Miracle-dz/UniFAR-FTUs huggingface dataset:
The effects of cultivation on the composition of organic matter and structural stability of soils

Soil samples were obtained from the surface horizons of five untilled sites and adjacent sites under short- and long-term cultivation. The soil samples were fractionated based on density and organic materials were concentrated in various fractions which enabled comparative chemical composition of the organic materials in cultivated and uncultivated sites by solid-state C-13 CP/MAS NMR spectroscopy. Changes in the nature of organic carbon with cultivation were different in different soils and resulted from variations in the chemistry of carbon inputs to the soils and a greater extent of decomposition of organic materials in cultivated soils. Differences in the chemical composition of organic carbon between cultivated and uncultivated soils resided mostly in organic materials occluded within aggregates, whereas the chemistry of organic matter associated with clay particles showed only small changes. The results indicate a faster decomposition of O-alkyl C in the cultivated soils. Wet aggregate stability, mechanically dispersible clay and modulus of rupture tests were used to assess the effects of cultivation on structural stability of soils. In four of five soils, the virgin sites and sites which had been under long-term pasture had a greater aggregate stability than the cultivated sites. Neither total organic matter nor total O-alkyl C content was closely correlated with aggregate stability, suggesting that only a part of soil carbon or carbohydrate is involved in aggregate stability. The fractions of carbon and O-alkyl C present in the form of particulate organic matter occluded within aggregates were better correlated with aggregate stability (r = 0.86** and 0.88**, respectively). Cultivation was not the dominant factor influencing water-dispersible clay across the range of soil types used in this study. The amount of dispersible clay was a function of total clay content and the percentage of clay dispersed was controlled by factors such as clay mineralogy, CaCO3 and organic matter content of soils. The tendency of different soils for hard-setting and crusting, as a result of structural collapse, was reflected in the modulus of rupture (MOR). The cultivated sites had significantly higher MOR than their non-tilled counterparts. The soils studied had different MOR due to differences in their physical and chemical properties.
Aircraft measurements of the latitudinal, vertical, and seasonal variations of NMHCs, methyl nitrate, methyl halides, and DMS during the First Aerosol Characterization Experiment (ACE 1)

Canister sampling for the determination of atmospheric mixing ratios of nonmethane hydrocarbons (NMHCs), selected halocarbons, and methyl nitrate was conducted aboard the National Center for Atmospheric Research (NCAR) C-130 aircraft over the Pacific and Southern Oceans as part of the First Aerosol Characterization Experiment (ACE 1) during November and December 1995. A latitudinal profile, flown from 76°N to 60°S, revealed latitudinal gradients for most trace gases. NMHC and halocarbon gases with predominantly anthropogenic sources, including ethane, ethyne, and tetrachloroethene, exhibited significantly higher mixing ratios in the northern hemisphere at all altitudes. Methyl chloride exhibited its lowest mixing ratios at the highest northern hemisphere latitudes, and the distributions of methyl nitrate and methyl iodide were consistent with tropical and subtropical oceanic sources. Layers containing continental air characteristic of aged biomass burning emissions were observed above about 3 km over the remote southern Pacific and near New Zealand between approximately 19°S and 43°S. These plumes originated from the west, possibly from fires in southern Africa. The month-long intensive investigation of the clean marine southern midlatitude troposphere south of Australia revealed decreases in the mixing ratios of ethane, ethyne, propane, and tetrachloroethene, consistent with their seasonal mixing ratio cycle. By contrast, increases in the average marine boundary layer concentrations of methyl iodide, methyl nitrate, and dimethyl sulfide (DMS) were observed as the season progressed to summer conditions. These increases were most appreciable in the region south of 44°S over Southern Ocean waters characterized as subantarctic and polar, indicating a seasonal increase in oceanic productivity for these gases.
The vertical distribution of BrO and aerosols in the Arctic: Measurements by active and passive differential optical absorption spectroscopy

[1] We present results from multiaxis differential optical absorption spectroscopy (MAX-DOAS) and long-path DOAS (LP-DOAS) measurements performed at the North Slope of Alaska from February to April 2009 as part of the Ocean-Atmosphere-Sea Ice-Snowpack Barrow 2009 campaign. For the first time, vertical profiles of aerosol extinction and BrO in the boundary layer were retrieved simultaneously from MAX-DOAS measurements using the method of optimal estimation. Even at very low visibility, retrieved extinction profiles and aerosol optical thickness are in good agreement with colocated ceilometer and Sun photometer measurements, respectively. BrO surface concentrations measured by MAX-DOAS and LP-DOAS are in very good agreement, and it has been found that useful information on the BrO vertical distribution can be retrieved from MAX-DOAS even in cases when blowing snow strongly reduces visibility. The retrieved BrO and extinction vertical profiles allow for a thorough characterization of the vertical structure of the boundary layer during numerous ozone depletion events observed during Barrow 2009. High BrO concentrations are usually present during the onset of ozone depletion events, and BrO disappears as ozone concentrations approach zero. The finding that elevated BrO concentrations occur mainly in the presence of high extinction near the surface strongly suggests that release of reactive bromine from airborne aerosols and/or ice particles at high wind speed plays an important role. Back trajectory calculations indicate that the particles were transported from the frozen ocean to the measurement site and that the release of reactive bromine from sea ice and/or frost flowers occurs when low temperatures (<250 K) prevail in the regions where reactive bromine is emitted.
Microbial biomass and activities in soil aggregates affected by winter cover crops

Winter cover crops may increase soil organic matter (SOM) and improve soil structure in intensively managed summer vegetable cropping systems. Our study examined the influence of three cover crop treatments (fallow, cereal, and legume within a summer crop rotation of sweet corn and broccoli) on microbiological properties associated with five soil aggregate-size classes (<0.25, 0.25 to 0.5, 0.5 to 1.0, 1.0 to 2.0, and 2.0 to 5.0 mm) of a Willamette silt loam (Pachic Ultic Argixerolls), The distributions of total organic C (TOC), total Kjeldahl N (TKN), soil microbial biomass C (SMBC), readily mineralizable C and N, and two enzyme activities (β-glucosidase and fluorescein diacetate [ FDA] hydrolysis) were compared among aggregate-size classes of surface (0-20 cm) soils at seedbed preparation (June 1996) and after harvest of either broccoli (September 1995) or sweet corn (September 1996). Although cover cropping did not significantly influence aggregate-size distribution, TOC, nor TKN on any sampling date, it did significantly (P < 0.05) influence SMBC in September 1995, mineralizable C and N and FDA hydrolysis and β-glucosidase activities in June 1996, and levels of mineralizable C and N and β-glucosidase activity in September 1996. Significant (P < 0.01) interactions occurred among the cover crop treatments and aggregate-size classes for SMBC in September 1995, and among mineralizable C and N and FDA hydrolysis in June and September 1996. Mineralizable C and N and FDA hydrolysis differed (P < 0.01) among aggregate-size classes between June and September 1996: these changes were significantly (P < 0.01) affected by cover crop treatment. These studies identified focal points for further research on the effects of aggregate-size classes and cover cropping on the activities and dynamics of their respective microbial communities.
Seed Size Effects on Seedling Emergence of Desert Psammophytes in China

To investigate the effects of seed size on the behavior of seeds and seedlings in sand, seedling emergence from sand was examined in Caragana korshinskii (Fabaceae; mean seed weight 65 mg) and Atraphaxis bracteata (Polygonaceae; mean seed weight 5.7 mg), two shrubs with nonphotoblastic seeds that grow on desert sand dunes in China. Seeds were sown at depths of 0 to 50 mm in sand-filled pots, and the pots were irrigated under different regimes. The results suggest that for both species, a high proportion of the seeds buried fairly deep germinate during the summer rainy season with or without producing emergent seedlings, whereas at shallow depths, where moisture is more likely to be lost by evaporation, some proportion of the seeds remain ungerminated and viable. Comparison of results in this study with those on several smaller-seeded species used in our previous studies shows that larger seeds did not always give rise to seedlings capable of emerging from deeper depths in sand. We suggested that for nonphotoblastic seeds, seed size is not a crucial determinant of the proportion of seeds that produce emergent seedlings in field conditions.
Wet deposition of major ions and trace elements in the eastern Mediterranean basin

Elemental and ionic composition of the eastern Mediterranean precipitation was determined on the Mediterranean coast of Turkey between January 1992 and January 1994. Measured concentrations were comparable with the concentrations reported from other rural stations. Concentrations of elements and ions show strong short-term and well-defined long-term variations. Short-term variations are due to transport from different source areas whereas long-term (seasonal) variations are governed by the seasonal changes in the wet removal of particles during their transport from source areas to the eastern Mediterranean region. The most important characteristic of the precipitation in the eastern Mediterranean region is the extensive neutralization of acidity by the airborne CaCO3 particles from soil. Wet deposition fluxes of elements and ions are smaller than the fluxes reported from other rural stations owing to small annual rainfall in the region. Except for soil-related elements, wet deposition fluxes of all elements are significantly higher in the winter season. Annual wet deposition fluxes are highly episodic, with only 10–20 of the samples accounting more than 50% of annual fluxes for most of the measured elements and ions.
Permafrost thermal state in the polar Northern Hemisphere during the international polar year 2007–2009: a synthesis

The permafrost monitoring network in the polar regions of the Northern Hemisphere was enhanced during the International Polar Year (IPY), and new information on permafrost thermal state was collected for regions where there was little available. This augmented monitoring network is an important legacy of the IPY, as is the updated baseline of current permafrost conditions against which future changes may be measured. Within the Northern Hemisphere polar region, ground temperatures are currently being measured in about 575 boreholes in North America, the Nordic region and Russia. These show that in the discontinuous permafrost zone, permafrost temperatures fall within a narrow range, with the mean annual ground temperature (MAGT) at most sites being higher than −2°C. A greater range in MAGT is present within the continuous permafrost zone, from above −1°C at some locations to as low as −15°C. The latest results indicate that the permafrost warming which started two to three decades ago has generally continued into the IPY period. Warming rates are much smaller for permafrost already at temperatures close to 0°C compared with colder permafrost, especially for ice‐rich permafrost where latent heat effects dominate the ground thermal regime. Colder permafrost sites are warming more rapidly. This improved knowledge about the permafrost thermal state and its dynamics is important for multidisciplinary polar research, but also for many of the 4 million people living in the Arctic. In particular, this knowledge is required for designing effective adaptation strategies for the local communities under warmer climatic conditions. Copyright © 2010 John Wiley & Sons, Ltd.
Bathymetric and isotopic evidence for a short-lived Late Ordovician glaciation in a greenhouse period

The end Ordovician glaciation is distinct among Phanerozoic glaciations in that CO 2 , levels were generally high, yet major continental ice sheets accumulated on the Gondwana supercontinent. New oxygen isotopic data indicate substantial changes in sea-water temperatures and ice volume coinciding with glacio-eustatic changes in sea level reflecting the growth and decay of the Gondwana ice cap. Major glaciation was apparently confined to the Hirnantian and was 0.5-1 m.y. long, rather than the 35 m.y. of earlier estimates. Carbon isotope values indicate significant changes in carbon cycling as the oceans changed from a state with warm saline bottom waters to a state with cold deep-water circulation and then back again. We believe that the changes in the carbon cycle effected a reduction in P CO 2 levels in the oceans and atmosphere and thus promoted glaciation but were unable to sustain icehouse conditions in a greenhouse world.
Kinetics of the reaction H2O + O = 2OH in rhyolitic and albitic glasses: Preliminary results

Abstract The kinetics of homogeneous reactions are important in understanding the cooling history of rocks and in understanding experimental speciation data. We have experimentally studied the kinetics of the interconversion reaction between H2O molecules and OH groups in natural rhyolitic glasses (0.5-2.3% total water) and a synthetic albitic glass (1 % total water) at 400-600 °C. The reaction rate increases with temperature and total water content. Equilibrium is not always approached monotonically; the speciation may first depart from equilibrium and then come back to equilibrium. Experimental reaction rates agree with those inferred from previous speciation data of rhyolitic glasses quenched from 850°C. The experimental data are modeled successfully by considering both the reaction and the diffusion of OH that brings OH groups together to react. This study shows that species concentrations in glasses quenched from ≤600 °C reflect those at experimental temperatures unless the water content is higher than that used in the present study. Species concentrations in glasses with total water contents ≥0.8 wt% and which were rapidly quenched in water from 850°C do not represent their equilibrium concentrations in the melt at 850 °C, but record a lower apparent equilibrium temperature that depends on water content and quench rate. Natural rhyolitic glasses and glass inclusions do not record preeruptive melt speciation, though total water content may be conserved. The experimental data are used to infer cooling rates for natural obsidian glasses. Pyroclastic glass fragments from the bb site of Mono Craters have cooling rates similar to air-cooled experimental charges (~ 3 °C/s). Different types of glasses from the Mono Craters have different cooling rates, which cover four orders of magnitude. Some natural obsidians appear to have had complex cooling histories. The wide range of cooling rates and thermal histories is consistent with previous inferences that some obsidian clasts at the Mono Craters formed as glass selvages lining volcanic conduits or dikes that were subsequently caught up in the explosive eruption, which led to variable degrees of transient heating followed by rapid cooling and deposition. These experimental data reveal surprisingly rich detail in water speciation in volcanic glasses and show how, at least in principle, quantitative constraints on thermal histories can be extracted by experimentation and application of kinetic models.
Polar cap electric field structures with a northward interplanetary magnetic field

Polar cap electric fields patterns are presented from times when the S3-2 Satellite was near the dawn-dusk meridian and IMF data were available. With Bz ≥ 0.7 γ, two characteristic types of electric field patterns were measured in the polar cap. In the sunlit polar cap the convection pattern usually consisted of four cells. Two of the cells were confined to the polar cap with sunward convection in the central portion of the cap. The other pair of cells were marked by anti-sunward flow along the flanks of the polar cap and by sunward flow in the auroral oval. These observations are interpreted in terms of a model for magnetic merging at the poleward wall of the dayside polar cusp. The sunward flow in the auroral zone is not predicted by the magnetic model and may be due to a viscous interaction between the solar wind and magnetosphere. The second type, which was observed in some of the summer hemisphere passes and all of the winter ones, was characterized by an electric field pattern which was very turbulent, and may be related to inhomogeneous merging.
Long-term Climate Change: Projections, Commitments and Irreversibility

This chapter assesses long-term projections of climate change for the end of the 21st century and beyond, where the forced signal depends on the scenario and is typically larger than the internal variability of the climate system. Changes are expressed with respect to a baseline period of 1986–2005, unless otherwise stated.
Inferring D region parameters using improved incoherent scatter radar techniques at Arecibo

[1] With the increased sensitivity and bandwidth, Arecibo 430 MHz incoherent scatter radar was run on 23 July 2006 using two radar modes with a focus on measuring D region parameters. One mode measured the ion line spectra over D region altitudes; the other mode was used as a new way to calibrate the electron densities in the D region and also to correct the ion line spectra. The ion line primarily provided a power profile connecting the D region to altitudes where the plasma line is useful. The plasma line provided the absolute electron density, used in the lower altitudes for calibration, and at F region altitudes for determining the baseline level in the D region spectra due to the folding-in of F region scattered power. It is found that the electron line contribution is about 1–3 times the ion line between 60–75 km altitude ranges. Electron concentration was found to be in the range of a few hundred to 5000 cm−3 in the 65–90 km altitude range. The new technique agrees well with the previous measurements. The D region spectral widths were used to calculate the ratio of negative ion to electron concentration (λ). Between 0900 and 1100 LT, a 4 km thick layer of negative ions was observed with λ ∼ 1.6 ± 0.3 around 73–77 km. In the altitude range of 81–91 km, we inferred temperatures ∼ 195–215 K using ion-neutral collision frequencies determined from the spectral widths.
Site‐Specific Nitrogen Management of Irrigated Maize

Site-specific N management (SSNM) has been suggested as one means of further increasing the efficiency with which N fertilizers are used and reducing environmental impact. Field studies to evaluate the potential for SSNM to reduce NO 3 -N leaching from irrigated maize (Zea mays L.) were conducted from 1994 to 1997. Uniform management (UM) was compared with a SSNM strategy (variable rate technology, VRT) based on an existing N recommendation algorithm for maize using grid sampled soil organic matter and root zone soil residual NO 3 -N. A third treatment (reduced variable rate technology, RVRT) evaluated the potential for a reduced rate of N to adequately supply crop N demand when combined with variable rate application. Averaged across all site-years, there was no significant difference in the total amount of N applied, 142 kg N ha -1 with UM, 141 kg N ha -1 with VRT. Treatment mean grain yields ranged from 4.5 to 13.9 Mg ha -1 and were influenced relatively little by treatment, with VRT yield significantly reduced compared with UM in two site-years, and UM yield significantly reduced compared with VRT in one site-year. Treatment mean soil residual NO 3 -N in the 0.9-m root zone ranged from 2.7 to 14.0 mg kg -1 , and was low ( 6 mg kg -1 ), there were no significant differences between UM and VRT treatments, while RVRT treatment reduced residual NO 3 -N for three site-years. We conclude that the spatial application of the existing recommendation algorithm developed for uniform application may be inappropriate, at least for these sites, and that unique recommendation equations for major soils and climatic regions may be necessary to achieve substantial increases in N-use efficiency. This study also suggests that improved recommendation algorithms may often need to be combined with methods (such as remote sensing) to detect crop N status at early, critical growth stages followed by carefully timed, spatially adjusted supplemental fertilization to achieve optimum N-use efficiency.
Biochemical and Haematological Blood Parameters of Sows and Piglets Fed a Diet with a Dried Fermented Rapeseed Meal

Abstract Animal health and welfare can be assessed using biochemical and haematological markers of the blood. The values of these parameters depend in part on the quantity and quality of feed ingredients, i.e. feed protein and feed additives. The aim of the study was to determine the effect of including fermented rapeseed meal (FRSM) in dry feeding system on haematological and biochemical blood parameters of sows and piglets. The experimental material comprised 30 primiparous gilts and 30 multiparous sows after their second lactation. They were randomly divided into two groups of equal size – control and experimental. The animals in control groups CG (15 gilts) and CS (15 sows) received a standard diet for pregnant or lactating sows, depending on the reproductive period. Experimental groups EG and ES were 15 gilts and 15 multiparous sows, respectively, receiving feed with a 4% share of FRSM in place of soybean meal up to 100 d of gestation. In addition, from 100 d of gestation to 7 d of lactation, the sows in these groups received feed with a 9% share of FRSM, and then again a diet with a 4% share of FRSM until the end of lactation. Blood samples were taken from 6 animals from each group in two periods: at 100 days of pregnancy (late pregnancy) and at 27 days of lactation (late lactation). Blood from piglets was taken at 27 days of age (before weaning), from two piglets from each sow (one gilt and one barrow), taking into account the average body weight in the litter. Haematological parameters: Ht, Hb and RBC were determined in whole blood. The plasma content of minerals, activity of selected enzymes and biochemical parameters of sows, gilts and piglets were determined. The diet containing fermented rapeseed meal, fed to pregnant and lactating sows, increased the level of Ht and Hb and RBC content and mineral content (phosphorus, calcium and iron) in the plasma. This effect was mainly observed in primiparous sows. The inclusion of FRSM in the diet of sows reduced the plasma content of total cholesterol and triacylglycerols in sows and piglets, as well as liver enzyme activity, particularly AST in piglets. The use of fermented rapeseed meal in sow diet resulted in better use of mineral compounds, improvement of production effects and health parameters of sow and piglet blood.