Sand-Fixing Characteristics of Carex Brunnescens of Desert Grassland in Maqu County of the Yellow River
KANG Jianjun;ZHAO Ming;LI Guangyu;Gansu Academy of Forestry;Cold and Arid Regions Environmental and Engineering Research Institute,Chinese Academy of Sciences;
Carex brunnescens is pioneer plant to fix sand of desert grassland in Maqu,the first bend of the Yellow River. It is of great significance on keeping the biodiversity and ecosystem stability of alpine grassland in Maqu. In order to reveal the propagation characteristics and sandfixing of Carex brunnescens population,the paper studied the characteristics of morphological structure of its underground part and population propagation and the interrelationship between the population density and accumulated sand feature,quantity index of the underground part and accumulated sand feature. The outcomes show that the underground stems( horizontal stem) of Carex brunnescens are highly developed.When the land surface is covered by sandstorm,the horizontal stems will quickly extend and grow vertical stems at stem nodes and the vertical stems rapidly grow upward and penetrate the sand forming new plants( the cover depth is less than 50 cm). It develops in circles to form multi-layer network structure,playing the function of sand-fixing. When the population density is smaller than 146 plant / m~2,the diameter of underground stem is less than 1. 40 mm and the diameter of primary root system is greater than 0. 627 mm,it has obvious wind erosion; when the population density is 146-158 plant / m~2,the diameter of underground stem is 1. 40 mm and the diameter of primary root system is 0. 612-0.627 mm,it has sand-fixing effect; when the population density is great than 158 plant / m~2,the diameter of underground stem is great than 1.40 mm and the diameter of primary root system is smaller than 0. 612 mm,it has obvious sand accumulation. The above shows that Carex brunnescens can be used as excellent grass for ecological control of alpine desert grassland in Maqu through artificial assistant and engineering measures and it has good prospects of popularization and application.