The Nitrogen in Manure Production dataset of the Global Fertilizer and Manure, Version 1 Data Collection represents the amount of nitrogen manure produced and present on the
landscape. The manure production at grid cell level was computed based on livestock population and nutrient excretion rates. The livestock population per grid cell was computed by
multiplying the density values from FAO Gridded Livestock of the World by the area of grid cell. Spatially explicit manure produced and present on landscape is derived by combining the
number of livestock heads and the nutrient excretion rate. The data were compiled by Potter et al. (2010) and are distributed by the Columbia University Center for International Earth
Science Information Network (CIESIN).