Micro-irrigation of Trees and Vines


Larry Schwankl
UC Irrigation Specialist
Blaine Hanson
UC Irrigation and Drainage Specialist
Terry Prichard
UC Water Management Specialist

An estimated 700,000 acres of permanent crops such as citrus, olives, and grapes are micro-irrigated annually in California. This manual covers all the various types of micro-irrigation systems - micro-sprinkler, surface drip, and subsurface drip - as they are used by growers of tree and vine crops. It includes accurate information on emitters, pumps, valves, and flowmeters; how to design the best system for your needs; wetting patterns and pressure loss; and routine maintenance, clogging, and root intrusion. Tables, graphs, illustrations, appendixes glossary, references. Revised edition.

1996, 138 pp - Publication 93-03 - $25

Funded by the California Energy Commission and the U.S. Department of Agriculture Water Quality Initiative If you have comments or suggestions, please email the LAWR webmaster at lawrweb@ucdavis.edu

Last reviewed December 19, 2002

Water Management Handbook Series
Micro-Irrigation of Trees and Vines
Publication #93-03

Table of Contents


  • List of Tables
  • List of Figures

Why a Micro-irrigation System?

  • Advantages and Disadvantages
  • Components and Considerations: An Overview
  • Irrigating Efficiently
  • Applying Water Uniformly

Putting a System Together

  • Emission Devices
  • Pressure-Compensating Emitters
  • Pressure Variation
  • Selecting Drip Emitters and Microsprinklers
  • Choosing a Pump
  • Valves and Regulators
  • Flowmeters
  • Propeller Flowmeters
  • How Deep to Place a Subsurface System
  • Filtration Equipment
  • Injection Devices
  • Designing A System

Operating the System

  • Converting to Micro-irrigation
  • Wetting Patterns
  • How Often to Irrigate
  • How Much Water is Being Applied?
  • Calculating Pressure Loss in Mainlines and Submains
  • Calculating Pressure Loss in Lateral Lines
  • Fertigation

Maintaining a Micro-irrigation System

  • Routine Maintenance
  • Chlorination

Heading Off Problems

  • Maintaining the Drip System
  • Chlorination

Monitoring the System

  • Assessing Water Quality
  • Chemical Precipitate Clogging
  • Root Intrusion
  • Salt Patterns Under Drip Irrigation


  • Appendix I
  • Appendix II
  • Glossary


Micro-irrigation - applying small amounts of water slowly and frequently through emitters spaced along polyethylene tapes or tubing - makes it possible to apply water precisely where it is needed and to apply it with a high degree of uniformity, lessening 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 it can no longer be used by the plant.

Converting from conventional surface irrigation to a micro-irrigation system therefore can greatly improve how evenly water is applied over a field and how efficiently water is used. But this potential can only be realized if the micro-irrigation system is carefully designed, maintained, and managed. This handbook has been developed to provide the information necessary to help water managers achieve that goal. Intended as a practical guide to selecting and operating a micro-irrigation system, the handbook is written so as to be easily understandable to anyone with a general agricultural background. While the book is aimed primarily at micro-irrigation system managers, irrigation system designers and others interested in micro-irrigation may also find the handbook useful.

The information presented here is grounded both in technical research and in our own field experience. While the separate chapters complement one another when taken as a whole, each also stands on its own so that it is not necessary to start at the beginning of the book and read all the way through. We suggest instead that the reader use the table of contents or turn to the chapter "Components and Considerations: An Overview" for help in locating topics of interest.