Distribution characteristics and influencing factors of soil organic
carbon in alpine desert ecosystem of Qinghai Province
Yangong Du1,2#, Boliang Cui1#, Xun
Ke2#, Jingmei Li1,3, Guangmin
Cao2, Kelong Chen1*
1 College of Geosciences, Qinghai Normal University,
Xining, China, 810005
2 Qinghai Provincial Key Laboratory of Restoration
Ecology for Cold Region, Northwest Institute of Plateau Biology, Chinese
Academy of Sciences, Xining, China, 810008
3 Qinghai Academies of Social Sciences, Xining, China,
810012
Correspondence E-mail: caogm@nwipb.cas.cn, ckl7813@163.com
Abstract: Alkaline deserts soils acted as important soil pools
in arid and semiarid regions. Contents of soil organic carbon (SOC) and
its driven factors remained still not clear in alpine deserts on the
Tibetan Plateau. In this study, we analyzed 223 soil organic carbon
contents and total nitrogen and pH values, and its space distribution
pattern under 0-30 cm. It was indicated that average and median SOC were
approximate 4.86 and 3.80 g/kg with variation coefficient of 81.14%.
SOC contents ranged from 0.54 to 24.34 g/kg. Soils organic carbon
contents were divided into four groups. The largest group was around
3.32 g/kg (145 sites) when air temperature and altitude were higher than
1.49 oC and 2793 m. Alpine desert SOC were mainly
controlled by total nitrogen (TN) and pH and precipitation with
R2 of 0.87 (P<0.001). Furthermore, soil pH
was positively affected by air temperature not precipitation
(P<0.05). Models may predict SOC through precipitation, air
temperature and altitude
(R2= 0.40, P<0.001). In addition, increasing
regional precipitation perhaps decreased desert soils organic carbon
storage in future climate scenarios.
Key words: SOC, alpine deserts, precipitation, generalized
additive models
Introduction
Global mean temperature was 1.2 ± 0.1 °C above the 1850–1900 baseline
in 2020, the past six years have been the six warmest years on record
(WMO 2020). Increasing atmosphere greenhouse gases have been the major
driver of global warming due to anthropogenic activities (Bossio et al.,
2020, Topa et al., 2021).
Increasing soil carbon is an appealing way to prevent carbon emissions
(Bossio et al., 2020, Feyissa et al., 2021). Soil organic carbon (SOC)
may represent 25% of the potential of natural climate solutions (Bossio
et al., 2020). Chinese land biosphere was a robust sink of 1.11 ± 0.38
petagrams of carbon, and Tibetan Plateau ecosystems covered about 10%
(Wang et al., 2020). Alpine soils are increasingly recognized for carbon
sequestration in high‐altitude ecosystems (Liu et al., 2016, Du et al.,
2019, Zhou et al., 2021). Natural desert lands contain some 7.84
petagrams of organic carbon in China (Feng et al., 2002). Deserts soil
organic carbon contents were 4.37, 2.12 and 1.50 g/kg in the
northwestern China, Norwest Mexico and Israel Negev desert (Mamat et
al., 2011, Drahorad et al., 2013, Ayala-Niño et al., 2020).
Soil family types and land use were main driver factors on SOC contents
and storage (Bai and Zhou 2020, Vries et al., 2020). Grassland types
affected ecosystem carbon densities and contents (Liu et al., 2016, Du
et al., 2019). Root-derived inputs are major contributors to soil carbon
in temperate land ecosystems (Keller et al., 2021). Increased soil
available nutrients had higher positive effects on carbon contents (Topa
et al., 2021). Improving N-use efficiency are important for decreasing
soil carbon losses from acidification (Frac et al., 2020, Raza et al.,
2020). Soil nitrogen nitrification and denitrification rates increased
significantly with pH (Drahorad et al., 2013, Feyissa et al., 2021).
Addition of minimum temperature led to a significant increase in soil
carbon sequestration capacity (Zhou et al., 2021). Desert grasslands SOC
decreased with mean annual temperature, but increased significantly with
annual precipitation (Feng et al., 2002, Drahorad et al., 2013, Wang et
al., 2014). Greenhouse gas emissions from peatlands drained for
agriculture could be greatly reduced (Cooper et al., 2020, Evans et al.,
2021). Temperature and precipitation interaction significantly affected
SOC density in alpine steppe (Liu et al., 2016).
Qaidam Basin covered an area over 250,000 km2 (Tan et
al., 2009). However, SOC contents distribution characteristic and its
driven factors were underlying indistinct on the Tibetan Plateau. In
this study, we hypothesized that significant regional variability
changes in SOC contents in Qinghai. Moreover, soil pH and precipitation
and air temperature significant affected SOC contents in alpine deserts.