Drip Irrigation

Conserve Water and Irrigate Intelligently
Article provided by Toro.

Drip irrigation, also known as micro-irrigation or trickle irrigation, is a remarkable water technology first developed decades ago. Today, it is commonly used all over the world in agricultural, nursery, greenhouse, landscape, and a variety of industrial applications. In recent years, the demand for drip irrigation has grown rapidly and for good reason - the technology can help solve serious problems associated with water use.

Advantages of Drip
It is more important than ever to use water resources wisely and to irrigate intelligently. Many landscapers have enjoyed significant water and capital investment savings using drip, while simultaneously improving plant vigor by delivering water and nutrients directly to the plant roots and avoiding unnecessary wetting of plant leaves. In addition, drip irrigation allows for targeted water applications where runoff, leaching, and the wetting of non-targeted areas such as roads, plant leaves, tree trunks, sidewalks, cars, windows, and buildings are avoided or completely eliminated.

To achieve optimal results, one must first choose the right system and then use it properly. Choosing a system can be complicated because each application is slightly different and there are many options available. However, regardless of application, it is very important that the system deliver a very high application uniformity that will distribute water evenly throughout the system. In general, gravity irrigation systems deliver relatively low application uniformity, sprinklers deliver relatively moderate application uniformity, and drip systems deliver relatively high application uniformity. A thorough understanding of drip irrigation will assist the end user in making the right choices for virtually any terrain.

Components of a Drip Irrigation System
Drip IrrigationDrip irrigation systems consist of emission devices serviced by a water distribution network that ideally includes control zone equipment. At the water source, water is controlled with automatic valves, sometimes amended with nutrients or chemicals, filtered and regulated at levels suitable for the emission devices chosen and plants being grown.

From the valve and filter, water is then delivered to each of the emission devices through a network of PVC and PE pipes. The emission device, whether it is drip tape, a drip emitter, jet or micro-sprinkler, then delivers water and nutrients to the soil where plant roots may nourish the plant. All components have attributes that affect performance, and are traded off with initial installation, operation, and maintenance costs.

Drip systems are durable and built to withstand outdoor conditions for reasonable lengths of time, but care should be taken to avoid damage by wildlife, foot traffic, or field equipment. In many cases, the environmental conditions will dictate the choice of emission device for any given application.

Emission Devices
Emission devices vary according to their flow rate, hydraulic characteristics, and wetting pattern. The ideal emission device is durable (withstands outdoor conditions), resistant to clogging (large internal passageways, self flushing), insensitive to pressure variation that occurs as a result of slope lengths of run (pressure compensating), accurate (low manufacturing Coefficient of Variation), and economically affordable.

Driplines with built-in pressure-compensating, continuously-flushing emitters allow for even distribution and protection against clogging. For longer runs or hillier locations, the pressure-compensating emitters may be more appropriate. Application rates can be tailored to fit the soil and plant type, allowing for flexible water applications above or below the soil surface.