Micro Irrigation Techniques

• Water is a critical input for agriculture, consuming over 80% of a country's water resources.
• Conservation, efficient supply, and use of water are crucial for higher productivity.
• Poor irrigation efficiency leads to environmental issues like water logging and soil salinity.
• Improved irrigation methods include drip and sprinkler systems, as well as fertigation.

Reducing Water Demand

• Supply-side management includes watershed and water resource development.
• Demand management includes improved water management technologies/practices.
• Micro-irrigation technologies like drip and sprinkler systems save 40% to 80% of water.
• Water use efficiency, or WUE, can increase up to 100% with managed micro-irrigation.
• Conventional practices only have a 30-40% water use efficiency.

Micro-Irrigation

• Micro-irrigation systems apply water through small devices directly to the plant root zone.
• These systems deliver slow, frequent water using low-pressure distribution.
• Other names are drip, subsurface, bubbler, or trickle irrigation.
• Outlets are spaced closely along tubing to supply to individual plants or rows.
• Outlets include emitters, orifices, bubblers, sprays, or micro sprinklers.
• Discharge ranges from 2 to over 200 liters per hour.
• German experiments in the 1860s traced back to the basic idea of drip irrigation.
• House conducted the first drip irrigation study in the U.S.A in Colorado in 1913.
• In 1920, Germany introduced perforated pipe drip irrigation.
• Symcha Blass from Israel observed a tree's vigorous growth near a leaking tap in the 1940s.
• Blass conceived a system applying small quantities of water drop by drop.
• The earliest system used small diameter plastic capillary tubes attached to large pipes.
• Blass refined the system, and later experiments in Israel showed results in desert areas.
• Widespread use expanded to the USA, Australia, Israel, and Mexico.
• Plastic pipe availability and emitter development in Israel were key.
• It is now important in Australia, Europe, Israel, Japan, Mexico, South Africa, and the USA.
• India used indigenous methods such as earthenware/bamboo pipes and porous cups for irrigation.
• Tribal farmers in Meghalaya use bamboo drip systems for crops.
• Earthenware pitchers/cups were used in Rajasthan/Haryana for vegetables.
• Drip irrigation was introduced in the early 70s at Indian agricultural universities.
• Growth of drip irrigation has increased in water-scarce areas and commercial crops.
• It is used in Maharashtra, Andhra Pradesh, Karnataka, Tamil Nadu, and Gujarat.

Micro-Irrigation Use

• Accepted in arid regions for high value crops.
• Includes fruits, grapes, sugarcane, pineapples, strawberries, flowers and vegetables.
• Adapted by landscapers/growers for accurate water application.
• Commonly used in dry regions and urban/sub-humid areas.
• Utilized for ornamental plants in urban landscapes.
• Irrigation techniques such as Micro & Sprinkler Irrigation are needed for water conservation.
• Increases productivity per unit of water, and addresses water logging/salinization.
• Water source development and recharge of wells through watershed management are needed.
• It must be viewed as a total plant support system and technology package.

Micro-Irrigation Overview

• Delivers water to the root of the plant via pipes, tubes, and drippers.
• Uses less water and is more efficient.
• Ancient methods include clay pots with holes buried in the ground.
• Clay pipes evolved into perforated plastic tubing.
• Modern developments use plastic water emitters near the roots.
• It has been a valuable contribution in areas lacking rain.
• Other systems are bubblers (broader drip) and micro sprinklers (overhead sprays).
• Irrigations tubes close to the surface are ideal.
• A pump pressurizes water through emitters.
• Use with mulching reduces surface evaporation.
• Reduces foliage diseases by watering the roots directly.
• The technology is used in farms and greenhouses.
• Irrigation and fertilizer can be combined for automation.
• It avoids runoff on hilly or sloped lands, costing less than leveling the land and helping with soil erosion.
• It has helped growing strawberries and other closely spaced farm crops.

Micro-Irrigation Status

• About 42 million hectares are potential for drip and sprinkler irrigation.
• 30 million ha are suitable for sprinkler irrigation with oilseeds, pulses, and cereal crops.
• 12 million ha are potential for drip irrigation with vegetables, sugarcane, fruits, red gram, spices, and cotton.
• Drip irrigation's area covers a potential estimated varying from no coverage in Nagaland to 49.74% in Andhra Pradesh.
• Sprinkler irrigation's actual area is as low as 0.01% (Bihar) and as high as 51.93% (Andhra Pradesh) against the potential.
• Present area under current micro-irrigation is at 9.16% with 3.87 million ha.

Types of Micro-Irrigation Systems

• Micro-irrigation is classified by water application parameters.
• Includes drip, spray, subsurface and bubbler irrigation.

Drip Irrigation

• The newest commercial method of water application.
• Involves slow application to soils through mechanical emitters.
• Emitters dissipate pressure using orifices, vortexes, or long flow paths to allow volume discharge.
• Emitters on the ground can be buried.
• Water flow occurs within the soil system via unsaturation, which is essential to plant growth.
• Spaced emitters produce a standard elliptical wetted soil area.
• Soil hydraulics determines the need for more emission locations per plant.

Spray Irrigation

• Irrigation form in which water is pressurized and sprayed over plants.
• Sprayers range from small home sprinklers to large irrigation systems.
• Water travels through the air.
• Two equipments are micro-sprayers and micro-sprinklers.
• Micro-sprayers and static micro jets are non-rotating with flow rates from 20 to 150 l/h.
• Micro-sprinklers are rotating and have flow rates from 100 to 300 l/h.
• Systems vary from hand-held hoses to center-pivot systems.
• Sprinklers can be stationary or on movable frames.
• Heads can be directional or rotating to cover broader areas.
• Pivot Systems use metal frames on wheels with electric motors.
• Electric motors rotate each frame to move in a circle around the field.
• Water depth depends on travel rate.
• Standard units are 1,250-1,300 feet long, irrigating about 130 acres.
• High-pressure systems can have big water guns along the tube.
• Low-Pressure Sprinkler Systems gently spray water to prevent evaporation or wind drift loss.
• Wastewater utilization for irrigation reduces freshwater demand and wastewater runoff.
• Wastewater use on ornamental crops can be banned on edible harvests.
• Water sources used are wells, lakes, rivers and reservoirs.

Sub-Surface System

• Water is slowly applied below the surface through emitters.
• Systems are for permanent installations.
• Subsurface Drip Irrigation, or SDI, is a highly efficient system.
• Buried drip tubes meet crop water needs using low pressure for frequent, light irrigations.
• Suitable for arid, windy and limited water supply areas.
• Farm operations have less impediments and restrictions compared to irrigation systems above ground.
• Water is below the surface, so surface infiltration and other potential runoff is eliminated.
• SDI size is well-maintained with efficient, uniform application.
• Water movement is all directions around the tube.
• It saves water and improves yields by eliminating surface water evaporation.
• Irrigation reduces weeds and diseases by targeting the root zone and reducing weed seeds.
• Some crops get heat from dry surfaces, increasing crop biomass especially for managed fields.
• Fertilizer efficiency is enhanced and labor is reduced along with possible field operations.

Bubbler System

• Surface water application in a small stream/fountain.
• Emitter discharge rate is greater than drip/subsurface but less than 225 l/h.
• Small basin needed to contain water due to high discharge rate.
• Bubbler systems do not need elaborate filtration due to large amount of irrigation in a short period of time.
• It is suitable for watering trees with wide root zones and high water needs.

Merits of Micro-Irrigation

• Water savings occur due to smaller irrigation volumes and reduced runoff.
• Micro-irrigation can be applied only if needed to restrict deep percolation.
• Water usage is 25-40% less vs overhead systems, and 45-60% less compared to flood irrigation.
• The benefit is lessened evaporation and runoff.
• Low application rates permit the efficient use of filters, pumps and pipelines.
• Systems are designed for daily water requirements.
• Good uniformity of water use reduces water usage, power, and fertilizer.
• Consistent water use boosts optimal growth by providing equal water and nutrients for all plants.
• It saves energy because low-pressure delivery pipe systems require less pumping.
• Micro-irrigation increases control over chemical output.
• Direct application reduces total fertilizer by 25-50%.
• Application is more economical, provides better distribution of nutrients throughout the season and diminishes ground water pollution.
• Other chemicals can improve crop output, like carbon dioxide and fungicides.
• Weed growth and instances of disease greatly decreases due to constant wetted area.
• Micro-irrigation can apply on windy days and function without interrupting harvestion, increasing fleixibility of operations.
• Reduces sensitivity to soil conditions by maintaining moisture.
• Water application replaces moisture removed by the plant and moves salts out of the plant to the end of the root zone.
• Salinity and low moisture is reduced in the soil.
• There are advantages of high uniformity of water application, slow, measured irrigation and nutrient levels also improving crop quality. Damage from water of foliage reduces during the crops.
• Operation can efficiently function on any given topography.
• Low infiltration is ideal for clay soils with low infiltration.
• Irrigation is ideal for sandy soils because of small water intake capability.
• Fully automatic system via electrical solenoid valves.

Demerits of Micro-Irrigation

• Cost of setting up and running is higher relative to some methods.
• Emitters represent 35-37% micro-irrigation system cost.
• Design, install quality, and manage system well to improve system outputs.
• The irrigation water is pressurized, which is why there are still energy costs overall.
• Expertise in the use of micro-irrigation system is important.
• The new farming practices requires farmers to monitor the environment.
• Emitters are susceptible to clogging.
• Sand and soil particle and organic water are problems in micro-irrigation, as well as bacterial slime, and other biological materials.
• Salt accumulates near the root zone, with rainfall capable to move it back the root zone and damaging crops.
• Some don't germinate well when using this new tech which is why sprinklers should also be used for the process.
• Wet spots causes problems for soil and root movement.

Components of Micro Irrigation System

• Composed as pipes in branching fashion.
• Includes main, submain, and lateral.
• Matching main, submain, and lateral pipes according to the volume is important.
• Has a power unit, pump, a backflow prevention device, water distribution, filter, and volume controller.
• Direct water hookup possible from any source.
• Type and size depends on quantity, pumps, location.
• Electric power adaptable and preferable because it is automated.
• Network with types screen, disk, and sand.
• Distribution system of pipes and tubes are of varying mm.
• Pipes can carry to emitters with diameter tubes.
• Control heads are required for centrifugal pumps in small, orchard areas.
• Fertilizer requires by-pass pressure or venturi injector.
• Blocking increases filters.
• Media filters work using gravel or quartz sand.
• Effective at removing algae, sand and silt particles.
• Water is introduced at the top for removing algae and drainage.
• Steel wire mesh filters allows clean water in after physical impurity removals.
• Centrifugal filters uses cone that create circular movements, and separating material.
• Disks stacks captures debris, and captures organic algae.
• Pressure arrangements bypass pressures.
• Check valves are used prevent water flow, and to return chemicals.
• Micro irrigation has high uniformity in its distribution, leading to water being applied to the plants.
• Conical tank with poly and fiberglass is needed for flushing to make sure no wasted materials, and the tanks themselves have a simple downstream to valve so they easy to use.
• Types are venturi injector, pump, and tank which is why it is has flexible injectment.
• Injectors have a stream where negative pressure.
• Injection water can be pumped using small motors.

Water Distribution Network

• The water distribution network constitutes main line, submains line and laterals with drippers and other accessories.

Mainline

• he mainline transports water within the field and distribute to submains.
• Mainline is made of rigid PVC or High Density Polyethylene (HDPE).
• Pipelines of 65 mm diameter and above with a pressure rating 4 to 6 kg/cm2 pipes are used for main line pipes.

Submains

• Submains distribute water evenly to a number of lateral lines.
• For sub main pipes, rigid PVC, HDPE or LDPE (Low Density Polyethylene) of diameter range around 32-75mm.
• Pressure rating is 2.5 kg/cm2.

Laterals

• Laterals distribute the water uniformly along their length by means of drippers or emitters.
• It is manufactured from LDPE and LLDPE with a pipe diameter range of 10, 12 and 16 mm with wall thickness.

Equipment

• Devices called emitters measure and deliver through plastic.
• Emitters is volume measurement in liters per hour.
• Emission devices are dripper, bubblers and micropsrinklers.
• Droplets are the basis of drip, the bubble is what makes the mode for the bubbler, and sprinkles are where the microsprinklers comes in.
• Adapted emitters is the water that is needed to space water to grow, and even to harvest the produce by the amount grown.
• They function as dissipaters for energy, pressure can be high to where atmosphere at the outlet.
• Compensation drippers supplies water and are made with quality rubber.
• Used for water rows and slopes to prevent water from running back toward the flow
• Other drippers discharge to operate pressure water to use vortex-type and zig zag.
• The are cheap and are the most used.
• Point is outside distribution line to distribute water press using narrow chambers.
• Drip line water at the top is preferrable.
• Used for closely raw crops.
• Diameter, wall thickness, and flow all measure for water.
• Protect from heat and sunlight with drip line.
• Bubblers delivers via plant basis and is simliar to external pointers.
• The diaphragms is what reduces force as a water pressure.
• Micropsinkler can also be from jets, and water spray from air to preset.
• Sprinkler heads are connected using tubes.
• Using few sprinkler heads is how to water large areas.
• Size and water is the most important for choosing emitter.
• Pest and control and water efficiency are used as devices to measure the type in all produce.

Explore subsurface and bubbler irrigation systems. Learn about minimizing water loss, disease spread, and surface evaporation. Discover how micro-irrigation enhances water control and reduces soil surface crusting.