Industry pros to lead irrigation workshops

- Summer 1999 "Update" Newsletter Article -

Emitter Talk

Irrigation industry leaders gather to address emitter plugging issues, prospects for testing

Manufacturers and sellers of drip irrigation equipment gathered at the Center for Irrigation Technology (CIT) last month to seek consensus on an issue that has brought both great interest and some confusion to the industry during recent years. The issue is emitter plugging and how to test effectively for it, so that when a manufacturer makes claims about its product, those on the purchasing end of the process will know they are getting what they pay for.

"We get a lot of questions from growers about which product is better. How do we answer that?" asked CIT Director David Zoldoske near the opening of the half-day session, attended by more than 40 representatives of leading drip line and emitter manufacturing companies in the United States.

Participants at the session agreed that CIT is generally recognized as the premier entity in California and the United States for fair and independent testing of all types of irrigation equipment. Agricultural producers, along with turf and landscape managers, place high value on a product that has "passed" efficiency or other types of tests conducted by CIT.

However, a set of universal standards for rating emitter plugging resistance has remained elusive because of so many variables in drip irrigation, Zoldoske told participants. With a lack of standards to test against, buyers have found it difficult to discern which equipment traits might be best suited to their particular needs. They have often been forced to base purshasing decisions on unproven claims made by sellers or manufacturers.

"We ought to be able to come up with a procedure to quanfity those claims if we’re going to make them," Zoldoske said.

Emitter plugging can be caused by the growth of organic substances such as bacteria or mold, by the accumulation of inorganic matter such as sand or silt, by the combination of chemical elements such as salts and minerals, or by combinations of all these. In addition, water temperature, as well as chemical and organic components of water, differ from region to region of the country, which further complicates the list of variables.

"Plugging is one of the most difficult problems and the least quantifiable," concluded one participant.

Over the past two years CIT has conducted a series of emitter plugging tests focusing on the effect of inorganic particulates in the water. These tests were done privately under contract from manufacturers and growers. Problems arose when results were extrapolated beyond the narrow confines of the test parameters. Some manufacturer representatives at the meeting suggested that no testing results should be made public until industry-wide standards have been established.

"Until we have a protocol that we can agree to, we should agree to suspend [results of] all tests that we have done in the past," one company rep stated.

The broader consensus of the group was that past tests were valid for what they were specifically designed, but that manufacturers – and CIT- have a responsibility to ensure clarity in reporting results.Many participants asked that CIT assert more control over companies’ use of private test data. In response, Zoldoske indicated some changes would be coming.

First, he would begin drafting criteria that could be used to help control the use of information released to companies funding private CIT tests. One major issue to be addressed, Zoldoske said, would be the use of CIT’s name on results of tests that have not been accepted as standard by the industy.

Secondly, Zoldoske called for the formation of a committee to develop minimum emitter-plugging standards that can be used by manufacturers and users. The committee was organized and will work under the auspices of the Irrigation Association/Micro Common Interest Group.

Thirdly, CIT will place a moratorium on all public plugging tests until the committee has reached agreement on the issue of standards development.

Knowing the complexity of emitter plugging issues, participants agreed that developing standards would be a long-term objective, and that achievement would probably come in small steps.

"People in the sprinkler industry understand how to use the data they obtain. If we can get to that level of education in the drip end, then we will have done our job," Zoldoske said. There was high interest among the participants to make this type of meeting an annual event at CIT, Zoldoske said.

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