Chin J Plan Ecolo ›› 2005, Vol. 29 ›› Issue (2): 311-317.doi: 10.17521/cjpe.2005.0040

• Research Articles • Previous Articles     Next Articles

EFFECTS OF NITROGEN ADDITIONS ON A LEYMUS CHINENSIS POPULATION IN TYPICAL STEPPE OF INNER MONGOLIA

PAN Qing-Min, BAI Yong-Fei, HAN Xing-Guo, and Yang Jing-Cheng   

  1. (Inner Mongolia Grassland Ecosystem Research Station, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China)
  • Online:2005-03-10 Published:2005-03-10

Abstract:

Leymus chinensis, a rhizomatous graminoid, is a dominant species in the grasslands of northern China. The characteristics of L. chinensis populations have been well documented in many research papers. Because of overgrazing, grasslands of northern China have become degraded since the 1980s. As a result, the density and biomass of L. chinensis populations have decreased significantly. Fertilization is a common technique for management of pastures in many countries; however, it is not widely used in the grasslands of China. Nitrogen is an important driver of community succession in grassland ecosystems, but the response of L. chinensis populations to nitrogen additions in typical steppe, a semiarid area of northern China, remains unclear. We conducted a sequential nitrogen addition experiment in a lightly degraded grassland plot that was fenced in 1999. Nitrogen (NH4NO3) was applied on July 5 for two years at application rates of: 0, 1.75, 5.25, 10.5, 17.5, and 28 g N·m-2,respectively. There were 9 replicate 5 m×5 m plots of each of the six treatments with each plot spaced 1 m apart. A completely randomized design was used for this experiment. Before the experiment, soil samples were collected and dry bulk density, pH, soil nitrogen and soil carbon were analyzed. After two years of nitrogen fertilization, we measured the density, height, aboveground biomass and belowground biomass of L. chinensis in each plot. The results showed that L. chinensis population characteristics were highly responsive to nitrogen additions. With an increase in nitrogen application rates, the density, height, aboveground biomass, belowground biomass and total biomass of L. chinensis increased significantly whereas the ratio of aboveground biomass/belowground biomass decreased. The allocation of biomass among plant parts was significantly affected by nitrogen additions: the proportion of biomass allocated to rhizomes decreased remarkably with increasing nitrogen rates whereas that allocated to leaves and roots increased significantly. The relative biomass and relative density of L. chinensis also increased with increasing nitrogen additions. In summary, adding nitrogen to lightly degraded grassland not only increased the density and biomass of L. chinensis population but changed the resource partitioning among plant parts as well.

No related articles found!
Viewed
Full text


Abstract

Cited

  Shared   
  Discussed   
[1] Yu De-jun;Zheng Guang-hua and Zhang Jie. The Collection, Preservation and Research Work on Germplasm Resources of Wild Plants[J]. Chin Bull Bot, 1984, 2(23): 41 -43 .
[2] Hu Shiyi. Isolation and Cuture of Haploid Protoplasts in Reproductive System of Angiosperms[J]. Chin Bull Bot, 1986, 4(12): 20 -24 .
[3] Juan Shi Baohua Zhu Kehou Pan. Advances in Research into the Production of Very Long-chain Polyunsaturated Fatty Acids in Transgenic Plants[J]. Chin Bull Bot, 2007, 24(05): 659 -666 .
[4] ZHU Xin-Guang ZHANG Qi-De KUANG Ting-Yun. Damage to Photosynthetic Functions of Wheat by NaCl Results Mainly from Its Ionic Effect[J]. Chin Bull Bot, 2000, 17(04): 360 -365 .
[5] CHEN Xiong-Wen ZHOU Guang-ShengWANG Feng-You. Simulation of Dry Matter Accumulation in Changbai Larch Seedlings Under Controlled Environment[J]. Chin Bull Bot, 2000, 17(03): 246 -250 .
[6] CAI Neng YI Zi-Li LI Xiang. Advances in Improvement of Tissue Culture Conditions of Plants on Large Scale[J]. Chin Bull Bot, 2003, 20(06): 745 -751 .
[7] Liu Zhengyu. Gymnospermae Vertical Distribution and Ecological Features of Jia Feshan, Nanchuan Sichuan Province[J]. Chin Bull Bot, 1986, 4(12): 91 -94 .
[8] LIANG Ming-Mei. Application of Coexistence Approach to Quantitative Reconstruction of Palaeoclimate from Miocene Shanwang Palynoflora, China[J]. Chin Bull Bot, 2000, 17(专辑): 259 -260 .
[9] ZHANG Ming HUANG Hua-Rong WEI Xiao-Yong. Advances in Study on Artificial Seed of Plant[J]. Chin Bull Bot, 2000, 17(05): 407 -412 .
[10] Zheng Qi-cheng Zhu Yao-lan Chen Wen-hua Tang Xuan-min. The Effect of r-radiation on the Somaclonal Variation in Wheat[J]. Chin Bull Bot, 1991, 8(增刊): 78 -82 .