irrigation t decisions microirrigation · irrigation technology decisions: microirrigation dana o....
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IRRIGATION TECHNOLOGYDECISIONS:
MICROIRRIGATION
Dana O. Porter, PhD, PEResearch and Extension Agricultural Engineer
Texas A&M AgriLife Research and Extension Center – LubbockDepartment of Biological and Agricultural Engineering
Efficient, advanced irrigation technologies in the Texas High Plains:
Water capacity is a limiting factor throughout most of the region
Agricultural producers are progressive, relatively rapid adopters of technology ‐‐‐ “critical mass” of peer producers and success stories
The technologies are “good fits” for farm operations (fields, crops, managers) in the Texas High Plains
Excellent applied research programs in the area (Texas A&M Halfway, Bushland, Amarillo and Etter; USDA‐ARS‐Bushland)
Critical mass of well‐qualified and experienced irrigation dealers, designers, installers – ready access to technical expertise and support
USDA‐NRCS EQIP cost‐share and low interest loan options help offset high capital costs
Good collaboration among research, extension, industry, producers
Efficient advanced irrigation technologies: Important considerations
- suitability or adaptability of a technology to local production systems and conditions
- economic feasibility
- availability of irrigation industry, research and educational infrastructure and resources to support applications in the field
Successful application of irrigation technologies requires good design, installation, maintenance, and management.
Irrigation in Context: Integrated Production Systems
Goals: Crop yield, quality
Production efficiencyWater, Nitrogen, and Energy EfficiencyEfficiency and efficacy of all inputs
Manage the overall system for high returnOptimal response to inputsUnderstanding limiting factorsReducing losses and unnecessary inputs
Nutrient managementVariety selectionIntegrated Pest Management (IPM)Water management (irrigation, rainfall, soil moisture)
MICROIRRIGATION
Subsurface drip irrigation
Surface drip irrigation
Shallow subsurface drip irrigation
Microspray irrigation
Microspray Irriga on
Photo: USDA‐NRCS University of California Agriculture and Natural Resources
University of California Agriculture and Natural Resources
Microspray (microtube) Irriga on
Surface drip irriga on
Microirrigation on trellises in a vineyard
Shallow subsurface drip irriga on ‐ SSDI
Shallow subsurface drip irriga on
Subsurface Drip Irriga on ‐ SDI Photo courtesy: Jim Bordovsky
Filtra on
Disc filter
Media filters
Hydrocyclone Sand Separator
Soil Moisture Uptake by Plant Roots
Plants will get most of their water from the upper part of the root zone. As the shallow water is depleted, the plant will extract water from deeper in the profile – if it has roots there, and if water is available.
Limits to the Root Zone Depth
If roots encounter a confining condition in the soil profile, the effective root zone is limited.
Examples of confining conditions: compaction zone, caliche layer, dry layer, saturated layer, salt accumulation
Subsurface Drip IrrigationRoot Zone
every row alternate furrows
Potential salt & toxic element accumulation zone
Wetted area affects size of root zone
Subsurface Drip Irriga on: Tape Placement & Spacing
every row alternate furrows
Other configura ons:
SDI vs. Center Pivot
Photo courtesy: Jim Bordovsky
Rodent Damaged Drip Tape
SDI peanuts with cotton in the background, Gaines County, 2002. Timely rainfall in the spring made a big difference in germination in this sandy soil.
Subsurface Drip IrrigationAdvantages and Disadvantages
Advantages offered by SDI+ improved water use efficiency + energy savings+ improved nutrient management (spoon feeding)+ improved crop yield and/or quality+ decreased labor requirements+ system may be automated
Disadvantages of SDI ‐ high initial cost ‐ no deep tillage for control of disease and pests ‐ some designs offer limited flexibility‐ potential germination problems (esp. in coarse soils)‐ increased management & maintenance requirements‐ potential damage due to rodents and other influences
IRRIGATION TECHNOLOGY
DesignLayout InstallationMaintenanceManagement
Keys to successful implementation
Advanced irrigation technologies are good tools for good managers. Technology can reduce labor requirements and improve management options, but it does not replace good management.
SDI TipsStart with a good design and installation. Be realistic with well capacities & management capabilities.
Be diligent in system maintenancefiltration, flushing, chemical injection as needed). Monitor flow and pressure as indicators of system performance and as trouble‐shooting aids.
Manage irrigation and other crop inputs for optimal esults. SDI is a good tool for a good manager.
SDI SYSTEM MAINTENANCE
Regular flushing of drip lines is essential.
Proper system design facilitates flushing. ‐ design must address flush volume / pressure / velocity‐ design should address operator considerations (ease of flushing, access to flush valves, etc.)
Chemical Injection
Chemical injection is necessary with row crop drip irrigation systems.
‐ prevent emitter plugging
‐ fertilization of a limited root zone
‐ limited IPM applications
Chemical Injectionprevent emitter plugging
* requirements depend upon water quality
acid injection ‐ prevents calcium and magnesium carbonate precipitation; may be effective in controlling slimy bacteria; may be used to control root intrusion; soil pH adjustment may be warranted for other agronomic reasons.
chlorine ‐ controls growth of algae and slimy bacteria
Special requirements (i.e. H2O2 to prevent Mn precipitation)
SDI Water Quality Considerations
Recommended water quality tests
Electrical Conductivity (EC) ‐measured in ds/m or mmho/cm – a measure of total salinity or total dissolved solids
pH ‐ a measure of acidity ‐ where 1 is very acidic, 14 is very alkaline, and 7 is neutral
Cations ‐measured in meq/L, (milliequivalent/liter), includes: Calcium (Ca), Magnesium (Mg), and Sodium (Na)
Anions ‐measured in meq/L, includes: Chloride (Cl), Sulfate (SO4), Carbonate (CO3), and Bicarbonate (HCO3)
And others…. consult recommended references
Chemical InjectionFertilization, “Fertigation”
“spoon feeding” to meet crop requirements
* fertilizer savings and/or better crop response to applied nitrogen fertilizer
* reduced fertilizer costs
* reduced leaching losses
* address issue of limited root zone and other nutrient access factors
Chemical InjectionConsiderations:
Chemical labels ‐ EPA requires statements onpesticide labels addressing:‐ type of irrigation system(s)‐ risks associated with non‐uniform water application‐ calibration‐ backflow protection requirements
Backflow prevention – required!!
Injection (mixing, injection pumps, precipitate “jar” testing)
Compatibility with water quality
Note: these values do not take into account irrigation efficiency.
USEFUL INFORMATION,
TOOLS AND RESOURCES
USDA‐ARSOgallala Aquifer Program
USDA‐NIFAMicroirrigation Research Group
h p://www.ksre.ksu.edu/sdi/
Maintenance of Microirriga on Systems h p://micromaintain.ucanr.edu/#
Maintenance of Microirriga on Systems h p://micromaintain.ucanr.edu/#
Maintenance of Microirriga on Systems h p://micromaintain.ucanr.edu/#
Maintenance of Microirriga on Systems h p://micromaintain.ucanr.edu/#
Maintenance of Microirriga on Systems h p://micromaintain.ucanr.edu/#
Maintenance of Microirriga on Systems h p://micromaintain.ucanr.edu/#
Maintenance of Microirriga on Systems h p://micromaintain.ucanr.edu/#
Maintenance of Microirriga on Systems h p://micromaintain.ucanr.edu/#
Maintenance of Microirrigation Systems
http://micromaintain.ucanr.edu/#
ww.ksre.ksu.edu/mil/
https://watermgmt.tamu.edu/
watermgmt.tamu.edu/
Texas High Plains ET Network Weather Station, Lubbock, TX
757778
Subsurface Drip Irrigation ubsurface Drip Irrigation has gained a lot of ground in e High Plains – particularly in cotton production systems the Texas Southern High Plains.
DI is highly efficient, with little or no risk of runoff or rface evaporation (although as with any irrigation method, excessive
gation applications can be lost through deep percolation.)
sson from the drought: Good design – with adequate ning – is critical to flexibility to adjust to declining water pacities.
anagement and maintenance are key.
Subsurface Drip Irrigation
Subsurface Drip Irrigation is a good tool for a good manager. It does not solve all problems, and it does not fit every operation.
SDI fits well for a wide variety of applications, but shows particular advantage for operations with‐ Limited irrigation capacities‐ Small or irregularly shaped fields‐ Management capabilities to manage and maintain
the systems (equipment, chemicals, intensive crop management)