Maharashtra HSC NSQF Micro Irrigation Technician key terms

A method of supplying water directly to the root zone of crops in small, frequent, controlled amounts through pipes, emitters or sprinklers, using far less water than flood or furrow irrigation.

A micro irrigation system in which filtered water is delivered drop by drop through emitters placed along lateral pipes near the plant base, keeping only part of the soil wet.

A system that sprays water into the air through nozzles so it falls like rain over the crop, suited to close-growing crops and sandy soils where drip is less effective.

A small device fitted on a lateral pipe that releases water at a controlled low rate, usually 1 to 8 litres per hour, to the plant root zone.

The thin delivery pipe, often 12 to 20 mm, that carries filtered water from the submain and on which emitters or micro sprinklers are mounted along a crop row.

A secondary pipeline that distributes water from the main line to several laterals, often buried or laid along the headland and controlled by valves.

The onion-shaped volume of moist soil that forms under a drip emitter, whose size depends on soil type, emitter discharge and irrigation duration.

The amount of water a soil retains after excess water has drained away by gravity, usually one to three days after thorough wetting; it is the upper useful limit for irrigation scheduling.

The soil moisture level at which a plant can no longer extract water and stays wilted even in a humid atmosphere; irrigation must keep soil moisture well above this point.

The water held in soil between field capacity and permanent wilting point that plants can actually absorb, expressed as depth per unit soil depth.

The portion of available soil water that a crop can take up without suffering water stress; irrigation is scheduled before soil moisture falls below this level.

The combined loss of water from soil and plant surfaces by evaporation and from leaves by transpiration; crop water requirement is estimated from reference evapotranspiration and a crop coefficient.

A number, varying with crop type and growth stage, that converts reference evapotranspiration into the water use of a specific crop.

Deciding how often and how long to run the system, using soil moisture, evaporation data or tensiometer readings, so crops get enough water without over-irrigation.

A sealed tube filled with water and fitted with a vacuum gauge, inserted in soil to show how strongly roots must pull to extract water, guiding irrigation timing.

A measure of how evenly emitters across a block discharge water; low uniformity means some plants are under-watered and others over-watered, wasting water and reducing yield.

The ratio of the average of the lowest quarter of measured emitter or sprinkler discharges to the overall average discharge, expressed as a percentage; higher values indicate a better-designed system.

A sprinkler-system measure of how evenly water is applied over the wetted area, calculated from catch-can test data; values near 1 indicate uniform application.

The depth of water a sprinkler or drip system delivers per unit area per hour; it must not exceed the soil's infiltration rate or runoff will occur.

The speed at which water enters the soil surface, usually in millimetres per hour; it sets the maximum safe application rate for a sprinkler system.

Passing irrigation water through sand, screen or disc filters to remove sand, silt and organic matter that would otherwise clog emitters and valves.

A pressure vessel filled with graded sand or gravel through which water passes slowly, trapping fine organic and mineral particles; cleaned by backwashing.

A filter in which water passes through a fine stainless-steel or plastic mesh that catches particles larger than the mesh opening; cheap but easily torn and needing frequent cleaning.

Reversing the direction of water flow through a sand or disc filter to wash trapped dirt out to drain, restoring the filter's capacity and keeping pressure loss low.

Opening the ends of laterals or submains to let water run fast and carry out accumulated sediment and biological slime that could block emitters.

Injecting soluble fertiliser into the irrigation water so nutrients reach the root zone with each irrigation, using a venturi, dosing pump or tank.

A fertiliser-injection device with no moving parts that uses the pressure drop across a narrowing throat to suck a concentrated solution into the irrigation line.

Fitting a non-return valve or vacuum breaker so fertiliser or dirty water cannot be drawn back into the pump, well or public supply when pressure drops.

Applying pesticides or other chemicals through the irrigation system; it demands strict backflow protection, correct dosing and safe re-entry intervals.

A graph showing the discharge a pump delivers at each head; the duty point is where this curve meets the system's head-flow requirement.

The total pressure, expressed in metres of water column, that a pump must supply, covering suction lift, delivery height, friction losses in pipes and fittings, and emitter operating pressure.

The flow and head at which a pump actually operates when connected to a given system, found where the pump curve crosses the system curve.

An instrument fitted at the pump, filter and block valves to show operating pressure; readings before and after the filter reveal clogging.

A device that holds a steady downstream pressure, protecting drip laterals and emitters from excessive pressure that causes leaks and uneven discharge.

A valve at the far end of a lateral or submain that is opened periodically to release sediment-laden water and clean the pipeline.

The final stage of installation in which the system is pressurised, flushed, tested for leaks, pressure and discharge checked, and then handed over to the farmer.

The depth of soil explored by a crop's roots, from which water and nutrients are drawn; its depth sets the volume of soil that irrigation must refill.

A small low-volume sprinkler, often mounted on a stake or riser, that sprays water in a limited pattern under low pressure, suited to orchards and nurseries.