Total carbon and nitrogen in the soils of the world

Summary The soil is important in sequestering atmospheric CO 2 and in emitting trace gases (e.g. CO 2 , CH 4 and N 2 O ) that are radiatively active and enhance the ‘greenhouse’ effect. Land use changes and predicted global warming, through their effects on net primary productivity, the plant community and soil conditions, may have important effects on the size of the organic matter pool in the soil and directly affect the atmospheric concentration of these trace gases. A discrepancy of approximately 350 × 10 15 g (or Pg) of C in two recent estimates of soil carbon reserves worldwide is evaluated using the geo‐referenced database developed for the World Inventory of Soil Emission Potentials ( WISE ) project.…