Phosphorus nutrition of high rainfall pastures - Peel Harvey estuarine system study (phase II) and related phosphorus work

A. Sources, rates, time of application of phosphorus on high rainfall pastures. 80AL2, 80AL5, 81AL5, 81AL6, 81KE2, 81MA4, 82AL10, 82HA31, 82HA32, 83HA26, 83HA27. B. Soil test calibration curve trials on Bassendean sands. 82HA20, 82HA21, 82HA22, 82HA23, 82HA24, 82HA25, 82HA26, 82HA27, 82HA28, 82HA29, 82HA30. C. Soil test calibration curve trials on Coolup sands. 83HA20, 83HA21, 83HA22, 83HA23, 83HA24, 83HA25. D. Phosphorus rundown. 82HA14, 82HA15, 82HA16, 82HA18. NOTE: Summary is in two parts. 1. Peel Harvey catchment program (Deeley, Barker). 2. General program on high rainfall sandy soils (Yeates, Clarke). Summary of Experimental Work. General Aims. The work summarized here was commenced with the following aims: 1. To improve the efficiency of agricultural utilization of phosphorus applied to pastures on the deep leaching sands of the high rainfall areas. 2. To minimize phosphorus loss to drainage from the deep sand, and thus reduce eutrophication problems in adjacent waterways. Five potential ways of reducing the phosphorus losses from fertilizer sources while still maintaining optimum level of agricultural productivity were considered possible. These were: 1. The use of accurate soil tests for predicting phosphorus requirements and thus ensuring that only phosphorus actually required is applied. 2. Modification of times of application of soluble phosphorus fertilizer to maximise the plant utilisation.of applied P, and to minimise losses. 3. Development of phosphorus fertilizers of lower water solubility than ordinary superphosphate (and hence with reduced leaching losses). 4. Use of deep rooted and/or perennial plant species which are better able to utilize applied soluble P. 5. Modification of the sandy soils to increase phosphorus adsorption capacity and hence reduce or eliminate leaching losses. To date research has been chiefly concerned with the first three of these possibilities

Modifying fertiliser practices

If modified fertiliser practices are adopted phosphorus losses from the Peel-Harvey catchment can be reduced. Farmers can save money on fertiliser applications and the need for more expensive catchment management measures to reduce algal pollution of the estuary will be avoided. Research data available so far indicate that, with farmer co-operation and the use of the new slow release fertiliser New Coastal Superphosphate, long-term phosphorus application rates can be reduced by 30-40 per cent - and possibly even halved - without lowering agricultural production. This will also reduce phosphorus loss to drainage water. Although much of the research since 1982 has concentrated on the Peel-Harvey catchment, many of the results apply to all of the high rainfall coastal belt between Perth and Albany. Already farmers throughout this area have benefited from the researc

Rock phosphates : fertilisers for sandy soils?

Rock phosphates, from which water solubls phosphorus fertilisers such as superphosphate are manufactured, sometimes appear attractive to farmers because of their relatively low cost. But redearch has shown t6hat on most western australian soils they are not economical fertilisers. However, some deep sandy soils of the State\u27s high rainfall area are exeptions. On these soils, rock phosphates compare favourably with superphosphate for plant growth. But how can these deep sands be identified. This article describes research to define the soil characteristics necessary for rock phosphates and fertilisers containing rock phosphate, such as Coastal superphosphate, to be effective substitutes for superphosphate

Phosphorus nutrition of high rainfall pastures - Peel Harvey estuarine system study

1. Field experiments. A. Sources, rates, time of application of phosphorous on high rainfall Pastures - 80AL2, 80ALS, 81AL5, 81AL6, 81KE2, 81MA4, 82AL10, 82HA31, 82HA32, 83HA26, 83HA27. B. Soil test calibration curve trials. 82HA20, 82HA26, 82HA29, 83HA20, 83HA21, 83HA22, 83HA23, 83HA24, 83HA25. C. P sources and rates on sandy soils of the high rainfall areas - 84AL33, 84AL34, 84HA18, 84HA25. D.Maintenance P trials - 84AL32, 84HA17, 84HA24, 84HA28. 2.Glasshouse Experiments. 84GL5 - 1. Phosphorus sources on subterranean clover on sandy soils. 2. Soil test calibration experiment

Phosphorus nutrition of high rainfall pastures, Sulphur nutrition of pastures and Sulphur - low rainfall.

Phosphorus nutrition of high rainfall pastures - Peel Harvey Estuarine System Study and related phosphorus work. (1) Sources, rates, time of application of phosphorous on high rainfall pastures. 81AL5, 81AL6, 82AL10, 82HA32, 83HA26, 83HA27. (2) P sources and rates on sandy soils of the high rainfall areas. 84AL33, 84AL34, 84HA18, 84HA25. (3) Maintenance rate of P on pastures on sandy soils. 84AL32, 84HA17, 84HA24, 84 HA28. Sulphur nutrition of pastures A. Sulphur - high rainfall (2684 EX/4054EX) (1) Sources, rates, time of application of sulphur to pastures. 80AL4, 80AL4B (2) S sources and rates on pastures on sandy soils of the high rainfall areas. 84HA20, 84HA27 (3) Maintenance rate of S on pastures on sandy soils. 84AL35, 84HA19, 84HA26 B. Sulphur - low rainfall (1) Sulphur on pastures. 82AL9, 82KA4 (2) Sulphur requirements of wheat. 85TS24 81AL5, 81AL6, 82AL10, 82HA32, 83HA26, 83HA27, 84AL33, 84AL34, 84HA18, 84HA25, 84AL32, 84HA17, 84HA24, 84HA28, 80AL4, 80AL4B, 84HA20, 84HA27, 84AL35, 84HA19, 84HA26, 82AL9, 82KA4, 85TS24

Fluid observers and tilting cosmology

We study perfect fluid cosmological models with a constant equation of state parameter $\gamma$ in which there are two naturally defined time-like congruences, a geometrically defined geodesic congruence and a non-geodesic fluid congruence. We establish an appropriate set of boost formulae relating the physical variables, and consequently the observed quantities, in the two frames. We study expanding spatially homogeneous tilted perfect fluid models, with an emphasis on future evolution with extreme tilt. We show that for ultra-radiative equations of state (i.e., $\gamma>4/3$), generically the tilt becomes extreme at late times and the fluid observers will reach infinite expansion within a finite proper time and experience a singularity similar to that of the big rip. In addition, we show that for sub-radiative equations of state (i.e., $\gamma < 4/3$), the tilt can become extreme at late times and give rise to an effective quintessential equation of state. To establish the connection with phantom cosmology and quintessence, we calculate the effective equation of state in the models under consideration and we determine the future asymptotic behaviour of the tilting models in the fluid frame variables using the boost formulae. We also discuss spatially inhomogeneous models and tilting spatially homogeneous models with a cosmological constant

The Futures of Bianchi type VII0 cosmologies with vorticity

We use expansion-normalised variables to investigate the Bianchi type VII$_0$ model with a tilted $\gamma$-law perfect fluid. We emphasize the late-time asymptotic dynamical behaviour of the models and determine their asymptotic states. Unlike the other Bianchi models of solvable type, the type VII$_0$ state space is unbounded. Consequently we show that, for a general non-inflationary perfect fluid, one of the curvature variables diverges at late times, which implies that the type VII$_0$ model is not asymptotically self-similar to the future. Regarding the tilt velocity, we show that for fluids with $\gamma<4/3$ (which includes the important case of dust, $\gamma=1$) the tilt velocity tends to zero at late times, while for a radiation fluid, $\gamma=4/3$, the fluid is tilted and its vorticity is dynamically significant at late times. For fluids stiffer than radiation ($\gamma>4/3$), the future asymptotic state is an extremely tilted spacetime with vorticity.Comment: 23 pages, v2:references and comments added, typos fixed, to appear in CQ

Automatic Redshift Determination by use of Principal Component Analysis --- I: Fundamentals

With the advent of very large redshift surveys of tens to hundreds of thousands of galaxies reliable techniques for automatically determining galaxy redshifts are becoming increasingly important. The most common technique currently in common use is the cross-correlation of a galactic spectrum with a set of templates. This series of papers presents a new method based on Principal Component Analysis. The method generalizes the cross-correlation approach by replacing the individual templates by a simultaneous linear combination of orthogonal templates. This effectively eliminates the mismatch between templates and data and provides for the possibility of better error estimates. In this paper, the first of a series, the basic mathematics are presented along with a simple demonstration of the application.Comment: 23 pages, 9 Figures, minor revisions, accepted for publication in Astrophysical Journa