Chin J Plant Ecol ›› 2020, Vol. 44 ›› Issue (1): 56-69.DOI: 10.17521/cjpe.2019.0230

• Research Articles • Previous Articles     Next Articles

Stoichiometric characteristics of soils and dominant shrub leaves and their responses to water addition in different seasons in degraded karst areas in Southern Yunnan of China

JING Hong-Xia1,SUN Ning-Xiao2,Muhammad UMAIR2,LIU Chun-Jiang2,DU Hong-Mei1,*()   

  1. 1School of Design, Shanghai Jiao Tong University, Shanghai 200240, China
    2School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai 200240, China
  • Received:2019-09-02 Revised:2020-01-08 Online:2020-01-20 Published:2020-01-19
  • Contact: DU Hong-Mei
  • Supported by:
    National Key R&D Programe of China(2016YFC0502501)

Abstract:

Aims Drought is a limiting factor for plant growth in southern karst areas. Climate change may affect the amount and distribution pattern of precipitation in these areas. It is important to understand the stoichiometric characteristics of soil and plants and how they respond to increasing precipitation in karst areas.
Methods In Jianshui karst areas in southern Yunnan, a water addition experiment was conducted since April 2017 and the concentrations of carbon (C), hydrogen (H), nitrogen (N), phosphorus (P), sulfur (S), potassium (K), calcium (Ca), magnesium (Mg), aluminum (Al), sodium (Na), iron (Fe), manganese (Mn), zinc (Zn), copper (Cu) in the soils and leaves of two dominant shrubs (Bauhinia brachycarpa and Carissa spinarum) were measured in the dry season (April) and rainy season (August) in 2018.
Important findings Water addition affected the content of C, N and Na in the soil. Compared with the dry season, the concentrations of Na and S in the soil significantly decreased in the rainy season. The remaining soil elements did not show any significant differences between treatments and seasons. With the increase of soil moisture content, the concentrations of K decreased while Ca in both plant species increased. These results also indicated that soil moisture changes could significantly affect plant ecological traits. With soil moisture changes, the stabilities of leaf elements were related to their contents. The closer the leaf element contents are to the corresponding maximum or minimum values, the smaller are the coefficients of variation. And the variation coefficients of P, S and Mg with the concentrations close to 1 mg·g-1were the highest. Under the changes of soil moisture conditions, the stability of C, N, P and other major elements in C. spinarum was significantly higher than that B. brachycarpa. Changes in soil water content, which was caused by both rainfall changes and water addition, had different effects on different the contents of different elements in both soil and plants. These results may shed light on the restoration of soil and plants in karst regions.

Key words: karst landform, water addition, stoichiometry, leaf, shrub, soil