Chapter 14

Drip Irrigation for Greenhouse Crops

(draft book excerpts)

In greenhouse drip irrigation systems, water is applied slowly to the soil surface as discrete or continuous drops or tiny streams through a small orifice in the emitter. Rather than irrigating the entire field surface, as with overhead sprinklers or boom irrigation systems, drip irrigation is capable of delivering water precisely at the plant where nearly all of the water can be used for plant growth. Because very little water spreads to the soil between the crop rows, little water is wasted in supporting surface evaporation or weed growth. A well designed and maintained drip irrigation system is capable of an application efficiency of 90 percent. Drip irrigation pipeline systems are generally described as branching systems. Various branches are given names such as main, submain, and lateral. Choosing the right size main, submain, and lateral pipe to match the flow rates from the water source is important. Basic components can include a pump and power unit, a backflow prevention device if chemicals are used with water, a filter, a water distribution system, and some devices for controlling the volume of water and pressure in the system. Depending upon the source and quality of well water, the grower may need a water filter system on the water supply. Removing particulate matter will extend the life of pumps, valves, pressure regulators, and injectors, and is important in reducing emitter clogging.

Click on the following topics for more information on drip irrigation for greenhouse crops.

Topics Within This Chapter:

  • Drip Irrigation System Components
  • Pumping Station
  • Pipe Network
  • Main and Manifold Pipelines
  • Laterals
  • Emitters
  • Line-Source Emitters
  • Point-Source Emitters
  • Filters
  • Sand Separator (centrifugal or hydrocyclone) Filters
  • Sand Media Filters
  • Screen Filters
  • Disc Filters
  • Valves for Drip Irrigation Systems
  • Check/backflow Valves
  • Shut-off Valves or Stop Valves
  • Electronic Remote Control Valves
  • Pressure Regulators
  • Air/Vacuum Relief (AVR) Valves
  • Water Flow Meters
  • Propeller Flow Meter
  • Magnetic Flow Meter
  • Fertigation/Chemigation Components
  • Drip Irrigation Control Systems
  • Types of Control Systems
  • Open Loop Systems
  • Closed Loop Systems
  • Controllers
  • Electromechanical Controllers
  • Electronic Controllers
  • Sensors
  • Computer-based Irrigation Control Systems
  • Interactive Systems
  • Automatic Systems
  • Centralized Irrigation Control
  • Central Control Components
  • Communication between Central Control Components
  • Water Quality for Drip Irrigation Systems
  • Water Quality Analysis
  • Physical Properties
  • Chemical Properties
  • Calcium Carbonate (lime scale)
  • Biological Properties
  • Maintenance of Drip irrigation Systems
  • Filter Maintenance
  • Sand Separator (centrifugal or hydrocyclone) Filters
  • Screen Filters
  • Sand Media Filters
  • Monitoring Filter Pressure Differential
  • Line Flushing
  • Emitter Inspection
  • Chemical Treatment Chlorination
  • Chlorine Concentration Schemes
  • Sources of Chlorine
  • Calculations for Liquid Chlorine
  • Chlorine Application Precautions
  • Chemical Treatment Acidification
  • Types of Acids
  • Determining the Amount of Acid Needed
  • Application
  • Chemical Treatment Organic Farming
  • References