Demand for corn is such that more land is also being ploughed up in drier regions of the Great Plains states to the west of the corn belt, where irrigation in required, increasing water demand further.

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Fair enough, but if there is so much attractive wilderness up for grabs, why haven't farmers already ploughed it up?

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Djokovic responded by breaking twice at the start of the third set to establish a 3-0 lead and he wrapped up the set in just 28 minutes and ploughed through the fourth set to set up a third-round meeting with countryman Viktor Troicki.

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Prop Horan then picked up the ball and ploughed his way through the Cardiff defence and over the line for Munster's first try, with Manning adding the two points.

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The 34-year-old ploughed forward in the first few rounds, backing Mayweather up with some heavy combinations to the body.

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Monty Panesar wrapped up the innings for 250 and Northants soon ploughed on.

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And a few years before that, an 80-tonne space rock called 2008 TC3 ploughed into the Earth's atmosphere, largely burning up and scattering fragments over the Sudan - just 20 hours after it was discovered.

BBC: Science & Environment