مزارع مشابه، پاسخ‌های متفاوت: وقتی برآوردهای آلودگی نیتروژن جمع نمی‌شوند

Same farms, different answers: When nitrogen pollution estimates don't add up

To reduce nitrogen pollution stemming from synthetic fertilizer and livestock waste, California's Central Valley relies on five data sets to estimate surplus nitrogen. However, most parts of the United States use just one or two data sets—the U.S. Department of Agriculture's agricultural survey and census—to estimate nitrogen surplus.