2.3 Plant sampling
The dominant plant species, S . krylovii , was chosen to
examine the effects of N and P addition upon seed production in this
study. Being a widespread perennial tussock grass in typical temperate
steppe, it is an important fodder species used in China, Mongolia,
Kazakhstan, and Russia (Ronnenberg et al., 2011; Wu & Raven, 2006). The
vegetative and reproductive tillers of S . krylovii can
attain heights of 50 cm during the growing season (Li et al., 2017).
In the experiment, three plant individuals were selected in each plot to
measure tiller number per individual, inflorescence number per
individual, and seed number per inflorescence in late August, from 2015
to 2017. Meanwhile, maximum plant height and density were investigated
in a randomly selected subplot (1 m × 1 m) within each plot. Seed
production per individual was calculated as the product of seed number
per inflorescence and inflorescence number per individual (Brys et al.,
2005).