7 November 1997

Scheduling is best way to keep water on tap

Using water more efficiently

was the theme at this

years Water for Farming

event in Peterborough.

Edward Long reports

ONLY about 1 in 10 farmers who irrigate use any form of scheduling system to target water to where it is most needed at the most appropriate time.

But the need for some form of water management is increasing as it becomes more costly, supplies dry up, and integrated crop management protocols are implemented. That is the opinion of ADAS Huntingdon-based water specialist Colin Smith.

A trial at ADAS Gleadthorpe in Nottinghamshire between 1992 and 1995 showed the benefits of scheduling. Potatoes irrigated at a fixed seven-day interval received 308mm and yielded 49.8t/ha. Assuming a price of £80/t and £3.50/mm/ha for the water, the margin over the unirrigated was £1074/ha.

Where the interval was adjusted to allow for rainfall with a one-day delay for every 5mm of "free" water only 242mm of irrigation was needed. The crop yielded slightly less at 49.5t/ha but the margin was better at £1281/ha.

A fully scheduled approach brought an even greater benefit. The crop given 192mm of water yielded 49.2t/ha and a margin of £1432/ha.

"But the real advantage comes in a dry season when growers are short of water, as most who irrigate are. Then scheduling allows it to be better targeted. If it is in very short supply yield will be lost, but scheduling will help to reduce losses," Mr Smith says.

Too few growers schedule their irrigation and lose up to £350/ha as a result, says Colin Smith.

WATERFORFARMING

&#8226 Only 1 in 10 growers use irrigation scheduling.

&#8226 Scheduling can boost profit by over £350/ha.

&#8226 Full better than partial irrigation.

&#8226 Reconsider water supply.