The total amount of commercial fert

The total amount of commercial fertilizer consumed in a given state or region is the sum of all
synthetic nitrogen, multiple-nutrient, and organic fertilizer applied (measured in mass units of
nitrogen). Fertilizer data by type and state can be obtained from the Tennessee Valley Authority’s
National Fertilizer and Environmental Research Center. In the case of organic fertilizers, such as
manure from livestock operations, data may be available from state or local Agricultural Extension
offices. There may be instances in which fertilizer consumption is given as the total mass of fertilizer
consumed rather than as nitrogen content. In such cases, total mass by fertilizer type may be
converted to nitrogen content using the percentages in Table 14.1-1.