Intercropping in maize silage versus solo-seeding for alfalfa establishment in Wisconsin and Idaho

Alfalfa (Medicago sativa L.) intercropping with maize (Zea mays L.) silage is being developed in the northern United States to improve the profitability and environmental sustainability of forage production. This study, conducted under rainfed conditions inWisconsin and semiarid irrigated conditions in Idaho, compared the establishment of alfalfa and dry matter yield of four intercropping systems to three conventional systems. The former systems included alfalfa interseeded at planting or the vegetative emergence (VE) stage of maize and grown with or without prohexadione growth retardant. The latter systems included alfalfa seeded in spring, summerseeded after barley (Hordeum vulgare L.), or late summer-seeded after maize silage. Spring seeded and interseeded alfalfa inWisconsin also received foliar fungicide and insecticide during establishment. During alfalfa establishment, yield of intercropped maize silage was 1.8- to 4.4-fold greater than spring-seeded alfalfa. Compared to spring-seeded alfalfa, interseeded alfalfa had similar or somewhat lower stand density but similar first cut yield the following year, provided that intercropped maize was harvested near September 1 to allow ample alfalfa fall regrowth. Shifting interseeding from maize planting to the VE stage decreased early-season alfalfa growth, but improved maize silage yield, with minor effects on alfalfa fall growth, stand density, and first cut yield. Prohexadione application had little impact on establishment or yield of interseeded alfalfa. While having high plant density, alfalfa seeded after barley or especially maize had less fall growth and low first cut yield. Overall, alfalfa establishment and yield of intercropping systems compared favorably with conventional systems

Patterns and associations between dominant crop productions and water quality in an irrigated watershed

Irrigation consumes the largest share of freshwater resources but is a necessary practice to boost agricultural output to meet increasing global demand for food and fiber. Irrigation not only impacts water quantity but can also degrade water quality. Research efforts have explored various aspects of irrigation efficiency and irrigated crop productivity, but few studies have examined how different crops collectively modulate water utilization and water quality at the watershed scale. In this study long-term water quantity and quality monitoring data collected as part of the Conservation Effect Assessment Project (CEAP) combined with crop and evapotranspiration (ET) modeling products were used to elucidate relationships between crop and water processes in an irrigated watershed. We use a correlational approach to build relationships between water quantity and quality metrics and the fractional volumes of ET associated with major crops in the Twin Falls Canal Company irrigation tract. Results suggest that sub-watershed size and subsurface flow contribution in drainage tunnels influenced hydrologic patterns observed and led to 2 distinct groups. Group 1 sub-watersheds were large, typically included subsurface drain tunnels and had high return flow volumes and low sediment concentration while group 2 sub-watersheds were smaller in size, had low return flow volumes and high sediment concentration. Irrigation return flow volume normalized by sub-watershed area was positively associated with ET fractions of potato (Solanum tuberosum) in group 1 during the spring and summer months. Spring sediment loss per return flow volume showed a negative association with ET fractions of sugar beet and combined alfalfa (Medicago sativa) and pasture crops in group 2. A negative association was found between phosphorus (P) load per return flow volume and ET fractions of alfalfa / pasture, corn (Zea mays), dry beans (Phaseolus vulgaris), and sugar beet (Beta vulgaris) across sub-watershed groups. Nitrate (NO3-N) load per return flow volume was negatively associated with potato and corn ET fractions in group 1 especially during the spring and fall month but positively associated with dry beans over the irrigation season. While direct cause and effect were not established between crops and water quantity and quality, results from this study provide valuable information on management factors associated with various crop production systems that may control observed hydrologic response. Example of factors considered in explaining some of the observed patterns include early germination and ground coverage, tight control on soil water content, and the erosion attenuation effect of sedimentation ponds

Advanced PFBC transient analysis

Transient modeling and analysis of Advanced Pressurized Fluidized Bed Combustion (PFBC) systems is a research area that is currently under investigative study by the United States Department of Energy`s Morgantown Energy Technology Center (METC). The object of the effort is to identify key operating parameters affecting plant performance and then quantify the basic response of major sub-systems to changes in operating conditions. PC-TRAX, a commercially available dynamic software program, was chosen and applied in this modeling and analysis effort. This paper summarizes and describes the development of a series of TRAX-based transient models of Advanced PFBC power plants. These power plants generate a high temperature flue gas by burning coal or other suitable fuel in a PFBC. The high temperature flue gas supports low-Btu fuel gas or natural gas combustion in a gas turbine topping combustor. When utilized, low-Btu fuel gas is produced in a bubbling bed carbonizer. High temperature, high pressure combustion products exiting the topping combustor are expanded in a modified gas turbine to generate electrical power. Waste heat from the system is used to generate and superheat steam for a reheat steam turbine bottoming cycle that generates additional electrical power. Basic control/instrumentation models were developed and modeled in PC-TRAX and used to investigate off-design plant performance. System performance for various transient conditions and control philosophies was studied

ariable thermal crop water stress index reference temperatures for irrigated spring malt barley in a semi-arid climate

Application of canopy temperature-based crop water stress index (CWSI) for monitoring plant water stress and scheduling irrigation requires reliable estimation of well-watered (TLL) and non-transpiring (TUL) canopy temperatures under identical climatic conditions. A 3-year field study was conducted to develop and evaluate the use of data driven models to estimate TLL and TUL of irrigated spring malt barley. Five irrigation rates with four replicates each were used: full irrigation (FIT), 75, 50 and 25% of FIT and no irrigation. Three replicate continuous canopy temperatures measurements were taken in each irrigation treatment starting the first week in June ending in mid-July along with meteorological conditions. A feed forward neural network (NN) model was used to predict TLL between 13:00 and 15:00 MDT based on model inputs: solar radiation, air temperature, relative humidity, and wind speed for the same period. A physical model calibrated to the data set was used to estimate TUL. The NN model predicted TLL was well correlated with measured TLL (R2 = 0.99) with root mean square error 0.89 degrees C and mean absolute error 0.70 degrees C. There were significant differences in calculated daily average CWSI between irrigation treatments. Relative evapotranspiration, relative malt barley seed yield and percent plump kernels were negatively correlated with season average CWSI. Malt barley seed test weight was positively correlated with season average CWSI. The relationship between daily average CWSI and fraction available soil water was well described by a two-parameter exponential decay function (R2 = 0.72). These results indicate applicability of data driven models for computing CWSI of irrigated spring malt barley in a semi-arid environment and demonstrate malt barley yield response to crop water stress

Soil health indicators reveal that past dairy manure applications create a legacy effect

Understanding the long-term effects of manure applications on soil biological measurements in agricultural systems receiving animal manure in semiarid climates is important. From 2004 to 2009, dairy manure solids were applied to plots at rates of 0, 134, and 237 dry Mg/ha. The study was a randomized complete block with three replicates. Soil samples were taken from each manure rate in the spring of 2020 at 0-15 and 15-30 cm. Eleven years after manure applications ceased, many of the soil chemical and biological indicators were different between the manure and control treatments. In general, soil organic carbon (SOC), biological indicators were significantly greater in the 134 Mg/ha and 237 Mg/ha treatments as compared to the 0 Mg/ha. Therefore, it is evident that manure applications had a long-term or legacy effect (at least 11 years post manure application) on soil properties, especially those related to nutrient cycling

Establishing a standard protocol for soil texture analysis using the laser diffraction technique

Optical methods including laser diffraction have been increasingly used to measure soil texture and particle size distribution. However, they have not been adopted yet as a routine methodology mainly due to the difficulties in comparing their results to more commonly-used techniques (i.e., sedimentation methods). Many attempts exist in the literature to find an agreement between methodologies with relative success. In this work, we aim to improve the agreement between methodologies by adjusting parameters of the laser diffraction analysis, including sample treatment (chemical dispersion, carbonate removal, sand separation), mode of sample addition (sub-sampling versus transmittance matching), and analysis parameters (time of sonication, refractive index). Soil texture class determined by laser diffraction agreed with the sieve-hydrometer method in 98% of the runs when the following parameters were used: (1) Refractive index of 1.44 - 0.100i, (2) 180 seconds of sonication, (3) sand sieving prior to analysis, and (4) sample dispersion by shaking the sample for 1 hour with 5% of sodium hexametaphosphate. We observed that adding the entire sample to the analyzer (1 g of soil in 100 mL of dispersant) while keeping the appropriate levels of transmittance through dilution (transmittance matching) is a better way of sample addition in comparison to sub-sampling, especially for coarser soil samples. This work proposes a standard operation procedure that may broaden the adoption of laser diffraction analysis as a routine soil texture methodology

Langevin Simulations of Two Dimensional Vortex Fluctuations: Anomalous Dynamics and a New IVIV-exponent

The dynamics of two dimensional (2D) vortex fluctuations are investigated through simulations of the 2D Coulomb gas model in which vortices are represented by soft disks with logarithmic interactions. The simulations trongly support a recent suggestion that 2D vortex fluctuations obey an intrinsic anomalous dynamics manifested in a long range 1/t-tail in the vortex correlations. A new non-linear IV-exponent a, which is different from the commonly used AHNS exponent, a_AHNS and is given by a = 2a_AHNS - 3, is confirmed by the simulations. The results are discussed in the context of earlier simulations, experiments and a phenomenological description.Comment: Submitted to PRB, RevTeX format, 28 pages and 13 figures, figures in postscript format are available at http://www.tp.umu.se/~holmlund/papers.htm

Moving on from Weiser's Vision of Calm Computing: engaging UbiComp experiences

A motivation behind much UbiComp research has been to make our lives convenient, comfortable and informed, following in the footsteps of Weiser's calm computing vision. Three themes that have dominated are context awareness, ambient intelligence and monitoring/tracking. While these avenues of research have been fruitful their accomplishments do not match up to anything like Weiser's world. This paper discusses why this is so and argues that is time for a change of direction in the field. An alternative agenda is outlined that focuses on engaging rather than calming people. Humans are very resourceful at exploiting their environments and extending their capabilities using existing strategies and tools. I describe how pervasive technologies can be added to the mix, outlining three areas of practice where there is much potential for professionals and laypeople alike to combine, adapt and use them in creative and constructive ways

Azimuthal asymmetries in lepton-pair production at a fixed-target experiment using the LHC beams (AFTER)

A multi-purpose fixed-target experiment using the proton and lead-ion beams of the LHC was recently proposed by Brodsky, Fleuret, Hadjidakis and Lansberg, and here we concentrate our study on some issues related to the spin physics part of this project (referred to as AFTER). We study the nucleon spin structure through $pp$ and $pd$ processes with a fixed-target experiment using the LHC proton beams, for the kinematical region with 7 TeV proton beams at the energy in center-of-mass frame of two nucleons $\sqrt{s}=115$ GeV. We calculate and estimate the $\cos2\phi$ azimuthal asymmetries of unpolarized $pp$ and $pd$ dilepton production processes in the Drell--Yan continuum region and at the $Z$-pole. We also calculate the $\sin(2\phi-\phi_S)$, $\sin(2\phi+\phi_S)$ and $\sin2\phi$ azimuthal asymmetries of $pp$ and $pd$ dilepton production processes with the target proton and deuteron longitudinally or transversally polarized in the Drell--Yan continuum region and around $Z$ resonances region. We conclude that it is feasible to measure these azimuthal asymmetries, consequently the three-dimensional or transverse momentum dependent parton distribution functions (3dPDFs or TMDs), at this new AFTER facility.Comment: 15 pages, 40 figures. Version accepted for publication in EPJ

Structural, electronic, and magneto-optical properties of YVO3_3

Optical and magneto-optical properties of YVO$_3$ single crystal were studied in FIR, visible, and UV regions. Two structural phase transitions at 75 K and 200 K were observed and established to be of the first and second order, respectively. The lattice has an orthorhombic $Pbnm$ symmetry both above 200 K as well as below 75 K, and is found to be dimerized monoclinic $Pb11$ in between. We identify YVO$_3$ as a Mott-Hubbard insulator with the optical gap of 1.6 eV. The electronic excitations in the visible spectrum are determined by three $d$-bands at 1.8, 2.4, and 3.3 eV, followed by the charge-transfer transitions at about 4 eV. The observed structure is in good agreement with LSDA+$U$ band structure calculations. By using ligand field considerations, we assigned these bands to the transitions to the $^4A_{2g}$, $^2E_{g} + ^2T_{1g}$, and $^2T_{2g}$ states. The strong temperature dependence of these bands is in agreement with the formation of orbital order. Despite the small net magnetic moment of 0.01 $\mu_B$ per vanadium, the Kerr effect of the order of $0.01^\circ$ was observed for all three $d$-bands in the magnetically ordered phase $T_{\text{N\'eel}}<116 K$. A surprisingly strong enhancement of the Kerr effect was found below 75 K, reaching a maximum of $0.1^\circ$. The effect is ascribed to the non-vanishing net orbital magnetic moment.Comment: Submitted to Phys. Rev.