Image caption Dry as dust: Where irrigation is not in use, crops across the state of Texas have failed thanks to a severe drought

"Water availability is gradually declining. Even 30 years ago we had probably twice as much water as we have now."

Glenn Schur has been farming for 30 years.

His father first moved to the plains around Plainview, Texas in the late 1940s, and after graduating from college Mr Schur returned home to work on the farm he now owns.

Almost half of the property's 1,800 acres are given over to cotton production, the rest is divided between grain sorghum, wheat, seed crops and livestock.

Times are hard for Texan farmers. The state is in the grip of a severe drought, and there has been no rain in Plainview for nearly a year.

"What we're having to do is irrigate rather extensively to make a crop. In all the dry areas, the seed is still laying in the ground like the day we planted it," he says.

"We recorded the highest average temperature for the month of July since records have been kept, and that was in 1911. We've experienced record wind speeds as well."

Image caption Glenn Schur says technology in water management has improved over the last 15 years

When the rains fail, this area of the United States relies on the Ogallala aquifer, which stretches from North Dakota all the way down to Texas. But this is a finite resource, and one that is in danger of drying out.

The farmers of Texas aren't giving up without a fight though.

Water level

Mr Schur is part of the Texas Alliance for Water Conservation. Across 32 sites in two counties, the group is monitoring the rainfall and the water that is pumped, calculating the gross profit margin for every crop.

"What we're trying to do is to come up with ways to conserve water and maximise profits," says Mr Schur.

"We're using all the newest available technology for water management."

Pumping water costs money. Although the farmers in this area don't have to pay for the supply, they do have to pay for the electricity to bring it to the surface.

Over-watering an area can also mean using more pesticides and fertilisers than you need to - and when the crop stops absorbing them, the only place left to go is down into the water table.

Cloud cover

To tackle this Mr Schur uses drought-resistant seed, evaporation transpiration technologies, and a system of water probes that harness cloud computing and the internet to predict when to water and when to turn the taps off.

The solar-powered probes are placed in the fields, buried to a depth of about 60 inches (1.5 metres), with soil moisture sensors every four inches along a vertical column.

Image caption The solar-powered probes have a small mobile phone mast so they can send the data for analysis

The sensors send signals every three minutes, tracking moisture and salinity at each level, and the state of the roots of your crop.

At the top of the probes are mini mobile phone masts that transmit the data gathered to servers where it is processed using complex algorithms.

The results are then held in the cloud and displayed on a dashboard accessible online from any computer or smart phone.

The system can also send text alerts and emails with instructions on when irrigation should next take place, whether to fertilise, and if pesticides can be used.

Mr Schur says technology like this has saved him $30 an acre per year on energy costs alone, before adding in savings on chemicals, and the increase in yield that precision agriculture like this can give.

"With the probes it gives us an idea of the water movement into the soil profile, it also allows us to look at the plant development all along, and in several cases we've been able to stop an irrigation or delay it for several days."

Appliance of science

The system has been developed by a company called AquaSpy. The firm started out in Australia before expanding across water-scarce areas of the US.

They are in the process of rolling out a new version, with an improved online dashboard on what they feel is a more cost-effective subscription model.

Bruce Moeller is AquaSpy's chief executive. He says that by monitoring the conditions of the roots, farmers can ensure the plant is given exactly what it needs - and no more. Avoiding over-watering is just as important as under-watering.

Image caption Aqua Spy's subscribers can access crop data from this dashboard from any computer or smartphone

"The reason that's important is because a plant will grow through certain growth stages when it's getting ready to fruit," he says.

"It also needs to be trained to have its roots go down further and deeper to look for the ground water, so it's not getting lazy.

"It's just like raising a child - if you give it everything it wants right away, it doesn't have to work for anything. It gets lazy and somewhat indolent."

Mr Moeller says that by monitoring the crop, and using data gathered over long periods to predict how it will behave, farmers can maximise crop yield.

"With precision agriculture you can even control the size of the crop.

"You can dial in with a fair degree of accuracy the water content that's in an orange, the size of that orange, and then when you're shipping it there are certain receivers of those goods who will only accept a certain size and quality.

"With corn at close to $7 per bushel the payback on that is within the same season for sure, a per cent or two of extra yield will pay for the service."

The great challenge in all aspects of water management is making people value it Dr David Lloyd Owen, Water consultant

The cost works out at about $1.35 per acre per month, and Mr Moeller plans to reduce that further.

"Our model is to do more of this at ever lower cost so we can penetrate more and more places on the globe.

"My mantra is: let's cover the earth with a green solution and make it a financially-viable no-brainer for the grower."

Although water sensor technology has been around for some time, using the internet and communications technology to deliver data to farmers is newer.

Other companies doing similar things include John Deere and PureSense, who launched a smartphone app to complement their system last year.

Water shortage

There are currently between 1-2bn people living in places where water is in short supply, and this is expected to increase significantly.

Population growth, urbanisation, climate change, and damming (70% of the world's rivers are shared by more than one country) mean water is often quite simply in the wrong place.

Water consultant Dr David Lloyd Owen says often supply is not the problem.

Image caption Dr Lloyd Owen: "Getting water from one place to another is an energy intensive and costly process"

"What humans are not very good at is managing it. What there's a shortage of is management capacity and political will to put our natural resources to beneficial use."

Agriculture is all too often an example of this, says Dr Lloyd Owen.

"In a typical traditional irrigation system maybe 10-20% of water put into the system actually gets anywhere near a root. It's an extremely wasteful way of using what is already a scarce resource."

Water is not the only scarce resource, he says. Not only can fertilisers damage the environment when used in excess - supplies of nitrogen and phosphorous are also finite.

"We can't run away from food production. Wherever people are around the world there ought to be an appropriate amount of food growing.

"The art here is with what water you use - whether through water harvesting, waste water reuse, desalination, [or] ground water - to use it in the most effective way. The great challenge in all aspects of water management is making people value it."

And this means technology that controls water use is doubly important.

"If areas have continued population growth, and they're not able to improve the efficiency of irrigation agriculture, they're going to have increasing and quite frankly terrifying problems in feeding their people in the decades to come," says Dr Lloyd Owen.

Under a baking sun, in the cotton fields of Texas, Mr Schur at least is optimistic.

"Technology in agriculture is moving very fast, and we're looking at a lot of ways of using the internet to gain information on what is happening on our farm," he says.

"What I'm seeing is, in the last 15 years, that technology as far as water management goes has really improved, and our crops have become more water-efficient as well, especially cotton.

"We're seeing higher yields than we've ever experienced, with less water."