Soil moisture determines effects of climates and soil properties on nitrogen cycling: Examination of arid and humid soils.

While soil moisture has a significant effect on nitrogen (N) cycling, how it influences the dependence of this important biological process on environmental factors is unknown. Specifically, it is unclear how the relationships of net N mineralization (N) and soil moisture vary with soil properties and climates. In turn, how the relationships of N vs.

Aridity shapes distinct biogeographic and assembly patterns of forest soil bacterial and fungal communities at the regional scale.

Climate change is exacerbating drought in arid and semi-arid forest ecosystems worldwide. Soil microorganisms play a key role in supporting forest ecosystem services, yet their response to changes in aridity remains poorly understood. We present results from a study of 84 forests at four south-to-north Loess Plateau sites to assess how increases in aridity level (1- precipitation/evapotranspiration) shapes soil bacterial and fungal diversity and community stability by influencing community assembly.

Contrasting carbon cycle responses of semiarid abandoned farmland to simulated warmer-drier and warmer-wetter climates.

Rewilding abandoned farmlands provides a nature-based climate solution via carbon (C) offsetting; however, the C-cycle-climate feedback in such restored ecosystems is poorly understood. Therefore, we conducted a 2-year field experiment in Loess Plateau, China, to determine the impacts of warming (∼1.4 °C) and altered precipitation (±25 %, ±50 %, and ambient), alone or in concert on soil C pools and associated C fluxes.

Deterministic assembly of grassland soil microbial communities driven by climate warming amplifies soil carbon loss.

Perturbations in soil microbial communities caused by climate warming are expected to have a strong impact on biodiversity and future climate-carbon (C) feedback, especially in vulnerable habitats that are highly sensitive to environmental change. Here, we investigate the impact of four-year experimental warming on soil microbes and C cycling in the Loess Hilly Region of China. The results showed that warming led to soil C loss, mainly from labile C, and this C loss is associated with microbial response.

Natural restoration exhibits better soil bacterial network complexity and stability than artificial restoration on the Loess Plateau, China.

Natural restoration (NR, e.g., secondary succession) and artificial restoration (AR, e.

Decreased soil multifunctionality is associated with altered microbial network properties under precipitation reduction in a semiarid grassland.

Our results reveal different responses of soil multifunctionality to increased and decreased precipitation. By linking microbial network properties to soil functions, we also show that network complexity and potentially competitive interactions are key drivers of soil multifunctionality.

[Effects of Warming and Increased Precipitation on Soil Respiration of Abandoned Grassland in the Loess-Hilly Regions].

Clarifying the changing trends and driving factors of soil respiration in fragile habitats under the background of climate change is of great significance for understanding the regional carbon cycle and the conversion of ecosystem carbon source and sink functions. This research focused on grasslands that had been naturally abandoned and restored for 12 years in the loess hilly region of northern Shaanxi, using an open top chamber (OTC) and artificially increased natural rainfall to simulate climate warming and precipitation increase and their interaction. Furthermore, we used a combination of field monitoring and indoor analysis to explore soil water content, temperature, and nutrient characteristics and the response characteristics of soil respiration rate to warming and increased precipitation and further analyzed the key factors driving changes in soil respiration.

Microbial traits determine soil C emission in response to fresh carbon inputs in forests across biomes.

Soil priming is a microbial-driven process, which determines key soil-climate feedbacks in response to fresh carbon inputs. Despite its importance, the microbial traits behind this process are largely undetermined. Knowledge of the role of these traits is integral to advance our understanding of how soil microbes regulate carbon (C) emissions in forests, which support the largest soil carbon stocks globally.

[Effects of Farmland Abandonment on Soil Enzymatic Activity and Enzymatic Stoichiometry in the Loess Hilly Region, China].

Clarifying the characteristic of soil enzymatic activity and stoichiometry variations as well as their influencing factors following farmland abandonment have important implications for understanding soil nutrient availability after revegetation and for illuminating the underlying mechanisms of soil nutrient cycling in ecosystems. To determine microbial nutrient limitations after farmland abandonment and to explore the driving factors of the variations in soil enzymatic activity and stoichiometry along a chronosequence of abandoned farmlands (0-, 10-, 20-, and 30-year-old) in the Loess Hilly Region, China, the potential activities of carbon (C)-, nitrogen (N)-, and phosphorus (P)-acquiring enzymes, soil physicochemical properties, and plant diversity and family composition were measured. The results showed that the activities of -1,4--acetylglucosaminidase (NAG), leucine aminopeptidase (LAP), and alkaline phosphatase (ALP) increased significantly with the increasing years of land abandonment, whereas the activity of -1,4-glucosidase (BG) showed the opposite change trend.

[Relationship Between the Composition of Soil Aggregates and the Distribution of Organic Carbon Under Long-Term Abandoned Restoration].

Soil aggregates are important carriers of soil organic carbon (SOC) accumulation, and play an important role in the evaluation of soil structure and quality. Natural recovery can promote change in soil aggregate structure and quantity via the redistribution of SOC in the aggregates. Natural restoration from farmland is an important vegetation restoration model on the Loess Plateau.

Effects of Robinia pseudoacacia afforestation on aggregate size distribution and organic C dynamics in the central Loess Plateau of China: A chronosequence approach.

Afforestation has been proven to have enormous potential for carbon (C) sequestration; however, the dynamics of aggregate-associated organic carbon (OC) following afforestation and their contribution to changes in bulk soil OC are not well understood in regions with serious soil erosion. Therefore, we investigated the dynamics of OC associated with aggregates along a Robinia pseudoacacia (RP) afforestation chronosequence in the Loess Plateau. Soil aggregate size distribution and OC dynamics in bulk soil were analyzed 10, 18, 28, and 42 years after RP afforestation at depths of 0-20 cm and 20-40 cm.

Dynamics of bacterial community in litter and soil along a chronosequence of Robinia pseudoacacia plantations.

As the driver of plantation ecosystem function, microorganisms can decompose plant residues and soil organic matter. To identify dynamics of microbial communities in litter and soil and its influence by vegetation and soil at regional scales, the plantations of Robinia pseudoacacia at different successional stages (13, 19, 29, and 44 y) was selected on the Loess Plateau. High-throughput sequencing of the 16S rRNA gene was used to examine bacterial communities in litter and soil, and changes in vegetation, litter, and soil characteristics were analyzed.

Differential responses of soil microbial biomass, diversity, and compositions to altitudinal gradients depend on plant and soil characteristics.

Alt'itudinal gradients strongly affect plant biodiversity, but the effects on microbial patterns remain unclear, especially in the large scale. We therefore designed an altitudinal gradient experiment that covered three climate zones to monitor soil microbial community dynamics and to compare those with plant and soil characteristics. Illumina sequencing of the 16S rRNA gene and ITS gene was used to analyze soil microbial (bacterial and fungal) diversity and composition, and fumigation-extraction was used to determine microbial biomass; the plant community metrics (i.