Physical Sciences and Mathematics Commons^™

Multi-Year Incubation Experiments Boost Confidence In Model Projections Of Long-Term Soil Carbon Dynamics, Siyang Jian, Jianwei Li, Gangsheng Wang, Laurel A. Kluber, Christopher W. Schadt, Junyi Liang, Melanie A. Mayes

Agricultural and Environmental Sciences Faculty Research

Global soil organic carbon (SOC) stocks may decline with a warmer climate. However, model projections of changes in SOC due to climate warming depend on microbially-driven processes that are usually parameterized based on laboratory incubations. To assess how lab-scale incubation datasets inform model projections over decades, we optimized five microbially-relevant parameters in the Microbial-ENzyme Decomposition (MEND) model using 16 short-term glucose (6-day), 16 short-term cellulose (30-day) and 16 long-term cellulose (729-day) incubation datasets with soils from forests and grasslands across contrasting soil types. Our analysis identified consistently higher parameter estimates given the short-term versus long-term datasets. Implementing the short-term and …

Relationships Between Vegetation And Soil Seed Banks Along A Center-To-Edge Gradient On A Tropical Coral Island, Yao Huang, Hai Ren, Jun Wang, Nan Liu, Shuguang Jian, Hongyue Cai, Dafeng Hui, Qinfeng Guo

Biology Faculty Research

Few studies have focused on the relationships between vegetation and soil seed banks on small islands. To better understand the pattern and regeneration potential of seed banks on tropical coral islands, we measured environmental factors and the species composition, and species richness of soil seed banks and vegetation along a gradient from the center to the edges on East Island in the South China Sea. The results showed that the similarity between the species composition of vegetation and seed banks increased from the center to the edge. In the center, species richness in both vegetation and seed banks was positively …

Soil Microbial Community Composition And Respiration Along An Experimental Precipitation Gradient In A Semiarid Steppe, Cancan Zhao, Yuan Miao, Chengde Yu, Lili Zhu, Feng Wang, Lin Jiang, Dafeng Hui, Shiqiang Wan

Biology Faculty Research

As a primary limiting factor in arid and semiarid regions, precipitation strongly influences soil microbial properties. However, the patterns and mechanisms of soil microbial responses to precipitation have not been well documented. In this study, changes in soil microorganisms along an experimental precipitation gradient with seven levels of precipitation manipulation (i.e., ambient precipitation as a control and ±20%, ±40% and ±60% of ambient precipitation) were explored in a semiarid temperate steppe in northern China. Soil microbial biomass carbon and respiration as well as the ratio of fungal to bacterial biomass varied along the experimental precipitation gradient and peaked under the …

Convergence Of Microbial Assimilations Of Soil Carbon, Nitrogen, Phosphorus And Sulfur In Terrestrial Ecosystems, Xiaofeng Xu, Dafeng Hui, Anthony W. King, Xia Song, Peter E. Thornton, Lihua Zhang

Biology Faculty Research

How soil microbes assimilate carbon-C, nitrogen-N, phosphorus-P and sulfur-S is fundamental for understanding nutrient cycling in terrestrial ecosystems. We compiled a global database of C, N, P and S concentrations in soils and microbes and developed relationships between them by using a power function model. The C:N:P:S was estimated to be 287:17:1:0.8 for soils and 42:6:1:0.4 for microbes. We found a convergence of the relationships between elements in soils and in soil microbial biomass across C, N, P and S. The element concentrations in soil microbial biomass follow a homeostatic regulation curve with soil element concentrations across C, N, P …

Responses Of Soil Respiration And Its Temperature/Moisture Sensitivity To Precipitation In Three Subtropical Forests In Southern China, H. Jiang, Qi Deng, Guoyi Zhou, Dafeng Hui, Deqiang Zhang, S. Liu, Guowei Chu, J. Li

Biology Faculty Research

Both long-term observation data and model simulations suggest an increasing chance of serious drought in the dry season and extreme flood in the wet season in southern China, yet little is known about how changes in precipitation pattern will affect soil respiration in the region. We conducted a field experiment to study the responses of soil respiration to precipitation manipulations – precipitation exclusion to mimic drought, double precipitation to simulate flood, and ambient precipitation as control (abbr. EP, DP and AP, respectively) – in three subtropical forests in southern China. The three forest sites include Masson pine forest (PF), coniferous …

Effects Of Precipitation Increase On Soil Respiration: A Three-Year Field Experiment In Subtropical Forests In China, Qi Deng, Dafeng Hui, Deqiang Zhang, Guoyi Zhou, Juxiu Liu, Shizhong Liu, Guowei Chu, Jiong Li

Biology Faculty Research

Background

The aim of this study was to determine response patterns and mechanisms of soil respiration to precipitation increases in subtropical regions.

Methodology/Principal Findings

Field plots in three typical forests [i.e. pine forest (PF), broadleaf forest (BF), and pine and broadleaf mixed forest (MF)] in subtropical China were exposed under either Double Precipitation (DP) treatment or Ambient Precipitation (AP). Soil respiration, soil temperature, soil moisture, soil microbial biomass and fine root biomass were measured over three years. We tested whether precipitation treatments influenced the relationship of soil respiration rate (R) with soil temperature (T) and soil …