Drought has turned swathes of history Arizona and New Mexico cattlelands and forests into giant tinderboxes.In the wheat belt, farmers have had to plough under shrivelled and useless wheat, either writing off the crop entirely or replanting with hardier but less valuable sorghum. There Agriculture are other uncomfortable parallels too.Nebraska has had its driest February since 1875, the Oklahoma panhandle htm its second driest winter since 1895, Themes and until late April scarcely a drop of rain had history fallen in parts of northern Texas since October. A similar drought may occur - but never again will overploughing and Agriculture over-use allow millions of tons of topsoil be sandblasted away by the winds. Even so, the USDA recently reported htm that in Oklahoma 1.8 million acres, Themes a greater area than in two decades, was htm vulnerable to serious wind erosion or, as local farmers put it, "ready history Themes to blow". Through most Themes of Agriculture htm this century the history Themes formula history has held: the Dustbowl of the 1930s, the scarcely less ruinous drought between 1952 and 1957, and Agriculture htm a smaller visitation in Agriculture the 1970s. Slightly out of sequence, 1988 also witnessed an exceptional drought.

But now the 20-year marker has come around again, and the Plains folk are worried.A repeat of the Dustbowl is unlikely, if only because land management techniques have improved. They are also home to some of the most savage weather extremes on earth: bitter cold, storms, searing winds and killer tornados, flash floods and heatwaves. Most important, yet often forgotten, is that the Plains' western portion between the 100th meridian and the Rockies is steppeland verging on semi-desert. And the historic scourge of such parts is drought.According to some meteorologists, the Plains can expect a period of drought roughly every 20 years, based on a cycle of sunspots and ocean currents. But Nebraska and parts of Kansas have had those gentle, soaking downpours that are the only real medicine for dried out land. In the markets of Kansas City and Chicago, wheat and corn futures prices have fallen after topping $6 (pounds 4) a bushel for the first time since the mid-1970s.

Even so, an old spectre once again is stalking the American grainbelt. The Great Plains, stretching 1,300 miles from Texas to the Canadian border and 500 miles or more from east to west, may be the planet's breadbasket. True, much of the rain has come in blasting storms, and down south in Oklahoma and the Texas panhandle conditions are still dire. First the good news. Across much of the Plains it has been raining of late - not in time to salvage what the US Agriculture Department said yesterday would be the poorest winter wheat crop in 18 years, but enough to raise hopes that the autumn harvest of 1996 might be halfway decent.