Thursday, April 18, 2013

Drip Irrigation

With all the rain and flooding we have been having you may be asking, why are you posting about drip irrigation?  Well, spring is time for rain.  Summer is time for sun.  And come summer, many of you may be wishing you could have figured out how to save some of this rain!
Drip irrigation, often referred to as micro or trickle irrigation, slowly and precisely delivers water (and sometimes nutrients) directly to a plant's root zone, making it a very efficient method of irrigation. With a drip system, water moves through a pipe system that is under pressure that is then distributed through emitters or drippers that are strategically placed close to the plants. The pressure needed in a drip system tends to be low but this is dependent upon the distance from the water source to the plants. The average drip system requires about 15 to 30 PSI (pounds per square inch) and the average home water pressure is rated between 40 and 80 PSI. As a result, there is little, if any, noticeable difference in water pressure in the home when the drip irrigation system is operating. This low pressure also makes for a very simple system to put together and manage as it does not require hard-to-connect components, glues, or clamps that are often needed in higher-pressure irrigation systems.

Drip irrigation is more efficient than conventional irrigation systems in that it is measured in gallons per hour rather than in gallons per minute. Other efficiency benefits include:
• Delivering water directly where it is needed reduces water evaporation and runoff
• Easy to install and maintain and can be used in rough terrains
• Can reduce pest, weed, and disease populations
• Water, energy, and money savings

A few disadvantages should be noted and include:
• Irrigation tubing and tape is susceptible to rodent damage
• Mowing and weed whacking around a system can be a challenge
• A filter is required to prevent clogging
• Leaks can be difficult to locate
• Management of plant water needs may increase

There are several key components to consider in designing a drip system. First, it is important to collect as much site information as you can. This not only includes the location of the are(s) you are looking to irrigate, but also looking at the location of any other existing features, the direction of any slopes, and the soil type and condition. Designing a system will require all of this to be mapped out. Second, it is important to locate all possible water sources and to determine the type and size of the pipe of the water source as it will help in sizing and figuring out flow rates for the drip system.

Next, you will need to determine the flow rate. This can be done by timing how long it takes to fill up a five-gallon bucket. Other components to consider in the design include whether or not you are looking to install a timer as well as if a backflow fixture is required by state or municipal plumbing codes.

Once the system is installed and operating, it is important to follow all recommend maintenance routines by the manufacturer. Many companies recommend flushing the system regularly to remove sand and silt particles and mineral deposits, cleaning the filters, as well as adding chlorine or other chemicals to the drip line to prevent bacteria and algae from building up.

If you are following the National Organic Program (NOP) regulations, it is important to note:
205.601 Synthetic materials allowed for use in organic crop production states:
"In accordance with restrictions specified in this section, the following synthetic substances may be used in organic crop production: As algicide, disinfectants, and sanitizer, including irrigation system cleaning systems
(1) alcohols (i) Ethanol (ii) Isopropanol
(2) Chlorine materials—Except, That residual chlorine levels in the water shall not exceed the maximum residual disinfectant limit under the Safe Drinking Water Act [4 ppm]. (i) Calcium hypochlorite (ii) Chlorine dioxide (iii) Sodium hypochlorite
(3) Hydrogen peroxide
(4) Soap-based algicide/demisters"

Allowed materials include anything else that is considered "natural," including acetic acid (vinegar) or citric acid, as long as they are in compliance with the NOP regulations.

(From ATTRA website)

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