The Native Soil by Alan Edward Nourse (beach read book .TXT) 📕

"But why? We weren't hurting them. There's plenty of mud on Venus."

"Ah—but not so much of the blue-gray stuff we were after, perhaps. Suppose a space ship settled down in a wheatfield in Kansas along about harvest time and started loading wheat into the hold? I suppose the farmer wouldn't mind too much. After all, there's plenty of vegetation on Earth—"

"They're growing the stuff?"

"For all they're worth," said Kielland. "Lord knows what sort of metabolism uses tetracycline for food—but they are growing mud that yields an incredibly rich concentration of antibiotic ... their native food. They grow it, harvest it, live on it. Even the way they shake whenever they come out of the mud is a giveaway—what better way to seed their crop far and wide? We were mining away their staff of life, my friend. You really couldn't blame them for objecting."

"Well, if they think they can drive us off that way, they're going to have to get that brilliant intelligence of theirs into action," Simpson said ominously. "We'll bring enough equipment down there to mine them out of house and home."

"Why?" said Kielland. "After all, they're mining it themselves a lot more efficiently than we could ever do it. And with Piper warehouses back on Earth full of old, useless antibiotics that they can't sell for peanuts? No, I don't think we'll mine anything when a simple trade arrangement will do just as well." He sank back in his cot, staring dreamily through the port as the huge orbital transport loomed large ahead of them. He found his throat spray and dosed himself liberally in preparation for his return to civilization. "Of course, the natives are going to be wondering what kind of idiots they're dealing with to sell them pure refined extract of Venusian beefsteak in return for raw chunks of unrefined native soil. But I think we can afford to just let them wonder for a while."