Surface Irrigation

Blaine Hanson
UC Irrigation and Drainage Specialist
Larry Schwankl
UC Irrigation Specialist

Surface irrigation - by furrow, border, or basin - is the most common irrigation method in California. Effectively using the soil surface to convey water, however, requires that the irrigator understand a number of factors. This handbook provides comprehensive coverage of these factors, including advance and recession, uniformity, infiltration, field lengths, flowrates, slope, soil variations, blocked furrows, runoff, salt, siphons, timing, and fertilizer application. Illustrations, tables, graphs, appendixes, glossary, references.

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
Surface Irrigation
Publication #94-01

Introduction

Surface irrigation is the most common irrigation method in California. Types of surface irrigation include furrow, border, and basin irrigation. Surface irrigation involves flowing water across the soil surface, thus using the soil to convey water along the field length. This results in a low capital cost. However, using the soil surface to convey water across the field introduces problems in its design and management. Both design and management depend to a high degree on the soil properties such as infiltration rate and surface roughness. These properties can be difficult to measure thus requiring a trial-and-error approach to develop proper design and managemnt strategies. This manual addresses various aspects of the design and management of surface irrigation systems to help irrigators better understand the complex behavior of these systems. The information in this manual is based on the field experience of University of California irrigation specialists and farm advisors. Because furrow irrigation is the most common surface irrigation method, this manual emphasizes furrow irrigation.

This handbook, which draws on the field experience of University of California irrigation specialists and farm advisors, is intended to help water managers use surface irrigation. Designed as a practical guide, it explains how to make water infiltration more uniform and improve overall irrigation efficiency.

Table of Contents

Introduction

  • List of Figures
  • List of Tables
  • Benefits of Irrigation Scheduling
  • Uniformity and Irrigation Efficiency
  • How Much Water was Applied and How Long Should I Irrigate?

The Soil, Plant, and Atmosphere: How Do They Interact?

  • Evapotranspiration
  • Evapotranspiration, Applied Water, and Crop Yield
  • Water Flow in Plants
  • Water Stress in Plants
  • Critical Periods for Soil Moisture Stress

Procedures for Irrigation Scheduling

  • Irrigation Scheduling for Furrow, Border (Flood), and Sprinkler Irrigation
  • Irrigation Scheduling for Micro-irrigation of Trees and Vines
  • Irrigation Scheduling for Drip Irrigation of Row Crops

Climate-based Approaches to Estimating Evapotransiration

  • Determining Crop Evapotranspiration
  • Reference Crop Evapotranspiration
  • Evaporation Pans
  • Crop Coefficients
  • Crop Coefficients Under Subsurface Drip Irrigation
  • Irrigating Young Trees
  • Using Real-Time Reference Crop Evapotranspiration for Irrigation Scheduling
  • Using Historical Reference Crop Evapotranspiration for Irrigation Scheduling and for System Design
  • Seasonal Crop Evapotranspiration
  • Calculating Irrigation System Flow Rate

Soil Moisture-based Approach to Irrigation Scheduling

  • Soil Texture
  • Soil Water
  • Root Depths
  • Monitoring Soil Moisture
  • Soil Sampling
  • Estimating Soil Moisture Depletion by Soil Appearance and Feel Tensiometers
  • Electrical Resistance or Gypsum Blocks
  • Neutron Moisture Meters
  • Capacitance Probes for Measuring Soil Moisture
  • Time Domain Reflectometry (TDR)

Plant-based Approaches to Scheduling Irrigations

  • Visual Symptoms
  • Pressure Chamber (Bomb) Method with Emphasis on Cottong Irrigation
  • Infrared Thermometers (Guns)

Special Considerations

  • Irrigation Scheduling Under Shallow Water Tables
  • Irrigation Frequency, Salinity and Yield
  • Irrigation Scheduling Under Low-Infiltration Soils
  • Effective Rainfall
  • Regulated Deficit Irrigation of Trees and Vines
  • Regulated Deficit Irrigation of Row Crops
  • Irrigating with Limited Water

Appendices

  • Appendix A. Crop Coefficients of Annual Crops
  • Appendix B. Crop Coefficients of Trees and Vines
  • Appendix C. Historical Reference Crop Evapotranspiration
  • Appendix D. Available Soil Moisture, Allowable Depletions and Typical Root Depths