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May 2025Archived

 

Field picture submitted by Elizabeth Fichtner

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Maintenance of Microirrigation Systems: Page

Disc Filters

Disc filter. Photo: Jack Kelly ClarkA disc filter consists of a stack of discs, each with a series of microscopic grooves. The dimension of the grooves determines the effective mesh size of the filter, ranging from 40 to 600 mesh. Water is filtered as it flows through the grooves.
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Maintenance of Microirrigation Systems: Page

Chemical precipitation

Venturi injector. Photo: L. Schwankl Naturally occurring chemicals in groundwater that is used for irrigation can leave chemical precipitates in emitters, such as calcium carbonate (lime), iron and manganese compounds, and iron sulfide.
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Maintenance of Microirrigation Systems: Page

Treatments to Minimize Clogging

Pump, filters, and injection system for a small drip irrigation system. Photo: L. Schwankl Of the commonly occurring chemical precipitates, lime (calcium carbonate) and iron (and manganese) are the most common in microirrigation systems.
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Maintenance of Microirrigation Systems: Page

Chemical precipitate clogging caused by injected chemicals

Venturi injection system using a small electric pump Photo: L. SchwanklFertilizers are commonly injected into the irrigation water of microirrigation systems, a process called fertigation. Injection of fertilizers, however, can cause clogging problems in the emitters.
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Maintenance of Microirrigation Systems: Page

Lime (calcium carbonate)

Sulfuric acid injection system to mitigate calcium carbonate clogging problems. Photo: L. SchwanklPrecipitation of calcium carbonate (lime) is a common clogging problem in microirrigation systems. Water with a pH of 7.
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Maintenance of Microirrigation Systems: Page

Iron, manganese

Empty storage reservoir used to settle out precipitated iron from a high iron groundwater source. Photo: L. SchwanklEven at low concentrations, iron and manganese can clog microirrigation systems. Iron is a more common problem because it is more plentiful than manganese.
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Maintenance of Microirrigation Systems: Page

Additional flow meter information

A flow meter installed at the head of a microirrigation system or small flow meters placed at the head of selected lateral lines can help you detect clogging. Saddle-mount propeller meter installed at the head of a drip system. Note the instantaneous (gpm) and totalizing (gal) registers. Photo: L.
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Maintenance of Microirrigation Systems: Page

Interactions which can cause precipitation

The best policy is to not mix fertilizers. However, if mixing is necessary for microirrigation, follow the considerations below. These considerations are based on information contained in a UNOCAL compatibility chart.
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Maintenance of Microirrigation Systems: Page

Prevention and Mitigation

Mixing a fertilizer that contains calcium with one that contains sulfate can cause calcium sulfate (gypsum) to precipitate. One example of this occurs when you mix calcium nitrate with potassium sulfate.
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Maintenance of Microirrigation Systems: Page

Biological Clogging Solutions

Microirrigation system that uses a tablet form of sodium hypochlorite as a biocide. Photo: L. SchwanklAdding acid (e.g., sulfuric acid, phosphoric acid, etc.
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