A field that is not level wastes water. The high corners do not get wet until the low corners are flooded. Traditional levelling with a scraper and a bullock or tractor achieved perhaps a few centimetres of variation.
Laser levelling uses a rotating laser and a receiver on a scraper blade to grade a field to within a centimetre or two. Water applied to a laser-levelled field spreads evenly and the saving is measured at fifteen to thirty per cent for paddy.
Punjab has subsidised the machines and there are custom hiring operators in most districts. Adoption is substantial and not universal.
It is the single cheapest water-saving intervention available in Punjab and it requires no change of crop, no change of policy and no sacrifice by anyone.
That it is still only partly adopted after twenty years says something about how agricultural technology actually spreads, which is through neighbours and contractors rather than through announcements.
A laser guided blade levels a field to within a couple of centimetres, which cuts the water needed to flood it by a fifth or more. The gain is immediate and it is measurable.
It is one of the very few water saving measures in Punjab that farmers took up quickly, because the benefit shows in the same season.
The machines are owned by cooperative societies and by contractors and are hired by the acre. It is a rare case of a technology that reduced water use spreading without being forced.