95 research outputs found
The effect of soil and foliar boron fertilization on canola yield
Non-Peer ReviewedBoron represents one of the least studied micronutrients in prairie soils. Earlier studies had to contend with inefficient and often cumbersome chemistries for determination of this nutrient. The advent of ICP (Inductively Coupled Plasma Spectrometry) has allowed development of routine techniques for determination of low boron levels in soils. No calibration work has taken place in western Canada on boron. Hot-water extractable boron, initially developed by Berger and Truog (1939), and subsequently modified by Wear (1965) and Gupta (1979), still remains the prevalent method for assessing soil âavailableâ boron. Hot-water soluble levels of <0.35 ppm are generally considered as deficient (Sims and Johnson 1991). An attempt to calibrate N NH4Oac-extractable boron by Tomasiewicz et al. (1989) using 19 sites the majority of which contained âavailableâ boron levels of less than 0.35 ppm and growing canola, mustard, wheat and flax was unsuccessful. Recent work in Saskatchewan (Malhi et al. 2000) resulted in no consistent results of boron application to seed yield, seed characteristics or disease pressure of canola. The objective of this project was to attempt to identify soils in western Canada that might respond to boron application, calibrate the existing soil test (hot-water extractable) and derive proper fertilization techniques
Effect of phosphorus form on short-term solubility and availability in soils
Non-Peer ReviewedA laboratory experiment was set up to compare solubility and âavailabilityâ of four phosphate
fertilizer sources over a period of 32 d after application to soils with varying pH levels. Three
soils, one acidic and two alkaline, one of which was non-calcareous and one calcareous, of
similar texture and organic matter, were selected. A large number of samples treated with four
phosphate products, namely, two ammonium orthophosphate (9-18-9 and 6-24-0), a
polyphosphate (10-34-0), and an ammonium mono phosphate (11-52-0) at a rate of at 100 mg P
kg-1 soil and an unfertilized control were incubated for a period of 32 d. Destructive sampling at
0, 1, 2, 4, 8, 16 and 32 d was used to assess water soluble and bicarbonate-extractable
phosphorus (P). All treatments were replicated four times. Wide differences in soluble and
bicarbonate extractable P levels from all four products in all three soils at the onset of incubation
became insignificant after 2 to 4 d of incubation suggesting that when any of these products
applied at seeding time would offer any advantage over the rest
Biomass and nutrient accumulation in hybrid canola
Non-Peer ReviewedMeasuring and characterizing aboveground biomass and nutrient accumulation may help us understand the fertility requirements of hybrid canola and lead to better fertilization programs for this crop. The original objective was to measure Nitrogen use by hybrid canola; appropriate timing of N application, if a window of opportunity does exist in season, will reduce N rate and NO3-N remaining at the end of the season. This was extended to all nutrients. A study was initiated in 2003 that included experiments out at four sites (two in Manitoba and two in Alberta) using one cultivar (45H21). The basic design was a control, two N rates, 54 and 90 lb N/acre (60 and 100 kg N ha-1), and 54 lb N/acre plus topdressing of 36 lb N/acre (40 kg N ha-1) at 3, 4, 5, 6 and 7 weeks after seeding. We carried out weekly sampling of canola and determined biomass, and N, P, K, S, Ca, Mg, B, Cu, Fe, Mn and Zn concentration. Peak of N, P and S uptake, as an example, was at the 6-leaf growth stage of canola. Only the N data are presented here. We used
topdressing of N at 3, 4, 5, 6, and 7 weeks after seeding as an alternative practice. Its success was directly related to timing of precipitation
Changes in the chemical and mineralogical properties of Mt. Talang volcanic ash in West Sumatra during the initail weathering phase.
Eruptions from Talang volcano on 12 April 2005 distributed volcanic ash over portions of the Solok District of West Sumatra, Indonesia. Unleached and leached pristine volcanic ash were collected immediately after the eruption, and the third sample was collected after 2 years. The mineralogy and chemical properties of pristine volcanic ash and volcanic ash deposits that were weathered for 2 years from the 2005 eruption of Mt. Talang, Sumatra, were studied to characterize the volcanic ash, identify the primary minerals present, and determine its chemical properties. Results showed that the volcanic ash contained 30% noncrystalline minerals (or volcanic glass); the remaining ash is composed of crystalline minerals such as labradorite, hypersthene, augite, hornblende, olivine, opaque ferromagnetic minerals, and rock fragments. Notable differences in pH values were observed as the pH tended to become more acidic from the unleached, leached, and weathered volcanic ash, but the ash did not give much response to the sodium fluoride (NaF) test. Total sulfur gradually decreased from 3.28% in unleached ash to 1.93% after 2 years. Available phosphorus (P) in the unleached volcanic ash was 68 mg kgâ1, and this value was decreased by 15 % after 2 years of being exposed to the atmosphere, while phosphate retention ranged between 52.8% and 66.8%. Cation exchange capacity (CEC) was low with the value of 10 cmolc kgâ1 although base saturation was high, exceeding 75%. The low acid oxalateâextractable silicon (Si), aluminum (Al), and iron (Fe) values of 0.07%, 0.25% and 1.17%, respectively, show the scarcity of secondary amorphous compounds in the ash. Total elemental analysis indicated that no differences were found in total silica oxide (SiO2) content of all samples, with a value about 56%, and this volcanic ash can be classified as basaltic andesite. We observed that removal of chemical elements by leaching was large for calcium oxide (CaO), magnesium oxide (MgO), and sodium oxide (Na2O) as the values decreased in time. Solid-state 29Si and 27Al magic angle spinning (MAS) nuclear magnetic resonance (NMR) studies indicated that Al occurred in both tetrahedral and octahedral forms. Silicon was not present in the tetrahedral layer. An intense peak at â92 ppm was indicative of the presence of aluminosilicates
Search for jet extinction in the inclusive jet-pT spectrum from proton-proton collisions at s=8 TeV
Published by the American Physical Society under the terms of the Creative Commons Attribution 3.0 License. Further distribution of this work must maintain attribution to the author(s) and the published articles title, journal citation, and DOI.The first search at the LHC for the extinction of QCD jet production is presented, using data collected with the CMS detector corresponding to an integrated luminosity of 10.7ââfbâ1 of proton-proton collisions at a center-of-mass energy of 8 TeV. The extinction model studied in this analysis is motivated by the search for signatures of strong gravity at the TeV scale (terascale gravity) and assumes the existence of string couplings in the strong-coupling limit. In this limit, the string model predicts the suppression of all high-transverse-momentum standard model processes, including jet production, beyond a certain energy scale. To test this prediction, the measured transverse-momentum spectrum is compared to the theoretical prediction of the standard model. No significant deficit of events is found at high transverse momentum. A 95% confidence level lower limit of 3.3 TeV is set on the extinction mass scale
Proceedings of the 2016 Childhood Arthritis and Rheumatology Research Alliance (CARRA) Scientific Meeting
First measurement of Ωc0 production in pp collisions at s=13 TeV
The inclusive production of the charmâstrange baryon 0 c is measured for the first time via its hadronic â decay into âÏ+ at midrapidity (|y| <0.5) in protonâproton (pp) collisions at the centre-of-mass energy s =13 TeV with the ALICE detector at the LHC. The transverse momentum (pT) differential cross section multiplied by the branching ratio is presented in the interval 2 < pT < 12 GeV/c. The pT dependence of the 0 c-baryon production relative to the prompt D0-meson and to the prompt 0 c-baryon production is compared to various models that take different hadronisation mechanisms into consideration. In the measured pT interval, the ratio of the pT-integrated cross sections of 0 c and prompt + c baryons multiplied by the âÏ+ branching ratio is found to be larger by a factor of about 20 with a significance of about 4Ï when compared to e+eâ collisions
Elliptic flow of charged particles at midrapidity relative to the spectator plane in PbâPb and XeâXe collisions
Measurements of the elliptic flow coefficient relative to the collision plane defined by the spectator neutrons v2{ SP} in collisions of Pb ions at center-of-mass energy per nucleonânucleon pair â 2.76 TeV and Xe ions at â sNN = sNN =5.44 TeV are reported. The results are presented for charged particles produced at midrapidity as a function of centrality and transverse momentum for the 5â70% and 0.2â6 GeV/c ranges, respectively. The ratio between v2{ SP} and the elliptic flow coefficient relative to the participant plane v2{4}, estimated using four-particle correlations, deviates by up to 20% from unity depending on centrality. This observation differs strongly from the magnitude of the corresponding eccentricity ratios predicted by the TRENTo and the elliptic power models of initial state fluctuations that are tuned to describe the participant plane anisotropies. The differences can be interpreted as a decorrelation of the neutron spectator plane and the reaction plane because of fragmentation of the remnants from the colliding nuclei, which points to an incompleteness of current models describing the initial state fluctuations. A significant transverse momentum dependence of the ratio v2{ SP}/v2{4} is observed in all but the most central collisions, which may help to understand whether momentum anisotropies at low and intermediate transverse momentum have a common origin in initial state f luctuations. The ratios of v2{ SP} and v2{4} to the corresponding initial state eccentricities for XeâXe and PbâPb collisions at similar initial entropy density show a difference of (7.0 ±0.9)%with an additional variation of +1.8% when including RHIC data in the TRENTo parameter extraction. These observations provide new experimental constraints for viscous effects in the hydrodynamic modeling of the expanding quarkâgluon plasma produced in heavy-ion collisions at the LHC
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