Response of biomass allocation strategies to plant-soil C:N:P
stoichiometry in Alfalfa artificial grassland of different ages on the
Mu Us Desert, China
Zhouchang Yu
College of Grassland Agriculture, Northwest A&F University, Yangling,
712100, Shaanxi, China
Email:yuzhouchang@outlook.com2. Wei Zhang
College of Grassland Agriculture, Northwest A&F University, Yangling,
712100, Shaanxi, China
Email: zwgwyd@163.com
3. Xiao-pin Xin
National Hulunber Grassland Ecosystem Observation and Research Station
Institute of Agricultural Resources and Regional Planning, Chinese
Academy of Agricultural Sciences, Beijing 100081, China
Email: xinxiaoping@caas.cn
4. Yuanying Li
College of Grassland Agriculture, Northwest A&F University, Yangling,
712100, Shaanxi, China
Email: 931163407@qq.com5. Yi Zhou
School of Agriculture, Food & Wine, The University of Adelaide,
Urrbrae, 5064, South Australia,
Email: yi.zhou@adelaide.edu.au
6. Ruirui Yan
National Hulunber Grassland Ecosystem Observation and Research Station
Institute of Agricultural Resources and Regional Planning, Chinese
Academy of Agricultural Sciences, Beijing 100081, China
Email: yanruirui@caas.cn7. Zhiguo Xie
Shaanxi Academy of Forestry, Xi’an, 710082, Shaanxi, China
Email: zhiguoxiesx@163.com
8. Peizhi Yang (Corresponding author)
College of Grassland Agriculture, Northwest A&F University, Yangling,
712100, Shaanxi, China
Email: yangpeizhi@126.com
Abstract
C:N:P stoichiometry is widely used in ecological research, but its role
in the allocation of plant biomass is unclear. To explore this issue, we
collected soil and alfalfa samples from 1, 2, 3, 5, 7, 9 and 10 year of
alfalfa (Medicago sativa ) plantations on the Mu Us Desert, China.
We examined the aboveground and underground biomass of each plantation,
the C, N, P contents, stoichiometric ratio of plants and soil, and soil
biological characteristics. The C content of alfalfa increased first and
then decreased with the growth age, which was opposite to N and P
content, their most significant changes were in the 7-year stand. The
individual changes of C-N-P in alfalfa led to the C:N and C:P increased
first and then decreased, N:P increasing with the growth age. Soil OC,
TN, C:P and N:P were increasing with the stand age, and TP content and
C:N were increasing first and then decreasing. The C contents, C:P and
N:P between alfalfa and soil were strongly correlated. N:P and
underground biomass were positively correlated, while negatively
correlated to aboveground. Our results show that the nutrient content
and stoichiometric ratio in soil and plants were closely associated,
after 7 years planting, the alfalfa’s growth was limited by P, it
responds to the increased N:P by increasing root-shoot ratio, and soil
fertility had also been improved at same time. Overall, these results
provide a reference for further research on stoichiometry as an
indicator to alfalfa yields on the Mu Us Desert.
Keywords ：P-limitation; stoichiometry; aboveground;
underground; root-shoot ratio