Associated Press: Walking on a dusty field of cut rice that was once rainforest, researcher Flavio Wruck explains how farming, the Amazon’s biggest killer, can be turned into its best defender. At the government-run experimental farm where he works, he points toward plots where crops, cattle and timber live together. It’s a simple system, long practiced in the U.S., of rotating crops and revitalizing pasture instead of simply chopping down forest and planting new grasslands. But here in the …