Irrigation Scheduling

Suggested Objectives

1. Determine available water-holding capacity of the root-zone (WHC).
2. Determine soil moisture content.
3. Given the Management Allowed Depletion (MAD) and consumptive use rate, determine when to irrigate and how much water to apply.
4. Perform irrigation scheduling using various methods ranging from the feel and appearance method to computer assisted programs.

Suggested Items to Consider

• Water Holding Capacity (WHC) of soils in root zone.
• Management allowed depletion (MAD).
• Allowable plant stress.
• Soil Moisture Release Curves.
• When to irrigate.
• How much to apply.
• Estimate crop Evapotranspiration rates (ET) - various models.
• Irrigation scheduling methods.
• Soil and crop monitoring.
• Crop water use monitoring.
• Soil moisture monitoring.
• Checkbook method.
• Computerized assisted methods.

Note: Note all copies of documents that were contained in the original Irrigation Training Toolbox are available electronically.

If you are unable to find a hard copy of a document in your state, you may be able to borrow a copy from the Water Management Engineer at your regional National technology Support Center

• Publication “Irrigation Scheduling: A Water Quality Must!”, NRCS, Franklin Conservation District, Pasco, WA.
• Publication “Scheduling Irrigations: A Guide For Improved Irrigation Water Management through Proper Timing and Amount of Water Application”, SCS, ARS, Cooperative Extension, CO.

 

• Video 015 “Introducing Irrigation Scheduler”, IMC, Michigan State University, MI (10:04)
  
• Video 016 “Agricultural Irrigation Scheduling - The Irrometer Story”, Irrometer Company (22:19)

There are many extension documents about irrigation scheduling. The following is a sample of 10.

• Colorado Irrigation Scheduling
• Nevada Alfalfa Irrigation Scheduling with an Automated Evaporation Pan System
• Michigan Irrigation Scheduling Tools
• Colorado Crop Water Use and Growth Stages
• Florida Basic Irrigation Scheduling in Florida

• Louisiana Irrigation Scheduling Made Easy: Using the “Look and Feel” method
• British Columbia Irrigation Scheduling With Tensiometers
• British Columbia Crop Coefficients For Use In Irrigation Schedulingg
• South Dakota Checkbook Irrigation Scheduling
• New Jersey Irrigation Scheduling with Tensiometers

1. Irrigation Scheduling Concepts
   17 slides
2. Irrigation Scheduling Methods
   18 slides
3. Irrigation Scheduling Methods 2
   9 slides
4. PRISM and SNOTEL
   72 slides