS AND SYMBOLS
REFERENCES
CHAPTER 14. BUBBLER IRRIGATION
14.1. APPLICATION AND GENERAL SUITABILITY
14.1.1. Advantages and disadvantages
14.1.1.1. Potential advantages
14.1.1.2. Potential disadvantages
14.2. SYSTEM DESIGN AND APPLICATION
14.2.1. Materials and components
14.2.1.1. Gravity system emitters
14.2.1.2. Pressurized system emitters
14.2.1.3. Laterals and manifolds
14.2.1.4. System design procedures
14.3. SAMPLE DESIGN—LOW HEAD BUBBLER SYSTEM
14.4. MANAGEMENT, EVALUATION, AND MAINTENANCE
14.4.1. Soil Issues
14.4.2. Crops
14.4.3. Evaluation and Maintenance
LIST OF TERMS AND SYMBOLS
REFERENCES
CHAPTER 15. MICROSPRINKLER IRRIGATION
15.1. APPLICATION AND SUITABILITY OF MICROSPRINKLERS
15.1.1. Advantages of Microsprinkler Systems
15.1.2. Disadvantages of Microsprinkler Systems
15.2. MATERIALS AND COMPONENTS
15.2.1. Materials Used in Systems
15.2.1.1. Ferrous materials
15.2.1.2. Non-ferrous metals
15.2.1.3. Plastics
15.2.1.4. Elastomers
15.2.2. Microsprinkler Emitters
15.2.2.1. Emitter hydraulic characteristics
15.2.3. Emitter Manufacturing Variation
15.2.4. Emitter Types
15.2.4.1. Orifice control emitters
15.2.4.2. Vortex control emitters
15.2.4.3. Pressure compensating emitters
15.2.5. Emitter Wetting Patterns
15.2.6. Stake Assemblies
15.2.7. Lateral Tubing
15.3. LATERAL AND MANIFOLD DESIGN
15.3.1. Head Losses in Lateral Lines
15.3.2. Pressure Variation
15.3.3. Lateral Design
15.4. UNIQUE MANAGEMENT CONSIDERATIONS
15.4.1. Young Trees
15.4.2. Application Volumes
15.4.4. Freeze Protection
15.5. EVALUATION OF MICROSPRINKLER SYSTEMS
15.5.1. Uniformity
15.5.2. Irrigation System Efficiency
15.5.3. Wetting Pattern
15.5.4. Effects of Wear
LIST OF TERMS AND SYMBOLS