Soil Science Commons^™

Quantifying The Short-Term Dynamics Of Soil Organic Carbon Decomposition Using A Power Function Model, Weiping Zhou, Jinhong He, Dafeng Hui, Weijun Shen

Biology Faculty Research

Introduction

Soil heterotrophic respiration (R _h, an indicator of soil organic carbon decomposition) is an important carbon efflux of terrestrial ecosystems. However, the dynamics of soil R _h and its empirical relations with climatic factors have not been well understood.

Methods

We incubated soils of three subtropical forests at five temperatures (10, 17, 24, 31, and 38 °C) and five moistures (20, 40, 60, 80, and 100% water holding capacity (WHC)) over 90 days. R _h was measured throughout the course of the incubation. Three types of models (log-linear, exponential, and power model) were fitted to the measurements …

Tungstate (Vi) Sorption On Hematite: An In Situ Atr-Ftir Probe On The Mechanism, Sudipta Rakshit, Bryan Sallman, Athénais Davantés, Grégory Lefèvre

Agricultural and Environmental Sciences Faculty Research

Owing to the suspected toxicity and carcinogenicity of tungstate (VI) oxyanions [i.e. mono tungstate and several polytungstate, generally represented by W (VI)], the environmental fate of W (VI) has been widely studied. Sorption is regarded as a major mechanism by which W (VI) species are retained in the solid/water interface. Iron (hydr)oxides have been considered important environmental sinks for W (VI) species. Here we report sorption mechanisms of W (VI) on a common iron oxide mineral-hematite under environmentally relevant solution properties using in situ attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopic probes. Initial W (VI) loadings varied from 10 …

Soil Salinity Increases The Tolerance Of Excessive Sulfur Fumigation Stress In Tomato Plants, Yuping Jiang, Xiaotao Ding, Dong Zhang, Qi Deng, Chih-Li Yu, Suping Zhou, Dafeng Hui

Agricultural and Environmental Sciences Faculty Research

To investigate the responses of plant photosynthesis and chlorophyll fluorescence to excessive sulfur fumigation stress (Sulfur) alleviated by pre-treated salt in the soil (Salt), seedlings of a tomato cultivar (Solanum lycopersicum L. ‘Money Maker’) were exposed to the Sulfur with or without the Salt treatment for 15h. Leaf fresh weight, dry weight, chlorophyll (Chl) content, carotenoid (Car) content, photosynthesis and chlorophyll fluorescence parameters were measured. The results showed that the Sulfur treatment significantly decreased leaf fresh weight, dry weight, Chl and Car contents, net photosynthetic rate (Pn), stomatal conductance (Gs), transpiration rate (Tr), maximum quantum efficiency of photosystem II (PSII) …

Soil Extracellular Enzyme Activities, Soil Carbon And Nitrogen Storage Under Nitrogen Fertilization: A Meta-Analysis, Siyang Jian, Jianwei Li, Ji Chen, Gangsheng Wang, Melanie A. Mayes, Kudjo E. Dzantor, Dafeng Hui, Yiqi Luo

Agricultural and Environmental Sciences Faculty Research

Nitrogen (N) fertilization affects the rate of soil organic carbon (SOC) decomposition by regulating extracellular enzyme activities (EEA). Extracellular enzymes have not been represented in global biogeochemical models. Understanding the relationships among EEA and SOC, soil N (TN), and soil microbial biomass carbon (MBC) under N fertilization would enable modeling of the influence of EEA on SOC decomposition. Based on 65 published studies, we synthesized the activities of α-1,4-glucosidase (AG), β-1,4-glucosidase (BG), β-d-cellobiosidase (CBH), β-1,4-xylosidase (BX), β-1,4-N-acetyl-glucosaminidase (NAG), leucine amino peptidase (LAP), urease (UREA), acid phosphatase (AP), phenol oxidase (PHO), and peroxidase (PEO) in response to N fertilization. The proxy …

Costimulation Of Soil Glycosidase Activity And Soil Respiration By Nitrogen Addition, Ji Chen, Yiqi Luo, Jianwei Li, Xuhui Zhou, Junji Cao, Rui-Wu Wang, Yunqiang Wang, Shelby Shelton, Zhao Jin, Laura M. Walker, Zhaozhong Feng, Shuli Niu, Wenting Feng, Siyang Jian, Lingyan Zhou

Agricultural and Environmental Sciences Faculty Research

Unprecedented levels of nitrogen (N) have been deposited in ecosystems over the past century, which is expected to have cascading effects on microbially mediated soil respiration (SR). Extracellular enzymes play critical roles on the degradation of soil organic matter, and measurements of their activities are potentially useful indicators of SR. The links between soil extracellular enzymatic activities (EEAs) and SR under N addition, however, have not been established. We therefore conducted a meta-analysis from 62 publications to synthesize the responses of soil EEAs and SR to elevated N. Nitrogen addition significantly increased glycosidase activity (GA) by 13.0%, α-1,4-glucosidase (AG) by …

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 …

Long-Term Manure Amendments Reduced Soil Aggregate Stability Via Redistribution Of The Glomalin-Related Soil Protein In Macroaggregates, Hongtu Xie, Jianwei Li, Bin Zhang, Lianfeng Wang, Jingkuan Wang, Hongbo He, Xudong Zhang

Agricultural and Environmental Sciences Faculty Research

Glomalin-related soil protein (GRSP) contributes to the formation and maintenance of soil aggregates, it is however remains unclear whether long-term intensive manure amendments alter soil aggregates stability and whether GRSP regulates these changes. Based on a three-decade long fertilization experiment in northeast China, this study examined the impact of long-term manure input on soil organic carbon (SOC), total and easily extractable GRSP (GRSPt and GRSPe) and their respective allocations in four soil aggregates (>2000 μm; 2000–250 μm; 250–53 μm; and <53 μm). The treatments include no fertilization (CK), low and high manure amendment (M1, M2), chemical nitrogen, phosphorus and potassium fertilizers (NPK) and combined manure and chemical fertilizers (NPKM1, NPKM2). Though SOC, GRSPe and GRSPt in soil and SOC in each aggregate generally increased with increasing manure input, GRSPt and GRSPe in each aggregate showed varying changes with manure input. Both GRSP in macroaggregates (2000–250 μm) were significantly higher under low manure input, a pattern consistent with changes in soil aggregate stability. Constituting 38~49% of soil mass, macroaggregates likely contributed to the nonlinear changes of aggregate stability under manure amendments. The regulatory process of GRSP allocations in soil aggregates has important implications for manure management under intensive agriculture.

Soil Carbon And Nitrogen Mineralization And Crop Parameters In Typical Maize-Bean Intercropping In Western Kenya, Judith A. Odhiambo, Urszula Norton, Emmanuel C. Omondi, Dennis Ashilenje, Jay B. Norton

Agricultural and Environmental Sciences Faculty Research

Smallholder farmers in western Kenya who plant maize (Zea mays L.) intercropped with beans (Phaseolus vulgaris L.) face many challenges associated with nutrient-poor soils and weather-related crop failures. In regions where temperatures are favorable, crops are grown twice per year during long and short rainy seasons and in other regions, once per year during one long growing season. Growing crops two times per year necessitates frequent land preparation using inversion-type tillage. Little is known about the impact of current tillage-intensive crop management on annual soil organic matter (SOM) recovery. The aim of this study was to assess changes to soil …

Soil Respiration Patterns And Controls In Limestone Cedar Glades, Jennifer Cartwright, Dafeng Hui

Biology Faculty Research

Aims

Drivers of soil respiration (R s ) in rock outcrop ecosystems remain poorly understood. We investigated these drivers in limestone cedar glades, known for their concentrations of endemic plant species and for seasonal hydrologic extremes (xeric and saturated conditions), and compared our findings to those in temperate grasslands and semi-arid ecosystems.

Methods

We measured R s , soil temperature (T s ), volumetric soil water content (SWC), soil organic matter (SOM), soil depth, and vegetation cover monthly over 16 mo and analyzed effects of these variables on R s .

Results

Seasonally, R s primarily tracked T …

Effects Of Soil Moisture On The Temperature Sensitivity Of Soil Heterotrophic Respiration: A Laboratory Incubation Study, Weiping Zhou, Dafeng Hui, Weijun Shen

Biology Faculty Research

The temperature sensitivity (Q10) of soil heterotrophic respiration (Rh) is an important ecological model parameter and may vary with temperature and moisture. While Q10 generally decreases with increasing temperature, the moisture effects on Q10 have been controversial. To address this, we conducted a 90-day laboratory incubation experiment using a subtropical forest soil with a full factorial combination of five moisture levels (20%, 40%, 60%, 80%, and 100% water holding capacity - WHC) and five temperature levels (10, 17, 24, 31, and 38°C). Under each moisture treatment, Rh was measured several times for each temperature treatment to derive Q10 based on …

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 …

Soil Biochemical Changes Induced By Poultry Litter Application And Conservation Tillage Under Cotton Production Systems, Regine Mankolo, Chandra Reddy, Zachary Senwo, Ermson Nyakatawa, Seshadri Sajjala

Agricultural and Environmental Sciences Faculty Research

Problems arising from conventional tillage (CT) systems (such as soil erosion, decrease of organic matter, environmental damage etc.) have led many farmers to the adoption of no-till (NT) systems that are more effective in improving soil physical, chemical and microbial properties. Results from this study clearly indicated that NT, mulch tillage (MT), and winter rye cover cropping systems increased the activity of phosphatase, β-glucosidase and arylsulfatase at a 0–10 cm soil depth but decreased the activity of these enzymes at 10–20 cm. The increase in enzyme activity was a good indicator of intensive soil microbial activity in different soil management …

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 …