Water-use efficiency and plant-soil C:N:P stoichiometry in response to
stand quality of Caragana korshinskii in Mu Us Sandy Land of China
Abstract
Water-use efficiency (WUE) and the stoichiometry of plant-soil carbon
(C), nitrogen (N), and phosphorus (P) are key indicators of plant
growth, while stand quality is an important index for evaluating
afforestation. Yet it remains unclear how WUE and stoichiometric
characteristics respond to changes in stand quality in desert
ecosystems. To that end, we studied the community characteristics of
sand-fixing Caragana korshinskii stands differing in age (planted
10, 30, 50, and 70 years ago) in Mu Us Sandy Land, China, and measured
their leaf water use efficiency (WUE) and leaf-soil C:N:P stoichiometry.
The relations among the stand quality index, leaf WUE, and plant-soil
stoichiometry were analyzed. After 70 years, WUE was at its lowest
level, but only significantly lower than that of a 10-year-old C.
korshinskii stand. Afforestation years had differential effects on C,
N, and P nutrients and their stoichiometric characteristics in leaves
and soil. For soil, its total P barely increased. Irrespective of stand
age, the N:P ratio of leaves was > 16, which suggests P is
the main factor limiting the development of C. korshinskii
plantations. Notably, WUE decreased significantly as the stand quality
index increased while soil stoichiometry responded more strongly than
plant stoichiometry. These results can guide investigations into the
role of C. korshinskii stands in plant and soil recovery effects,
providing a scientific basis to evaluate the rational use of C.
korshinskii sand-fixing forest in afforestation.