Farmers across the Midhurst and Petworth area have spoken of the 'dire' situation they face if the prolonged dry spell continues.
Grass is not growing as it normally would at this time of year and the yield on wheat and other other corn crops is predicted to be well down on what may be expected because of the lack of moisture in the ground.
Mark Chandler of Petworth and District Agricultural Association, who farms with his father Richard at Petworth, said: "We have the worst situation drought-wise at this time of year since 1975.
"In the past eight weeks we have had only seven millimetres of rain. It is absolutely dire.
"The dairy boys have had their first cut of silage and it is drastically reduced. If we do not get rain in the next week it is going to dramatically affect our harvest.
"Our yield potential has gone through the floor. If we get rain we might have a chance but we know we have already lost yield."
He added: "We are on heavier land here so the guys on the lighter land through Midhurst must be struggling even more than we are."
Keith Parks, manager of ACS agricultural contractors based at Buddington Farm, Easebourne, confirmed this view.
"We are irrigating to put an inch of water on everything – wheat, oats, potatoes, grass. We have got wheat in ear and dying because of lack of moisture, and oats coming into ear and dying off. Before long everyone will be running out of water. There is a limit how much we are allowed to draw from the river."