Contribution of soil microbial necromass carbon to soil organic carbon in grassland under precipitation change and its influencing factors in loess hilly region, Northwest China.

To investigate the contribution of microbial necromass carbon (MNC) to soil organic carbon (SOC) and its influencing factors under precipitation changes in grassland, we conducted a precipitation experiment with seven different precipitation levels in the restoration area in the loess hilly region. We analyzed the contents and characteristics of fungal necromass carbon (FNC), bacterial necromass carbon (BNC), and MNC in different fractions of SOC under different treatments, including natural precipitation (CK), and increased and decreased 20%, 40%, 60% of natural precipitation (I, I, I, D, D, D) . The results showed that 1) MNC content in mineral organic carbon (MAOC) ranged from 1.

Research advance on soil organic carbon stabilization mechanisms during vegetation restoration on the Loess Plateau, Northwest China.

The Loess Plateau is renowned for its deep soil layer and rich in organic carbon (C). In recent years, numerous ecological restoration projects have been undertaken on the Loess Plateau, with consequence on the stability of soil organic carbon (SOC). The SOC stability is pivotal for its capacity to sequestrate and store C.

Changes of soil nutrients and organic carbon fractions in forests with different restoration years in mountainous areas of southern Ningxia, China.

Vegetation restoration can effectively enhance soil quality and soil organic carbon (SOC) sequestration. In this study, the distribution characteristics of soil nutrients and SOC along soil profile (0-100 cm), and their responses to restoration years (16, 28, 38 years) were studied in plantations in the southern mountainous area of Ningxia, compared with cropland and natural grassland. The results showed that: 1) the contents of SOC, soil total nitrogen (TN), total phosphorus (TP), particulate organic carbon (POC), mineral-associated organic carbon (MAOC) and the proportion of particulate organic carbon to total organic carbon (POC/SOC) all decreased with increasing soil depth.

[Distribution characteristics of microbial necromass carbon along soil profiles in different restoration periods of in mountainous areas of Southern Ningxia, China].

Microbial necromass, an important and stable source of soil organic carbon (SOC), is an important index to evaluate the contribution of microorganisms to SOC transformation and accumulation. It is not clear about the accumulation of microbial necromass in deep soil layer and its contribution to SOC during the restoration process of forests. Combined with the biomarker method, we investigated the carbon contents of bacte-rial, fungal, and microbial necromass in the soil profiles (0-100 cm) of forests in 16, 28, and 38 years of restoration, with natural grassland as control.

[Advances in the research of transformation and stabilization of soil organic carbon from plant and microbe].

Soil organic carbon (SOC) is the core component of terrestrial carbon (C) sink. Exploring the transformation and stabilization mechanism of SOC is key to understand the function of terrestrial C sink which copes with climate change. The traditional perspective is that plant residues are the initial source of SOC.

[Soil microbial carbon pump conceptual framework 2.0].

Microorganisms are essential actors in the biogeochemical cycling of elements within terrestrial ecosystems, with significant influences on soil health, food security, and global climate change. The contribution of microbial anabolism-induced organic compounds is a non-negligible factor in the processes associated with soil carbon (C) storage and organic matter preservation. In recent years, the conceptual framework of soil microbial carbon pump (MCP), with a focus on microbial metabolism and necromass generation process, has gained widespread attention.

[Response of Soil Bacterial Community Structure to Precipitation Change in Grassland of Loess Plateau].

As the main participants of ecosystem functions, the response of microorganisms to variations in soil moisture caused by the changes in precipitation amounts should be quantified to evaluate the impact of climate change on semi-arid ecosystems. For this purpose, a two-year simulation of the changes in the rainfall patterns was conducted on the Loess Plateau, and five precipitation treatments (80% and 40% decrease in precipitation, D80, D40; natural precipitation, NP; 40% and 80% increase in precipitation, I40, I80) were set up. The results showed that: ① Compared with NP, the carbon-to-nitrogen ratio (C/N) was lower in DP80 or IP80, while it reached the maximum value in I40.

[oil microbial biomass and enzyme activities among different artificial forests in Ziwuling, Northwest China.].

Decades of ecological restoration on the Loess Plateau has achieved significant on-site benefits to reduce soil erosion and improve soil quality, with remarkable off-site effects of reducing sediment delivery to Yellow River. However, regional forest community succession is still far from being adequately developed. The Ziwuling forest region and its highly developed forest community, as an advanced eco-zone, can lend practical experience to other regions on the Loess Plateau and help to identify the most suitable tree species for a better regional restoration in the future.

[Ecological stoichiometry of leaf and litter of herbaceous plants in loess hilly and gully regions, China].

This study was conducted in the forest, forest-steppe and steppe vegetation zones along the Yanhe River Basin, where the leaf and litter samples from four dominant herbaceous plants including Lespedeza davurica, Stipa bungeana, Artemisia sacrorum, Artemisia giraldii were taken. By measuring the concentrations of carbon (C), nitrogen (N), phosphorus (P) and potassium (K), we measured the concentrations and their ratios to explore the limit and resorption of nutrient in the herbaceous plants. The results showed that the leaf N/P of four herbaceous plants was all lower than 14, suggesting their growth was mainly limited by N content.

[Effects of vegetation and topography features on ecological stoichiometry of soil and soil microbial biomass in the hilly-gully region of the Loess Plateau, China.].

The objectives of this study were to explore the effects of vegetation type, topographic features and their combined effects on soil microbial biomass stoichiometry, so as to better understand the interaction of soil, soil microbes and nutrient cycling under different vegetation types in the hilly-gully region of the Loess Plateau. Soils from three vegetation zones (forest zone, forest-steppe and steppe) and five slope positions (south/north backslope, south/north shoulder and summit) were chosen and the effects of vegetation types and topography features on soil and C:N:P ratios in soil microbial biomass were investigated in this study. The results showed that, among the five slope positions, the highest concentrations of soil and soil microbial biomass C, N, P were found at the backslope position and the north-facing slope.

[Ecological stoichiometric characteristics of plants and soil in grassland under different restoration types in Yunwu Mountain, China].

Carbon (C), nitrogen (N) and phosphorus (P) stoichiometry from the aboveground parts of plants, roots, plant litter and soils, as well as their relationships were studied in grassland under four distinct types of vegetation recovery including natural grassland, grassland with shrubs, grassland after grazing exclusion, and abandoned cropland in Yunwu Mountain, China. The results showed that there was significant correlation among the ecological stoichiometric characteristics of soils with the aboveground parts and roots. The relation between the aboveground parts and roots was closer in P concentration than in N concentration.

[Ecological stoichiometry characteristics of leaf-litter-soil in different plantations on the Loess Plateau, China].

In order to research into the influence of Grain to Green Project in Ziwuling forest region, this paper took three typical plantations which were Robinia pseudoacacia plantation, Pinus tabuliformis plantation, and Platycladus orientalis plantation in the Ziwuling forest region of Shaanxi Province as research objects and analyzed the carbon, nitrogen and phosphorus contents of leaf, litter and soil among the three plantations. The results showed that the contents of C, N and P in the three plantations were in order of leaf > litter > soil, the contents of N and P in leaf of R. pseu-doacacia plantation were significantly higher than that of P.

[Effects of stem and leaf decomposition in typical herbs on soil enzyme activity and microbial diversity in the south Ningxia loess hilly region of Northwest China].

With the method of litter bags, the characteristics of soil enzyme activities, soil microbial diversity at later stage of decomposition, and the relationships between soil enzyme activity and initial soil property were investigated in the process of stem and leaf decomposition of three typical herbs, i.e., Stipa bungeana, Artemisia sacrorum and Thymus mongolicus in the south Ningxia loess hilly region, Northwest China.

[Heidaigou Opencast Coal Mine: Soil Enzyme Activities and Soil Physical and Chemical Properties Under Different Vegetation Restoration].

Choosing the soils under different vegetation recovery of Heidaigou dump as the research objects, we mainly analyzed their basic physical and chemical properties and enzyme activities with the method of Analysis of Variance as well as their relations using Pearson correlation analysis and path analysis hoping to uncover the driving factors of the differences between soil enzyme activities under different vegetation restoration, and provide scientific suggestions for the plant selection as well as make a better evaluation to the reclamation effect. The results showed that: (1) Although the artificial vegetation restoration improved the basic physical and chemical properties of the soils while increasing their enzyme activities to a certain extent, the soil conditions still did not reach the level of the natural grassland; (2) Contents of soil organic carbon (SOC) and soil total nitrogen (TN) of the seabuckthorns were the nearest to those of the grassland, which reached 54. 22% and 70.

[Characteristics of soil organic carbon and enzyme activities in soil aggregates under different vegetation zones on the Loess Plateau].

In order to explore the distribution characteristics of organic carbon of different forms and the active enzymes in soil aggregates with different particle sizes, soil samples were chosen from forest zone, forest-grass zone and grass zone in the Yanhe watershed of Loess Plateau to study the content of organic carbon, easily oxidized carbon, and humus carbon, and the activities of cellulase, β-D-glucosidase, sucrose, urease and peroxidase, as well as the relations between the soil aggregates carbon and its components with the active soil enzymes were also analyzed. It was showed that the content of organic carbon and its components were in order of forest zone > grass zone > forest-grass zone, and the contents of three forms of organic carbon were the highest in the diameter group of 0.25-2 mm.

[Ecological stoichiometric characteristics in leaf and litter under different vegetation types of Zhifanggou watershed on the Loess Plateau, China].

The purpose was to characterize the effects of vegetation types on plant leaf and litter carbon (C), nitrogen (N), phosphorus (P), potassium (K) and C: N: P: K ecological stoichiometric characteristics in seven dominant plant species, including Robinia pseudoacacia, Syringa, Sophora viciifolia, Hippophae rhamnoides, Rosa xanthina, Artemisia sacrorum, Artemisia giraldii, of Zhifanggou Watershed on the Loess Plateau, China. This paper indicated the differences between the contents of C, N, P and K and the characteristics of ecological stoichiometric in the different vegetation types, including forest type, shrub type and grass type. Concentrations of C, N, P and K were measured, and C: N: P: K was estimated for different vegetation types.

[Effects of different aspects on soil microbial biomass and dissolved organic carbon of the loess hilly area].

Soil samples from different aspects (southern slope and northern slope) under the same vegetation in two typical vegetation zones (forest vegetation zone and steppe vegetation zone) of Yanhe basin in the loess hilly area were chosen and analyzed, in order to investigate the content and correlation of soil microbial biomass carbon (SMBC), soil microbial biomass nitrogen (SMBN), soil microbial biomass phosphorus (SMBP) and dissolved organic carbon (DOC). The results show that, in 0-10 cm soil layer of forest vegetation zone, SMBC in southern slope and northern slope are 532.1-792.

[Concentrations of different carbon and nitrogen fractions in rhizosphere and non-rhizosphere soils of typical plant species in mountainous area of southern Ningxia, Northwest China].

Taking the rhizosphere and non-rhizosphere soils of five typical plants Agropyron cristatum, Artemisia frigida, Pseudoraphis bungeana, Thymus mongolicus, and Artemisia sacrorum in a mountainous area of southern Ningxia as test objects, this paper studied their C and N forms contents. The C and N forms contents in the rhizosphere and non-rhizosphere soils differed with plant species. In the rhizosphere soil of A.

Soil water storage capacity under chronosequence of revegetation in Yanhe watershed on the Loess Plateau, China.

The relationship between vegetation and soil moisture deserves attention due to its scientific importance and practical applications. However, the effects of soil moisture on vegetation development and succession are poorly documented. Here we study soil water storage in Yanhe watershed at northern Shaanxi on five different land uses, namely shrubland, farmland, natural grassland, woodland, and artificial grassland, and in soil under restoration for 5, 10, 15, 20 and 25.

Soil nutrient assessment based on attribute recognition model in the Loess Plateau of China.

Soil fertility is important factors for growth and productivity of vegetation. The relationship between vegetation and soil fertility deserves attention due to its scientific importance and practical applications. However, the effects of soil fertility on vegetation development and succession are poorly documented.

Streptomyces ziwulingensis sp. nov., isolated from grassland soil.

A novel actinobacterium, designated strain F22(T), was isolated from grassland soil collected from the Ziwuling area on the Loess Plateau, China. The novel strain was found to have morphological and chemotaxonomic characteristics typical of members of the genus Streptomyces. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain F22(T) belonged to the genus Streptomyces, being most closely related to Streptomyces resistomycificus NBRC 12814(T) (98.