Water Management Handbook Series
Drip Irrigation for Row Crops
Publication #93-05
Table of Contents
Introduction
- List of Tables
- List of Figures
What Does a Drip System Offer?
- The Advantages and Disadvantages of a Drip System
- Making Irrigation More Efficient
- Applying Water Evenly
Putting a System Together
- Designing a Drip System
- Drip Tape and Tubing for Row Crop
- Deciding What Drip Tape to Buy
- Pressure Variation
- Pressure-Compensating Tape and Tubing
- How Much Pressure Will the System Lose to Friction?
- Deciding How Deep to Bury Tape
- Choosing a Pump
- Valves and Regulators
- Flowmeters
- Propeller Flowmeters
- Filtration Equipment
- Injection Devices
Operating a Drip System
- Using Drip Irrigation: An Overview
- How Much Water Does the Crop Need?
- Monitoring the Soil Moisture
- Soil Water Patterns Under Drip Irrigation
- Germinating Seeds
- Root Patterns
- Setting the Irrigation Time
- Deciding How Often to Irrigate
Fertilizing With A Drip System
- Using a Drip System to Apply Fertilizer
- Applying the Right Amount of Nitrogen
- Fertilizer Patterns Under Drip Irrigation
- Fertilizer-Water Interactions
Heading Off Problems
- Maintaining the Drip System
- Chlorination
Monitoring the System
- Assessing Water Quality
- Clogging
- Root Intrusion in Subsurface Drip Systems
- Preventing Backflow
- Salt Patterns Under Drip Irrigation
- Controlling Phytophthora Root Ro
- Weed Management
- Soil Ingestion
The Bottom Line
- Will Using a Drip System Increase Profits?
- Will Converting to Drip Irrigation Save Energy?
Appendix
- Glossary
- Index
Introduction
More and more growers in California are using drip irrigation on row crops. Drip irrigation - applying small amounts of water slowly and frequently through emitters spaced along polyethylene tape or tubing - is now the main method used in California to irrigate strawberries. Many lettuce, cauliflower, broccoli, celery, and tomato growers are also converting to drip irrigation.
The reasons for the growing popularity of drip irrigation are several. Drip irrigation offers improved yields, requires less water, decreases the cost of tillage, and reduces the amount of fertilizer and other chemicals to be applied to the crop. Because drip irrigation makes it possible to place water precisely where it is needed and to apply it with a high degree of uniformity, it lessens both surface runoff - excess water running off the lower end of the field - and deep percolation - water flowing down through the soil past the root zone where cannot be used by the crop. Drip irrigation can also be used in conditions unsuitable for other irrigation methods - on steep and undulating slopes, in very sandy soils, and in fields with widely varying soils.
These features make drip irrigation potentially much more efficient than other irrigation methods, which can translate to a significant water savings. But drip irrigation can only achieve this level of high efficiency if the system is carefully designed and managed so as to prevent such problems as emitter clogging and differences in emitter flowrates stemming from pressure variations in the irrigation system or from differences in emitters and flow passages originating in the manufacturing process.
This handbook is intended to serve as a practical guide to designing and managing a drip system for irrigating row crops and to addressing the unique problems associated with drip irrigation. It discusses patterns of root development, soil water content, and soil salinity under drip irrigation; how to apply water uniformly; how to determine how much water is being applied, how often to irrigate, and how long each irrigation should be; how to inject chemicals and fertilizers through a drip system; and how to prevent clogging from chemical precipitates, organic matter, and roots.
Our program is dedicated to the study of irrigation problems and techniques.
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