Acta Agrestia Sinica

Acta Agrestia Sinica ›› 2017, Vol. 25 ›› Issue (6): 1212-1220.DOI: 10.11733/j.issn.1007-0435.2017.06.008

Previous Articles     Next Articles

Change Characteristics of Soil Aggregates Organic Carbon in Degraded Alpine Meadow in the Northern Tibet Plateau

YU Bao-zheng, PENG Yue-lin, CAI Xiao-bu   

  1. College of Resoruces and Environment, Tibet Agricultural and Animal Husbandry College, Linzhi, Tibet 860000, China
  • Received:2017-05-22 Revised:2017-09-08 Online:2017-12-15 Published:2018-03-30

藏北高原退化高寒草甸土壤团聚体有机碳变化特征

于宝政, 彭岳林, 蔡晓布   

  1. 西藏农牧学院资源与环境学院, 西藏 林芝 860000
  • 通讯作者: 蔡晓布,E-mail:xbcai21@sina.com
  • 作者简介:于宝政(1986-),男,山东威海人,讲师,主要从事土壤碳循环研究,E-mail:yuzheng521777@sina.com
  • 基金资助:

    国家自然科学基金项目（41461054）；西藏农牧学院“雪域英才工程”项目（2015XYB02）资助

PDF

Abstract:

The studies were conducted on the soil aggregates organic carbon (SAOC) and its changes in different size fractions of surface (0~10 cm) and subsurface (10~20 cm) soil layers of alpine meadows in different degenerative degrees in Northern Tibetan Plateau using the wet screening method. The results showed that the steppe degeneration results in a decrease of SAOC content in surface and subsurface layers in cold and wet environment of the plateau, and the decreasing degree increased significantly with aggravating degeneration. The SAOC decreasing degree in different size fractions of the surface layers of light and seriously degraded steppes was obviously higher than that in the subsurface layer, but the SAOC content in different size fractions of the surface layer of the light degraded steppe was significantly higher than that in the subsurface layer, where the higher SAOC contribution rate keeps unchanged in different size fractions of subsurface layer, and SAOC content and its contribution rate in different size fractions of subsurface layer of seriously degraded steppe were significantly higher than that in the surface layer. The steppe degeneration has shrinked the difference of SAOC content among different soil layers, and the higher degenerative degree means the less difference of SAOC content between surface and subsurface layers. SOC content distribution in macroaggregate (>0.25 mm) and microaggregate (<0.25 mm) was the same in soil layer. The SOC in macroaggregates presented a higher decreasing degree in different soil layers of the light degraded steppe, while the microaggregate SOC content showed a higher decreasing degree in different soil layers of the severely degraded steppe. The ratios of macroaggregate SOC/microaggregate SOC in the surface layer of normal steppe and light and severely degraded steppes were 0.95, 0.87 and 1.55, respectively, and 0.96, 0.72 and 2.33 in the subsurface layer, respectively. This indicated microaggregate SOC content more likely tended to decrease and increase with deepening the soil layer in light and severely degraded steppes, respectively. Similar to normal steppes, the SAOC contribution rate in the size fractions of degraded surface and subsurface layers followed the order of 2~0.25 mm, >2 mm, 0.25~0.053 mm, and <0.053 mm, indicating there was a higher microaggregate SOC contribution rate in different soil layers. The relation of soil aggregates with SAOC and of SOC with SAOC were affected by steppe degenerative degree.

Key words: Soil aggregate organic carbon, Alpine meadow, Grassland degradation, The northern Tibet Plateau

摘要：

采用湿筛法对藏北高原退化高寒草甸表层（0~10 cm）、亚表层（10~20 cm）土壤团聚体有机碳及其变化进行了研究。结果表明，高原冷湿环境中退化草地表层、亚表层SAOC的下降幅度随草地退化加剧均趋于显著提高，轻度、严重退化草地表层各粒级SAOC降幅均明显高于亚表层；草地退化缩小了不同土层间SAOC含量的差异，草地退化程度越高则表层、亚表层间SAOC含量的差异越小，退化草地大团聚体（>0.25 mm） SOC、微团聚体（<0.25 mm） SOC含量的土层分布亦呈相同趋势。轻度退化草地不同土层大团聚体SOC降幅均较高，严重退化草地不同土层微团聚体SOC降幅则较高；正常草地、轻度退化草地、严重退化草地表层大团聚体SOC/微团聚体SOC比值分别为0.95，0.87，1.55，亚表层分别为0.96，0.72，2.33，表明轻度、严重退化草地中大团聚体SOC含量随土层加深分别更趋下降、更趋提高。退化草地表层、亚表层SAOC贡献率在总体上亦均按2~0.25 mm，>2 mm，0.25~0.053 mm，<0.053 mm的顺序依次大幅降低，表明不同土层大团聚体SOC贡献率均较高。土壤团聚体与SAOC、SOC与SAOC间的关系受草地退化程度的影响。

关键词: 土壤团聚体有机碳, 高寒草甸, 草地退化, 藏北高原

CLC Number: