Digital Commons Network^™

Evaluating Sustainable Options For Valorization Of Rice By-Products In Sri Lanka: An Approach For A Circular Business Model, W. A. M. A. N Illankoon, Chiara Milanese, A. K. Karunarathna, Kumuditha D. Hikkaduwa Epa Liyanage, A. M. Y. W. Alahakoon, Puhulwella G. Rathnasiri, Maria Cristina Collivignarelli, Sabrina Sorlini

Agricultural and Environmental Sciences Faculty Research

Due to the significant quantities of waste generated by the Sri Lankan rice industry, circular bioeconomy methodologies were applied to examine value-adding entrepreneurial activities for rice industry by-products (RIB). The study was conceived after scouring the existing literature on agricultural waste management and interviewing experts in the field and the rice industry. In the first phase, the suitability of valorizing alternatives for RIB was considered via a multi-criteria decision-making method. Valorization options, such as biochar production, energy purposes, composting, and other activities, were evaluated using an analytical hierarchy process (AHP) based on four criteria, namely environmental, social, technical, and economic …

Effect Of Nitrogen Fertilization On Central Tendency And Spatial Heterogeneity Of Soil Moisture, Ph And Dissolved Organic Carbon And Nitrogen In Two Bioenergy Croplands, Xuehan Wang, Siyang Jian, Lahiru Gamage, Jianwei Li

Agricultural and Environmental Sciences Faculty Research

Background

Soil moisture, pH, dissolved organic carbon and nitrogen (DOC, DON) are important soil biogeochemical properties in switchgrass (SG) and gamagrass (GG) croplands. Yet their spatiotemporal patterns under nitrogen (N) fertilization have not been studied.

Aims

The objective of this study is to investigate the main and interactive effects of N fertilization and bioenergy crop type on central tendencies and spatial heterogeneity of soil moisture, pH, DOC and DON.

Methods

Based on a 3-year long fertilization experiment in Middle Tennessee, USA, 288 samples of top horizon soils (0–15 cm) under three fertilization treatments in SG and GG croplands were collected. …

Soil Health Beneath Amended Switchgrass: Effects Of Biochar And Nitrogen On Active Carbon And Wet Aggregate Stability, Priya Saini, Jason P. De Koff, Richard Link, Chris Robbins

Agricultural and Environmental Sciences Faculty Research

Perennial crops, like switchgrass (Panicum virgatum L.), are important for bioenergy production and long-term carbon sequestration. Biochar, a byproduct of certain bioenergy production processes, is also identified as a potential tool for carbon sequestration and soil quality improvements, especially in marginal soils. Despite the focus on switchgrass, soil health characteristics under switchgrass production for biomass are unclear. This study focused on identifying the effects of four N rates (0, 17, 34, and 67 kg N ha−1) and biochar application (0 and 9 Mg ha−1) in a 3-year switchgrass field study on a silt loam soil. Soil active carbon (AC) and …

A Research Road Map For Responsible Use Of Agricultural Nitrogen, Michael Udvardi, Frederick E. Below, Michael J. Castellano, Alison J. Eagle, Ken E. Giller, Jagdish Kumar Ladha, Xuejun Liu, Tai Mcclellan Maaz, Barbara Nova-Franco, Nandula Raghuram, G. Philip Robertson, Sonali Roy, Malay Saha, Susanne Schmidt, Mechthild Tegeder, Larry M. York, John W. Peters

Agricultural and Environmental Sciences Faculty Research

Nitrogen (N) is an essential but generally limiting nutrient for biological systems. Development of the Haber-Bosch industrial process for ammonia synthesis helped to relieve N limitation of agricultural production, fueling the Green Revolution and reducing hunger. However, the massive use of industrial N fertilizer has doubled the N moving through the global N cycle with dramatic environmental consequences that threaten planetary health. Thus, there is an urgent need to reduce losses of reactive N from agriculture, while ensuring sufficient N inputs for food security. Here we review current knowledge related to N use efficiency (NUE) in agriculture and identify research …

Container Color And Compost Substrate Affect Root Zone Temperature And Growth Of “Green Giant” Arborvitae, Anthony L. Witcher, Jeremy M. Pickens, Eugene K. Blythe

Agricultural and Environmental Sciences Faculty Research

Container-grown nursery crops are commonly exposed to root zone stress due to inadequate moisture and supraoptimal root zone temperature (RZT). Compost substrates can improve water and nutrient retention but plant responses can vary due to physical and chemical properties. Dark color containers absorb solar radiation through the container side wall leading to excessive heat buildup in the substrate, yet white containers can reduce RZT. Compost substrates and container color were examined for effects on RZT and growth of “Green Giant” arborvitae (Thuja standishii × plicata “Green Giant”). “Green Giant” arborvitae were transplanted into white or black containers (11.3 L) filled …

Methods For Management Of Soilborne Diseases In Crop Production, Milan Panth, Samuel C. Hassler, Fulya Baysal-Gurel

Agricultural and Environmental Sciences Faculty Research

The significant problems caused by soilborne pathogens in crop production worldwide include reduced crop performance, decreased yield, and higher production costs. In many parts of the world, methyl bromide was extensively used to control these pathogens before the implementation of the Montreal Protocol—a global agreement to protect the ozone layer. The threats of soilborne disease epidemics in crop production, high cost of chemical fungicides and development of fungicide resistance, climate change, new disease outbreaks and increasing concerns regarding environmental as well as soil health are becoming increasingly evident. These necessitate the use of integrated soilborne disease management strategies for crop …

Weak Effects Of Biochar And Nitrogen Fertilization On Switchgrass Photosynthesis, Biomass, And Soil Respiration, Dafeng Hui, Chih-Li Yu, Qi Deng, Priya Saini, Kenya Collins, Jason De Koff

Agricultural and Environmental Sciences Faculty Research

Application of nitrogen (N) fertilizer plus biochar may increase crop yield, but how biochar will interact with N fertilization to affect bioenergy crop switchgrass physiology, biomass, and soil CO₂ emission (i.e., soil respiration) from switchgrass fields remains unclear. Here, we assessed this issue by conducting a field experiment near Nashville TN with two levels of biochar treatment (a control without biochar addition and biochar addition of 9 Mg ha⁻¹), and four N fertilization levels (0 kg N ha⁻¹, 17 kg N ha⁻¹, 34 kg N ha⁻¹, and 67 kg N ha …

Differential Responses Of Carbon-Degrading Enzyme Activities To Warming: Implications For Soil Respiration, Ji Chen, Yiqi Luo, Pablo García-Palacios, Junji Cao, Marina Dacal, Xuhui Zhou, Jianwei Li, Jianyang Xia, Shuli Niu, Huiyi Yang, Shelby Shelton, Wei Guo, Kees Jan Van Groenigen

Agricultural and Environmental Sciences Faculty Research

Extracellular enzymes catalyze rate-limiting steps in soil organic matter decomposition, and their activities (EEAs) play a key role in determining soil respiration (SR). Both EEAs and SR are highly sensitive to temperature, but their responses to climate warming remain poorly understood. Here, we present a meta-analysis on the response of soil cellulase and ligninase activities and SR to warming, synthesizing data from 56 studies. We found that warming significantly enhanced ligninase activity by 21.4% but had no effect on cellulase activity. Increases in ligninase activity were positively correlated with changes in SR, while no such relationship was found for cellulase. …

Differential Effects Of Warming And Nitrogen Fertilization On Soil Respiration And Microbial Dynamics In Switchgrass Croplands, Jianwei Li, Siyang Jian, Jason P. De Koff, Chad S. Lane, Gangsheng Wang, Melanie A. Mayes, Dafeng Hui

Agricultural and Environmental Sciences Faculty Research

The mechanistic understanding of warming and nitrogen (N) fertilization, alone or in combination, on microbially mediated decomposition is limited. In this study, soil samples were collected from previously harvested switchgrass (Panicum virgatum L.) plots that had been treated with high N fertilizer (HN: 67 kg N ha−1) and those that had received no N fertilizer (NN) over a 3-year period. The samples were incubated for 180 days at 15 °C and 20 °C, during which heterotrophic respiration, δ13C of CO2, microbial biomass (MB), specific soil respiration rate (Rs: respiration per unit of microbial biomass), and exoenzyme activities were …

Responses Of Corn Physiology And Yield To Six Agricultural Practices Over Three Years In Middle Tennessee, Chih-Li Yu, Dafeng Hui, Qi Deng, Junming Wang, K. Chandra Reddy, Sam Dennis

Agricultural and Environmental Sciences Faculty Research

Different agricultural practices may have substantial impacts on crop physiology and yield. However, it is still not entirely clear how multiple agricultural practices such as tillage, biochar and different nutrient applications could influence corn physiology and yield. We conducted a three-year field experiment to study the responses of corn physiology, yield and soil respiration to six different agricultural practices. The six treatments included conventional tillage (CT) or no tillage (NT), in combination with nitrogen type (URAN or chicken litter) and application method, biochar, or denitrification inhibitor. A randomized complete block design was applied with six replications. Leaf photosynthetic rate, transpiration, …

Corn Yield And Soil Nitrous Oxide Emission Under Different Fertilizer And Soil Management: A Three-Year Field Experiment In Middle Tennessee, Qi Deng, Dafeng Hui, Junming Wang, Stephen Iwuozo, Chih-Li Yu, Tigist Jima, David Smart, Chandra Reddy, Sam Dennis

Agricultural and Environmental Sciences Faculty Research

Background

A three-year field experiment was conducted to examine the responses of corn yield and soil nitrous oxide (N2O) emission to various management practices in middle Tennessee.

Methodology/Principal Findings

The management practices include no-tillage + regular applications of urea ammonium nitrate (NT-URAN); no-tillage + regular applications of URAN + denitrification inhibitor (NT-inhibitor); no-tillage + regular applications of URAN + biochar (NT-biochar); no-tillage + 20% applications of URAN + chicken litter (NT-litter), no-tillage + split applications of URAN (NT-split); and conventional tillage + regular applications of URAN as a control (CT-URAN). Fertilizer equivalent to 217 kg N ha-1 was applied to …