Summary
Quantifying short‐ and long‐term availability of animal manure nitrogen (N) is of practical interest to ensure adequate crop yield, minimize N pollution and reduce inputs of mineral‐N ...fertilizer. We measured short‐term carbon (C) and N dynamics after one or six repeated additions to soil (every 56 days) of ammonium sulphate (AS) and undigested (PS) and anaerobically digested (DPS) pig slurry in a laboratory incubation experiment. Soil CO2 emissions, pH and mineral N (ammonium + nitrate) were measured during the period of 0–56 days following fertilizer additions. An accompanying experiment was conducted with similar but 15N‐labelled fertilizers to measure soil mineral N 56 and 112 days after one, three or six repeated additions, and to estimate the increase in slurry available N after repeated additions. Nitrogen from slurries potentially available for plants (77–91, 44–58 and 57–66% of added N for AS, PS and DPS, respectively) was close to that supplied in mineral form with the fertilizer, indicating negligible net mineralization of slurry organic N, after both one and repeated additions. In fact, soil mineral N increased in most of the treatments because of repeated additions, but the increases were small, on average 0.5–2.1% of added N per period of 56 and 112 days. Calculations of availability of fertilizer N based on unlabelled N were equally precise compared with those estimated with 15N, but trends over time were more variable. We conclude that many repeated additions (simulating a long manuring history) are needed to obtain a marked increase in available slurry N, even under controlled conditions.
Highlights
We studied slurry decomposition after single or repeated additions in two laboratory incubations
We used unlabelled and 15N‐labelled pig slurries to estimate N availability
N potentially available for plants was close to that supplied in mineral form with slurries
Slurry N availability increased with repeated additions, but residual effects were small for both slurries
Repeated applications of animal slurry to soil can lead to residual nitrogen (N) effects from mineralization of organic N carried over from the previous year and from remineralization of previously ...immobilized N. We studied the effect of repeated slurry applications on soil mineral N (SMNt: nitrate‐N plus soluble, exchangeable and non‐exchangeable ammonium‐N) dynamics in a simplified, aerobic laboratory incubation. The experiment evaluated the effects of up to four applications (84‐day intervals) of two different liquid cow slurries, ammonium sulphate and water (unfertilized control, CON) to sandy loam and clay loam soils. The slurries came from heifers (HEI) and lactating dairy cows (COW). Both soil types showed net N mineralization in HEI during each 84‐day interval after application (3–6% of slurry‐N), whereas decomposition of COW induced net N immobilization at 16% of slurry‐N. The effect observed for COW might have come from its larger C to organic‐N ratio. After each application to the clay loam soil, 36–64% of the ammonium applied was not recoverable at day 0 because of ammonium fixation by clay minerals, and an average of 20% of fertilizer‐N was measured as non‐exchangeable ammonium at day 84. Recovery of N applied with both HEI and COW at day 84 increased significantly with subsequent applications to clay loam soil, but not to sandy loam soil. Residual effects in clay loam soil ranged from 2 to 11% of applied N, which probably resulted from slow mineralization of recalcitrant organic fractions in the slurry and partial stabilization of microbial by‐products within the soil.
Highlights
A novel incubation approach was used to study residual N effects of ammonium sulphate and slurries.
Fertilizers were applied one, two, three or four times to a sandy loam (SL) and a clay loam (CL) soil.
Residual N effects were small; less slurry NH4‐N was available in CL than SL because of clay fixation.
Mineralization of residual slurry‐N and stabilization of microbial by‐products were slow.
The role played by subsurface flow in the rainfall–runoff transformation is still poorly understood. In particular, two aspects are highly debated. The first one is the relatively fast response of ...the catchments to rainfall input which is often observed. The rapid response contradicts the general notion of slow movement of water in the subsurface. Another important issue is the control of pre-event water to streamflow. In the present work, we perform a series of 2D numerical simulations in order to gain understanding on the above problems. The platform is the experimental site described in Montgomery and Dietrich Montgomery, D.R., Dietrich, W.E., 2002. Runoff generation in a steep, soil-mantled landscape. Water Resour. Res. 38(9), 1168, doi:10.1029/2001WR000822. The aim is not to replicate exactly the experimental conditions but rather to use the model as a numerical laboratory for investigating streamflow generation processes. The simulations show that a Darcian formulation of subsurface flow in a combined soil–bedrock system can generally reproduce fast catchment streamflow responses comparable to observations. The principal mechanisms for the streamflow generation are subsurface flow along the soil–bedrock interface combined with groundwater ridging in the vicinity of the hillslope base. Numerical analysis of solute transport indicates high proportions of pre-event water in the resulting hydrograph.
Poor-quality Corsican pine (Pinus nigra subsp. laricio (Poir.) Maire) and Douglas fir (Pseudotsuga menziesii (Mirb.) Franco) wood samples were heat treated with the aim of testing the improvement of ...wood quality that could increase their economic value. Wood properties were measured to assess quality in treated and non-treated materials, including density, hardness, anti-swelling efficiency (ASE), modulus of elasticity (MOE), modulus of rupture (MOR), and compression strength. The results showed higher dimensional stability in heat-treated wood, yet mechanical performance in compression and bending strength were only marginally affected by loss of density. Despite having a relatively low density after heat treatment, Corsican pine sapwood has potential in manufacturing higher-value products. In contrast, heat treatment applied to Douglas fir wood did not appear economically viable; insufficient differences were detected between the naturally desirable characteristics of this species and heat-treated samples.
A module of the ATLAS electromagnetic barrel liquid argon calorimeter was exposed to the CERN electron test-beam at the H8 beam line upgraded for precision momentum measurement. The available ...energies of the electron beam ranged from 10 to 245
GeV. The electron beam impinged at one point corresponding to a pseudo-rapidity of
η
=
0.687
and an azimuthal angle of
φ
=
0.28
in the ATLAS coordinate system. A detailed study of several effects biasing the electron energy measurement allowed an energy reconstruction procedure to be developed that ensures a good linearity and a good resolution. Use is made of detailed Monte Carlo simulations based on GEANT4 which describe the longitudinal and transverse shower profiles as well as the energy distributions. For electron energies between 15 and 180
GeV the deviation of the measured incident electron energy over the beam energy is within 0.1%. The systematic uncertainty of the measurement is about 0.1% at low energies and negligible at high energies. The energy resolution is found to be about 10%
·
E
for the sampling term and about 0.2% for the local constant term.
Analysis of the liquid argon purity in the ICARUS T600 TPC Amoruso, S; Aprili, P; Arneodo, F ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
2004, 2004-1-00, Letnik:
516, Številka:
1
Journal Article
Recenzirano
The results reported in this paper are based on the analysis of the data recorded with the first half-module of the ICARUS T600 liquid argon Time Projection Chamber (LAr TPC), during a technical run ...that took place on surface in Pavia (Italy). We include results from the linearity, uniformity and calibration of the electronics, measurements on the electron drift velocity in LAr at different electric fields, as well as the LAr purity achievement of the detector. Two complementary techniques were used to measure the drift electron lifetime inside the active volume: the first, from the data of a purity monitor, gives a measurement localized in space; the second, based on the study of the signals produced by long minimum ionizing tracks crossing the detector, provides a LAr volume averaged value. Both methods yield consistent results over the whole data taking period and are compatible with an uniform LAr purity over the whole volume. The maximal drift electron lifetime value was recorded before the run stop and was about
1.8
ms
. From an interpretation of the observed drift electron lifetime as a function of time, we conclude that the adopted technology would allow for drift distances exceeding
3
m
.
Agroecological services of cover crops depend mostly on their biomass accumulation, which in turn depends on growing season weather and on nitrogen (N) availability. We hypothesised that cover crop ...growth and weed control can be increased with an early sowing date and under high residual soil inorganic N left after the previous cash crop harvest. This hypothesis was tested in Northern Italy, with a two-year field experiment in two locations with five cover crops, comparing two cover crop sowing dates (beginning of September, SD1, and mid September, SD2), and evaluating the effects of pre-plant soil mineral N addition (N0 and N1). The cover crops, grown between two maize crops, were terminated in March. Weather conditions in both years were drier than normal, reducing on average cover crop growth. In November, cover crop aboveground biomass and N content ranged between 0.5 and 3.3 t DM ha−1 and between 18 and 70 kg N ha−1, respectively, with significantly lower values for SD2 compared to SD1 for most species. In most cases high pre-plant soil mineral N significantly increased cover crop biomass and N content, suggesting that cover crop growth was N-limited. Weed growth was higher in Egyptian clover and hairy vetch (0.7 t DM ha−1 on average) than in white mustard and black oat (0.2 t DM ha−1 on average), due to limited competitive ability of legumes. Cover crop biomass accumulation and weed control were enhanced by early sowing (in particular for legumes) and in conditions of high mineral N residue in the soil (in particular for non-legumes).
•Five cover crops in two years and two sites in Northern Italy were compared.•Cover crop biomass was significantly lower with late than with early sowing date.•Cover crop biomass was significantly higher in white mustard than in other species.•Pre-plant N increased cover crop biomass, suggesting cover crops were N-limited.•Weed growth was higher in legumes than in white mustard and black oat.
Response uniformity of the ATLAS liquid argon electromagnetic calorimeter Aharrouche, M.; Colas, J.; Di Ciaccio, L. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
2007, Letnik:
582, Številka:
2
Journal Article
Recenzirano
Odprti dostop
The construction of the ATLAS electromagnetic liquid argon calorimeter modules is completed and all the modules are assembled and inserted in the cryostats. During the production period four barrel ...and three endcap modules were exposed to test beams in order to assess their performance, ascertain the production quality and reproducibility, and to scrutinize the complete energy reconstruction chain from the readout and calibration electronics to the signal and energy reconstruction. It was also possible to check the full Monte Carlo simulation of the calorimeter. The analysis of the uniformity, resolution and extraction of constant term is presented. Typical non-uniformities of
5
‰
and typical global constant terms of
6
‰
are measured for the barrel and endcap modules.
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