bluuebunny/crossref_metadata_2025 huggingface dataset:
Can Assessing for Potential Contribution of Soil Organic and Inorganic Components for Butachlor Sorption Be Improved?
Authors: He Yan , Liu Zhongzhen , Zhang Jian , Wang Haizhen , Shi Jiachun , Xu Jianming
Published: December 2011

Sorption of butachlor to various types of common soil components was investigated. Six pure minerals (montmorillonite [Mont], kaolinite [Kaol], Ca homoionic montmorillonite [Ca‐Mont] and kaolinite [Ca‐Kaol], amorphous hydrated Al and Fe oxides [AHOs‐Al, AHOs‐Fe]), four soil alkali‐extractable pure humic acids (HAs), and the four corresponding HAs originated real unmodified and H2O2–treated soils were selected as the representative sorbents. Results showed that the HAs played a crucial role, and clay minerals (especially Mont) also showed an important effect in butachlor sorption. The AHOs may likely influence only in a mediator way by enhancing the availability of sorption domains of HAs. By removing 78% (on average) of the total organic carbon (TOC) from the soils with H2O2, the content ratio of clay to TOC (RCO) increased by an average of 367% and became >60. This change simultaneously decreased the sorption capacity of soils (40%, on average). Considering that the surface sorption domain on clay minerals may be highly exposed and more competitive after the partial removal of soil organic matter (SOM), this reaffirmed the potential contribution from clay minerals. It can thus be inferred that in the real soil where SOM and clay minerals are associated, the coating of clay minerals may have weakened the partition function of SOM or blocked some sorption domain within SOM, resulting in a decreased sorption of butachlor. Therefore, clay minerals, especially 2:1 type expanding minerals, may play a dual function vs. SOM content for the sorption of butachlor in soil.
Water and Nitrogen Management Effects on Water and Nitrogen Fluxes in Florida Flatwoods
Authors: Hendricks Gregory S. , Shukla Sanjay
Published: December 2011

The effects of water and fertilizer best management practices (BMPs) have not been quantified for groundwater nitrogen (N) beneath seepage irrigated vegetable fields with shallow water table environments. This effect was evaluated by a 3‐yr study conducted in the Flatwoods of south Florida for watermelon (Citrillus lanatus cv. Mardi Gras and Tri‐X 313) and tomato (Solanum lycopersicum cv. BHN 586) using three treatments of water and inorganic fertilizer N (Nfert) rates: (i) high fertilizer and water rates with seepage irrigation (HR), (ii) recommended fertilizer and water rates (BMP) with seepage irrigation (RR); and (iii) RR with subsurface drip irrigation (RR‐SD). These treatments were implemented on six hydraulically isolated plots. The Nfert rate treatments for high (HR) and recommended (RR and RR‐SD) were based on a grower survey and BMP recommendations, respectively. Water applied, water table depth, and soil moisture content were regularly monitored for each treatment. Plant, soil, and groundwater N sampling and analyses were conducted for each season of the 3‐yr study. The average water applied in HR (187 cm) was greater than RR (172 cm) and RR‐SD (94 cm). Soil N maintained in crop beds for HR was significantly higher than RR and RR‐SD. Soil solution analyses showed that N leached beneath HR (112 mg L−1) was greater (p = 0.053) than RR (76 mg L−1) and RR‐SD (88 mg L−1). Shallow groundwater concentrations of dissolved inorganic nitrogen (NH3–N + NO3–N) were higher (p = 0.02) in HR (37 mg L−1) compared with RR (15 mg L−1) and RR‐SD (19 mg L−1). Decreased Nfert and water table levels can improve groundwater quality by reducing N leachate in shallow water table environments with seepage irrigated vegetable production systems.
Dietary Crude Protein and Tannin Impact Dairy Manure Chemistry and Ammonia Emissions from Incubated Soils
Authors: Powell J. M. , Aguerre M. J. , Wattiaux M. A.
Published: December 2011

Excess crude protein (CP) in dairy cow diets is excreted mostly as urea nitrogen (N), which increases ammonia (NH3) emissions from dairy farms and heightens human health and environmental concerns. Feeding less CP and more tannin to dairy cows may enhance feed N use and milk production, abate NH3 emissions, and conserve the fertilizer N value of manure. Lab‐scale ventilated chambers were used to evaluate the impacts of CP and tannin feeding on slurry chemistry, NH3 emissions, and soil inorganic N levels after slurry application to a sandy loam soil and a silt loam soil. Slurry from lactating Holstein dairy cows (Bos taurus) fed two levels of dietary CP (low CP [LCP], 155 g kg−1; high CP [HCP], 168 g kg−1) each fed at four levels of dietary tannin extract, a mixture from red quebracho (Schinopsis lorentzii) and chestnut (Castanea sativa) trees (0 tannin [0T]; low tannin [LT], 4.5 g kg−1; medium tannin [MT], 9.0 g kg−1; and high tannin [HT], 18.0 g kg−1) were applied to soil‐containing lab‐scale chambers, and NH3 emissions were measured 1, 3, 6, 12, 24, 36, and 48 h after slurry application. Emissions from the HCP slurry were 1.53 to 2.57 times greater (P < 0.05) than from the LCP slurry. At trial's end (48 h), concentrations of inorganic N in soils were greater (P < 0.05) in HCP slurry–amended soils than in LCP slurry–amended soils. Emissions from HT slurry were 28 to 49% lower (P < 0.05) than emissions from 0T slurry, yet these differences did not affect soil inorganic N levels. Emissions from the sandy loam soil were 1.07 to 1.15 times greater (P < 0.05) than from silt loam soil, a result that decreased soil inorganic N in the sandy loam compared with the silt loam soil. Larger‐scale and longer‐term field trails are needed to ascertain the effectiveness of feeding tannin extracts to dairy cows in abating NH3 loss from land‐applied slurry and the impact of tannin‐containing slurry on soil N cycles.
A Comparison of Reliability of Soil Cadmium Determination by Standard Spectrometric Methods
Authors: McBride M. B.
Published: December 2011

Inductively coupled plasma emission spectrometry (ICP–OES) is the most common method for determination of soil Cd, yet spectral and matrix interferences affect measurements at the available analytical wavelengths for this metal. This study evaluated the severity of the interference over a range of total soil Cd by comparing ICP–OES and inductively coupled plasma mass spectrometry (ICP–MS) measurements of Cd in acid digests. Using the emission at 226.5 nm, ICP–OES was generally unable to quantify soil Cd at low (near‐background) levels and gave unreliable values compared with ICP–MS. Using the line at 228.8 nm, a marked positive bias in Cd measurement (relative to the 226.5 nm measurement) was attributable to arsenic (As) interference even at soil As concentrations below 10 mg kg−1. This spectral interference in ICP–OES was severe in As‐contaminated orchard soils, giving a false value for soil total Cd near 2 mg kg−1 when soil As was 100 to 150 mg kg−1. In attempting to avoid these ICP emission‐specific interferences, this study evaluated a method to estimate total soil Cd using 1 M HNO3 extraction followed by determination of Cd by flame atomic absorption (FAA), either with or without preconcentration of Cd using an Aliquat‐heptanone extractant. The 1 M HNO3 extracted an average of 82% of total soil Cd. The FAA method had no significant interferences and estimated the total Cd concentrations in all soils tested with acceptable accuracy. For Cd‐contaminated soils, the Aliquat‐heptanone preconcentration step was not necessary, as FAA sensitivity was adequate for quantification of extractable soil Cd and reliable estimation of total soil Cd.
Waterfowl Abundance Does Not Predict the Dominant Avian Source of Beach Escherichia coli
Authors: Hansen Dennis L. , Ishii Satoshi , Sadowsky Michael J. , Hicks Randall E.
Published: December 2011

The horizontal, fluorophore enhanced, rep‐PCR (HFERP) DNA fingerprinting technique was used to identify potential sources of Escherichia coli in water, nearshore sand, and sediment at two beaches in the Duluth‐Superior Harbor, near Duluth, MN, and Superior, WI, during May, July, and September 2006. An animal or environmental source could be identified for 35, 29, and 30% of E. coli strains in water, sand, and sediments, respectively. Waterfowl, including Canada geese, ring‐billed gulls, and mallard ducks, were the largest source of E. coli that could be identified in water (55–100%), sand (59–100%), and sediment (92–100%) at both beaches. Although ring‐billed gulls were more abundant in this harbor, Canada geese were usually the dominant source of waterfowl E. coli found at these beaches. The percentage of E. coli identified from treated wastewater was always less than the percentage of E. coli originating from waterfowl. At both beaches, the percentage of E. coli in water contributed by treated wastewater was higher in May compared with July and September. The larger proportion of wastewater‐derived E. coli seen in May probably reflected a smaller contribution of E. coli from geese when these birds were less abundant rather than an absolute increase in E. coli from treated wastewater. Microbial source analysis and bird census data both indicated that waterfowl were a major source of E. coli at beaches in the Duluth‐Superior Harbor. These data also indicated it is risky to assume that the most abundant waterfowl species present in waterways will also be the largest source of avian‐derived E. coli in water, nearshore sand, and sediments at beaches.
Phosphorus Runoff from Sewage Sludge Applied to Different Slopes of Lateritic Soil
Authors: Chen Yan Hui , Wang Ming Kuang , Wang Guo , Chen Ming Hua , Luo Dan , Ding Feng Hua , Li Rong
Published: December 2011

Sewage sludge (SS) applied to sloping fields at rates that exceed annual forest nutrient requirements can be a source of phosphorus (P) in runoff. This study investigates the effects of different slopes (18, 27, 36, and 45%) on P in runoff from plots amended with SS (120 Mg ha−1). Lateritic soil (pH 5.2) was exposed to five simulated rainfalls (90 mm h−1) on outdoor plots. When sludge was broadcast and mixed with surface soils, the concentrations and loss in runoff of total P in the mixed sample (MTP), total P in the settled sample (STP), total particulate P (TPP), total suspended P (TSP), and total dissolved P (TDP) were highest at 1 or 18 d after application. Initially, pollution risks to surface waters generally increased to different degrees with steeper slopes, and then diminished gradually with dwindling differences between the slopes. The runoff losses coefficient of MTP increased in the order 36 > 45 > 27 > 18%. The initial event (1 and 18 d) accounted for 67.0 to 83.6% of total runoff P losses. Particulate fraction were dominant carriers for P losses, while with the lower slopes there was higher content of P per unit particulate fraction in runoff. Phosphorus losses were greatly affected by the interaction of sludge–soil–runoff and the modification of soil properties induced by sludge amendment. It is recommended to choose lower slopes (<27%) to reduce risk of P losses. Thus, the risk of application sludge to sloping fields in acid soils should be studied further in the field under a wider diversity of conditions.
Using Data Mining to Predict Soil Quality after Application of Biosolids in Agriculture
Authors: Cortet Jérôme , Kocev Dragi , Ducobu Caroline , Džeroski Sašo , Debeljak Marko , Schwartz Christophe
Published: December 2011

The amount of biosolids recycled in agriculture has steadily increased during the last decades. However, few models are available to predict the accompanying risks, mainly due to the presence of trace element and organic contaminants, and benefits for soil fertility of their application. This paper deals with using data mining to assess the benefits and risks of biosolids application in agriculture. The analyzed data come from a 10‐yr field experiment in northeast France focusing on the effects of biosolid application and mineral fertilization on soil fertility and contamination. Biosolids were applied at agriculturally recommended rates. Biosolids had a significant effect on soil fertility, causing in particular a persistent increase in plant‐available phosphorus (P) relative to plots receiving mineral fertilizer. However, soil fertility at seeding and crop management method had greater effects than biosolid application on soil fertility at harvest, especially soil nitrogen (N) content. Levels of trace elements and organic contaminants in soils remained below legal threshold values. Levels of extractable metals correlated more strongly than total metal levels with other factors. Levels of organic contaminants, particularly polycyclic aromatic hydrocarbons, were linked to total metal levels in biosolids and treated soil. This study confirmed that biosolid application at rates recommended for agriculture is a safe option for increasing soil fertility. However, the quality of the biosolids selected has to be taken into account. The results also indicate the power of data mining in examining links between parameters in complex data sets.
Sorption of Aromatic Ionizable Organic Compounds to Montmorillonites Modified by Hexadecyltrimethyl Ammonium and Polydiallyldimethyl Ammonium
Authors: Xu Huaizhou , Wan Yuqiu , Li Hui , Zheng Shourong , Zhu Dongqiang
Published: December 2011

Environmental residues of aromatic ionizable organic compounds (AIOCs) have received considerable attention due to their potential human health and ecological risks. The main objective of this study was to investigate the key factors and mechanisms controlling sorption of a series of anionic and zwitterionic AIOCs (two aromatic sulfonates, 4‐methyl‐2,6‐dinitrophenol, tetracycline, sulfamethoxazole, and tannic acid) to montmorillonites modified with hexadecyltrimethyl ammonium (HDTMA) and polydiallyldimethyl ammonium (PDADMA). Compared with naphthalene (a nonpolar and nonionic solute), all AIOCs showed stronger sorption (the sorbent‐to‐solution distribution coefficient was in the order of 103–104 L kg−1) to the two organoclays in spite of the much lower hydrophobicity, indicating the predominance of electrostatic interaction in sorption. The proposed electrostatic mechanism of the tested AIOCs was supported by the pH dependency of sorption to the two organoclays. The two organoclays manifested weaker sorption affinity but faster sorption kinetics for bulky AIOCs than commercial activated carbon, resulting from the high accessibility of sorption sites in the open, ordered clay interlayer. The findings of this study highlight the potential of using HDTMA‐ and PDADMA‐exchanged montmorillonites as effective sorbents for AIOCs in water and wastewater treatments.
17β‐Estradiol and Testosterone Sorption in Soil with and without Poultry Litter
Authors: Bera M. , Radcliffe D. E. , Cabrera M. L. , Vencill W. K. , Thompson A. , Hassan S.
Published: December 2011

17β‐estradiol and testosterone are naturally occurring steroids that co‐occur in poultry litter. The effects of litter on sorption of these hormones to soil are not known. Sorption isotherms were developed for 14C‐labeled testosterone and 3H‐labeled estradiol in a Cecil sandy clay loam with and without poultry litter addition. The effect of applying the hormones alone (single‐sorbate) or together (multisorbate) was also investigated. 14C‐testosterone sorption in soil increased from 2 to 48 h and remained relatively constant thereafter. 3H‐estradiol sorption in soil was relatively constant from 2 to 24 h and then decreased to 72 h. These differences may reflect transformation of the parent hormones to products with different solid‐phase affinity. The maximum sorption coefficient (Kd) in soil for 14C‐testosterone (20.2 mL g−1) was similar to that for 3H‐estradiol (19.6 mL g−1) in single‐sorbate experiments. When hormones were applied together, sorption of both hormones in soil decreased, but the 14C‐testosterone Kd (12.5 mL g−1) was nearly twice as large as the 3H‐estradiol Kd (7.4 mL g−1). We propose this resulted from competition between the hormones and their transformation products for sorption sites, with 14C‐testosterone and its expected transformation product (androstenedione) being better competitors than 3H‐estradiol and its expected transformation product (estrone). When poultry litter was mixed with soil, sorption increased for 3H‐estradiol but decreased for 14C‐testosterone. This may have been because poultry litter slowed the transformation of parent hormones. Our results show that poultry litter could have important effects on the mobility of estradiol and testosterone.
Broadcast Urea Reduces N2O but Increases NO Emissions Compared with Conventional and Shallow‐Applied Anhydrous Ammonia in a Coarse‐Textured Soil
Authors: Fujinuma Ryosuke , Venterea Rodney T. , Rosen Carl
Published: December 2011

Despite the importance of anhydrous ammonia (AA) and urea as nitrogen (N) fertilizer sources in the United States, there have been few direct comparisons of their effects on soil nitrous oxide (N2O) and nitric oxide (NO) emissions. We compared N oxide emissions, yields, and N fertilizer recovery efficiency (NFRE) in a corn (Zea mays L.) production system that used three different fertilizer practices: urea that was broadcast and incorporated (BU) and AA that was injected at a conventional depth (0.20 m) (AAc) and at a shallower depth (0.10 m) (AAs). Averaged over 2 yr in an irrigated loamy sand in Minnesota, growing season N2O emissions increased in the order BU < AAc < AAs. In contrast, NO emissions were greater with BU than with AAc or AAs. Emissions of N2O ranged from 0.5 to 1.4 kg N ha−1 (50–140 g N Mg−1 grain), while NO emissions ranged from 0.2 to 0.7 kg N ha−1 (20–70 g N Mg−1 grain). Emissions of total N oxides (NO + N2O) increased in the order AAc < BU < AAs. Despite having the greatest emissions of N2O and total N oxides, the AAs treatment had greater NFRE compared with the AAc treatment. These results provide additional evidence that AA emits more N2O, but less NO, than broadcast urea and show that practices to reduce N2O emissions do not always improve N use efficiency.
Relationships between Sunflower Plant Spacing and Yield: Importance of Uniformity in Spacing
Authors: McMaster Gregory S. , Buchleiter Gerald W. , Bausch Walter C.
Published: December 2011

Sunflower (Helianthus annuus L.) production systems in semiarid regions often have poor seedling emergence and patchy stands leading to lower yield. We hypothesized plant spacing was positively related to individual plant yield and this relationship would strengthen as water deficits increased. In a 2‐yr study in Colorado, individual plant spacing and associated seed was measured for different irrigation treatments. Highly significant positive linear and second‐order polynomial regressions of individual plant spacing and yield (p < 0.001) were observed for all irrigation treatments in both years. However, given highly variable individual plant yield with spacing, regression explained no more than 16% of the variation. No consistent pattern in linear regression slope, y‐intercept, or R2 values among irrigation treatments were noted, thereby not supporting the expectation that the relationship would be greater as water deficits increased, although rainfall events may have confounded the results. Leverage plots showed similar results as the regression equations but indicated plant spacing explained yield variation more than irrigation treatment. Regression tree analysis further confirmed that plant spacing was more important than irrigation treatment in explaining final plant yield. These results suggest there is a cost to final yield per unit area where large spacing results in lower yields even though these plants have the highest yields per plant of any spacing classes.
Soybean Response to Soil Rhizobia and Seed‐applied Rhizobia Inoculants in Wisconsin
Authors: Furseth Branden J. , Conley Shawn P. , Ané Jean‐Michel
Published: December 2011

Seed‐applied rhizobia inoculants can be used to promote biological nitrogen fixation in soybean [Glycine max (L.) Merr.] production, yet their efficacy remains highly variable. The goal of this study was to improve the predictability of a positive soybean seed yield and quality response to inoculation by (i) characterizing inoculant product response in multiple environments, and (ii) quantifying the response of soybean to indigenous soil rhizobia populations. Two inoculants and a control were tested on three soybean varieties at nine locations in Wisconsin during 2009 and 2010. Soil samples were collected from each plot for the quantification of soil rhizobia. Seed yield, protein, and oil did not respond to inoculation across all 18 environments (P = 0.15, 0.38, and 0.30, respectively). Three environments responded positively to inoculation (P < 0.05), while the remainder showed no response. Yield of the control treatment was positively correlated with the soil rhizobia population level across all environments (P = 0.005), while the inoculated treatments showed no response. These data indicate a yield advantage for inoculation at lower rhizobia populations; however, given the large range of response with only three of 18 environments showing a positive response, a rhizobia population threshold to aid in the decision to treat soybean seeds with a rhizobia inoculant cannot be determined.
Basis for Selecting Soft Wheat for End‐Use Quality
Authors: Souza Edward J. , Sneller Clay , Guttieri Mary J. , Sturbaum Anne , Griffey Carl , Sorrells Mark , Ohm Herbert , Van Sanford David
Published: December 2011

Within the United States, end‐use quality of soft wheat (Triticum aestivum L.) is determined by several genetically controlled components: milling yield, flour particle size, and baking characteristics related to flour water absorption. In 2007 and 2008, we measured the soft wheat quality of 187 soft winter wheat cultivars, released from 1801 to 2005, for the eastern United States. Wheat cultivars were grown in nine eastern United States environments. Quality traits included test weight, flour yield, softness equivalent (an estimator of break flour yield), flour protein concentration, solvent retention capacity (SRC) of flour, and sugar‐snap cookie quality. All of the traits had large variance components due to genotype. Flour milling characteristics had the largest ratio of genotype variance to genotype × environment interaction variance. Based on multivariate analysis of the trait correlation structure, breeders should focus on milling yield, flour softness equivalent, and sucrose SRC, as they predict long‐flow flour milling performance and have value for commercial milling and baking. These traits also have large genetic variance relative to genotype × environment interactions and represent distinct aspects of quality. Although some improvement in soft wheat milling and baking quality has been observed over the past 200 yr, the dominant effect of selection appears to be a stable standard of quality that is associated with the soft wheat classes of the eastern United States.
Herbage Mass, Herbage Rejection, and Chemical Composition of Signalgrass under Different Stocking Rates and Distances from Dung Pads
Authors: Teixeira V. I. , Dubeux J. C. B. , de Mello A. C. L. , Lira M. A. , Saraiva F. M. , dos Santos M. V. F. , Lira M. A.
Published: December 2011

Nutrients from fecal return may improve herbage growth and chemical composition, but herbage rejection may occur around dung pads. Rejected herbage increases in maturity and might be rejected in future grazing cycles. The aim of this study was to determine the influence of dung pad on soil and herbage characteristics of signalgrass [Urochloa decumbens (Stapf) R. D. Webster (syn. Brachiaria decumbens Stapf.)] pastures managed under three stocking rates (1.9, 3.2, and 4.2 animal units (AUs) ha−1; 1 AU = 450 kg of cattle live weight). Herbage and soil responses were measured at different distances from the dung pad border (0 to 20, 20 to 40, and 40 to 60 cm). A rotational stocking was applied with 3 d of grazing and 32 or 67 d of resting for the dry and rainy seasons, respectively. Herbage mass increased near the dung pad by 40% compared to the surrounding areas but was not affected by stocking rate. Herbage rejection was greater near the dung pad and rejection was greater at lower stocking rate. Plants distant from the dung pad presented lower P concentration. Regardless of stocking rate, K, N, and P fecal and herbage concentrations were affected by the grazing cycle, and there was a higher nutrient concentration during the rainy season. Soil beneath dung pad had higher pH value (5.6 vs. 5.2), Mehlich‐I P (22.4 vs. 12.5 g m−3), and K concentration (9 vs. 5 mol m−3) compared to soil from the surrounding areas. Grazing management practices should improve fecal distribution in pastures to maximize nutrient return via this pathway.
Genetic Diversity of Turf‐Type Tall Fescue Using Diversity Arrays Technology
Authors: Baird James H. , Kopecký David , Lukaszewski Adam J. , Green Robert L. , Bartoš Jan , Doležel Jaroslav
Published: December 2011

Turf‐type tall fescue (Festuca arundinacea Schreb.) germplasm available both commercially and in cultivar trials is surprisingly similar in quality and performance. To test genetic diversity within this germplasm, Diversity Arrays Technology (DArT) was used to detect DNA polymorphism among 93 entries from the 2006 National Turfgrass Evaluation Program tall fescue test in Riverside, CA. Based on the analysis of 190 polymorphic DArT markers, we found little variability in the turf‐type cultivars. These data are in agreement with field observations showing very few distinguishable differences in turf quality among the entries, with the exception of ‘Kentucky‐31’, a forage‐type standard entry. This cultivar ranked lowest for turf quality. The 93 entries were then compared with 14 forage‐type and four turf‐type accessions collected worldwide, further demonstrating narrow diversity among the entries and overall lower genetic diversity among turf‐types relative to forage‐types. Such low genetic polymorphism of turf‐type genotypes indicates a very close relationship regardless of the origin. It may have been caused by either a severe genetic bottleneck in the conversion of germplasm from forage to turfgrass use, or by extensive sharing of germplasm. This indicates an urgent need to rapidly broaden the genetic diversity in commercial germplasm of turf‐type tall fescue.
Worldwide Core Collection of Olive Cultivars Based on Simple Sequence Repeat and Morphological Markers
Authors: Díez Concepción M. , Imperato Annalisa , Rallo Luis , Barranco Diego , Trujillo Isabel
Published: December 2011

Core collections reflecting the diversity of large germplasm collections are valuable tools to conserve and evaluate the genetic resources more effectively. Three strategies using two different search algorithms were trained to develop the most representative nested core collection of the World Olive Germplasm Bank (WOGB) of Cordoba (Spain), the largest and best characterized collection of olive (Olea europaea L.) cultivars worldwide. The original dataset was composed of 378 olive accessions from 21 different countries characterized by 14 microsatellite markers (simple sequence repeats [SSRs]). Each nested core collection included five subsets representing different percentages of the base collection (5, 10, 15, 20, and 30%). The strategy maximizing the allele coverage implemented in the software Core Hunter was chosen as the best. The five subsets developed by this method captured the maximum number of alleles showing fewer significant differences in their frequencies with respect to the whole collection. Additionally, a balanced geographical composition was observed in the nested subsets in spite of the strong overrepresentation of western Mediterranean accessions present in the WOGB. The results of this study are aimed at improving both the conservation and management of olive genetic resources and the study of differential genotype × environment interactions by testing a minimum number of accessions
Agronomic and Physiological Responses of Cool‐Season Turfgrass to Fall‐Applied Nitrogen
Authors: Bauer Sam , Lloyd Dan , Horgan Brian P. , Soldat Doug J.
Published: December 2011

Turfgrass is an integral component of the urban and suburban landscape and plays a key role in water quality and nutrient cycling. Nitrogen (N) is the mineral nutrient most limiting for turfgrass growth and development and is often applied as fertilizer to maintain adequate soil levels. Rising energy and subsequent N costs and environmental concerns have pressured turfgrass managers to schedule N applications to maximize N use efficiency. Late‐fall N fertilization for cool‐season turfgrass is a widely accepted practice among turf managers, with application rates ranging from 49 to 98 kg N ha−1 and accounting for 25 to 50% of annual N applied. Reported benefits from late‐fall N fertilization include improved color in fall and spring without stimulation of shoot growth, improved rooting in late fall and early spring, carbohydrate accumulation in late fall, and the ability to delay or avoid fertilizing in the spring. However, research supporting these benefits in cool‐season turfgrass is limited and has yielded mixed results. Much of this work was conducted in relatively warm or temperate coastal climates and may not be applicable to cooler temperature regimes of more northern climates. More recent research has indicated a greater potential for nitrate leaching losses from late‐fall N due to cooler temperatures reducing plant uptake and microbial immobilization of N. This literature review finds that the often cited physiological and agronomic benefits of applying late‐fall N applications are poorly supported by peer‐reviewed research, with the exception of fall and spring color responses. More climate‐specific research on plant utilization and response to fall‐applied N is necessary to determine appropriate N rates and optimal timings for this highly specific application.
Development of Simple Sequence Repeat Markers and the Analysis of Genetic Diversity and Ploidy Level in a Centipedegrass Collection
Authors: Harris‐Shultz Karen R. , Milla‐Lewis Susana R. , Zuleta M. Carolina , Schwartz Brian M. , Hanna Wayne W. , Brady Jeff A.
Published: December 2011

Little is known about the genetic variability of centipedegrass [Eremochloa ophiuroides (Munro) Hack.] and few genetic tools have been available for this species. In this study, 69 unique Eremochloa sequences were generated by using a compound simple sequence repeat (SSR)‐based cloning method. Twenty‐nine of these clones contained an internal SSR and 30 specific primer pairs were developed that produced suitable amplification. The level of genetic diversity was assessed using 55 centipedegrass accessions and one Eremochloa zeylanica Hack. accession using primer pairs developed from the compound SSR‐based cloning technique. Twenty‐four polymorphic fragments could be scored and unweighted pair‐group method using arithmetic averages (UPGMA) cluster analysis showed that the Eremochloa accessions clustered into two groups: a large cluster of E. ophiuroides accessions and a group containing the single E. zeylanica accession. Principle coordinate analysis further divided the centipedegrass accessions into three groups. Ploidy analysis revealed all centipedegrass accessions were diploid while the single E. zeylanica accession was found to be a putative tetraploid. Furthermore, many of these markers can be used for other species belonging to the subfamily Panicoideae. The division of the centipedegrass accessions into groups and analysis of ploidy level provides information that will aid in the effective use of this germplasm in breeding programs.
Mediterranean and Continental Tall Fescue: II. Effects of Cold, Nonfreezing Temperatures on Leaf Extension, Proline, Fructan, and Abscisic Acid
Authors: Dierking R. M. , Kallenbach R. L.
Published: December 2011

Continental tall fescue [Festuca arundinacea Schreb. syn. Lolium arundinaceum (Schreb.) Darbysh.] is the predominant forage used by cattle producers throughout much of the Midwest. However, Mediterranean tall fescue is gaining popularity in warmer, drier climates. One major difference of Mediterranean tall fescue is that it enters a semidormant period during hot dry summers but resurges during the fall and winter months. During the autumn resurgence it has exceptional growth but does not survive prolonged freezing conditions typically found in the Midwest. To determine how both Continental and Mediterranean tall fescues respond to low temperatures that are typically encountered during the fall, the leaf extension rate (LER) was measured along with proline, simple sugars, fructan, and abscisic acid (ABA). Three Mediterranean and four Continental accessions were tested, including Kentucky‐31 and Flecha as “typical” Continental and Mediterranean accessions, respectively. The greatest difference observed between these types of tall fescue occurred at 4.5°C. The Mediterranean genotypes had greater LER and fructan concentrations while the Continental genotypes possessed greater proline, ABA, and simple sugar concentrations. Kentucky‐31 was typically found in the middle between the Mediterranean and the remaining Continental accessions. These data indicate that Mediterranean germplasm possesses superior cold growth, but the high proline levels produced by the Continental types may be critical for survival under cold conditions.
Environmentally Sustainable Nitrogen Fertilizer Management for ‘Tifton 85’ Hay Production in Sandy Soils
Authors: Agyin‐Birikorang S. , Newman Y. C. , Kasozi G. N.
Published: December 2011

Nitrogen is a critical element for sustainable forage production but N surpluses in sandy soils could result in nitrate leaching and water contamination. Our objective was to identify a N application rate that optimizes yield and quality of ‘Tifton 85’ bermudagrass (Cynodon Rich. spp.) with minimal N leaching losses in a typical Florida sandy soil. Four N application rates (30, 50, 70, and 90 kg N ha−1 per harvest) and an unfertilized (0 N) control in a Tifton 85 bermudagrass hay field were evaluated. Suction lysimeters were installed in each plot at 30 and 100 cm below the soil surface to measure soil water nitrate concentration. Nitrogen application at the recommended rate of 90 kg N ha−1 per harvest produced the greatest total dry matter yield (DMY) (∼22 Mg ha−1 yr−1), but a modeled optimum DMY of ∼18 Mg ha−1 yr−1 occurred at 57 kg N ha−1 per harvest. Nitrogen application increased herbage nutritive value, but the difference was not significant above 30 kg N ha−1 per harvest. Treatments with N rates ≤ 50 kg N ha−1 per harvest had leachate nitrate concentration below the maximum contaminant limit (MCL) of 10 mg L−1. However, N rates ≥ 70 kg N ha−1 per harvest had leachate nitrate concentration that exceeded the MCL, suggesting a risk of impacting groundwater quality. The results demonstrate that although Tifton 85 bermudagrass is an efficient N remover, there is potential for N leaching in sandy soils. Therefore, site‐specific evaluation of appropriate N management is critical.
High Degree of Genetic Variation of Winter Hardiness in a Panel of Beta vulgaris L.
Authors: Kirchhoff Martin , Svirshchevskaya Anna , Hoffmann Christa , Schechert Axel , Jung Christian , Kopisch Obuch Friedrich J.
Published: December 2011

Growing sugar beet (Beta vulgaris L. subsp. vulgaris [sugar beet cultivar group]) as a winter crop requires the development of a winter sugar beet with controlled bolting and sufficient winter hardiness. To evaluate the genetic variation for winter hardiness in B. vulgaris L., we determined the survival rate (SR) in a panel of 396 accessions tested in eight overwintering field trials in Germany and Belarus. The panel included the cultivar groups sugar beet, fodder beet, garden beet, and leaf beet, as well as the wild beet B. vulgaris subsp. maritima (L.) Arcang. (BVM). Across all environments the effects of accession, environment, and accession × environment interaction were highly significant. Despite the complexity of the trait, the heritability for SR was estimated as h2 = 0.81, reflecting a large genetic variation in the panel. Environmental SRs ranged from 0.7 to 86.3% with a grand mean of 28.4%. In all environments at least one accession completely died while the maximum SR ranged from 39.9 to 100%. On average, sugar beet accessions performed best while accessions with the highest SR were among BVMs and leaf beets. The largest variation for SR was found in BVMs, followed by the leaf beets, whereas sugar beets showed the smallest variation. Our results suggest that winter hardiness in sugar beet is sufficient to survive mild winters but needs to be improved for continental climates with colder winters. Whether the limited variation in sugar beet is sufficient for this has to be further investigated.
Genetic Analysis of Green Leaf Duration in Spring Wheat
Authors: Naruoka Y. , Sherman J. D. , Lanning S. P. , Blake N. K. , Martin J. M. , Talbert L. E.
Published: December 2011

Genetic approaches to lengthening green leaf duration are becoming more important in spring wheat (Triticum aestivum L. em. Thell.) as increasing temperatures hasten leaf senescence. Green leaf duration after heading (GLDAH) has been reported to provide drought and heat tolerance in several crops. This study was conducted in Montana under a range of temperature and moisture conditions to evaluate the relationship of GLDAH to agronomic traits and to identify quantitative trait loci (QTL) for GLDAH using a recombinant inbred line (RIL) population derived from Reeder (longer GLDAH) and Conan (intermediate GLDAH). Correlation analysis showed a positive relationship between GLDAH and test weight, seed weight, and seed diameter under late‐season heat and drought stress conditions but not under cool, well‐watered conditions. Green leaf duration after heading was negatively correlated with grain yield under cool, well‐watered conditions. Earlier heading was consistently associated with longer GLDAH in a wide range of environments. The QTL QGfd.mst‐4A had an effect on GLDAH under stress conditions in the Conan/Reeder population and an RIL population derived from McNeal/Reeder. The Reeder allele of QGfd.mst‐4A resulted in longer GLDAH and also increased the amount of xylem exudate from de‐topped plants, indicating higher root mass and/or activity. Our results suggest that the impact of alleles at QGfd.mst‐4A may vary depending on the degree of heat and drought stress.
Development and Characterization of Low‐Phytate Pea
Authors: Warkentin T. D. , Delgerjav O. , Arganosa G. , Rehman A. U. , Bett K. E. , Anbessa Y. , Rossnagel B. , Raboy V.
Published: December 2011

The majority of the total phosphorus in seeds is stored in the form of phytate, a mixed‐cation salt of phytic acid. Phytate is not well digested by humans and monogastric animals. Phosphorus excretion is one of the major pollutants of surface waters in many locations in the world. Important micronutrients such as iron and zinc bound to phytate are also excreted, potentially leading to micronutrient deficiencies. Low‐phytate mutants have been developed in several crop species as one strategy to deal with the phytate problem. The objective of this research was the development of low‐phytate pea (Pisum sativum L.) using chemical mutagenesis of cultivar CDC Bronco, and the agronomic characterization of two resulting lines. In these lines, phytate phosphorus concentration was reduced by approximately 60%, with a compensating increase in inorganic phosphorus. The low‐phytate lines were similar in agronomic performance to CDC Bronco, except for somewhat slower time to flowering and maturity, slightly lower seed weight, and slightly lower grain yield. Low‐phytate field pea should have potential to improve phosphorus and micronutrient bioavailability in human and animal diets.
Probability of Yield Response and Breaking Even for Soybean Seed Treatments
Authors: Esker Paul D. , Conley Shawn P.
Published: December 2011

Earlier soybean [Glycine max (L.) Merr.] planting coupled with increasing seed cost and commodity prices has led to an increase in the number of hectares treated with seed treatments. Ultimately, growers would like to know if applying such treatment is cost effective. Therefore, the objectives of this experiment were to quantify the effects of seed treatment on early season plant population and seed yield and investigate the probability that yield response covered the cost of the seed treatment. Trials were conducted in Wisconsin from 2008 to 2010 at nine locations each year to compare no seed treatment, mefenoxam + fludioxonil (ApronMaxx), and mefenoxam + fludioxonil + thiamethoxam (CruiserMaxx). Results indicated differences in early‐season plant population due to cultivar and seed treatment and that seed yield was affected by a cultivar × seed treatment interaction. At a low seed treatment price, the percentage of environments where the probability of breaking even was >50% and ranged from 56 to 67%, while it ranged from 22 to 56% at a higher price. Both ApronMaxx and CruiserMaxx had positive response ratios of 1.5 (p = 0.030) and 2.9% (p < 0.0001), respectively, but responses were cultivar dependent. Given annual environmental variability, a general lack of field information regarding field history of pathogens or insects, and the high turnover rate of soybean cultivars, soybean seed treatments can be a cost‐effective component to integrate into soybean production systems.
Maize Water Use in Living Mulch Systems with Stover Removal
Authors: Wiggans Dustin R. , Singer Jeremy W. , Moore Kenneth J. , Lamkey Kendall R.
Published: December 2011

Constraints to maize (Zea mays L.) stover biomass harvest may be mitigated by using a living mulch (LM) to offset C exports and control soil erosion. Living mulches can compete with the main crop for resources, particularly water. The objectives of this research were to quantify soil water dynamics and maize water use in continuous maize with stover removal. Continuous soil water content (SWC) and reproductive whole‐plant water use were measured in no‐till maize growing in LMs of creeping red fescue (CF) (Festuca rubra L.), Kentucky bluegrass (KB) (Poa pratensis L.), and a no‐LM control between 2008 and 2010 near Ames, IA. In 2 yr with excessive rainfall (2008 and 2010), LMs increased SWC compared to the control at 15 cm. No‐till LM treatments lowered grain yield in 2008 and 2010 compared to the control, although a KB fall strip‐till treatment, which was part of the larger research study, produced yields that were not different than the control all 3 yr. Reproductive water use efficiency for no‐till KB in 2008 and 2009 (51 and 42 g grain per cm water) was 21 and 14% greater than the control (42 and 37) but 24% lower in 2010 (41 vs. 51). Maize water use in the control exhibited a bimodal response averaged across the 3 yr with peak water use occurring at the R1 through R2 period (0.58 cm d−1) and declining to 0.26 cm d−1 during R5 through R6. In contrast, no‐till KB exhibited a simple negative linear relationship with water use rates declining from a high of 0.47 cm d−1 during the R1 through R2 period to 0.22 cm d−1 during R5 through R6. These results indicate LMs may increase SWC and utilize water more effectively, particularly when combining strip‐till and herbicide management.
Summer Percent Green Cover among Kentucky Bluegrass Cultivars, Accessions, and Other Poa Species Managed under Deficit Irrigation
Authors: Bushman B. Shaun , Waldron Blair L. , Robins Joseph G. , Bhattarai Kishor , Johnson Paul G.
Published: December 2011

Kentucky bluegrass (Poa pratensis L.) is a widely used, high‐quality, sod‐producing turfgrass. To maintain an acceptable level of quality and function requires irrigation in the semiarid regions of the western United States. Landscape water use, however, is coming under increased scrutiny, and reducing water inputs is a goal of many municipalities. To identify Poa germplasm that maintains green color under deficit irrigation over summer seasons, this study was designed to evaluate the percent of green cover of 24 Kentucky bluegrass cultivars, accessions (including core collections), and other Poa species. Cultivars generally had a higher percent green cover in spring and fall, while several accessions and old U.S. cultivars showed higher green cover during summer months. Other Poa species did not have percent green cover values above any cultivars and as a group consistently performed the lowest. Core collections of Kentucky bluegrass, aimed at representing overall variability of the species with fewer accessions, had variance estimates equal to or higher than the overall group of accessions. Seven cultivars and accessions consistently had higher percent green cover than the Midnight cultivar check during the August data collection dates, highlighting the potential to improve Kentucky bluegrass green cover over summer seasons under deficit irrigation.
Facile synthesis of bis(indolyl)methanes using iron(III) phosphate
Authors: Behbahani Kargar , Sasani Masoumeh
Published: December 2011

A new, convenient and high yielding procedure for the preparation of
bis(indolyl)methanes in glycerol by electrophilic substitution reaction of
indole with aldehydes in the presence of catalytic amount of FePO4 (5.0
mol%) as a highly stable and reusable catalyst is described.
Fractionation of soil phosphorus in a long-term phosphate fertilization
Authors: Amaizah Nasser , Cakmak Dragan , Saljnikov Elmira , Roglic Goran , Mrvic Vesna , Krgovic Rada , Manojlovic Dragan
Published: December 2011

The changes in inorganic and organic phosphorus (P) fractions of soil
resulting from long-term fertilization (40 years) were investigated. In
order to improve understanding of the sink and sources of phosphorus,
P-fractions were extracted from soil samples of 0-30 and 30-60 cm depth with
different amounts of monoammonium-phosphate (MAP) and then determined.
Stagnosol was the type of the studied soil. Phosphate fertilizer was applied
in 26, 39 and 52 kgP/ha amounts during the period of 40 years. Samples were
subjected to sequential extraction according to the modified Chang and
Jackson method and BCR (Community Bureau of Reference) sequential extraction
procedure in order to extract different forms of phosphorus. The Certified
Reference material CRM 684 (River Sediment Extractable Phosphorus) was used
to provide accuracy of the instrument and both used methods. Furthermore,
the association of phosphorus with substrates was provided by comparison of
the results of sequential methods of phosphorus species with the sequential
extraction of metals (Fe, Al, Mn and Ca). Results of continuous
fertilization during 40 years indicated the increase of all the phosphorus
forms in the soil except of phosphorus bound to calcium and organic
phosphorus. Application of higher amounts of P-fertilizer resulted in
dominance of Al-P fraction in studied soil which indicated that this
fraction was the most responsible for the migration of phosphorus along the
soil profile.