bluuebunny/crossref_metadata_2025_split huggingface dataset:
Transplanting Native Plants to Revegetate Abandoned Farmland in the Western Mojave Desert
Authors: Grantz David A. , Vaughn David L. , Farber Robert J. , Kim Bong , Ashbaugh Lowell , VanCuren Tony , Campbell Rich , Bainbridge David , Zink Tom 
Published: July 2010

AbstractNursery‐grown, native plant species have potential application for revegetating disturbed arid and semiarid lands. We evaluated nursery‐grown fourwing saltbush [Atriplex canescens (Pursh) Nutt.], allscale saltbush [A. polycarpa (Torrey) S. Watson], bladderpod (Isomeris arborea Nutt.), honey mesquite [Prosopis glandulosa Torrey var. torreyana (L. Benson) M. Johnston], and rubber rabbitbrush [Chrysothamnus nauseosus (Pallas) Britton] transplanted to abandoned agricultural land throughout the western Mojave Desert. Two types of temporary plant enclosure for herbivory and environmental protection (plastic cones and wire cages) and three mulch treatments (straw, bark, and none) were tested at all six sites. Rubber rabbitbrush was difficult to propagate in the nursery and is not recommended for transplanting. Significant differences in plant performance occurred between sites with similar aerial environments but contrasting degrees of edaphic disturbance. Plastic cones were significantly superior to wire cages for plant vigor and survival but no differences were detected between mulch treatments. Fourwing saltbush was generally successful over all treatments and sites and is recommended for transplanting in this area. In a larger plot study, narrow augered holes led to superior survival of honey mesquite relative to wide, hand‐dug holes, and plastic cones were superior to wire cages. Mortality of all species was high due to dry, but not atypical, weather during the 2 yr of the study. We conclude that transplanting without intensive irrigation does not guarantee survival of even the most successful species. Its greater cost relative to direct seeding may not be warranted for large‐scale restoration of arid and semiarid environments.
Airborne Elements, Cell Membranes, and Chlorophyll in Transplanted Lichens
Authors: Garty J. , Cohen Y. , Kloog N. 
Published: July 2010

AbstractThe objective of the present study was to test the concentration of airborne mineral elements in the lichen Ramalina lacera (With.) J.R. Laund. in comparison with its physiological status. Thalli of Romalina lacera were collected in a remote unpolluted site and transplanted in a polluted region for 10 mo. An analysis of 20 elements in addition to an analysis of the status of cell membranes and the integrity of chlorophyll was performed after this period of transplantation. The lichen manifested a great potential for the accumulation of Pb, V, Ni, Zn, and Cu. Potassium and P were found to leach out. High concentrations of Ni, Mg, and B coincided with damage caused to cell membranes. The integrity of chlorophyll correlated with the concentration of K and correlated inversely with the concentration of Cr, Fe, Mn, Ni, Pb, and B.
Soil‐Climate Effects on Nitrate Leaching from Cattle Excreta
Authors: Stout W. L. , Gburek W. J. , Schnabel R. R. , Folmar G. J. , Weaver S. R. 
Published: July 2010

AbstractManagement intensive grazing (MIG) is a grazing system in which animals at a high stocking density are rotated through several paddocks at short time intervals (12–24 h) so that animal performance is maximized. Although MIG has the potential to increase dairy farm profitability in the northeast USA, recent work in this region has shown that a substantial amount of N recycled through urine is leached below the root zone. How soil properties, particularly water‐holding capacity, can affect NO3‐N leaching from beneath urine and feces spots under the climatic conditions of the northeast USA is not known. We conducted a field study to measure NO3‐N leaching loss from spring‐, summer‐, and fall‐applied urine and summer applied feces beneath N‐fertilized orchardgrass (Dactyls glomerata L., cv. Pennlate) using large drainage lysimeters installed in two soils that differed greatly in soil water storage capacity. The study sites were located in central Pennsylvania on a Hagerstown silt loam soil (fine, mixed, mesic Typic Hapludalf) and a Hartleton channery silt loam (loamy‐skeletal, mixed, mesic Typic Hapludult). Compared to the Hagerstown soil, the Hartleton soil provided an 85% decrease in plant N uptake, a 52% increase in leachate volume, but no significant increase in NO3‐N leaching beneath urine spots. However, the lower soil water‐holding capacity of the Hartleton soil caused the NO3‐N leaching losses to be more evenly distributed over the year.
Herbicide Distribution and Variability Across Goodwater Creek Watershed in North Central Missouri
Authors: Donald W. W. , Hjelmfelt A. T. , Alberts E. E. 
Published: July 2010

AbstractOne objective of the Missouri Management Systems Evaluation Area was to monitor and assess surface water quality, including spatial and temporal variability in herbicide concentrations within the 7250 ha Goodwater Creek Watershed. Stream water was sampled at all stream‐road intersections across the watershed on 10 occasions in 1993 and 1994. Maps of herbicide distribution established that widespread, seasonal contamination of streams in Goodwater Creek Watershed was due to nonpoint sources (e.g., widespread, but normal farm use) rather than from point sources. Box plots documented concentration variability over time. Concentrations of atrazine (2‐chloro‐4‐ethylamino‐6‐isopropylamino‐s‐triazine), deethylatrazine [2,4‐diamino‐6‐chloro‐N‐(1‐methylethyl)‐1,3,5‐triazine], deisopropylatrazine [2,4‐diamino‐6‐chloro‐N‐ethyl‐1,3,5‐triazine], and metolachlor [2‐chloro‐N‐(2‐ethyl‐6‐methylphenyl)‐N‐(2‐methoxy‐1‐methylethyl)acetamide] were also monitored at least weekly from 1993 to 1994 at three V‐notch weirs through which 16.7, 43.4, and 100% of the watershed drained. Atrazine, deethylatrazine, and metolachlor were detected year round at concentrations above 0.1 µg/L. Atrazine concentrations observed at weirs were occasionally >100 µg/L and were similar to edge‐of‐field concentrations observed elsewhere shortly after spraying in May to June, probably because the watershed's poorly drained, silt loam soils contain a restrictive claypan horizon that limits infiltration and encourages surface runoff.
Nitrate Losses from a Corn‐Alfalfa Rotation: Lysimeter Measurement of Nitrate Leaching
Authors: Toth John D. , Fox Richard H. 
Published: July 2010

AbstractAn array of 18 zero‐tension pan lysimeters installed 1.2 m below the soil surface in 1988 was used to examine NO3 leaching in 1991 to 1995. The experiment was designed to study NO3 losses from continuous, fertilized corn, alfalfa, and the first year of corn rotated from alfalfa as a function of crop type, applied N fertilizer rate and longer‐term weather variability. The flow‐weighted mean leachate NO3‐N concentration from the 3‐yr alfalfa stand was 4 mg L−1. Annual leachate NO3‐N concentrations from continuous, fertilized corn and corn following alfalfa at the estimated Economically Optimum N (EON) rate averaged 15 mg L−1. Annual flow‐weighted average NO3‐N concentrations in leachate from post‐alfalfa corn receiving 50 and 100 kg N ha−1, which were above the EON rate, were 18 and 24 mg L−1, respectively. The masses of NO3‐N leached from the root zone of continuous corn at the estimated EON rate were 81 and 55 kg ha−1 in 1991 to 1992 and 1994 to 1995, respectively. Nitrate‐N losses from alfalfa in 1991 to 1992 were 9 kg ha−1. Nitrate concentrations in leachate from an alfalfa stand were one‐quarter to one‐fifth as high as from corn receiving the EON rate. This research provides evidence that including alfalfa in a rotation would result in a considerable reduction in the amount of NO3 leaving a farm in leachate.
How Humic Substances Dominate Mercury Geochemistry in Contaminated Floodplain Soils and Sediments
Authors: Wallschläger Dirk , Desai Madhukar V. M. , Spengler Markus , Windmöller Cláudia Carvalhinho , Wilken Rolf‐Dieter 
Published: July 2010

AbstractThe interaction of mercury (Hg) and humic substances (hs) was studied in floodplain topsoils and surface sediments of the contaminated German river Elbe. An intimate coupling exists between the geochemical cycles of Hg and organic carbon (OC) in this ecosystem. Humic substances exert a dominant influence on several important parallel geochemical pathways of Hg, including binding, transformation, and transport processes. Significant differences exist between the Hg‐hs associations in floodplains and sediments. Both humic acids (ha) and fulvic acids (fa) contribute to Hg binding in the sediments. In contrast, ultrafiltration experiments proved that Hg in the floodplain soils is almost exclusively bound to very large humic acids (ha) with a nominal molecular weight (MW) >300 000. Successive cation and anion exchange experiments demonstrated that those Hg‐ha complexes are inert toward competition by other cations, and also apparently predominantly electroneutral. Speciation transformation reactions in the solid phase were investigated by sequential extraction and thermal release experiments. Upon addition of Hg model compounds to a sediment matrix, all species were transformed to the same new speciation pattern, regardless of their original speciation. The accompanying alterations in availability and solubility were partially due to interconversion between the different Hg redox states, including Hg(I). Simultaneously, partial transformation of added Hg2+ into volatile Hg compounds (35% in 10 d) was observed. Finally, Hg association with water‐soluble ha continuously increased downstream, indicating that hs play a key role in both lateral and longitudinal Hg transport in the Elbe ecosystem.
The Phytoavailability of Cadmium to Lettuce in Long‐Term Biosolids‐Amended Soils
Authors: Brown Sally L. , Chaney Rufus L. , Angle J. Scott , Ryan James A. 
Published: July 2010

AbstractA field study was conducted to assess the phytoavailability of Cd in long‐term biosolids‐amended plots managed at high and low pH. The experiment, established 13 to 15 yr prior to the present cropping, on a Christiana fine sandy loam soil (a clayey, kaolinitic, mesic Typic Paleudult) used a variety of biosolids. Two of the biosolids had total Cd concentrations of 13.4 and 210 mg kg−1. A Cd salt treatment, with Cd added to soil at a rate equivalent to the Cd added by the higher Cd biosolids applied at 100 Mg ha−1, was also included. The lettuce (Lactuca sativa var. longifolia) cultivar (Paris Island Cos) used in the initial study was also used in the current study. Lettuce Cd was compared between treatments, and in relation to the soil Cd/soil organic C (OC) ratio. There has been no significant increase in plant Cd since the initial cropping. With 16% of the biosolids added OC remaining, lettuce grown on the soil amended with the more contaminated biosolids was not different than that of the initial cropping. Further, significantly less Cd was taken up by lettuce grown on biosolids‐amended soil than lettuce grown on soil amended with equivalent rates of Cd salt. The Cd concentration in lettuce grown in the low Cd biosolids treatment was not different from the control. These results indicate that the potential hazards associated with food chain transfer of biosolids‐applied Cd are substantially lower than equivalent Cd salt treatments, and that the hazards do not increase over time.
Constrained Optimization of Spatial Sampling using Continuous Simulated Annealing
Authors: van Groenigen J. W. , Stein A. 
Published: July 2010

AbstractSpatial sampling is an important issue in environmental studies because the sample configuration influences both costs and effectiveness of a survey. Practical sampling constraints and available preinformation can help to optimize the sampling scheme. In this paper, spatial simulated annealing (SSA) is presented as a method to optimize spatial environmental sampling schemes. Sampling schemes are optimized at the point‐level, taking into account sampling constraints and preliminary observations. Two optimization criteria have been used. The first optimizes even spreading of the points over a region, whereas the second optimizes variogram estimation using a proposed criterion from the literature. For several examples it is shown that SSA is superior to conventional methods of designing sampling schemes. Improvements up to 30% occur for the first criterion, and an almost complete solution is found for the second criterion. Spatial simulated annealing is especially useful in studies with many sampling constraints. It is flexible in implementing additional, quantitative criteria.
Greenhouse Gas Fluxes following Tillage and Wetting in a Wheat‐Fallow Cropping System
Authors: Kessavalou Anabayan , Doran John W. , Mosier Arvin R. , Drijber Rhae A. 
Published: July 2010

AbstractLittle is known about the relative contributions of episodic tillage and precipitation events to annual greenhouse gas emissions from soil. Consequently, we measured carbon dioxide (CO2), nitrous oxide (N2O), and methane (CH4) fluxes from soil in wheat‐fallow cropping system in western Nebraska using vented surface chambers, before and immediately after tillage and wetting with 5.1 cm of water, during the fallow period in 1995/1996. Replicated fallow management treatments included no‐tillage, subtillage, and plow representing a wide range in degree of soil disturbance. Soil bulk density, water‐filled pore space, electrical conductivity (EC1:1), nitrate (NO3), and pH within the top 30.5 cm soil, and soil temperature at 0 to 7.6 cm were measured to assess their correlation with variations in gas flux and tillage and wetting. Atmospheric concentrations above the soil (at ~40 cm) increased by 15% for CO2 and 9 to 31% for N2O and 6 to 16% for CH4 within 1 min after tillage and returned to background concentrations within 2 h. Except immediately after tillage, net CH4 flux was negative, from the atmosphere into soil, and is referred to as CH4 uptake. Overall, increases (1.5–4‐fold) in CO2 and N2O losses from soil, and CH4 uptake by soil were short lived and returned to background levels within 8 to 24 h after tillage. Losses of CO2 and N2O increased to 1.7 and 5 times background emissions, respectively, for 24 h following wetting, while CH4 uptake declined by about 60% for 3 to 14 d after wetting. Water‐filled pore space in the surface soil fell below 60% within 24 h after saturation and exhibited an inverse relationship (R2 = 0.66) with CH4 uptake. A significant decline in soil NO3 and EC1:1 in the top 7.6 cm occurred following wetting. Under our experimental conditions, and the expected frequency of tillage and wetting events, failure to include these short‐lived episodic gas pulses in annual flux estimations may underestimate annual CO2 and N2O loss up to 13 and 24%, respectively, and overestimate CH4 uptake by up to 18% in this cropping system.
Biopore Mediated Subsurface Transport of Dissolved Orthophosphate
Authors: Jensen Marina Bergen , Jørgensen Peter R. , Hansen Hans Christian Bruun , Nielsen Niels Erik 
Published: July 2010

AbstractLeaching of phosphorous (P) from structured agricultural soil may cause eutrophication of receiving fresh waters. Especially subsurface storm flows seem capable of subsurface transfer of surface‐located P. We used 32P‐autoradiography to trace preferential pathways supporting dissolved orthophosphate (Pi) transport through an undisturbed column of water‐saturated clayey subsoil (Aerie Giossaqualf, 0.48 m diam., height 0.73 m, water content 50.2 L). At a flow rate near the saturated hydraulic conductivity (Ksat) of the column, a pulse of 32P was applied to the column surface. To stain the water flow paths a pulse of Brilliant Blue dye was applied afterwards. Upon drainage, hyperfilms sensitive to 32P‐radiation were exposed horizontally at four depths within the upper 15 cm; below this depth a Geiger‐Müller detector showed no increased radioactivity. The 32P‐sorption pattern appearing on the hyperfilms consisted of discrete, circular spots, which coincided with the position of larger biopores (diam. >3 mm). In contrast, the water infiltration pattern depicted by the dye tracer was not restricted to biopores, but covered much larger areas of the column cross sections. Solute transport was further characterized by analyzing breakthrough curves of pulse‐applied 32P and tritium. The results of the study suggest that only macropores with wide apertures can provide the necessary conditions for vertical long distance transport of Pi through structured soil. Estimates suggest the rate‐limiting step of the Pi‐sorption process to be the diffusion from central stream tubes to sorption sites at macropore wall. Nonequilibrium caused by this sorption barrier is termed macropore nonequilibrium (MNE).
Spatial and Temporal Variations in Nitrate Contamination of a Rural Aquifer, California
Authors: Williams A. E. , Johnson J. A. , Lund L. J. , Kabala Z. J. 
Published: July 2010

AbstractThe quality of ground water in the Sierra Pelona watershed, California is examined as an example of a small rural groundwater basin in a mountainous area of arid climate. Water quality in this region has been seriously impacted by nitrate (NO3) contamination with 42% of wells sampled exceeding the EPA public drinking water maximum contaminant level (MCL) of 10 mg/L as NO3‐N at some point during 1992–1993. High NO3‐N concentrations reported from this region suggest degradation of water quality due to anthropogenic activity. Dissolved ion concentrations, particularly NO3, chloride and calcium varied radically in 55% of well waters sampled prior to, following, and months after an unusually wet winter. Our extensive well sampling program, chemical results and delineation of spatial and temporal NO3‐N variation allow us to constrain possible contamination sources and transport mechanisms active in the Sierra Pelona basin. The spatial distribution and temporal variability of NO3 indicate three patterns of contamination: (i) isolated wells impacted by numerous, localized NO3 sources which erratically affect a single well without significantly contaminating neighboring ones; (ii) a tight cluster of wells, unusually low in other ions but consistently high in NO3; (iii) moderate and generally consistent NO3 concentrations, found over a large, diffuse region of the Sierra Pelona alluvial aquifer. An understanding of the differing NO3 source(s) and contamination mode(s) that contribute to these observed contaminant patterns is critical to development and success of any strategy for contaminant mitigation and/or remediation.
Nitrogen and Phosphorus in Surface Runoff and Sediment from a Wheat‐Pea Rotation in Northeastern Oregon
Authors: Douglas C. L. , King K. A. , Zuzel J. F. 
Published: July 2010

AbstractRunoff and erosion from cultivated fields are suggested as major sources of nitrogen (N) and phosphorus (P) entering lakes and streams. Loss of these nutrients can be impacted by soil and crop management practices. There is relatively little information on nutrients leaving agricultural fields in the dryland areas of the Pacific Northwest, especially as impacted by different crops and crop rotations. Nutrients in surface runoff and soil leaving a series of plots in northeast Oregon were evaluated for 5 yr. Objectives were to evaluate the effects of a wheat‐pea (Triticum aestivium L.‐Pisum sativum L.) rotation on N and P in surface runoff and eroded soil. Cumulative N and P lost in runoff were less than 3 and 0.2 kg ha−1, respectively. Total N lost from continuous fallow (CF) plots, even though they were never fertilized, ranged from 20 to 100 kg ha−1 yr−1. This was much more N than was lost from winter wheal (WW) (5–70 kg ha−1 yr−1) and spring pea (SP) (25–40 kg h−1 yr−1), because there was much more sediment loss from CF than from WW or SP plots. The same scenario occurred with P as with N, with loss from CF of 8 to 48 kg ha−1 yr−1, WW of 2 to 28 kg ha−1 yr−1, and from SP of 8 to 16 kg ha−1 yr−1. All fertilizer was surface‐applied and 25 to 76% of the fertilizer applied was lost in 5 yr, depending on the time of fertilizer application and the type of crop growing. Nutrient loss from these fields can be controlled by controlling soil erosion.
Evaluation of a Stepwise Procedure for Comparative Validation of Pesticide Leaching Models
Authors: Thorsen Mette , Jørgensen Peter R. , Felding Gitte , Jacobsen Ole H. , Spliid Niels H. , Refsgaard Jens Christian 
Published: July 2010

AbstractFour pesticide leaching model codes (PELMO, PESTLA, MACRO, and MIKE SHE) were evaluated and compared through a rigorous validation procedure combined with the application of statistical evaluation criteria. The validation procedure followed a strict Stepwise approach based on suggestions put forward by a European work group on regulatory use of pesticide models (FOCUS). The experimental background comprised two different types of data sets. A laboratory and field lysimeter experiment were conducted on a Danish macroporous sandy loam soil. The aim of the study was to evaluate whether a priori model calibration on controlled laboratory data could improve the physical description of the flow and solute transport in the soil and hence the performance of uncalibrated models for predictions of field lysimeter data. The validation procedure proved to be valuable in terms of ensuring process‐based evaluation of model performances and consistent model comparisons. Controlled laboratory experiments and lysimeter experiments consistently showed very significant influence of preferential flow on water and solute transport. Model codes including a description of preferential flow processes (MACRO and MIKE SHE) required less calibration efforts to meet the selected performance criteria on the investigated soil type than those without such description (PELMO and PESTLA).
Seeding Native Plants to Restore Desert Farmland and Mitigate Fugitive Dust and PM10
Authors: Grantz David A. , Vaughn David L. , Farber Rob , Kim Bong , Zeldin Mel , VanCuren Tony , Campbell Rich 
Published: July 2010

AbstractWindblown fugitive dust contributes to violations of air quality standards for particulate matter <10 pm aerodynamic diameter (PM10). In the western Mojave Desert of California, approximately 1070 ha of previously filled or over‐grazed land impacted downwind metropolitan areas by wind‐driven emissions of dust. A protocol of furrowing across the wind and direct seeding of three native perennial shrubs and a bunch grass helped reduce fugitive dust emissions in this area by more than 95%. Seeded species varied from 35 to 97% of living plant cover in individual years, reflecting rainfall patterns. In areas of deep sand, Indian ricegrass (Achnatherum hymenoides Roemer & Shultes) outperformed the shrubs, while fourwing saltbush [Atriplex canescens (Pursh) Nutt.] exhibited the most widespread establishment. This revegetation was achieved in an anomalous year with above average and late rainfall that eliminated early competition from annual species and later fostered abundant shrub growth. This success was not reproducible in more normal years, when minimal disturbance protocols such as broadcasting of seed on the untilled soil surface were as effective and less costly. We conclude: (i) direct seeding can lead to plant establishment in favorable years, but is likely to fail in any given year, (ii) direct seeding should be implemented with little soil disturbance, (iii) the native fourwing saltbush is the most likely species to become established in this environment, and (iv) unpredictable rainfall and temperature require that direct seeding be backed up with alternative strategies to achieve reliable dust and PM10 mitigation in arid environments.