Ecological stoichiometry of plant-litter-soil and stoichiometric
homeostasis of plant tissues under three restoration modes for
desertified grasslands in southern Horqin Sandy Land, Northern China
Abstract
Afforestation is the primary ecosystem measure to address the issue of
ecosystem degradation in in the Horqin sandy region of northern China.
However , It is yet unclear how afforestation may affect the recovery of
sandy grassland. This study took the ecological stoichiometry as
indicators, and conducted a field investigation and indoor analysis to
assess the afforestation strategies of three indigenous tree species for
the restoration of sandy grassland , three restoration strategies were:
(1) grasslands were enclosed via a Populus × beijingensis
shelterbelt (FG); (2) Pinussylvestris var. mongolica was used for
the afforestation of small, well-distributed grassland patches (MG); (3)
Ulmus pumila was used for the afforestation of small,
well-distributed patches (UG). Our result showed that the C, N, and P
contents as well as the C: N: P ratio in plants, litters, and soils
varied significantly between FG, MG, and UG. All three treatments were
found to significantly impact the soil ratios of C:N, N:P, and C:P
relative to CK treatment after more than 20 years of recovery. The
results of N : P in different tissues showed that FG , MG and UG
vegetation restorations were N-limited. N and P homeostasis was present
in trees, especially Ulmus pumila, while the degree of
homeostasis was significantly impacted by afforestation species and
plant tissues. The N:P results suggested that lower N deficiency stress
may have been experienced by three experimental plants. We concluded
that UG was better suited to the dry climate in Horqin Sandy Land.