Datasets:
msu-ceco
/
aec_v1

Dataset card Data Studio Files Community
1
text
stringlengths
0
1.09k
This guide should help you understand how to maintain drip irrigation systems.
Water for drip irrigation can come from wells, ponds, rivers, lakes, municipal water systems, or plastic-lined pits.
Water from these various sources will have large differences in quality.
Well water and municipal water is generally clean and may require only a screen or disk filter to remove particles.
However, no matter how clean the water looks, a water analysis/quality test prior to considering installation of a drip irrigation system should be completed to determine if precipitates or other contaminants are in the water.
This water quality analysis should identify inorganic solids such as sand and silt; organic solids such as algae, bacteria, and slime; dissolved solids such as iron, sulphur, sodium chlorides, and calcium; and pH of the water.
Water testing can be done by a number of laboratories in the state.
Your local Cooperative
Extension Service county agent can supply a list of laboratories or suggest a local lab that can do water quality analysis.
Check with the lab first to obtain a sample kit containing a sampling bottle that is clean and uncontaminated.
In addition to quality factors, ask for any additional tests that might be necessary.
If the water also is to be used as a household supply or as a drinking water source, a basic drinking water analysis, which includes bacterial counts, nitrates, or other suggested tests, should be done.
Most well water in Kansas has relatively high pH and hardness.
Shallow wells in river valleys often contain high concentrations of iron and manganese.
Hydrogen sulfide often can be detected by a bad "rotten egg" smell and is fairly rare in Kansas.
If a review of your water test indicates factors that may cause plugging , then special care in drip system maintenance needs to be practiced.
High levels of a factor might not render a well unsuitable for drip irrigation but will make appropriate water treatment a requirement before successful use in a drip irrigation system.
Any surface water such as streams, ponds, lakes, rivers, or pits will contain bacteria, algae, or other aquatic life.
Sand media filters are absolute necessities.
Even though sand media filters will be more expensive than screen or grooved-disk filters, they are highly recommended for water sources that have high levels of suspended organic and inorganic materials.
KEYS TO SUCCESSFUL ADOPTION OF SDI: MINIMIZING PROBLEMS AND ENSURING LONGEVITY
Since 1989, research studies and demonstration studies at the Northwest and Southwest Research-Extension Centers of Kansas State University have indicated that subsurface drip irrigation systems can be efficient, long-lived, and adaptable for irrigating corn and other deep-rooted crops.
A survey of all Kansas SDI users in 2003 revealed an estimated 14,000 acres were irrigated with SDI systems.
Though system usage has grown steadily over the years, SDI systems are currently used on less than 1% of total irrigated acres.
The 2006 Kansas Irrigation Water Use Report indicated that 10,250 acres were exclusively irrigated by SDI systems and an additional 8,440 acres were irrigated partially by SDI in combination with another system type, such as an irrigated SDI corner of a center pivot sprinkler or a surface gravityirrigated field partially converted to SDI.
Many producers have had successful experiences with SDI systems despite minor technical difficulties during the adoption process.
In a 2005 survey of SDI users, nearly 80% of Kansas producers indicated they were at least satisfied with the performance of their SDI system, and less than 4% indicated they were not satisfied.
However, even satisfied users indicated a need for additional SDI management information.
The most noted concern was the damage and repairs caused by rodents.
A few systems had failed or had been abandoned after a short-use period due to inadequate design, inadequate management or a combination of both.
Design and management are closely linked in a successful SDI system.
Research studies and on-farm producers both indicate that SDI systems result in high-yielding crops and water-conserving production practices only when the systems are properly designed, installed, operated and maintained.
A system that is improperly designed and installed will be difficult to operate and maintain and most likely will not achieve high irrigation water application uniformity and efficiency goals.
However, proper design and installation does not ensure high SDI efficiency and long system life.
An SDI system must also be operated
according to design specifications and utilize good irrigation water management procedures to achieve high uniformity and efficiency.
An SDI system is also destined for early failure without proper maintenance.
This paper will review key factors for successful adoption of SDI for Kansas irrigated agriculture.
MINIMUM SDI COMPONENTS FOR EFFICIENT WATER DISTRIBUTION AND SYSTEM LONGEVITY
SDI system design must consider individual management restraints and goals, as well as account for specific field and soil characteristics, water quality, well capabilities, desired crops, production systems, and producer goals.
However, certain basic features are a part of all SDI systems, as shown in Figure 1.
The long-term ability of the producer to operate and maintain the system in an efficient manner is seriously undermined if any of the minimum components are omitted during the design process.
Minimum SDI system components should not be sacrificed as design and installation cost-cutting measures.
If minimum SDI components cannot be included as part of the system, an alternative type of irrigation system or a dryland production system should be considered.
Figure 1.
Minimum components of an SDI system.
K-State Research and Extension Bulletin MF-2576, Subsurface Drip Irrigation Component: Minimum Requirements
Water distribution components of an SDI system include the pumping station, the main, submains and dripline laterals.
Sizing requirements for the mains and submains are somewhat similar to underground service pipe to center pivot sprinklers or main pipelines for surface-irrigated gravity systems and are determined by the flow rate and acceptable friction loss within the pipe.
In general, the flow rate and friction loss determines the dripline size for a given dripline lateral length and land slope.
An SDI system consisting of only the distribution components would have no method to monitor system performance and the system would not have any protection from clogging or any methods to conduct system maintenance.
Clogging of dripline emitters is the primary reason for SDI system failure.
In addition to basic water distribution components, additional components allow the producers to monitor SDI system performance, allow flushing, and protect or maintain performance by injection of chemical treatments.
The injection equipment can also be used to provide additional nutrients or chemicals for crop production.
A backflow prevention device is required to protect the source water from accidental contamination if backflow should occur.
The actual characteristics and field layout of an SDI system vary from site to site, but irrigators often add additional capabilities to their systems.
For example, the SDI system in Figure 2 shows additional valves that allow the irrigation zone to be split into two flushing zones.
When the well or pump does not have the capacity to provide additional flow and pressure to meet the flushing requirements for the irrigation zone, splitting the zone into two parts may be an important design feature.
The American Society of Agricultural and Biological Engineers recommends a minimum flushing velocity of 1 ft/s for microirrigation lateral maintenance.
This flushing velocity requirement needs to be carefully considered at the design stage, and may dictate larger sizes for submains and flushlines to assure that maximum operating pressures for the driplines are not exceeded.
Filter systems are generally sized to remove particles that are approximately 1/10 the diameter of the smallest emitter passageway.
However, small particles still pass through the filter and into the driplines, and over time, they can clump together.
Also, biological or chemical processes produce materials that need to be removed to prevent emitter clogging or a build-up of material at the outlet or distal end of the system.
Opening the flushline valves allows water to rapidly pass through the driplines, carrying away any accumulated particles.
A good design should allow flushing of all pipeline and system components.
The frequency of flushing is largely determined by the quality of the irrigation water and to a degree, the level of filtration.
A good measure of the need to flush is to evaluate the amount of debris caught in a mesh cloth during a flushing event.
When only a small amount of debris is found, the flushing interval may be increased.
Heavy accumulations of debris, however, mean more frequent flushing is needed.
Figure 2.
Layout for a well-designed SDI system.
In SDI systems, all water application is underground.
Because no surface wetting occurs in properly installed and operated systems, no visual cues of system operation are available to the manager.
Therefore, the flow meter and pressure gauges act as operational feedback cues.
The pressure gauges along the submain of each zone measure the inlet pressure to driplines.
Decreasing flow rates and/or increasing pressure may indicate clogging, and increasing flow rates with decreasing pressure may indicate a major line leak.
The inlet pressure gauges along with those at the distal ends of the dripline laterals at the flushline valve help establish the baseline performance characteristics of the system.
Good quality pressure gauges should be used at each of these measurement locations and the gauges should be periodically replaced or inspected for accuracy.
The flow rate and pressure measurements should be recorded and retained for the life of the system.
A time series of flow rate and pressure measurements can be used as a diagnostic tool to discover operational problems and determine appropriate remediation techniques, as illustrated in Figure 3.
Anomaly A: The irrigator observes an abrupt flowrate increase with a small pressure reduction at the Zone inlet and a large pressure reduction at the Flushline outlet.
The irrigator checks and finds rodent damage and repairs the dripline.
Anomaly B: The irrigator observes an abrupt flowrate reduction with small pressure increases at both the Zone inlet and the Flushline outlet.
The irrigator checks and finds an abrupt bacterial flare-up in the driplines.
He immediately chlorinates and acidifies the system to remediate the problem.
Anomaly C: The irrigator observes an abrupt flowrate decrease from the last irrigation event with large pressure reductions at both the Zone inlet and Flushline outlet.
A quick inspection reveals a large filtration system pressure drop indicating the need for cleaning.
Normal flowrate and pressures resume after cleaning the filter.
Anomaly D: The irrigator observes a gradual flowrate decrease during the last four irrigation events with pressure increases at both the Zone inlet and Flushline outlet.
The irrigator checks and find that the driplines are slowly clogging.
He immediately chemically treats the system to remediate the problem.
Figure 3.
Hypothetical example of how pressure and flowrate measurement records could be used to discover and remediate operational problems.
The heart of the protection system for the dripline emitters is the filtration system.
The type of filtration system depends on the quality characteristics of the irrigation water and the clogging hazards.
The illustration in Figure 1 depicts a pair of screen filters, while Figure 2 shows a series of sand media filters.
Screen filters are the simplest type of filtration and provide a single plane of filtration.
They are most often used in situations where the water source is relatively clean.
Sand media filtration systems, which consist of two or more large pressure tanks with specially graded filtration sand, provide three dimensional filtration and are well-suited for surface water sources.
Surface water supplies may require settling basins and/or several layers of bar screen barriers at the intake site to remove large debris and organic matter.