Soil sampling bulk-density in the coastal lowlands of South-East Queensland

Bulk density is commonly measured in compaction, cultivation, land evaluation and site classification studies in forestry. Typically, measurements are made using a small-diameter core sampler (an integral open drive sampler) which is manually driven into the soil profile. The study reported in this paper was designed to determine the effects of sampler size on bulk density estimates, and to identify optimal sampling intensities for the coastal lowlands of south-east Queensland. Four sampler sizes were tested (internal diameters of 3.48, 4.83, 5.98 and 9.12 cm, and all approximately 10 cm in length). All sampler sizes provided consistent estimates of bulk density for a range of soil types and conditions. The accuracy of bulk density assessment was not improved by increasing sampler diameter beyond 5.98 cm. The results suggested that the core sampler technique can be used efficiently in a wider range of soil conditions than that recommended in the literature. Comparison of variances estimated for the four sampler sizes indicated no significant differences between either sampler size or site, and no significant 'site by sampler size' interaction. A single pooled estimate of variance was therefore used to recommend sampling intensities for coastal lowland soils. With any of the samplers used in this study, five replications will provide a point estimate of bulk density with a precision of ± 0.1 g cm -3; at the 95% probability level

Relationships between cone penetration resistance, bulk density, and moisture content in uncultivated, repacked, and cultivated hardsetting and non-hardsetting soils from the coastal lowlands of south-east Queensland

Relationships between cone penetration resistance (PR), soil moisture (SM), and bulk density (BD) were derived for: (i) cultivated (ripped) and uncultivated, hardsetting and non-hardsetting, field soils; and (ii) repacked cores of the uncultivated soils. Each of the soils supports commercial Pinus plantations in the coastal lowlands of south-east Queensland, Australia. Penetration resistance was positively correlated with bulk density and negatively correlated with soil moisture for all soils. In the uncultivated soils, penetration resistance was less sensitive to bulk density than typically reported in the literature, or than observed in the cultivated soils where a wider range of bulk density values was studied. In both the cultivated and the repacked soils, penetration resistance was more sensitive to soil moisture at higher bulk density, and more sensitive to bulk density at lower soil moisture. It was not possible to fit the same models to uncultivated, repacked, and cultivated soils, and therefore not possible to compare relationships for each statistically. Relationships between penetration resistance, bulk density, and soil moisture were best described by additive models in the uncultivated soils and multiplicative models in the cultivated soils. For the repacked soils, models had to be developed relating penetration resistance to bulk density for each soil moisture class separately. The study demonstrated that: (i) relationships between penetration resistance, bulk density, and soil moisture were insufficiently sensitive to predict responses in the penetration resistance of field soils tochanges in soil moisture, as might occur temporally, or bulk density, as might occur with compaction or reconsolidation after cultivation; and (ii) repacked soils could not be used to simulate the relationships between penetration resistance, bulk density, and soil moisture for cultivated field soils. Therefore, penetration resistances measured at different times in studies in which either bulk density or soil moisture are expected to change cannot be easily compared. In these situations, which include compaction and consolidation studies, both penetration resistance and bulk density, or bulk density alone, should be used to monitor change. Relationships between penetration resistance, soil moisture, and bulk density, together with moisture characteristic drying curves for individual soils, were used to define relationships between penetration resistance and matric suction. These relationships define a soil characteristic that may be useful for: (i) explaining varying responses of different soils to drying; (ii) explaining various Pinus seedling growth responses to cultivation and compaction; and (iii) delineating soils which are functionally hardsetting upon drying

Site preparation for Pinus establishment in south-eastern Queensland 1. Temporal changes in bulk density

In south-eastern Queensland, Australia, standard site preparation practices used for Pinus plantation establishment are mounding (bedding) on poorly drained soils and blade cultivation (subsurface, wing rip) on well-drained soils. This paper reports the impacts of both site preparation treatments on soil bulk density over time. Following site preparation, the extent of bulk density reduction and the nature of bulk density consolidation was affected by soil type, soil depth and the site preparation technique used. On high strength, hardsetting soils, bulk density reductions from both mounding and blade cultivation persisted throughout the 28-month period, and contrasted with non-hardsetting soils in the plantation estate, which consolidated more rapidly and had higher bulk densities relative to precultivation levels for the period 4-28 months following site preparation. The studies reported in this paper were the first in south-eastern Queensland to investigate the impact of site preparation for Pinus establishment on the nature and longevity of bulk density reductions. Previously, plantation managers assumed that positive site preparation impacts would be relatively short-lived, and therefore developed a prudential policy of planting Pinus seedlings immediately following site preparation. For the soils studied, delays of 2-4 months, and perhaps up to 6 months, between site preparation and planting would not compromise Pinus growth, but would assist management planning

Site preparation for Pinus establishment in south-eastern Queensland. 2. Effect of cultivation and cultivation width on growth

The standard site preparation practice used for Pinus plantation establishment on well-drained soils in south-eastern Queensland is blade (subsurface, wing rip) cultivation to a width of 2.0 m and a depth of 0.2 m. This operation requires high drawbar power and is difficult to achieve in high strength soils, or in soils where roots and stumps hinder progress of the blade through the soil. The aim of the study reported in this paper was to better define cultivation growth relationships for Pinus caribaea var. hondurensis plantations in order to determine if site preparation objectives could be achieved with a reduced cultivation effort. A highly significant 'soil type x cultivation' interaction was observed. In contrast to the growth responses observed on hardsetting soils, cultivation did not improve growth on non-hardsetting soils. There is an opportunity therefore to reduce reforestation site preparation costs by only cultivating soils that show a growth response. The cultivation response on hardsetting soils has increased throughout the study period, and is attributed to a reduction in soil penetration resistance. The response however shows diminishing gains with increasing cultivation widths. Blade cultivation widths of 1.2 m were found to capture 97% of the gains that could be expected from widths of 2.0 m. A significant 'family x soil penetration resistance' interaction was observed. An opportunity to increase plantation productivity by targeting better performing families to hardsetting soils is suggested

Resonance-continuum interference in the di-photon Higgs signal at the LHC

A low mass Standard Model Higgs boson should be visible at the Large Hadron Collider through its production via gluon-gluon fusion and its decay to two photons. We compute the interference of this resonant process, gg -> H -> gamma gamma, with the continuum QCD background, gg -> gamma gamma induced by quark loops. Helicity selection rules suppress the effect, which is dominantly due to the imaginary part of the two-loop gg -> gamma gamma scattering amplitude. The interference is destructive, but only of order 5% in the Standard Model, which is still below the 10-20% present accuracy of the total cross section prediction. We comment on the potential size of such effects in other Higgs models.Comment: 10 pages, 2 figure

Evaluation of the potential to dispose of sewage-sludge. 1. Soil hydraulic and overland-flow properties of Pinus plantations in Queensland

The studies reported in this paper were designed to evaluate the potential for disposal of sewage sludge in commercial Pinus plantations at Beerburrum, 50 km north of Brisbane. Soil descriptions and measurements of hydraulic properties were made in three soils, covering the range of perceived site suitability for sludge application. Disc permeameters and a rainfall simulator were used to characterize surface infiltration properties both with and without sludge, and ponded rings were used to assess permeability of the upper B horizon. Although surface hydraulic conductivities were potentially high, infiltration into dry soil was reduced by water repellence associated with fungal matting at the soil surface and mycelia extending through the Al horizon. Surface runoff could be generated from dry soils by relatively low intensity rainfall events, and the rate and volume of runoff was not increased by broadcast sludge application. Hydraulic conductivities of the upper Bt horizons in the lateritic and yellow podzolic soils were high, suggesting that persistent perched watertable development was unlikely. However, the presence of bleached A2 horizons and gleyed Bt horizons with prominent mottling in these soils were interpreted as evidence of periodic regional ground-water intrusion. By contrast, hydraulic conductivity in the Bt horizon of the soloth was low, suggesting that locally restricted drainage occurs. Likely pathways of water movement were inferred for three representative soil types in the proposed sludge application project. There is potential for both Hortonian runoff when antecedent conditions are dry, and saturated runoff during prolonged wet periods. Potential off-site pollution could therefore occur if either solids or solutes from the sludge are susceptible to transport. In addition, preferential how paths of water infiltration were demonstrated, and the potential for accelerated water and solute movement to ground watertables was inferred. The studies reported in this, and the second, paper in the series were used to appraise the potential for either surface water or ground water pollution from land-based sludge disposal

The parentage of 'Sangiovese', the most important Italian wine grape

A previous microsatellite study pointed out a possible parent-offspring relationship between 'Sangiovese', the most widespread red grape cultivar in Italy, and 'Ciliegiolo', an ancient Tuscan variety. Testing 'Sangiovese' as a parent of 'Ciliegiolo', we searched for the putative other parent in our extensive, private and standardized database, but we did not find any candidate. Testing 'Ciliegiolo' as a parent of 'Sangiovese', we found four candidate cultivars. After the analysis of 50 microsatellites, only one stood the paternity test and we established with a strong statistical support that 'Sangiovese' is a progeny of 'Ciliegiolo' and 'Calabrese di Montenuovo', an obscure grapevine from Campania, Italy. This cultivar does not have a registered name and is supposed to have been introduced from Calabria. Among 180 additional local grape cultivars from Calabria, Campania or Tuscany, we did not find any matching variety. As a consequence, we propose to adopt the name 'Calabrese di Montenuovo' for this grape cultivar. In addition, we found relatives of 'Sangiovese' and 'Calabrese di Montenuovo' in Calabria, thus strongly suggesting a Calabrian origin for 'Calabrese di Montenuovo' and indicating that 'Sangiovese' has ancestors and/or progenies in Tuscany and in Southern Italy.

Non-equilibrium phase transition in a sheared granular mixture

The dynamics of an impurity (or tracer particle) immersed in a dilute granular gas under uniform shear flow is investigated. A non-equilibrium phase transition is identified from an exact solution of the inelastic Boltzmann equation for a granular binary mixture in the tracer limit, where the impurity carries either a vanishing (disordered phase) or a finite (ordered phase) fraction of the total kinetic energy of the system. In the disordered phase, the granular temperature ratio (impurity "temperature" over that of the host fluid) is finite, while it diverges in the ordered phase. To correctly capture this extreme violation of energy equipartition, we show that the picture of an impurity enslaved to the host fluid is insufficient

Evaluación de la capacidad de rebrote en avena con distinta intensidad de defoliación y dos frecuencias de corte

La finalidad del presente trabajo fue estudiar el efecto de la frecuencia de corte y la intensidad de defoliación de la avena (Avena sativa), sobre la producción de materia seca y la persistencia. El ensayo se llevó a cabo en la Facultad de Agronomía de la UNLPam, durante el ciclo de cultivo en el año 1989. El diseño experimental empleado fue el de bloques completos al azar involucrando un arreglo de tratamiento factorial con cuatro repeticiones. En la experiencia se determinó producción de materia seca y stand de plantas. La comparación de las distintas frecuencias de corte dentro de una misma intensidad de defoliación, mostró diferencias altamente significativas en producción de materia seca en favor del intervalo entre cortes más prolongados y a su vez al comparar distintas intensidades de defoliación dentro de una misma frecuencia, se encontraron diferencias altamente significativas siendo mayor la producción de materia seca a mayor I.A.F. (índice de área foliar) remanente. En lo que respecta a stand de plantas se observó una pérdida muy importante en el corte más intenso, donde las pérdidas fueron del ochenta y cinco por ciento. Para lograr una alta producción de materia seca y buena persistencia se deben combinar una baja frecuencia con un elevado LA.F. remanente.Director: Ing. Agr. Oscar Hernández. Profesor Titular Cátedra de Forrajicultura y Manejó de pasturas

Diffusion Process in a Flow

We establish circumstances under which the dispersion of passive contaminants in a forced, deterministic or random, flow can be consistently interpreted as a Markovian diffusion process. In case of conservative forcing the repulsive case only, $\vec{F}=\vec{\nabla }V$ with $V(\vec{x},t)$ bounded from below, is unquestionably admitted by the compatibility conditions. A class of diffusion processes is exemplified, such that the attractive forcing is allowed as well, due to an appropriate compensation coming from the "pressure" term. The compressible Euler flows form their subclass, when regarded as stochastic processes. We establish circumstances under which the dispersion of passive contaminants in a forced, deterministic or random, flow can be consistently interpreted as a Markovian diffusion process. In case of conservative forcing the repulsive case only, $\vec{F}=\vec{\nabla }V$ with $V(\vec{x},t)$ bounded from below, is unquestionably admitted by the compatibility conditions. A class of diffusion processes is exemplified, such that the attractive forcing is allowed as well, due to an appropriate compensation coming from the "pressure" term. The compressible Euler flows form their subclass, when regarded as stochastic processes.Comment: 10 pages, Late