The landscape irrigation industry, as in many others, features some equipment components that never change, and others that seem to change continuously. New developments in pipes, fittings, valves and wires are rare, whereas changes in controllers and control systems appear to occur every month. Sprinklers basically stay the same; from year to year there are only minor manufacturer changes that most irrigation end users would never notice. However, some exciting equipment is currently being developed for landscape irrigation, and it all serves a common purpose: better uniformity, efficiency and scheduling versatility. Add these three objectives together and you discover an underlying theme of water conservation...

Nozzle development has improved the distribution uniformity of rotary sprinklers over the past several years. Better uniformities result in less water being needed per application-- which saves water and, in some cases, energy. During the last year, some sprinkler manufacturers have attempted to improve the uniformities of spray sprinklers. Although many people believe that spray sprinklers have a better distribution because of their continuous pattern, the opposite is true. Many of the spray sprinklers on the market today-- especially the adjustable arc type-- have poor uniformities. Due to the high gallonage use of spray sprinklers, improved uniformities of spray sprinklers-- when properly applied-- can significantly save water.

Also gaining popularity this year in the irrigation industry are combination rain/freeze sensors. Although not used in some parts of the country, freeze sensors (like rain sensors) inhibit the operation of the irrigation system when the temperature falls below a certain level. A rain sensor inhibits operation of the irrigation system if a certain amount of rainfall occurs. Until recently, these units had to be purchased separately. Now for a lower overall cost, especially from a labor standpoint, these units can be purchased as one item.

One of the more exciting new irrigation trends is the use of interactive systems that combine both rain and moisture sensors as a single system to help manage irrigation schedules. Several interactive systems have been unveiled in the last year. One product's premise lies in the fact that just because it is raining does not mean your soil does not need moisture-- but it is considered poor public relations to have an irrigation system operating in the rain. Another system tracks both rainfall and evapotranspiration (ET), only allowing irrigation when needed. These various devices are decidedly different than older scheduling aids.

For example, a controller is scheduled to irrigate and it begins to rain. Your landscape needs to be watered, but you do not want to have your sprinklers on during rainfall because of the image it projects (wasting water). Instead of allowing a certain amount of rain to fall before shutting off your system, as is customary, the impact of the rain on the sensor immediately prohibits all system operation. Then every eight minutes, the system checks to see if it is still raining. When the weather clears, the system checks with a moisture sensor to see if irrigation is still needed. If so, the system allows the irrigation to continue when scheduled; if no additional irrigation is needed, the system is prohibited from operating by the moisture sensor. A similar device has a combination rain gauge/ET monitor wired to a master valve on the water supply of an irrigation system. The system is scheduled to come on, but the rain gauge shows sufficient moisture, and no further irrigation is needed. The master valve remains closed. Two days later the schedule calls for an irrigation and the ET/rainfall gauge indicates that the water budget is now at a deficit; the master valve opens to allow moisture. Although rather expensive, these interactive devices justify the initial investment by quickly paying for themselves through water savings both at the residential and commercial levels.

Subsurface landscape drip irrigation, which has been a focus of much study over the last decade, continues to gain popularity. Preliminary research on its turf application is positive, indicating that its use may be as good for turf as for plant material application. Several large manufacturers are promoting the use of their subsurface drip irrigation products for turf use. Attention to detail and a thorough analysis of site specific conditions are important for this type of turf irrigation to work for an extended period of time.

Remote control technology continues to improve as more and more "wireless" communications are available on the market. The use of wireless irrigation system control allows for the remote management of sites, and will probably soon be a service tool for large maintenance contractors as a way to manage irrigation without having to travel to the site.

Two wire control systems, or decoder type systems, are also entering the commercial landscape irrigation market. Popular in overseas markets and in golf course irrigation, these systems-- although requiring a wire-- are easily expandable with a great deal of versatility built into the irrigation controls. This type of control is also usually less expensive than comparable central/hard wire systems.

Each of these irrigation trends focuses on tighter control-- which leads to better scheduling, higher efficiencies and less water use. The irrigation market of the 90's is concentrated on saving water by improving uniformities and efficiencies. The adage that "irrigation wastes water" is now being met with new product developments that better manage irrigation water supplies. This trend is sure to continue into the turn of the century...LASN