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Acta Prataculturae Sinica ›› 2015, Vol. 24 ›› Issue (10): 22-32.DOI: 10.11686/cyxb2015152

• Orginal Article • Previous Articles     Next Articles

Analysis of soil respiration under different grazing management patterns in the alpine meadow-steppe of the Qinghai-Tibet Plateau

LI Wen1, CAO Wen-Xia1, *, LIU Hao-Dong1, LI Xiao-Long1, XU Chang-Lin1, SHI Shang-Li1, FENG Jin2, ZHOU Chuan-Meng3   

  1. 1.Grassland Science College of Gansu Agricultural University, Grassland Ecosystem Key Laboratory of Ministry of Education, Sino-U.S. Research Centers for Sustainable Grassland and Livestock Management, Lanzhou 730070, China;
    2.General Grassland Station of Gansu Province, Lanzhou 730046, China;
    3.College of Agronomy, Gansu Agricultural University, Lanzhou 730070, China
  • Online:2015-10-20 Published:2015-10-20

Abstract: In recent decades, the carbon cycle of terrestrial ecosystems has become a hot topic in global climate change research. Soil respiration is the main route by which soil organic carbon (SOC) enters the atmosphere, and also the main contributor to increased atmospheric carbon globally. As the earth’s largest terrestrial ecosystem, grassland is a very important carbon sink that stores one-quarter of the world’s SOC. The alpine meadow-steppe of the Qinghai-Tibet Plateau is known as the roof of the world, as it is the highest, largest, and most unique type of grassland in the world. The Qinghai-Tibet Plateau alpine meadow-steppe is becoming seriously degraded because of its unique geographical location and harsh natural environmental conditions, combined with recent global climate change, human occupation and animal grazing, and rats and insect pests. Reasonable grazing management is one of the main measures to restore the grassland ecosystem, and has important implications for the healthy development and sustainable use of grassland. However, there is little information on soil respiration under different grazing management models in the Qinghai-Tibet Plateau. In this study, an LI-8100A Automated Soil CO2 Flux system was used to investigate soil respiration under four grassland management strategies: no grazing (NG); grazing rest at the growing stage (RG); traditional grazing rest in summer (TG); and continuous grazing (CG). The aim of this study was to deepen our understanding of soil respiration in the alpine meadow-steppe ecosystem, to assess the impacts of global warming, and to evaluate the effects of rest grazing on the alpine meadow-steppe ecosystem. The results showed that: 1) soil respiration differed from month to month under the different grazing patterns, first increasing and then decreasing. In all of the treatments except for CG, the highest soil respiration rates were in August, and were significantly higher than those in the other months. There was no significant difference in soil respiration between August and September in the CG treatment, but the rates in both months were significantly higher than those in other months. 2) In the growing season, soil respiration was significantly higher in the NG, RG, and TG plots than in the CG plot, and there was no significant difference in soil respiration between the NG and RG plots. 3) There was a significant positive correlation between soil respiration and soil temperature under all of the rest grazing patterns, but not under CG. Based on their Q10 values, the plots were ranked as follows: NG>RG>TG>CG. 4) There was a threshold at which the effects of soil water content on soil respiration changed; that is, the two were positively correlated at soil water contents of 30% or lower, and negatively correlated at soil water contents of >30%. 5) Soil respiration was significantly correlated with aboveground and belowground biomass. Considering the economic income stability of the herdsmen, the management pattern of grazing rest at the growing stage could promote the efficient use of grassland resources, and help to restore forage productivity and maintain the grassland ecosystem. Therefore, grazing rest at the growing stage is the best management strategy for the alpine meadow-steppe grassland in the Qinghai-Tibet Plateau.