Water and Plant Research Center

Florence, United States

Water and Plant Research Center

Florence, United States
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Ducey T.F.,Water and Plant Research Center | Collins J.C.,South Carolina Governor's School for Science and Mathematics | Ro K.S.,Water and Plant Research Center | Woodbury B.L.,U.S. Department of Agriculture | Griffin D.D.,University of Nebraska - Lincoln
Frontiers of Environmental Science and Engineering | Year: 2017

Hydrothermal carbonization (HTC), utilizing high temperature and pressure, has the potential to treat agricultural waste via inactivating pathogens, antibiotic resistance genes (ARG), and contaminants of emerging concern (CEC) in a environmental and economical manner. Livestock mortality is one facet of agricultural waste that can pose a threat to the surrounding environment. While several methods are utilized to treat livestock mortality, there remains a paucity of data on the elimination of microbially-derived DNA in these treatment practices. This DNA, most notably ARGs, if it survives treatment can be reintroduced in agricultural environments where it could potentially be passed to pathogens, posing a risk to animal and human populations. HTC treatments have been successfully utilized for the treatment of CECs, however very little is understood on how ARGs survive HTC treatment. This study aims to fill this knowledge gap by examining the survivability of microbially-derived DNA in the HTC treatment of livestock mortality. We examined three treatment temperatures (100°C, 150°C, and 200° C) at autogenic pressures at three treatment times (30, 60, and 240 min). We examined the amplification of a plasmid-borne reporter gene carried by Escherichia coli DH10B introduced to both beef bone and tissue. Results indicate that while all three temperatures, at all treatment times, were suitable for complete pathogen kill, only temperatures of 150°C and 200°C were sufficient for eliminating microbial DNA. These results serve as the basis for future potential HTC treatment recommendations for livestock mortality when considering the elimination of pathogens and ARGs.[Figure not available: see fulltext.] © 2017, Higher Education Press and Springer-Verlag Berlin Heidelberg.

Karunanithi R.,University of South Australia | Szogi A.A.,Water and Plant Research Center | Bolan N.,University of South Australia | Naidu R.,University of South Australia | And 6 more authors.
Advances in Agronomy | Year: 2015

Phosphorus (P) is a macronutrient essential for all living organisms. Regrettably, it is a finite resource since phosphate rock (PR) is the main material used for production of P fertilizers. Globally, the demand for quality PR is escalating due to many factors including increasing human population. Inevitably, the demand for PR will exceed its supply capacity. This condition will be very difficult to manage as living systems have no alternative for P. Moreover, P use efficiency is low; only 15-20% of applied P is used by crops and animals. Globally, the remaining P is shunted into various waste streams. These waste streams include large quantities of effluents rich in P from both municipal and industrial wastewater treatment systems and manure from livestock production. The P present in these waste streams poses a threat to the environment by nutrient enrichment resulting in serious ecological issues such as eutrophication of waterways. However, P in these waste streams, if economically recovered, can contribute to a sustainable management of P resources. This review covers the following aspects: global importance of P as an essential nutrient; efficient and sustainable utilization of P; waste stream production, their suitability for P recovery, and limitations; current and emerging technologies for recovery of P; and the use of recovered P material. Finally, future research needs are identified associated with P recovery from waste streams and reuse in agriculture. © 2015 Elsevier Inc.

Lamm F.R.,Kansas State University | Stone K.C.,Water and Plant Research Center | Dukes M.D.,University of Florida | Howell T.A.,U.S. Department of Agriculture | And 2 more authors.
Transactions of the ASABE | Year: 2016

This article is an introduction to the "Emerging Technologies in Sustainable Irrigation: A Tribute to the Career of Terry Howell, Sr." Special Collection in this issue of Transactions of the ASABE and the next issue of Applied Engineering in Agriculture, consisting of 16 articles selected from 62 papers and presentations at the joint irrigation symposium of ASABE and the Irrigation Association (IA), which was held in November 2015 in Long Beach, California. The joint cooperation on irrigation symposia between ASABE and IA can be traced back to 1970, and this time period roughly coincides with the career of Dr. Howell. The cooperative symposia have offered an important venue for discussion of emerging technologies that can lead to sustainable irrigation. This most recent symposium is another point on the continuum. The articles in this Special Collection address three major topic areas: evapotranspiration measurement and determination, irrigation systems and their associated technologies, and irrigation scheduling and water management. While these 16 articles are not inclusive of all the important advances in irrigation since 1970, they illustrate that continued progress occurs by combining a recognition of the current status with the postulation of new ideas to advance our understanding of irrigation engineering and science. The global food and water challenges will require continued progress from our portion of the scientific community. This article serves to introduce and provide a brief summary of the Special Collection. © 2016 American Society of Agricultural and Biological Engineers.

Forbes D.A.,North Carolina A&T State University | Reddy G.B.,North Carolina A&T State University | Hunt P.G.,Water and Plant Research Center | Poach M.E.,Water and Plant Research Center | And 2 more authors.
Journal of Environmental Science and Health - Part A Toxic/Hazardous Substances and Environmental Engineering | Year: 2010

Increased swine production in North Carolina has resulted in greater waste generation and is demanding some emerging new innovative technologies to effectively treat swine wastewater. One of the cost-effective and passive methods to treat swine wastewater is using constructed wetlands. The objective of this study was to evaluate the N removal under two N loads in 3 different wetland systems: aerated marsh-pond-marsh (M-P-M), aerated marsh-covered pond-marsh (M-FB-M), and continuous marsh (CM) with two days drain and five days flood cycle. Swine wastewater from an anaerobic lagoon was applied to the constructed wetland cells (11 m wide x 40 m length) at two N loading rates of 7 and 12 kg N ha-1day-1from June to July and August to September 2005, respectively. Weekly inflow and outflow samples were collected for N, P, TS, and COD analysis. Total N reductions (%) at low and high N loading rates were 85.8 and 51.8; 86.3 and 63.3; and 86.2 and 61.8 for M-P-M, M-FB-M, and CM, respectively. Aeration had no significant (P > 0.05) impact on N removal. However, significant (P < 0.05) differences were observed for wetland systems between low and high N loading rates. No difference (P > 0.05) in N reduction was found among wetland systems. Vegetation uptake of N was negligible, ranging from 1.2 to 1.8 %. No significant (P > 0.05) differences in TS and COD removal were observed between the wetland systems. Copyright © Taylor & Francis Group, LLC.

Stone K.C.,Water and Plant Research Center | Sadler E.J.,U.S. Department of Agriculture
Transactions of the ASABE | Year: 2016

Spatial irrigation of agricultural crops using site-specific variable-rate irrigation (VRI) systems is beginning to have widespread acceptance. However, optimizing the management of these VRI systems to conserve natural resources and increase profitability requires an understanding of the spatial crop responses. In this research, we utilize a recently developed spatially explicit analysis model to reanalyze spatial corn yield data. The specific objectives of this research were to (1) calculate a suite of estimates (estimated yield, rainfed yield, maximum yield, and irrigation at maximum yield) and provide credible intervals (measures of uncertainty) around these estimates for comparing with the previous analysis, and (2) examine whether the conclusions from this rigorous re-analysis were different from the prior analysis and if the results would force any modifications to the conclusions obtained with the prior analyses. The spatially explicit analysis was achieved using a mixed model formulation of bivariate penalized smoothing splines and was implemented in a Bayesian framework. This model simultaneously accounted for spatial correlation as well as relationships within the treatments and had the ability to contribute information to nearby neighbors. The model-based yield estimates were in excellent agreement with the observed spatial corn yields and were able to estimate the high and low yields more accurately than the previous analysis. Credible intervals were calculated around the estimates, and the majority encompassed the observed yields. After calculating estimates of yield, we then calculated estimates of other response variables, such as rainfed yield, maximum yield, and irrigation at maximum yield. These estimated response variables were then compared with previous results from a classical statistical analysis. Our conclusions supported the original analysis in identifying significant spatial differences in crop responses across and within soil map units. These spatial differences were great enough to be considered in irrigation system design and management. The major improvement in the 2014 re-analysis is that the model explicitly considered spatial dependence in calculating the estimated yields and other variables and thus should provide improved estimates of the impact of spatial differences for use in irrigation system design and management. © 2016 American Society of Agricultural and Biological Engineers.

Cantrell K.B.,Water and Plant Research Center | Bauer P.J.,Water and Plant Research Center | Ro K.S.,Water and Plant Research Center
Biomass and Bioenergy | Year: 2010

Sunn hemp (Crotolaria juncea), is a fast growing, high biomass yielding tropical legume that may be a possible southeastern bioenergy crop. When comparing this legume to a commonly grown summer legume - cowpeas (Vigna unguiculata), sunn hemp was superior in biomass yield (kgha-1) and subsequent energy yield (GJha-1). In one year of the study after 12 weeks of growth, sunn hemp had 10.7Mgha-1 of biomass with an energy content of 19.0Mgha-1. This resulted in an energy yield of 204GJha-1. The energy content was 6% greater than that of cowpeas. Eventhough sunn hemp had a greater amount of ash, plant mineral concentrations were lower in some cases of minerals (K, Ca, Mg, S) known to reduce thermochemical conversion process efficiency. Pyrolytic degradation of both legumes revealed that sunn hemp began to degrade at higher temperatures as well as release greater amounts of volatile matter at a faster rate. © 2010.

Sigua G.C.,Water and Plant Research Center | Stone K.C.,Water and Plant Research Center | Hunt P.G.,Water and Plant Research Center | Cantrell K.B.,Water and Plant Research Center | Novak J.M.,Water and Plant Research Center
Agronomy for Sustainable Development | Year: 2015

Biochar is a black solid formed by pyrolysis of biomass such as crop residues. Biochar could be used for soil fertilization, carbon sequestration, and improvement of soil structure. Here, we tested the effect of sorghum biochars on winter wheat, with or without supplemental inorganic phosphorus, in a greenhouse. The application rate for sorghum residues and sorghum biochars based on a yield goal of 200 bushels ha−1 was 13 Mg ha−1. Inorganic phosphorus was added at the rate of 40 kg P ha−1. Results show that addition of sorghum biochars increased the total biomass of winter wheat grown by about 31 % over the control plants. Addition of supplemental inorganic phosphorus did not increase the total biomass. Our findings suggest that the pyrolitic transformation of sorghum residues into sorghum biochars is a better strategy for both environmental and crop productivity improvement in the Coastal Plains region. © 2014, INRA and Springer-Verlag France.

Jalankuzov T.,Institute of Soil Science after Uspanov | Suleimenov B.,Institute of Soil Science after Uspanov | Busscher W.J.,Water and Plant Research Center | Stone K.C.,Water and Plant Research Center | Bauer P.J.,Water and Plant Research Center
Communications in Soil Science and Plant Analysis | Year: 2013

The Gloldnaya steppe has large areas of fertile sierozem soils that are important for crop production and its accompanying economic development. The soils are fertile loams, but because of the steppe's dry environment, they need to be irrigated. Our objective was to study irrigation management of cotton production on sierozem soils in southern Kazakhstan. From 2006 to 2008, we grew irrigated cotton on low, moderately, and highly saline sierozem soils in the South Kazakhstan Oblast. Soils were irrigated to reduce salinity and improve growth. Yields increased with reduced salinity especially because the highly saline soil could not support growth every year and because it had 33 to 40% less yield when cotton was grown on it. Soils were managed with multiple tillage and cultivations by machinery and hand, which maintained low bulk densities near the surface and a tillage pan at about the 30-cm depth. Future management improvements include fewer tillage operations, which would decrease energy needs and compaction. Reduced upstream salinity would reduce preplanting irrigation needs. © 2013 Copyright Taylor and Francis Group, LLC.

Stone K.C.,Water and Plant Research Center | Bauer P.J.,Water and Plant Research Center | Andrae J.,Clemson University | Busscher W.J.,Water and Plant Research Center | And 3 more authors.
Transactions of the ASABE | Year: 2012

In the southeastern region of the U.S., the cattle industry has a critical need for sustainable hay production. Yet this production is threatened by frequent short-term regional drought. This drought threat can be mitigated by properly managed irrigation. In this study on Tifton 85 bermudagrass, irrigation management, nitrogen fertility levels, and harvest interval were evaluated for their impact on hay quality and yield. The experimental treatments were arrayed in a split-plot design with harvest interval as the main treatment; irrigation by nitrogen (N) levels were the subplots. Treatments had four replicates and were repeated for two years. The optimal irrigation rate was set to maintain soil water potentials below -30 kPa. When needed, the full irrigation treatment received a 12.5 mm irrigation application. The reduced irrigation treatments received water at rates of 0%, 33%, and 66% of the full irrigation rate. In addition, each irrigation treatment had nitrogen rates of 168, 336, and 504 kg N ha-1. The irrigation and nitrogen treatments were harvested at four-week or eight-week intervals. Total harvests per year ranged from three to six. Over both years and for all harvests, there was no irrigation-nitrogen interaction for hay yield. Over all harvests, nitrogen significantly increased bermudagrass hay yield, nutrient concentrations, and forage quality. Forage quality was higher for the four-week harvest interval. Throughout the study, forage quality was maintained within desired industry standards. When irrigation was required, it significantly increased hay yield. During these periods, the four-week and eight-week 100% irrigation treatments yielded 612 and 1600 kg ha-1 greater, respectively, than the non-irrigated treatments. The four-week harvest interval was more sensitive to irrigation. Additionally, we observed a linear relationship between non-irrigated bermudagrass hay yields and average soil water potential. As soil water was depleted, non-irrigated hay yields decreased 31 kg ha-1 per kPa. Timely supplemental irrigation to maintain soil water potentials above -30 kPa can increase bermudagrass yields. Thus, irrigation management should be critically assessed for its potential role in sustaining hay production in the southeastern Coastal Plain. © 2012 American Society of Agricultural and Biological Engineers.

Viguria M.,Tecnalia | Ro K.S.,Water and Plant Research Center | Stone K.C.,Water and Plant Research Center | Johnson M.H.,Water and Plant Research Center
Journal of the Air and Waste Management Association | Year: 2015

Recently, the U.S. Environmental Protection Agency (EPA) posted a ground-based optical remote sensing method on its Web site called Other Test Method (OTM) 10 for measuring fugitive gas emission flux from area sources such as closed landfills. The OTM 10 utilizes the vertical radial plume mapping (VRPM) technique to calculate fugitive gas emission mass rates based on measured wind speed profiles and path-integrated gas concentrations (PICs). This study evaluates the accuracy of the VRPM technique in measuring gas emission from animal waste treatment lagoons. A field trial was designed to evaluate the accuracy of the VRPM technique. Control releases of methane (CH4) were made from a 45 m × 45 m floating perforated pipe network located on an irrigation pond that resembled typical treatment lagoon environments. The accuracy of the VRPM technique was expressed by the ratio of the calculated emission rates (QVRPM) to actual emission rates (Q). Under an ideal condition of having mean wind directions mostly normal to a downwind vertical plane, the average VRPM accuracy was 0.77 ± 0.32. However, when mean wind direction was mostly not normal to the downwind vertical plane, the emission plume was not adequately captured resulting in lower accuracies. The accuracies of these nonideal wind conditions could be significantly improved if we relaxed the VRPM wind direction criteria and combined the emission rates determined from two adjacent downwind vertical planes surrounding the lagoon. With this modification, the VRPM accuracy improved to 0.97 ± 0.44, whereas the number of valid data sets also increased from 113 to 186. © 2015 A&WMA.

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