Water flow in UK rivers is predicted to drop by as much as 80% in summer months by 2050, meaning growers will have to adapt to growing crops with less water.

Figures highlighted by Trevor Bishop, head of water resources policy for the Environment Agency, suggested river flows could be reduced by 50-80% in the summer and 15% overall.

If this happened, the quantity of water available for farmers to abstract would be significantly reduced, he told delegates at the 2010 Crop World Conference.

Reducing water demand through good land management, investing in water efficient technology and managing demand was needed to make the most of limited supplies, he said.

Water abstraction groups would play a valuable role in demand management, allowing producers to share the water supply and trade irrigation water volumes, Mr Bishop added.

Antoine Meyer, head of new crop protection business for BASF, said technology was already helping to reduce water use.

Super-absorbent granules that held water next to plant roots were being used in the horticultural industry and had potential to be used in mainstream agriculture, he said.

“They sit next to plant roots and retain water when it rains. In drier times this water is released when the plant needs it.”

The polymer granules can absorb and retain up to 300 times their own weight in water which they will release as the soil moisture level decreases.

But more work was needed before these products could be used for field-scale agriculture, he said.

Application was one barrier as the granules needed to be placed in the plants’ root zone and they would have to be replaced every year as the new crop was established.

BASF had also developed a range of crop protection products containing the active ingredient pyraclostrobin, which helped retain water on the leaf surface. Water use efficiency could increase by 7% in cereals, he said. The products are not available in the UK, but are being used in some parts of South America, Canada and Europe.

Mr Meyer said small steps such as improving chemical packaging could also reduce agricultural water use. Making containers easy to rinse meant less water is needed when filling the sprayer, he said.