Microirrigation Systems for Vineyards
Types of Microirrigation Systems
As mentioned, there are two main types of low-pressure irrigation systems for vineyards: drip or trickle systems and micro-sprinkler systems. Both systems can be installed to vary water application rates based on soil texture or vine vigor within the vineyard.
Drip Irrigation Systems
Drip irrigation is one of the most efficient types of irrigation systems in use today. Also commonly known as trickle or low-volume irrigation, water is rationed and applied to the plants’ root zone as needed. Drip irrigation offers an excellent alternative to sprinkler or micro-sprinkler irrigation for vineyards. Drip irrigation involves small-diameter polyethylene (poly) tubing with specially designed water-release devices installed in or on the lines. Point-source emitters are the most popular type and usually simplify the installation for drip irrigation systems. These are called line-source or point-source emitters and are used to apply a specific, low-volume rate of water—generally 0.5 to 2 GPH—directly to the root zone of a crop. The emitter’s rate of flow depends on the inlet pressure. With higher pressure, the flow will increase, and with lower inlet pressure, it will decrease. Nominal flow rates for most drip emitters are set to 0.5, 1, and 2 GPH at a 15-psi inlet pressure.
Micro-Sprinkler Systems
Micro-sprinkler systems operate at low pressure but operate at higher flow rates than drip emitters. They function as a middle ground between traditional sprinklers and drip irrigation, providing wider coverage than drip but with more water savings and efficiency than conventional systems. Micro-sprinklers are designed for areas where drip irrigation is not advisable or practical. Micro-sprinklers are rated by flow rate, wetted diameter, strip patterns (full or partial circle, flat, circular, or square), and spray method (mist, spinner, or streams). A micro-sprinkler is installed at the base of a vine, watering only that vine in most cases. However, in some cases, a micro-sprinkler is installed between two vines. Micro-sprinkler systems are similar to drip irrigation systems except that—rather than discharging water at discrete points—the water is sprayed out through a small sprinkler device at much lower rates than conventional sprinkler heads. Micro-sprinkler flow rates are generally measured in gallons per hour. Rates typically range from 2 to 50 gallons per hour (GPH) (0.03 to 0.83 GPM).
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