Drip Irrigation

Drip irrigation delivers water in slow, precise drops directly at the base of each plant, instead of flooding or spraying the whole field. Because water goes only where roots actually are, evaporation from bare soil between rows and deep percolation past the root zone both fall sharply, which is why it cuts water use 40–60% against flood irrigation — a mechanical result of root-zone delivery, not a marketing figure.

It earns its cost back fastest on wide-spaced row crops with real cash value — cotton, sugarcane, onion, tomato — where fertigation adds a second saving on top of the water one. It is a poor fit for closely sown or broadcast crops like wheat or gram, where laying enough laterals to cover every row costs more than the crop can return; those stay on sprinkler or flood, covered in full on the Irrigation hub.

A drip system is six parts working as one chain: a pump lifting water from the source, a filter cleaning it, an optional fertigation unit dosing nutrient into it, main and sub-main lines carrying it to each block, laterals carrying it along each row, and emitters releasing it at each plant — see the components section above for what each one actually does.

The chain is only as good as its weakest link. An undersized pump starves every emitter downstream; a missing or undersized filter clogs emitters within a season regardless of how well everything else is installed. This is why installation quality, not just the equipment bought, decides whether a system delivers its rated 90% field efficiency or something well short of it.

Fertigation is dissolving water-soluble fertiliser into the irrigation water and applying both together through the drip system’s existing network. Because the nutrient arrives exactly where the water does — at the root zone, in small frequent doses rather than one broadcast application — fertiliser-use efficiency typically rises by around 30% compared with a single soil-applied dose, since less nitrogen is lost to volatilisation or leaching past the root zone.

It needs water-soluble grades, not standard urea or DAP, which do not dissolve cleanly enough for an emitter, plus a venturi injector or fertigation pump to meter the dose into the line — a modest extra cost on top of the system itself, usually justified quickly on a crop already paying for fertigation-suitable inputs like NPK 19:19:19 or calcium nitrate. See the Fertilizer Calculator to plan the dose.

The subsidy explained in the PMKSY section above changes the arithmetic of switching to drip more than most farmers realise before checking: a 55% capital subsidy on a ₹36,000-per-acre system brings the actual outlay down to roughly ₹16,200 for a small or marginal farmer — often recoverable within two to three seasons on a cash crop through water, labour and fertiliser savings alone, before counting any yield gain.

Budget is not just the net cost after subsidy — it includes bridging the gap between paying the dealer in full and receiving the PMKSY subsidy as DBT afterward, which for many small farmers is the real constraint. The scheme also intersects with the broader Government Schemes directory — a farmer applying for PMKSY is often, in the same visit to the agriculture office, also eligible to ask about Kisan Credit Card financing for the farmer’s share of the cost.

A drip system not acid-flushed every season loses efficiency to clogging within two to three years, at which point it performs little better than a poorly maintained sprinkler — the water saving quoted for drip assumes basic maintenance is actually done, not just that the system is installed. Filters need cleaning on a schedule, not only when flow visibly drops; by the time flow drops, some emitters have likely already clogged silently.

The common problems section above covers the specific symptoms and fixes for clogging, uneven flow, algae and physical damage — walking the lateral lines periodically to catch a small leak or a slowly clogging emitter early is far cheaper than replacing a section of lateral or losing a season’s water saving to an undetected problem.

Beyond the mistakes listed above, the pattern underneath most of them is treating the system as equipment that works on its own once bought, rather than a chain that needs the water source checked, the filter matched to it, the laterals laid along the contour, and the maintenance schedule started from day one.

A second, quieter mistake is buying from an unregistered dealer to save a step on paperwork — the PMKSY subsidy claim is rejected outright on equipment from an unregistered, non-BIS-certified supplier, which costs far more than the time the shortcut was meant to save.

Subsurface drip irrigation buries the lateral lines a few centimetres to a foot below the surface instead of laying them on top of it — the same drip principle, delivered where evaporation from the soil surface cannot touch it at all. It pushes efficiency higher still than surface drip, at a materially higher installation cost and the added complication of a buried line being harder to inspect for clogging or damage.

In India it remains a niche choice, mostly on high-value orchard and plantation crops — grapes, pomegranate, banana — where the extra cost is justified over a multi-year planting, rather than an annual field crop replanted every season.

As a general rule: a wide-spaced cash crop on sandy or loam soil, with a borewell, well or canal source that can sustain the design discharge, and a budget that can bridge the gap to the PMKSY subsidy, is the clearest fit for drip. The Irrigation hub’s system advisor works through the same crop, soil, water source and budget questions an irrigation consultant would ask in person, and returns a recommendation with its cost, subsidy and payback period.

Where the crop is closely sown or broadcast — wheat, gram, most pulses — sprinkler or flood usually remain the better fit, since laying enough drip laterals to cover every row costs more than those crops can return; the full four-way comparison is on the hub.