Net primary productivity (NPP) is an important index for evaluating carbon budgets of ecosystem.
In order to determine the NPP of three kinds of typical sandy shrubs, harvest method and ingrowth cores
method were used to determine aboveground and belowground growth, and elemental analyzer was used to
measure each organ carbon content rate. The results showed that NPP of Astragalus mongolicum, Salix
psammophila and Artemisia ordosica was 63.13, 96.39 and 63.98 g/(m2year). The growth ratios of
root to shoot of A. mongolicum, S. psammophila and A. ordosica were 2.71, 2.02 and 1.32,
respectively. Three shrub species were accordance with isometric allocation relationship between the
growth of above-and belowground parts. The findings suggest that the belowground NPP of A.
mongolicum, S. psammophila and A. ordosica can be estimated based on the aboveground NPP.