Intensively-managed croplands and nitrogen (N) fertilizer use are expanding rapidly in tropical regions. We quantified fertilizer responses of maize yield, N2O emissions, and N leaching in an Amazon soybeanmaize double-cropping system on deep, highly-weathered soils in Mato Grosso, Brazil.

In their Policy Forum "National forests in the Amazon” (30 Aug., p. 1478), A. Veríssimo et al. seem assured that a new system of national forests will solve the problems of uncontrolled forest exploitation in the Brazilian Amazon. Unfortunately, we are far less...