bluuebunny/crossref_metadata_2025_split huggingface dataset:
Use of Mini‐Sprinklers to Strip Trichloroethylene and Tetrachloroethylene from Contaminated Ground Water
Authors: Berisford Yvette C. , Bush Parshall B. , Blake John I. , Bayer Cassandra L. 
Published: August 2012

ABSTRACTThree low‐volume mini‐sprinklers were tested for their efficacy to strip trichloroethylene (TCE) and tetrachloroethylene (PCE) from water. Deionized water spiked with TCE and PCE was pumped for approximately 1 h at 0.19 to 0.21 MPa (28 to 30 lb in−2) through a mini‐sprinkler supported on top of a 1.8‐m‐tall riser. Water was collected in collection vessels at 0.61 and 1.22 m above the ground on support columns that were spaced at 0.61‐m intervals from the riser base, and samples were composited per height and distance from the riser. Overall, air‐stripping reduced dissolved concentrations of TCE and PCE by 99.1 to 100 and 96.9 to 100%, respectively, from mean influent dissolved concentrations of 466 to 1675 μg L−1 TCE and 206 to 940 μg L−1 PCE. In terms of mass removed, the mini‐sprinklers removed TCE and PCE at a rate of approximately 1400 to 1700 and 700 to 900 μg L−1, respectively, over a 1‐h test period. Mini‐sprinklers offer the advantages of (i) easy setup in series that can be used on practically any terrain; (ii) operation over a long period of time that does not threaten aquifer depletion; (iii) use in small or confined aquifers in which the capacity is too low to support large irrigation or purging systems; and (iv) use in forests in which the small, low‐impact droplets of the mini‐sprinklers do not damage bark and in which trees can help manage (via evapotranspiration) excess waste water.
Metal Bioavailability and Speciation in a Wetland Tailings Repository Amended with Biosolids Compost, Wood Ash, and Sulfate
Authors: DeVolder Pam S. , Brown Sally L. , Hesterberg Dean , Pandya Kumi 
Published: August 2012

ABSTRACTLead poisoning of waterfowl from direct ingestion of wetland mine tailings has been reported at the Coeur d'Alene River basin in Idaho. A greenhouse study was conducted to evaluate the effects of surface applications of amendments on lead bioavailability in the tailings. Treatments included sediment only, and sediment with three different surface amendments: (i) biosolids compost plus wood ash, (ii) compost + wood ash + a low SO2−4 addition as K2SO4, and (iii) compost + wood ash + a high SO2−4 addition. Measured variables included growth and tissue Pb, Zn, and Cd concentration of arrowhead (Sagittaria latifolia Willd.) and cattail (Typha latifolia L.) and soil pH, redox potential (Eh), pore water Pb, Pb speciation by X‐ray absorption spectroscopy, and in vitro Pb bioavailability. The compost + ash amendment alleviated phytotoxicity for both plant species. Bioavailability of Pb as measured by a rapid in vitro extract decreased by 24 to 34% (over control) in the tailings directly below the amendment layer in the compost + SO4 treatments. The ratio of acid volatile sulfide (AVS) to simultaneously extracted metals (SEM) also indicated a reduction in Pb bioavailability (1:40 control, 1:20 compost, 1:8 compost + low SO4, and 1:3 compost + high SO4). Extended X‐ray adsorption fine structure (EXAFS) and X‐ray absorption near edge structure (XANES) spectroscopy data indicated that lead sulfide was greater after 99 d in the treatments that included additions of sulfate. These results indicated that, under reducing conditions, surface amendments of compost + wood ash (with or without sulfate) decreased the bioavailability of Pb in metal‐contaminated mine tailings.
Heavy Metal Release from Contaminated Soils
Authors: Voegelin Andreas , Barmettler Kurt , Kretzschmar Ruben 
Published: August 2012

ABSTRACTHeavy metals in soils may adversely affect environmental quality. In this study, we investigated the release of Zn, Cd, Pb, and Cu from four contaminated soils by column leaching and single and sequential batch extractions. Homogeneously packed soil columns were leached with 67 mL/g 10−2 M CaCl2 to investigate the exchangeable metal pool and subsequently with 1400 mL/g 10−2 M CaCl2 adjusted to pH 3 to study the potential of metal release in response to soil acidification. In two noncalcareous soils (pH 5.7 and 5.1), exchange by Ca resulted in pronounced release peaks for Zn and Cd that were coupled to the exchange of Mg by Ca, and 40 to 70% of total Zn and Cd contents were rapidly mobilized. These amounts compared well with exchangeable pools determined in single and sequential batch extractions. In two soils with near‐neutral pH, the effluent concentrations of Zn and Cd were several orders of magnitude lower and no pronounced elution peaks were observed. This behavior was also observed for Cu and Pb in all four soils. When the soils were leached at pH 3, the column effluent patterns reflected the coupling of CaCO3 dissolution (if present) and other proton buffering reactions, proton‐induced metal release, and metal‐specific readsorption within the soil column. Varying the flow rate by a factor of five had only minor effects on the release patterns. Overall, Ca exchange and subsequent acidification to pH 3 removed between 65 and 90% of total Zn, Cd, Pb, and Cu from the four contaminated soils.
Chemical Extraction Methods to Assess Bioavailable Arsenic in Soil and Solid Media
Authors: Rodriguez R. R. , Basta N. T. , Casteel S. W. , Armstrong F. P. , Ward D. C. 
Published: August 2012

ABSTRACTSoil ingestion by children is an important pathway in assessing public health risks associated with exposure to arsenic‐contaminated soils. Soil chemical methods are available to extract various pools of soil arsenic, but their ability to measure bioavailable arsenic from soil ingestion is unknown. Arsenic extracted by five commonly used soil extractants was compared with bioavailable arsenic measured in vivo by immature swine (Sus scrofa) dosing trials. Fifteen contaminated soils that contained 233 to 17 500 mg kg−1 arsenic were studied. Soil extractants were selected to dissolve surficially adsorbed and/or readily soluble arsenic (water, 1 M sodium acetate, 0.1 M Na2HPO4/0.1 M NaH2PO4) and arsenic in Fe and Mn oxide minerals (hydroxylamine hydrochloride, ammonium oxalate). The mean percent of total arsenic extracted was: ammonium oxalate (53.6%) ≥ hydroxylamine hydrochloride (51.7%) > phosphate (10.5%), acetate (7.16%) > water (0.15%). The strongest relationship between arsenic determined by soil chemical extraction and in vivo bioavailable arsenic was found for hydroxylamine hydrochloride extractant (r = 0.88, significant at the 0.01 probability level). Comparison of the amount of arsenic extracted by soil methods with bioavailable arsenic showed the following trend: ammonium oxalate, hydroxylamine hydrochloride > in vivo > phosphate, acetate > water. The amount of arsenic dissolved in the stomach (potentially bioavailable) is between surficially adsorbed (extracted by phosphate or acetate) and surficially adsorbed + nonsurficial forms in Fe and Mn oxides (extracted by hydroxylamine hydrochloride or ammonium oxalate). Soil extraction methods that dissolve some of the amorphous Fe, such as hydroxylamine hydrochloride, can be designed to provide closer estimates of bioavailable arsenic.
Herbicides in Ground Water beneath Nebraska's Management Systems Evaluation Area
Authors: Spalding Roy F. , Exner Mary E. , Snow Daniel D. , Cassada David A. , Burbach Mark E. , Monson Stephen J. 
Published: August 2012

ABSTRACTProfiles of ground water pesticide concentrations beneath the Nebraska Management Systems Evaluation Area (MSEA) describe the effect of 20 yr of pesticide usage on ground water in the central Platte Valley of Nebraska. During the 6‐yr (1991–1996) study, 14 pesticides and their transformation products were detected in 7848 ground water samples from the unconfined water table aquifer. Triazine and acetamide herbicides applied on the site and their transformation products had the highest frequencies of detection. Atrazine [6‐chloro‐N‐ethyl‐N′‐(1‐methylethyl)‐1,3,5‐triazine‐2,4,‐diamine] concentrations decreased with depth and ground water age determined with 3H/3He dating techniques. Assuming equivalent atrazine input during the past 20 yr, the measured average changes in concentration with depth (age) suggest an estimated half‐life of >10 yr. Hydrolysis of atrazine and deethylatrazine (DEA; 2‐chloro‐4‐amino‐6‐isopropylamino‐s‐triazine) to hydroxyatrazine [6‐hydroxy‐N‐ethyl‐N′‐(1‐methylethyl)‐1,3,5‐triazine‐2,4‐diamine] appeared to be the major degradation route. Aqueous hydroxyatrazine concentrations are governed by sorption on the saturated sediments. Atrazine was detected in the confined Ogallala aquifer in ultra‐trace concentrations (0.003 μg L−1); however, the possibility of introduction during reverse circulation drilling of these deep wells cannot be eliminated. In fall 1997 sampling, metolachlor [2‐chloro‐N‐(2‐ethyl‐6‐methylphenyl)‐N‐(2‐methoxy‐1‐methylethyl) acetamide] was detected in 57% of the 230 samples. Metolachlor oxanilic acid [(2‐ethyl‐6‐methylphenyl)(2‐methoxy‐1‐methylethyl)amino]oxo‐acetic acid] was detected in most samples. In ground water profiles, concentrations of metolachlor ethane sulfonic acid [2‐[(ethyl‐6‐methylphenyl)(2‐methoxy‐1‐methylethyl)amino]‐2‐oxo‐ethanesulfonic acid] exceeded those of deethylatrazine. Alachlor [2‐chloro‐N‐(2,6‐diethylphenyl)‐N‐(methoxymethyl)acetamide] was detected in <1% of the samples; however, alachlor ethane sulfonic acid [2‐[(2,6‐diethylphenyl)(methoxymethyl)amino]‐2‐oxoethanesulfonic acid] was present in most samples (63%) and was an indicator of past alachlor use.
Uptake and Release of Phosphorus from Overland Flow in a Stream Environment
Authors: McDowell R. W. , Sharpley A. N. 
Published: August 2012

ABSTRACTPhosphorus runoff from agricultural fields has been linked to freshwater eutrophication. However, edge‐of‐field P losses can be modified by benthic sediments during stream flow by physiochemical processes associated with Al, Fe, and Ca, and by biological assimilation. We investigated fluvial P when exposed to stream‐bed sediments (top 3 cm) collected from seven sites representing forested and agricultural areas (pasture and cultivated), in a mixed‐land‐use watershed. Sediment was placed in a 10‐m‐long, 0.2‐m‐wide fluvarium to a 3‐cm depth and water was recirculated over the sediment at 2 L s−1 and 5% slope. When overland flow (4 mg dissolved reactive phosphorus [DRP] and 9 mg total phosphorus [TP] L−1) from manured soils was first recirculated, P uptake was associated with Al and Fe hydrous oxides for sediments from forested areas (pH 5.2–5.4) and by Ca for sediments from agricultural areas (pH 6.5–7.2). A large increase (up to 200%) in readily available P NH4Cl fraction was noted. After 24 h, DRP concentration in channel flow was related to sediment solution P concentration at which no net sorption or desorption of P occurs (EPC0) (r2 = 0.77), indicating quasi‐equilibrium. When fresh water (approximately 0.005 mg P L−1; mean base flow DRP at seven sites) was recirculated over the sediments for 24 h, P release kinetics followed an exponential function. Microbial biomass P accounted for 34 to 43% of sediment P uptake from manure‐rich overland flow. Although abiotic sediment processes played a dominant role in determining P uptake, biotic process are clearly important and both should be considered along with the location and management of landscape inputs for remedial strategies to be effective.
Nitrogen Removal and Nitrate Leaching for Two Perennial, Sod‐Based Forage Systems Receiving Dairy Effluent
Authors: Woodard Kenneth R. , French Edwin C. , Sweat Lewin A. , Graetz Donald A. , Sollenberger Lynn E. , Macoon Bisoondat , Portier Kenneth M. , Rymph Stuart J. , Wade Brett L. , Prine Gordon M. , Van Horn Harold H. 
Published: August 2012

ABSTRACTIn northern Florida, year‐round forage systems are used in dairy effluent sprayfields to reduce nitrate leaching. Our purpose was to quantify forage N removal and monitor nitrate N NO−3–N concentration below the rooting zone for two perennial, sod‐based, triple‐cropping systems over four 12‐mo cycles (1996–2000). The soil is an excessively drained Kershaw sand (thermic, uncoated Typic Quartzipsamment). Effluent N rates were 500, 690, and 910 kg ha−1 per cycle. Differences in N removal between a corn (Zea mays L.)–bermudagrass (Cynodon spp.)–rye (Secale cereale L.) system (CBR) and corn–perennial peanut (Arachis glabrata Benth.)–rye system (CPR) were primarily related to the performance of the perennial forages. Nitrogen removal of corn (125–170 kg ha−1) and rye (62–90 kg ha−1) was relatively stable between systems and among cycles. The greatest N removal was measured for CBR in the first cycle (408 kg ha−1), with the bermudagrass removing an average of 191 kg N ha−1 In later cycles, N removal for bermudagrass declined because dry matter (DM) yield declined. Yield and N removal of perennial peanut increased over the four cycles. Nitrate N concentrations below the rooting zone were lower for CBR than CPR in the first two cycles, but differences were inconsistent in the latter two. The CBR system maintained low NO−3–N leaching in the first cycle when the bermudagrass was the most productive; however, it was not a sustainable system for long‐term prevention of NO−3–N leaching due to declining bermudagrass yield in subsequent cycles. For CPR, effluent N rates ≥ 500 kg ha−1 yr−1 have the potential to negatively affect ground water quality.
Increasing Hard Winter Wheat Yield Potential via Synthetic Wheat: I. Path‐Coefficient Analysis of Yield and Its Components
Authors: Cooper Jessica K. , Ibrahim A.M.H. , Rudd J. , Malla Subas , Hays Dirk B. , Baker Jason 
Published: August 2012

ABSTRACTSynthetic hexaploid wheat, created from a cross between durum [Triticum turgidumL. (syn.Triticum durumDesf.)] andAegilops tauschiiCoss., is a good source of new genes for bread wheat (Triticum aestivumL.) improvement. The purpose of this research was to evaluate the potential and performance of synthetic wheat in Texas. Ten elite primary synthetics from the International Maize and Wheat Improvement Center (CIMMYT) were backcrossed to two Texas cultivars, TAM 111 and TAM 112. Populations were bulked and “modified bulked” to advance generations. Yield‐related agronomic traits were measured on the BCF4and BCF5populations across five Texas locations. Improvement was observed in South Texas and the Blacklands, which had more disease pressure and fewer intermittent dry spells than locations in the Texas Rolling and High Plains. Selected bulks were not superior to nonselected bulks. Head number per unit area had the highest correlation with yield. Similar to crosses with spring wheat, synthetics contributed to yield through an increase in seed weight. Synthetic populations that produced higher grain yield than both TAM 111 and TAM 112 maintained their large seed size and weight but had increased number of heads and grains per head. Poorer performance in environments with harsh winters could be because of a lack of winter‐hardiness in the primary synthetics. Improved yield could result from selecting for increased number of heads per unit area and grains per head in lines derived from these populations.
Screening Method for Distinguishing Soybean Resistance to Fusarium virguliforme in Resistant × Resistant Crosses
Authors: Luckew Alexander S. , Cianzio Silvia R. , Leandro Leonor F. 
Published: August 2012

ABSTRACTCurrent greenhouse screening methods for soybean [Glycine max (L.) Merr.] sudden death syndrome (SDS) are not sensitive enough to evaluate progeny of resistant × resistant crosses, which can possess resistance alleles at up to 12 quantitative trait loci (QTL). The objective of the study was to modify the current greenhouse screening method, the layer method, to increase its sensitivity in distinguishing SDS‐resistant lines. Three experiments were conducted using infested sorghum [Sorghum bicolor (L.) Moench] as inoculum. In Exp. 1, five different inoculum densities (1:1, 1:5, 1:10, 1:15, and 1:20 inoculum:soil ratio) were compared, and the optimum density to distinguish genotypes was identified. In Exp. 2, the association between SDS field ratings and greenhouse severity scores was determined. In Exp. 3, the inoculum layer method was compared to the proposed modified mixed method. Inoculum ratios 1:15 and 1:20 showed the largest difference in SDS ratings between soybean genotypes. The best time to assess disease severity was 30 to 36 d after planting (DAP), with the highest correlation with field ratings at 36 DAP (r = 0.82, p < 0.05). The proposed modified method shifted the frequency distribution of SDS scores toward a normal curve. The findings indicate that the modified screening method using a 1:20 inoculum:soil ratio correlated well with field data and provided adequate screening of lines possessing up to 12 SDS resistant QTL without negatively impacting germination.
Association of Freezing Tolerance to LpCBFIIIb and LpCBFIIIc Gene Polymorphism in Perennial Ryegrass Accessions
Authors: Hulke Brent S. , Bushman Bradley S. , Watkins Eric , Ehlke Nancy J. 
Published: August 2012

ABSTRACTPerennial ryegrass (Lolium perenne L.) is considered a premier turfgrass and forage grass worldwide yet susceptibility to freezing damage limits its use. C‐repeat binding factor (CBF) dehydration‐responsive element‐binding protein (DREB) related genes are considered important for the regulation of abiotic stress in plants. In this study, CBF DREB‐related genes in perennial ryegrass, also known as LpCBF genes, were resequenced from cultivated and landrace plants from a worldwide collection. A total of 109 plants survived clonal propagation and were tested for freezing tolerance. The resulting data was subjected to mixed model analysis to determine whether the freezing tolerance is related to single nucleotide polymorphism (SNP) and indel markers within two genes, LpCBFIIIb and LpCBFIIIc. One major quantitative trait locus (QTL) was discovered in LpCBFIIIc for freezing tolerance, with the majority of the plants possessing the superior allele. Several minor loci were also discovered in this gene, but no significant loci were discovered in LpCBFIIIb.
Broadening Genetic Diversity in Canola Using the C‐Genome Species Brassica oleracea L.
Authors: Bennett Rick A. , Séguin‐Swartz Ginette , Rahman Habibur 
Published: August 2012

ABSTRACTGenetic diversity in spring type canola (Brassica napus L., AACC genome, 2n = 38) cultivars is narrow. Limited effort has been made to utilize genetic diversity from the diploid species Brassica oleracea L. (CC genome, 2n = 18) due to lack of canola quality traits in seeds of this species. The objectives of this study were to assess the feasibility of introgressing canola quality traits from B. napus into B. oleracea for the purpose of developing canola quality B. oleracea as well as development of B. napus with greater genetic diversity from B. oleracea while retaining canola quality traits. Two inbred (B. napus × B. oleracea) × B. oleracea populations were generated using B. napus ‘Hi‐Q’ and A01‐104NA and B. oleracea var. alboglabra (L. H. Bailey) Musil (Chinese kale). These populations were assessed for seed quality, effectiveness of selection based on morphological traits, genetic diversity using simple sequence repeat (SSR) markers, and ploidy levels using flow cytometry and cytological analysis of meiotic chromosomes. Zero‐erucic and low glucosinolate types were recovered from a relatively small segregating population. Morphological grouping could not reliably be used to select B. oleracea plants with 2n = 18; all BC1S6 families had nuclear DNA content similar to the B. napus parents. Marker analysis revealed a high level of B. oleracea alleles among backcross lines. These findings suggest that introgression of genetic diversity from the diploid B. oleracea C‐genome into stable, canola quality B. napus type lines is feasible and may have great potential in developing genetically diverse spring type varieties.
Germination Characteristics and Seedling Emergence of Switchgrass with Different Agricultural Practices under Arid Conditions in China
Authors: Fan Jing‐Wei , Du Yan‐Lei , Turner Neil C. , Li Feng‐Min , He Jin 
Published: August 2012

ABSTRACTSwitchgrass (Panicum virgatum L.) is an important feedstock for bioenergy production, but establishment is difficult in cold arid areas. This study determined the conditions required to improve its germination and emergence in the field. Under controlled conditions, the effects of temperature, water status, and light on germination were studied by exposure to 12‐h alternating temperatures of 15/5, 20/5, 20/10, 25/10, 35/20, 40/20, and 45/20°C (day/night) and water potentials of 0, −0.2, −0.4, −0.6, −0.8, and −1.2 MPa in culture medium. Maximum percentage germination occurred at 35/20°C, 0 MPa water potential, and in continuous dark. In the field when planted in early spring (April), no emergence occurred when there was no surface cover or covered with straw mulch (SM) whereas using plastic film mulch (FM), emergence reached 383 seedlings m−2 with pre‐sowing irrigation but only 273 without irrigation. This was associated with higher soil temperatures and better soil moisture. However, in July seeding, SM lead to better water status and cooler soil conditions and thus better stand establishment. In contrast, FM treatment had poor establishment primarily due to the high temperatures. Our study indicates that emergence of switchgrass in an arid environment was (i) enhanced by pre‐sowing irrigation and shallow seeding, (ii) made possible in spring by the use of FM, and (iii) improved with SM for summer seeding.
QTLs for Energy‐related Traits in a Sweet × Grain Sorghum [Sorghum bicolor (L.) Moench] Mapping Population
Authors: Felderhoff T. J. , Murray S. C. , Klein P. E. , Sharma A. , Hamblin M. T. , Kresovich S. , Vermerris W. , Rooney W. L. 
Published: August 2012

ABSTRACTTo meet anticipated markets for sweet sorghum [Sorghum bicolor (L.) Moench] production, the development of sweet sorghum hybrids is underway. As this development is in its infancy, genetic markers will be very useful to define the genetic basis of sugar yield components and reduce the time required to deliver new hybrids to market. The purpose of this research was to characterize genetic components that influence sweet sorghum productivity and agronomics. A grain × sweet sorghum mapping population was evaluated for 16 phenotypic traits across four environments. A population of 185 F3–derived F4 (F3:4) lines was derived from the parents ‘BTx3197’ and ‘Rio’, which are dry‐stalked grain and juicy‐stalked sweet sorghums, respectively. A genetic map was constructed with 381 single nucleotide polymorphisms, and quantitative trait locus (QTL) analysis was performed. A major and previously reported QTL for soluble solids was identified on chromosome 3, but in contrast to previous studies, this QTL colocalized with other QTLs that had negative influences on desirable traits. Therefore, selection for this QTL may not be advantageous. A limited number of QTLs for percent moisture were found, and results indicated that the dry‐stalk phenotype does not affect moisture content as measured in this study. Thus, breeding for moisture content will be more challenging than previously expected. The absence of dominance effects for the brix trait indicated that brix must be high in both parents to produce high brix in hybrids.