RICE is the country’s second staple and a source of major export earnings. But this season the area under rice cultivation has decreased due to delay in monsoon rainfall. Water situation has become critical and shortfall in water supply may hit the production target.

Delay in canal irrigation supply and high prices of fuel restricting pumping out water through tube-wells may squeeze the area under cultivation further which at is around 4.2 million acres. This may aggravate farmer’s production cost rather than its support price of procurement.

Considering scarcity of water, water inputs in rice can be reduced by practicing water saving technologies. Instead of continuous flooding, farmer may reduce water depth by keeping the soil near saturation or practice alternate wetting and drying (AWD) cycles.

In AWD, after nursery transplantation, field is kept flooded for 35 days. Subsequent irrigations are applied with 2-3 days interval or even more depending on the availability of water or just after the disappearance of pounded water. Fields are again re-flooded around flowering in October-November.

Safe AWD can be started 10 days after transplantation or 20 days after sowing and simple tool to apply irrigation is when water is 15-20 cm deep below the soil surface. AWD saves water by 30-35 per cent and improves water productivity without or less affects on yield which is even comparable or greater when ground water is within the root zone and crop does not experience water stress.

As Punjab is the hub of basmati varieties, AWD can be successfully practiced for these varieties. Yields of 3.5-5.0 tons/ha in farmer’s field trials using basmati varieties and 6.8-7.8 tons/ha for coarse ones have been obtained with water savings of 35 per cent through AWD.

Some dissemination trials by NARC at farmer’s field and by researchers at University of Agriculture, Faisalabad, have found that AWD saves up to 5-7 irrigations and net benefits are of Rs9,000-15,000 per ha. Even in demonstration trials of AWD at Rice Research Institute, Kala Shah Kakoo, increased yields of 8.5 per cent and 14.2 were found and water saving recorded were by 25 per cent and 32 per cent respectively. However, for water management, irrigation water to a depth of 5cm was applied when groundwater table was 30cm below the soil surface.

Nutrient management practices in AWD are not too much different from conventional system except for nitrogen use efficiency which is low in AWD due to repeated wetting and drying cycles. Farmer’s application of imbalanced and inappropriate high cost nitrogenous fertilisers to achieve high yield further reduces fertiliser use efficiency. This synchronises it with crop demand and reduces fertilisers inputs, economise the input costs and facilitate the adoption of AWD by reducing water inputs and sacrificing yield benefits.

One of the main advantages of AWD is the safe limit for irrigation application and can be successfully practised in direct seeded rice, system of rice intensification and bed plantation to save water without yield penalties. The AWD is a common practice to save irrigation water in many countries and its further propagation can help save groundwater.

As basmati lines have been developed from traditional rice system, any exposure to decline in moisture availability may affect yield and quality. Therefore, efforts to develop breeding lines with more closeness to basmati rice have been made and four promising high yielding basmati type cultivars under AWD — Bas 385, Bas 515, Super Bas, and Bas 2000 have been identified to be used.

Such breeding efforts need harnessing without compromising on yield and quality under current looming water crisis to improve rice production and compete in international market by exporting good quality rice.

Owing to climate change, rice crop vulnerability to biotic and abiotic stresses is increasing and genetic diversity in coarse and fine aromatic type should be explored. Expertise from extension department and rice research institutes should be taken to contact the farmers and accelerate the promotion of water-saving rice production technology.