Woody Vegetation and Soil Characteristics of Residential Forest Patches and Open Spaces along an Urban-to-Rural Gradient

As the process of urbanization advances across the country, so does the importance of urban forests, which include both trees and the soils in which they grow. Soil microbial biomass, which plays a critical role in nutrient transformation in urban ecosystems, is affected by factors such as soil type and the availability of water, carbon, and nitrogen. The aim of this study was to characterize residual forest patches and open fields in residential areas in the City of Knoxville. A field study was conducted to investigate tree species diversity and determine spatial and temporal soil characteristics along an urban-to-rural gradient. Tree diversity did not differ significantly for residential urban and rural plots in Knoxville, Tennessee. Biologically, there was no indication that soils were affected by tree diversity, in terms of soil microbial biomass C/N along an urban-to-rural gradient in Knoxville residential plots. Rural soils did differ physically from urban soils, cation exchange capacity (CEC) and soil moisture content (GSM). Similarly, physical soil properties such as bulk density, both urban and rural sites were negatively correlated with tree diversity. Results indicate that although the urban-rural gradient is subject to urban environmental stressors, the urban ecosystem is resilient in maintaining the ecosystem functions of more natural systems.

Cotton stomatal closure under varying temperature and vapor pressure deficit,correlation with the hydraulic conductance trait

Background:Cotton(Gossypium hirsutum L.)is often grown in locations characterized by high atmospheric evaporative demand.It has been hypothesized that plants which resist hydraulic flow under this condition will limit water use and conserve soil water.Therefore,in a series of controlled environment experiments ten cotton cultivars were exposed to two different temperature and vapor pressure deficit(VPD)conditions(i.e.,38℃,>3 kPa and 32℃,1∼1.5 kPa)as well as a progressive soil drying.Then,individual differences in shoot hydraulic conductance(K_(shoot))was measured using a hydraulic conductance flow meter(HCFM).Physiological parameters were reported included leaf area,dry leaf weight,stomatal conductance(g_(s)),and water use efficiency coefficient(WUE_(k)).Results:Differences were observed in K_(shoot) among cultivars under the 38℃,>3 kPa but not the 32℃,1∼1.5 kPa environment.Under the 38℃,>3 kPa environment,correlations were found between K_(shoot),stomatal conductance(gs),VPD breakpoint,WUEk,total leaf area,dry leaf weight,fraction transpirable soil water(FTSW)threshold,and slope of TR decline after FTSW threshold.Conclusion:Results show that the ability of some cotton cultivars to restrict water loss under high evaporative demand through early stomatal closure is associated with the cultivars’K_(shoot).The K_(shoot) is influential in the limitation of TR trait under high temperature and VPD.

Phosphorus Fertilization Differentially Influences Fatty Acids, Protein, and Oil in Soybean

Information is limited about phosphorus (P) fertilization effects on soybean seed composition. A field experiment was conducted to investigate the effects of P application rates on the concentrations of various fatty acids, protein, and oil in soybean under no-tillage on low and high testing P soils at Jackson and Milan, Tennessee from 2008 through 2011. Five P rates 0, 10, 20, 30, and 40 kg·P·ha-1 plus the recommended P fertilizer rate based on soil P testing results were arranged in a randomized complete block design with four replicates. Protein, oil, and fatty acid concentrations in seed responded differently to P fertilization. In general, protein concentrations were enhanced but oil levels decreased with increased P application rate. Palmitic and oleic concentrations responded positively to P application rate up to a certain level. However, the response of linolenic acid concentration was inconsistent (negative or positive). Stearic concentration was not influenced by P fertilization. Application of 10 kg·P·ha-1 resulted in higher production of protein and palmitic, oleic, and linolenic acids than zero P and the higher P application rates as well on the P deficient soil. Excessive P application rates could lower seed yield and the quality of some attributes in seed. In conclusion, linoleic acid concentration, a key quality attribute in soybean seed for human and animal consumption, can sometimes be enhanced by P fertilization;the indigenous soil P level and P application rate should be taken into account in breeding soybean cultivars with low linolenic acid level.

Soybean Seed Protein, Oil, Fatty Acids, and Isoflavones Altered by Potassium Fertilizer Rates in the Midsouth

Previous research has shown that the effect of potassium fertilizer on soybean ([Glycine max (L.) Merr.] seed composition (protein, oil, fatty acids, and isoflavones) is still largely unknown. Therefore, the objective of this research was to investigate the effects of potassium application on seed protein, oil, fatty acids, and isoflavones under Midsouth environmental conditions. A three-year experiment was conducted in two locations (Milan, TN and Jackson, TN). Potassium (K) rates were applied in the form of K2O at a rate of 0 (Control, C), 45 (T1), 90 (T2), 134 (T3), and 179 (T4) kg·ha-1 in a randomized complete block design. The results showed that increasing the K application rate did not result in consistent effects on yield. However, increasing K application rate did increase protein, oleic acid, and individual and total isoflavone concentrations at both locations in 2008 and 2009. In Jackson in 2010, the increase of K rate did not change oleic acid, but resulted in an increase in glycitein and genistein isoflavone concentrations. In 2010, increasing K application rate increased protein concentrations, decreased individual and total isoflavones, and did not change oleic acid concentration at Milan. At the highest rate of K, 179 kg·ha-1, yield and some seed composition constituents were negatively impacted. Generally, K concentration in leaves at V5, R1, R3, and seed at harvest maturity stage (R8) increased with the increase of K rate applications. The research demonstrated that K application can alter seed composition, but this alteration depended on location, environmental stress factors, mainly heat and drought, K level in soil, and K application rate. Higher rates of K application may negatively impact seed composition constituents.

Investigating Land-Use Change on Street Tree Ecosystems

In the early 1940’s, during the early stages of the Manhattan Project (WWII), of rural communities in Anderson County, Tennessee was rapidly converted into laboratory facilities and the city of Oak Ridge. The environment that became Oak Ridge experienced not only pollutants from the laboratory activities, but also alterations from the land-use change?from rural to urban areas. Therefore, a study was conducted to determine the impacts of land-use change from rural to urban area on 1) street tree diversity and performance;and 2) the biological, chemical and physical properties, and nutrient dynamics of street tree ecosystem soils. There were a total of 607 street trees, composed of 37 different species, on the five main roadways in Oak Ridge, Tennessee. The street tree inventory revealed that the street tree ecosystems had a high relative abundance of Acer rubrum (21.91%) and Pyrus calleryana (19.93%). Chemical, rather than physical, soil and site properties in street tree ecosystems had the greatest impact on street tree performance. Soils differed street by street in their biological, chemical, and physical properties but were not influenced by traffic rates. There were also differences in soil microbial biomass carbon (MBC) during the winter on streets based on their diversity of trees;however, the most diverse street was among the lowest in soil microbial biomass. Seasonally, the winter proved to have not only greater amounts of soil microbial biomass carbon and nitrogen (MBN), but significantly less extractable organic carbon (EOC) and nitrogen (EON) and total labile carbon (TLC) than that in the spring. Overall, this study provided insights into the post urbanization impacts on the street trees, soils, sites, and nutrient dynamics within street tree ecosystems of Oak Ridge.

基于元分析揭示全球尺度下反硝化反应器中基质材料对硝态氮去除的显著影响

反硝化生物反应器(DNBR)被广泛用于减少农业废水中过量的硝酸盐。其性能取决于基质的物理和化学性质。在以前的研究中,已经对一部分常见基质做了总结。然而,很少有研究尝试确定基质类型在硝酸盐去除中起作用的一般模式。本研究利用从63篇同行评审文章中收集的数据总结了41种基质类型,包括219个独立DNBR单元。基质分为四类:(1)天然碳(NC),如木屑;(2)非天然碳(NNC),如可生物降解聚合物[如聚己内酯(PCL)和废品(如纸板)];(3)无机材料(IM),如非碳材料(如氧化铁);(4)复合材料(MM),如上述材料的混合物。通过对硝酸盐去除速率[NRR,氮去除(g·m^(-3)·d^(-1))]和硝酸盐去除效率(NRE,%)的元分析,对这些材料进行比较和评估。本文综合阐述了基质效果(NRR和NRE)、潜在机理、污染交换和成本分析。我们的分析表明,木屑和玉米芯是NC中最具成本效益的基质。对比所有参与研究的基质,我们建议将MM作为最优基质,尤其是具有很大的改进空间的基于木屑和玉米芯的基质。该分析有助于优化DNBR的设计,以满足使用者对环境、经济和实用的需求。

食物-能源-水钮带关系研究能否与农业创新保持同步?

1.Introduction,The interconnection among food-energy-water(FEW)systems in meeting societal demands is broadly acknowledged[1].Similarly,competitive or synergistic allocations of water and energy resources for agricultural production,manufacturing,and human consumption are understood,and their economic impacts can be predicted[2].Far less appreciated and understood are the outcomes of the FEW nexus in response to operation changes in agricultural practices and the associated technological innovations for future generations[3,4].Also,the inter-scale and feedback effects of emerging technology-driven resource reallocation and decision-making on FEW systems are largely unknown.For example,how do the agroeconomic feedbacks of intelligent technologies influence the FEW nexus of agricultural production under environmental and demographic changes?How does the necessary water allocation for powering non-powered dams and pumped-storage hydropower generation influence agricultural production and municipal water supply maintenance?How do solar and wind energy farms influence land use for agriculture and the rural economy?

Creating a Research Enterprise Framework for Transdisciplinary Networking to Address the Food-Energy-Water Nexus

Urbanization,population growth,and the accelerating consumption of food,energy,and water(FEW)resources bring unprecedented challenges for economic,environmental,and social(EES)sustainability.It is imperative to understand the potential impacts of FEW systems on the realization of the United Nation’s Sustainable Development Goals(SDGs)as the world transitions from natural ecosystems to managed ecosystems at an accelerating rate.A major obstacle is the complexity and emergent behavior of FEW systems and associated networks,for which no single discipline can generate a holistic understanding or meaningful projections.We propose a research enterprise framework for promoting transdisciplinarity and top-down quantification of the interrelationships between FEW and EES systems.Relevant enterprise efforts would emphasize increasing FEW resource accessibility by improving coordinated interplays across sectors and scales,expanding and diversifying supply-chain networks,and innovating technologies for efficient resource utilization.This framework can guide the development of strategic solutions for diminishing the competition among FEW-consuming sectors in a region or country,and for minimizing existing inequalities in FEW availability when a sustainable development agenda is implemented.

Sustainable Production of Surfactants from Renewable Resources

Surfactants are important chemical products,serving as emulsifiers and interfacial modifiers in the household detergents,personal care products,paints and coatings,foods,cosmetics,and pharmaceuticals industries.This review focuses upon recent advances in research and development to improve the ecological sustainability of surfactants throughout their life cycle,including derivation from renewable resources,production using green manufacturing principles,and improved biocompatibility and biodegradability during their consumer use and disposal stages.Biobased surfactants,derived from vegetable oils,polysaccharides,proteins,phospholipids,and other renewable resources,currently comprise approximately 24%of the surfactant market,and this percentage is expected to increase,especially in Asia.The use of renewables is attractive to consumers because of reduced production of CO2,a greenhouse gas associated with climate change.Enzymes can greatly increase process sustainability,through reduced use of organic solvent,water,and energy,and reduced formation of by-products and waste products.Among the enzymes being investigated for surfactant synthesis,lipases are the most robust,due to their relatively high biocatalytic activity,operational stability and their ability to form or cleave ester,amide,and thioester bonds.For enzymes to be robust catalysts of surfactants,further research and development is needed to improve catalytic productivity,stability and reduce their purchase cost.

Microbial community coalescence and nitrogen cycling in simulated mortality decomposition hotspots

Background The pulsed introduction of dead plant and animal material into soils represents one of the primary mechanisms for returning organic carbon(C)and nitrogen(N)compounds to biogeochemical cycles.Decomposition of animal carcasses provides a high C and N resource that stimulates indigenous environmental microbial communities and introduces non-indigenous,carcass-derived microbes to the environment.However,the dynamics of the coalesced microbial communities,and the relative contributions of environment-and carcass-derived microbes to C and N cycling are unknown.To test whether environment-derived,carcass-derived,or the combined microbial communities exhibited a greater influence on C and N cycling,we conducted controlled laboratory experiments that combined carcass decomposition fluids and soils to simulate carcass decomposition hotspots.We selectively sterilized the decomposition fluid and/or soil to remove microbial communities and create different combinations of environment-and carcass-derived communities and incubated the treatments under three temperatures(10,20,and 30℃).Results Carcass-derived bacteria persisted in soils in our simulated decomposition scenarios,albeit at low abundances.Mixed communities had higher respiration rates at 10 and 30℃ compared to soil or carcass communities alone.Interestingly,at higher temperatures,mixed communities had reduced diversity,but higher respiration,suggesting functional redundancy.Mixed communities treatments also provided evidence that carcass-associated microbes may be contributing to ammonification and denitrification,but that nitrification is still primarily carried out by native soil organisms.Conclusions Our work yields insight into the dynamics of microbial communities that are coalescing during carcass decomposition,and how they contribute to recycling carcasses in terrestrial ecosystems.

Opposite effects of nitrogen fertilization and plastic film mulching on crop N and P stoichiometry in a temperate agroecosystem

Aims Crop nitrogen(N)and phosphorus(P)stoichiometry can influence food nutritive quality and many ecosystem processes.However,how and why N and P stoichiometry respond to long-term agricul-tural management practices(e.g.N fertilization and film mulching)are not clearly understood.Methods We collected maize tissues(leaf,stem,root and seed)and soil sam-ples from a temperate cropland under 30-year continuous N fer-tilization and plastic film mulching treatments,measured their C,N and P concentrations(the proportion(%)relative to the sample mass),and used structural equation models to uncover the re-sponding mechanisms for crop N and P contents(the total amount(g/m2)in crop biomass).Important Findings Long-term N fertilization increased N concentrations in all crop tissues but sharply decreased P concentrations in vegetative tis-sues(leaf,stem and root),thereby reducing their C/N ratio and increasing C/P and N/P ratios.The drop in P concentration in vegetative tissues was due to the dilution effect by biomass in-crement and the priority of P supply for seed production.In con-trast,film mulching decreased N concentration but increased P concentrations in most crop tissues,thereby increasing C/N ratio and reducing C/P and N/P ratios.Film mulching increased crop P content by increasing soil temperature and moisture;whereas,mulching showed little effect on crop N content,because a posi-tive effects of soil temperature may have canceled out a negative effect by soil moisture.This indicated a decoupling of P and N uptake by crops under film mulching.In conclusion,N fertiliza-tion and plastic film mulching showed opposite effects of on crop N and P stoichiometry.

A machine vision-intelligent modelling based technique for in-line bell pepper sorting

The uniformity of appearance attributes of bell peppers is significant for consumers and food industries.To automate the sorting process of bell peppers and improve the packaging quality of this crop by detecting and separating the not likable low-color bell peppers,developing an appropriate sorting system would be of high importance and influence.According to standards and export needs,the bell pepper should be graded based on maturity levels and size to five classes.This research has been aimed to develop a machine vision-based system equipped with an intelligent modelling approach for in-line sorting bell peppers into desirable and undesirable samples,with the ability to predict the maturity level and the size of the desirable bell peppers.Multilayer perceptron(MLP)artificial neural networks(ANNs)as the nonlinear modelswere designed for that purpose.TheMLP modelswere trained and evaluated through five-fold cross-validation method.The optimum MLP classifier was compared with a linear discriminant analysis(LDA)model.The results showed that the MLP outperforms the LDA model.The processing time to classify each captured image was estimated as 0.2 s/sample,which is fast enough for in-line application.Accordingly,the optimum MLP model was integrated with a machine vision-based sorting machine,and the developed system was evaluated in the in-line phase.The performance parameters,including accuracy,precision,sensitivity,and specificity,were 93.2%,86.4%,84%,and 95.7%,respectively.The total sorting rate of the bell pepper was also measured as approximately 3000 samples/h.

酸催化糖转化为5-羟甲基糠醛的动力学分析

在食品中,磷酸、柠檬酸等酸味物质可催化葡萄糖、果糖等甜味物质转化为5-羟甲基糠醛(5-HMF)。本研究中,将糖酸混合溶液放于安瓿瓶中,采用油浴加热,三种反应温度分别为373 K、393 K、413 K,以HPLC测定了加热时间8 h内的糖酸体系中5-HMF浓度随着时间的变化;利用origin 8.0对数据进行拟合,建立动力学模型。最终发现无机三元酸磷酸的催化效率高于有机三元酸柠檬酸,果糖转化程度高于葡萄糖。在葡萄糖磷酸体系(GP)、葡萄糖柠檬酸体系(GL)、果糖磷酸体系(FP)、果糖柠檬酸体系(FL)中,5-HMF的浓度随着时间的延长呈直线上升,符合零级动力学模型。动力学分析得到四种反应体系的反应活化能(Ea)分别为109.16k J/mol、121.09 k J/mol、102.89 k J/mol、112.36 k J/mol,GP体系中Ea最高,FL体系中最低。在糖酸食品热加工过程中,磷酸、果糖的含量对食品中的5-HMF含量影响很大。

The effect of hemicellulose on the interparticle frictional behavior of lignocellulosic biomass particulates

Lignocellulosic biomass material sourced from plants and herbaceous sources is considered as a prospective feedstock of inexpensive,potentially carbon-neutral energy.Lignocellulosic biomass is structurally built on cellulose,hemicellulose,and lignin,which are present in varying concentrations based on the feedstock type and play distinct and not well understood mechanical functions in the flow behavior.The frictional characteristics of lignocellulosic biomass particulates influence their flow behavior in biorefineries.Thus,it is important to fundamentally investigate the relative contribution of cellulose,hemicellulose,and lignin to the frictional behavior.However,these three biopolymers are interwoven into a complex matrix in the lignocellulosic biomass,thus making it hard to quantify the contribution of each biopolymer.In this study,we selectively remove hemicellulose from switchgrass and investigate the effects of its diminishing concentration on the coefficient of friction.We observed that the angle of repose and,therefore,the coefficient of friction for a loose assembly of the control and treated switchgrass samples decrease with decreasing hemicellulose content.This indicates the frictional resistance to flow for biomass particulate assemblies is at least proportional to the hemicellulose content.We also established that the observed changes in the frictional behavior were not due to particle morphological characteristics.