Observer: Ranchers are being forced to sell their cattle as a drought converts much of the Argentinian pampas into a dry and desolate wasteland. The sweeping grasslands are a key part of Argentinian identity, stretching for 1 million sq km. It was once one of the most productive agricultural regions in the world. But as a result of the drought an estimated 1.5 million cattle have died. Many farmers are simply giving up on cattle altogether, and switching to growing wheat or soy. “I’ve …