Maharashtra HSC NSQF Micro Irrigation Technician cheat sheet

Micro irrigation delivers water at low pressure and low flow directly to the root zone; typical emission rates are 1-8 L/h per dripper versus 50-200 L/h for a micro-sprinkler.

Application efficiency norms: drip 85-95%, micro-sprinkler 75-85%, conventional furrow 50-60%, flood 40-50% - efficiency gaps drive the water-saving case for subsidy.

Distribution uniformity (DU) = (average of lowest quarter of emitter flows) ÷ (mean emitter flow) × 100; design target DU ≥ 85% for drip, ≥ 80% for micro-sprinkler.

Emission uniformity (EU) accounts for pressure and manufacturing variation: EU = 100 × (1 − 1.27 × CV / √n), where CV is manufacturer's coefficient of variation and n is emitters per plant.

Classification by emission device: inline (integral) drippers moulded inside the lateral; online (button/PC) drippers punched onto the lateral; micro-tubes and micro-jets; micro-sprinklers and sprayers.

Classification by wetting pattern: surface drip, subsurface drip (SDI, buried 15-30 cm), bubbler, micro-spray, and mini-sprinkler under-canopy systems.

Pressure-compensating (PC) emitters hold a near-constant flow across roughly 0.5-4.0 bar; non-PC emitters vary with pressure, so they suit short, level blocks only.

Filtration requirement rises with emitter sensitivity: drip needs 120-200 mesh screen (or equivalent media/disc), micro-sprinklers can accept 80-100 mesh.

Drip suits wide-row and horticultural crops, orchards, greenhouse and polyhouse cultivation; sprinkler suits close-grown field crops, fodder, and frost-protection or germination duty.

Soil water constants: field capacity (FC) ≈ −0.33 bar, permanent wilting point (PWP) ≈ −15 bar; available water (AW) = FC − PWP, expressed in mm per metre depth.

Management allowed depletion (MAD) is the fraction of AW that may be used before stress; typical MAD is 0.5 for field crops, 0.3-0.4 for horticulture, 0.6-0.7 for drought-tolerant crops.

Readily available water RAW = MAD × AW × root-zone depth; irrigation interval (days) = RAW ÷ crop evapotranspiration (ETc).

Reference evapotranspiration ETo is estimated by the FAO-56 Penman-Monteith equation; ETc = Kc × ETo, with Kc varying by crop growth stage (initial, development, mid-season, late).

Crop coefficient staging: Kc initial ≈ 0.3-0.5, mid-season 0.8-1.2 for most field crops, and adjusted for ground cover, plant density, and wetting fraction under drip.

For drip, ETc is corrected by the fraction of ground shaded (or wetted) - the crop's effective area - before converting to litres per plant per day.

Soil texture controls intake: sandy soils have low AW (about 60-100 mm/m) and high infiltration; clay soils have high AW (about 180-220 mm/m) but low infiltration and risk of runoff.

Tensiometers read soil matric potential directly (0 to −80 kPa range typical); schedule irrigation when readings approach the MAD threshold for the crop and texture.

Water balance scheduling: net irrigation = ETc − effective rainfall − capillary rise + leaching requirement; gross irrigation = net ÷ application efficiency.

Source yield check: measure sustainable discharge (bucket-and-stopwatch or flow meter) and confirm it meets peak system demand; a low-yield borewell needs a storage tank and a booster pump.

Pump selection: total head = static lift + friction loss in suction and delivery + operating pressure of the system + emitter/riser elevation; flow must match design discharge at that head.

Centrifugal pumps suit shallow lifts and clean water; submersible pumps suit borewells; monoblock/booster pumps suit pressurised filtration skids.

Pump curve intersection with the system curve gives the duty point; a duty point far right of the best-efficiency point wastes power and can overload the motor.

Filtration train order: screen or hydrocyclone (sand separation) → media/sand filter → screen or disc filter → mainline. Screens are rated in mesh; sand filters in effective grain size and bed depth.

Backwash is triggered by differential pressure (typically 0.5-0.7 bar rise across the filter) or by a set timer; backwash velocity must fluidise the media bed.

Venturi injectors, diaphragm pumps, and proportional dosing pumps are the common fertigation injectors; a Venturi needs a pressure differential of about 0.3-0.7 bar to draw stock solution.

Fertigation safety: install a check valve and a vacuum breaker between the injection point and the water source to prevent backflow of fertiliser into the supply.

Stock solution concentration should stay below solubility limits; inject fertiliser in the middle third of the irrigation cycle and flush the lines with clean water afterwards.

Drip design sequence: crop water demand → emitter selection and spacing → lateral length and diameter → manifold/submain → mainline and pump → pressure check at the farthest emitter.

Emitter spacing sets the wetted bulb: closer spacing on sandy soil, wider on clay; the wetted diameter should overlap 20-30% between adjacent emitters for a continuous strip.

Lateral length limits are set by allowable pressure variation: keep flow variation under 10%, which corresponds to about 20% pressure variation along the lateral for non-PC emitters.

Friction loss in laterals and sub-mains is computed with the Hazen-Williams equation; use the Christiansen or Scobey factors for multiple outlets and add 10-15% for fittings and valves.

Sprinkler design uses spacing and nozzle pressure to hit the manufacturer's uniformity; the spacing should not exceed 55-60% of the wetted diameter for wind-free conditions, and less in wind.

Sprinkler application rate must not exceed the soil's basic intake rate; otherwise runoff and ponding occur - reduce nozzle size, lengthen spacing, or split sets.

System components: headworks (pump, filters, injector, valves, pressure gauge, flow meter), mainline, sub-main/manifold, laterals, emitters/sprinklers, air release and flush valves.

Flush valves at lateral ends and air-release valves at high points are mandatory for long-term hydraulic reliability; a pressure gauge at the headworks and at the farthest point verifies design pressure.

Layout drawing should record block numbers, lateral and sub-main lengths, pipe sizes, valve positions, and emitter spacing so installation and maintenance can be audited later.

Pre-installation checks: verify pump duty, trench alignment, pipe class and pressure rating, filter mesh, and that the drawing matches the field layout before any pipe is cut.

Lateral installation: keep laterals perpendicular to the slope contour where possible, orient emitter outlets upward, and allow slack for thermal expansion; bury mainline below plough depth.

Flushing sequence before commissioning: flush mainline, then sub-mains, then laterals with ends open until clear water runs; never flush through emitters or sprinkler nozzles.

Pressure test: pressurise the network to 1.5 times the design working pressure (or the pipe's rated test pressure) for the specified hold time, and check joints, valves, and fittings for leaks.

Commissioning steps: run the pump at design head, set the pressure-regulating valve, verify flow meter reading against design, and record pressure at the headworks and the farthest point.

Uniformity test: collect emitter discharge from a representative sample (at least 4 laterals × 4 emitters) for a fixed time, compute DU and EU, and record against the ≥85% target.

Sprinkler catch-can test: place cans on a grid within the sprinkler spacing, run for a set time, measure depth caught, and compute uniformity coefficient (Christiansen CU) - target ≥ 80%.

Fertigation commissioning: verify injector suction rate with a bucket test, confirm the check valve holds, and calibrate EC/pH of the outlet water before the first crop dose.

Handover documentation: as-built layout, test records, pump curve, filter and emitter specifications, maintenance schedule, and operator briefing on valve and flush routine.

Routine schedule: daily check of pressure and flow; weekly flush of laterals; monthly filter media inspection; seasonal chlorination and acid treatment of lines.

Pressure drop across the filter above 0.5-0.7 bar signals clogging - backwash first, then inspect and clean or replace the screen/disc element.

Emitter clogging causes: suspended silt, calcium carbonate scale, iron bacteria, and algae; chlorination (1-2 ppm free chlorine) handles organic and bacterial clogging, acid injection handles carbonate scale.

Low pressure at the farthest point with normal headworks pressure points to a burst lateral, an open flush valve, or a blocked sub-main - walk the block and check the end valves first.

Uneven wetting along a lateral with PC emitters suggests a damaged emitter or a lateral kink; with non-PC emitters it may also indicate excessive lateral length or undersized diameter.

Pump troubleshooting: no delivery - check priming, suction air leak, foot valve, and impeller; low discharge - check worn impeller, closed valve, or clogged suction strainer.

Sprinkler faults: worn nozzles lower pressure and distort the pattern; a stuck arm means a broken spring or debris in the bearing; replace rather than repair worn nozzles.

Winter/dormant shutdown: drain mainlines and laterals, blow out with air where freezing is possible, clean filters, and store removed emitters and sprinklers dry.

Maintenance log should record date, block, fault, action taken, parts replaced, and the pressure/flow readings before and after repair.

Electrical safety: all pump panels must have a working earth connection, an ELCB/RCCB, and an isolator; never open a panel or work on a wet pump without isolating the supply.

Confined-space entry into sumps, tanks, and borewell pits requires gas testing, a standby observer, and a harness - never enter alone.

Chemical handling: fertilisers and acids require gloves, goggles, boots, and a face shield; always add acid to water, never water to acid, and keep a water source for eye flushing nearby.

Fertigation backflow prevention (check valve plus vacuum breaker) protects the drinking-water source; this is both a legal and a public-health requirement.

Pesticide and fertiliser containers must be triple-rinsed, punctured, and disposed of per local rules - never reused for drinking water or food storage.

Machine safety: keep hands clear of rotating pump shafts, belt drives, and the Venturi suction line; lock out the pump before servicing the impeller or filter internals.

Field ergonomics: use two-person lifts for pipe coils and pump sets, keep trenches shored, and mark open trenches and excavated pits with barriers and reflective tape.

Environmental practice: schedule irrigation to avoid runoff and deep percolation, keep the leaching fraction minimal, and avoid fertigating before heavy rain to prevent nutrient loss to groundwater.

Project cost components: headworks (pump, filter, injector), mainline and sub-main pipe, laterals and emitters, fittings and valves, installation labour, and the water source/storage.

Per-hectare costing is built bottom-up: emitter count per hectare = 10,000 ÷ (row spacing × emitter spacing); multiply by unit rate, then add pipe, fittings, and labour.

Operating cost per season = pump energy (kW × hours × tariff) + filter and emitter replacement reserve + labour for flushing and maintenance + fertigation inputs.

Payback is computed against the baseline flood/furrow cost: benefit = (water saved × water charge) + (yield gain × crop price) − annual operating cost of the micro system.

Subsidy applications normally need land records, soil and water test reports, a layout drawing, a quotation from an empanelled supplier, and the beneficiary's bank and Aadhaar details.

Subsidy is typically released in instalments tied to verified installation stages; keep dated photographs, invoices, and the installation certificate ready for inspection.

Customer service protocol: site survey → written quotation with itemised rates → installation schedule → commissioning demonstration → warranty and after-sales visit schedule.

Quotation must state pipe class, emitter specification, filter type and mesh, pump head and discharge, warranty period, and what is excluded - vague quotations cause disputes later.

Record-keeping for the enterprise: job cards, material issue slips, labour attendance, and a maintenance contract register form the basis for repeat business and bank credit.

Job card contents: farmer name, survey number, crop, area, block layout, materials issued, labour hours, commissioning readings, and farmer's signature on completion.

Commissioning report should record pump discharge, headworks pressure, farthest-point pressure, DU/EU test result, filter type and backwash setting, and injector calibration.

As-built drawing conventions: plot the field boundary, blocks, mainline and sub-main routes, lateral spacing, valve numbers, and the headworks location with a north arrow and scale.

Digital tools used in the field: GPS or mobile mapping for layout, flow and pressure logging, soil-moisture sensor apps, and SMS/WhatsApp advisory for irrigation scheduling.

ET-based scheduling apps use local weather data to compute ETo and multiply by the crop coefficient; the farmer needs only the crop stage and the area under each valve.

Data protection: farmer contact details, land records, and bank details are personal data - share only with the subsidy agency and never post field photos with identifiable details publicly.

Communication with farmers should use local language, show the pressure gauge and flush valve physically, and demonstrate the backwash and filter-cleaning routine rather than only describing it.

Training records and demonstration plots are documentation assets: date, topic, attendance, and follow-up visits support subsidy claims and repeat service contracts.