Biodiv Sci ›› 2017, Vol. 25 ›› Issue (10): 1085-1094.DOI: 10.17520/biods.2017148

• Original Papers: Plant Diversity • Previous Articles     Next Articles

C, N and P stoichiometric characteristics of soil and litter fall for six common tree species in a northern tropical karst seasonal rainforest in Nonggang, Guangxi, southern China

Yili Guo1,2, Dongxing Li1,2, Bin Wang1,2, Kundong Bai1,2, Wusheng Xiang1,2, Xiankun Li1,2,*   

  1. 1 Guangxi Key Laboratory of Plant Conservation and Restoration Ecology in Karst Terrain, Guangxi Institute of Botany, Guangxi Zhuang Autonomous Region and Chinese Academy of Sciences, Guilin, Guangxi 541006
    2 Guangxi Youyiguan Forest Ecosystem National Research Station, Pingxiang, Guangxi 532699
  • Received:2017-05-17 Accepted:2017-10-16 Online:2017-10-20 Published:2018-05-05
  • Contact: Li Xiankun

Abstract:

Litter fall provides organic matter and nutrients to forest ecosystems and is central to the exchange of substances between soil and plants. It plays a vital role in the maintenance of soil organic matter and nutrient cycling in forest ecosystems and it is one of the main sources of soil fertility. We used litter fall data for six common tree species collected between March 2014 and February 2015 from 90 litter fall traps, and fifty soil samples collected in July 2014 along an altitudinal gradient from 185 to 368 m in a tropical karst forest in Guangxi, China. We studied the C, N and P stoichiometric characteristics of soil and litter fall, and their trends along an altitudinal gradient. Soil C and N contents were all positively associated with altitude, while P content was negatively associated with altitude. Soil C : N was negatively associated with altitude, while C : P and N : P were positively associated with altitude. Due to the narrow altitudinal range of the soil samples, we speculate that the association of soil nutrients with altitude is due to the effect of micro-topography and not a climatic effect. Apart from the higher slope and summit, the soil C, N, P contents reached the first classification level of the national criterion of soil nutrients. Compared with other forest ecosystems, we found greater C and N contents and lower P content than the average value of C, N, P contents for litter fall of six common species. There were no trends for C, N and P stoichiometric characteristics of the mixed sample of leaf litter for the six common tree species along an altitudinal gradient. The six common tree species have higher C content in spring and higher contents of N and P in summer. The per unit total basal area of trees in this forest was much lower than other forest ecosystems, indicating its low biomass stock. This study provides useful information for ecological restoration of a typical vulnerable karst ecosystem in China.

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Key words: karst seasonal rainforest, stoichiometric characteristics, soil, litter fall of leaves, altitude gradient, seasonal variation