Crop growth and drinking water could be severely affected if predicted changes in rainfall patterns over the coming years prove true, according to research from the Biotechnology and Biological Sciences Research Council (BBSRC).

Scientists at the BBSRC, funded by North Wyke Research, have found for the first time that the rate at which a dried soil is re-wetted impacts on the amount of phosphorus lost from the soil into surface water and subsequently into the surrounding environment, according to research published this month in Biology and Fertility of Soils.

Dr Martin Blackwell, who is one of the project leaders, said: "Our preliminary results show that despite best efforts, the changing climate may limit our ability to mitigate phosphorus losses at certain times of the year, especially summer.

"This is really worrying because high phosphorus concentrations in surface waters can lead to harmful algal blooms which can be toxic, cause lack of oxygen during their decay and disrupt food webs. This can also affect the quality of water for drinking and result in the closure of recreational water sport facilities."

Under laboratory conditions, Blackwell and his team re-wet dried samples of UK grassland soil over different time periods, ranging from two hours to 24 hours, using the same quantity of water. The leachate - water that has washed through the soil - was then analysed for phosphorus.

The study showed that the rate at which a dried soil is re-wetted affects the concentration and forms of phosphorus lost in leachate, which could potentially contaminate large surface areas of water such as rivers and lakes.

Further research will be carried out to determine whether other soil types would react in the same way.