Change in Characteristics of Soil Carbon and Nitrogen during the Succession of Nitraria Tangutorum in an Arid Desert Area

Abstract

The shrub Nitraria tangutorum is distributed widely in arid desert areas, and plays a critical role in the desert–oasis ecosystem. This study quantified varying characteristics of carbon (C) and nitrogen (N) in the soil at four stages—the initial stage (IS), stable stage (SS), degradation stage (DS), and severe degradation stage (SDS)—in a steppe ecosystem in the desert of northwestern China. The results indicated that N. tangutorum experienced both expansion and deterioration as a decline of 50.7% occurred in the available soil water due to agricultural utilization, and the plant community transformed from being shrub-dominated to annual herb-dominated. At soil layer depths between 0–100 cm in the N. tangutorum nebkha dune ecosystem, organic C and total N storage was 1195.84 g/m2 and 115.01 g/m2 during the SDS, respectively, with an increase of 11.13% and 12.59% from the IS. In addition, the storage of C and N in the soil increased during the IS as well as the SS, when most of the C and N were accumulated, and the storage decreased during the DS and SDS, as the N. tangutorum communities declined. At soil layer depths between 0–100 cm in the desert steppe ecosystem, the highest storage levels of C and N were 8465.97 g/m2 and 749.29 g/m2 during the SS, and the lowest were 1076.12 g/m2 and 102.15 g/m2 during the IS, respectively. The changes and accumulation of C and N were greater in the deeper (40–100 cm) layer than in the surface layer of soil (0–40 cm). Lastly, changes in soil organic carbon (SOC) as well as in the total nitrogen (TN) were strongly related to the coverage degree, water content in soil, and the ratio of fine soil particles (silt and clay). To sum up, the intensive development of water resources has vastly reduced the ability of N. tangutorum vegetation to sequester C and N in the desert of Minqin. Efforts to perform ecological restoration and reverse desertification in the Minqin Desert should focus on preventing the unreasonable exploitation of water resources in order to maintain stable N. tangutorum communities.

Changes in Morphology of <i>Nitraria tangutorum</i> Nebkhas at different Successional Stages in the Oasis-Desert Ecotone, Northwest China

“…Yet, the vegetation coverage ranged from 14.3 to 43.8% at different successional stages, thus leading to the N. tangutorum nebkhas being in a mounded state at other successional stages, whereas the N. tangutorum nebkhas being in a wind erosion state at DEG, and the size of N. tangutorum nebkhas decreases and finally disappears. Several previous studies have found that large nebkhas can conserve and increase soil moisture and nutrient content which stimulated the growth and activity of soil microorganisms, and promoted plant growth [14,20,45]. In this study, the length of new branch showed an increase, then decreasing trend with N. tangutorum nebkhas succession, indicating that in RUD and EDV, wind-deposited sand accumulated among roots, growing shoots, and shoots of N. tangutorum, thus driving the development of N. tangutorum nebkhas.…”

Salt Tolerance Strategies of Nitraria tangutorum Bobr. and Elaeagnus angustifolia Linn. Determine the Inoculation Effects of Microorganisms in Saline Soil Conditions

“…E. angustifolia belongs to the Elaeagnus genus in the Elaeagnaceae family. N. tangutorum and E. angustifolia are dominant halophytes in the Minqin Oasis; both of them are best known for excellent tolerance to salt and form the primary ecological barrier for that area [36,37]. However, both could not grow normally when salinity concentration exceeds 300 mM NaCl [39,40].…”

“…are the dominant halophytes that are widespread in the saline area in arid and semi-arid regions of northwestern China [34]. Both also play important roles in the restoration of saline land and the main-tenance of ecological balance in the saline desert ecosystem of the Minqin Oasis [35][36][37]. Although both halophytic species could reduce the damage induced by osmotic stress and ionic stress in saline soils via various strategies, the inhibition of seed germination and seedling growth occurs when salinity concentration exceeds their respective salt-tolerant thresholds in the Minqin Oasis.…”

Determination of Carbon, Nitrogen and Phosphorus Stocks and Stoichiometry in Broadleaf Mixed Forest Soil and Litterfall: A case study in Oltu district, Erzurum

“…To illustrate, most of the C substrate is distributed in the topsoil and litterfall layer. (Hu et al, 2008;Jobbagy and Jackson, 2001;Lal, 2009;Wang et al, 2019). For regulating the carbon and nutrient cycle, litterfall decomposition plays a vital role.…”