Key sources and seasonal dynamics of greenhouse gas fluxes from yak grazing systems on the Qinghai-Tibetan Plateau

Abstract

Greenhouse gas (GHG) emissions from livestock grazing systems are contributing to global warming. To examine the influence of yak grazing systems on GHG fluxes and relationships between GHG fluxes and environmental factors, we measured carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) fluxes over three key seasons in 2012 and 2013 from a range of potential sources, including: alpine meadows, dung patches, manure heaps and yak night pens, on the Qinghai-Tibetan Plateau. We also estimated the total annual global warming potential (GWP, CO2-equivalents) from family farm grazing yaks using our measured results and other published data. In this study, GHG fluxes per unit area from night pens and composting manure heaps were higher than from dung patches and alpine meadows. Increased moisture content and surface temperature of soil and manure were major factors increasing CO2 and CH4 fluxes. High contributions of CH4 and N2O (21.1% and 44.8%, respectively) to the annual total GWP budget (334.2 tonnes) strongly suggest these GHG other than CO2 should not be ignored when estimating GWP from the family farm grazing yaks on the Qinghai-Tibetan Plateau for the purposes of determining national and regional land use policies or compiling global GHG inventories.

Optimizing alfalfa productivity and persistence versus greenhouse gases fluxes in a continental arid region

“…Two sampling sites were randomly selected in each sampling plot on 13 April. Gases were sampled four times (i.e., 5:00, 10:00, 14:00 and 18:00) for three successively sunny days in each mid-month, after removing the above-ground plant and litter (Liu et al, 2017). The mean GHG fluxes during the three successive days were treated as the average daily fluxes for that month.…”

“…Gas was collected using a static opaque chamber (30 cm ×30 cm ×30 cm) (Liu et al, 2017). For each sampling event, four gas samples were taken within 30 min at a time interval of 10 min (i.e., 0, 10, 20 and 30 min).…”

The economic benefits of integrated farming system in the transitional region from Loess Plateau to Qinghai-Tibetan Plateau—A case study of Tongwei-Weiyuan-Xiahe transect

“…统牧区的过渡带, 也是全球生态环境最脆弱、破坏最 严重、对自然和人文环境变化响应最敏感的区域之 一 [22] . 地质时期形成的地貌和气候, 历史时期在各 种农业系统的交互作用下, 黄土高原-青藏高原过渡 带形成了既相对稳定又相对脆弱的独特的农业系统 结构和功能, 包括独特的经济特征, 不仅为黄土高原 和青藏高原生态可持续性, 也为农耕文化和草原文 化的传承与创新提供了农业系统基础 [23,24] . 以往的 [26] .…”

Prediction of Metabolizable Energy Concentrations of Herbage in the Qinghai–Tibetan Plateau Using Tibetan Sheep Digestibility Data

“…The Qinghai-Tibet Plateau (QTP) is the largest grassland area in the Eurasian continent and also the largest area of natural grasslands in China [4]. Grasslands, which cover about 30% of the total area, are the primary foundation of natural alpine meadow pastures in the QTP [5]. Approximately 50 million Tibetan sheep and 15 million yaks graze on these grasslands [6].…”