Depth-controlled modified combine for direct drilling and Lupin row spacing.

Trial 87WH52, (86M56) Depth-controlled modified combine for direct drilling. To compare soil penetration resistance, crop growth, water use, nutrient uptake and root development of wheat 1) sown after scarifying; 2) direct drilled with a combine; 3) direct drilled with the depth-controlled modified combine with loosening ties at 5, 9 or 13 cm; or 4) sown after deep ripping with an Agrowplow to 13 or 30 cm. Trial 87M82 Location: Merredin Research Station paddock T6 south. Lupin row spacin

Three-dimensional turbopump flowfield analysis

A program was conducted to develop a flow prediction method applicable to rocket turbopumps. The complex nature of a flowfield in turbopumps is described and examples of flowfields are discussed to illustrate that physics based models and analytical calculation procedures based on computational fluid dynamics (CFD) are needed to develop reliable design procedures for turbopumps. A CFD code developed at NASA ARC was used as the base code. The turbulence model and boundary conditions in the base code were modified, respectively, to: (1) compute transitional flows and account for extra rates of strain, e.g., rotation; and (2) compute surface heat transfer coefficients and allow computation through multistage turbomachines. Benchmark quality data from two and three-dimensional cascades were used to verify the code. The predictive capabilities of the present CFD code were demonstrated by computing the flow through a radial impeller and a multistage axial flow turbine. Results of the program indicate that the present code operated in a two-dimensional mode is a cost effective alternative to full three-dimensional calculations, and that it permits realistic predictions of unsteady loadings and losses for multistage machines

Progress report on a new search for free e/3 quarks in the cores of 10(15) - 10(16) eV air showers

The Leeds 3 sq m Wilson cloud chamber is being used in a new search for free e/3 quarks close to the axes of 10 to the 15th power - 10 to the 16th power eV air showers. A ratio trigger circuit is used to detect the incidence of air shower cores; the position of the shower center and the axis direction are determined from photographs of current-limited spark chambers. It is thus possible, for the first time, to know where we have looked for quarks in air showers and to select for scanning only those cloud chamber photographs where we have good evidence that the shower axis was close to the chamber. 250 g/sq cm of lead/concrete absorber above the cloud chamber serve to reduce particle densities and make a quark search possible very close to the shower axes. The current status of the search is given

Understanding crop growth on duplex soils.

Trial 88EB18 Location: East Beverley Research Station Impeded early root growth. Using aerial photography and crop growth data from previous seasons we identified areas on the site where crops grow well or poorly. One of the factors implicated in the poor growth areas is impeded early root growth (see Belford et al. and Tennant et at., 1990 Experimental Summaries, this section). Here we describe the problem and outline possible causes. Trial 88EB18 Growth and yield of wheat and lupin crops at East Beverley. Location: East Beverley Research Station. To measure the growth and yield of wheat and lupin crops in relation to waterlogging and other soil factors on the Duplex soil at East Beverley. Trial 88EB18 Water use and water efficiency of wheat and lupins at East Beverley. Based on observations made in 1988 and 1989, poor and good crop growth areas were identified. Several studies were undertaken on these areas to identify constraints to crop growth and to measure responses to ameliorative treatments. this report describes results of soil water measurements made to describe: 1. Water infiltration and water extraction patterns of wheat and lupins at poor and good growth areas. 2. Water use and water use efficiencies of wheat and lupins at poor and good growth areas. 3. Effects of treatments used to improve root penetration in the sand (Deep ripping) and to improve the permeability of the clay (Deep ripping and deep placement of gypsum) on water infiltration, extraction and use

Mapping the stability of spatial production in integrated crop and pasture systems: Towards zonal management that accounts for both yield and livestock-landscape interactions

Precision farming technologies are now widely applied within Australian cropping systems. However, the use of spatial monitoring technologies to investigate livestock and pasture interactions in mixed farming systems remains largely unexplored. Spatio-temporal patterns of grain yield and pasture biomass production were monitored over a four-year period on two Australian mixed farms, one in the south-west of Western Australia and the other in south-east Australia. A production stability index was calculated for two paddocks on each farm. An example is given here for one paddock from Western Australia. The stability index described here is unique in that it combines spatial and temporal variation across both cropping and pasture phases. Co-efficient of variation in yield was used as the threshold value for determining stability. Production in each stability zone was analysed statistically for consistency and correlation between the cropping and pasture phases. Results indicate that the stability index can be used in mixed farming systems to assist in management decisions and for the paddock described, spatial and temporal variation in production between crop and pasture phases was strongly correlated

Crop management in rows.

Trial 87M71 Effect of row spacing and stubble retention on the yield of wheat. Location: Merredin Research Station. Treatments, site management and results from 1987, 1988 and 1989 have been described in previous experimental summaries. Four row spacings (9, 18, 27 and 36 cm) are compared in either burnt or stubble retained plots, on a red brown earth on the Merredin Research Station. There are six replicates laid out in a randomised block design. Trial 90ME32 Effect of row spacing and variety on the yield of wheat. Location: duplex site at Crooks (see 1989 Experimental Summary) This trial was carried out on the duplex soil site at Crooks (see 1989 Experimental Summary); in 1990, the wheat crop was sown after lupins, and aimed to look at the interaction between row spacing and variety of wheat. Varieties which differ in their canopy characteristics might be expected to differ in the rate at which they develop ground cover, and might therefore influence the partitioning of ET between soil evaporation and crop transpiration. The varieties Kuhn (low tillering, small leaf area) and Aroona (higher tillering, larger leaf area) were compared at row spacings of 9, 18 and 36 cm

Long term effects of direct drilling and conventional cultivation on the distribution of nutrients and organic c in soils of south Western Australia

This experiment was part of a long term tillage trial designed to examine the effect of various tillage systems on the yield of wheat on a range of agricultural soils in Western Australia. A subset of results from the main experiment is presented here.This report describes the distribution of extractable P, extractable K, total N, organic C, and pH at 6 depths in the soil from 6 locations; Wongan Hills, Merredin (H) (calcic, red-brown earth), Avondale, Merredin (L) (acid, yellow earth), Esperance and Mt Barker. Three tillage systems (conventional cultivation, direct drilled with a combine, direct drilled with a triple discdrill) and 2 nitrogen rates were applied, to sites of continuously cropped wheat. Developments were monitored for a period of 9 years.The concentrations of extractable nutrients and organic C in the surface layers of the soil were generally higher with direct drilling than with conventional cultivation. Differences between treatments were generally evident within the first three years of the experiment. The effect of tillage tended to be similar at all locations except Esperance, where tillage had no effect on the concentration of extractable nutrients or organic C in the soil. Conventionally cultivated sandy and sandy clay loam soils also tended to have a slightly higher pH than direct drilled soils

Experiments on grain yield in a range of old and modern wheat varieties.

Growth, yield, water use and water use efficiency of old and modern wheat varieties in a mediterranean type environment, 87M17 and 87WH14. Ear and stem dry matter at anthesis and grain yield in a range of wheat varieties, 87M18

Stochastic Liouville equation treatment of the electron paramagnetic resonance line shape of an S-state ion in solution

The current approaches used for the analysis of electron paramagnetic resonance spectra of Gd3+ complexes suffer from a number of drawbacks. Even the elaborate model of [Rast et al., J. Chem. Phys. 113, 8724 (2000)] where the electron spin relaxation is explained by the modulation of the zero-field splitting (ZFS), by molecular tumbling (the so called static contribution), and deformations (transient contribution), is only readily applicable within the validity range of the Redfield theory [Advances in Magnetic Resonance, edited by J.-S. Waugh (Academic, New York, 1965), Vol. 1, p. 1], that is, when the ZFS is small compared to the Zeeman energy and the rotational and vibrational modulations are fast compared to the relaxation time. Spin labels (nitroxides and transition metal complexes) have been studied for years in systems that violate these conditions. The theoretical framework commonly used in such studies is the stochastic Liouville equation (SLE). The authors shall show how the physical model of Rast et al. can be cast into the SLE formalism, paying special attention to the specific problems introduced by the [Uhlenbeck and Ornstein, Phys. Rev. 36, 823 (1930)] process used to model the transient ZFS. The resulting equations are very general and valid for arbitrary correlation times, magnetic field strength, electron spin S, or symmetry. The authors demonstrate the equivalence of the SLE approach with the Redfield approximation for two well-known Gd3+ complexes