Phosphorus Nutrition on Leaching Sands.

The excessive amounts of nutrients entering the Peel-Harvey Estuarine system have resulted in a marked increase in the abundance of algal species .within the estuary and reduced production on the sandy coastal soils of the catchment from which the nutrients are being leached. Recent stream samplings by D.C.E have shown that the deep grey Bassendean sands may be contributing up to 40 per cent of the total P loading in the Harvey River. Agriculture Department trials around Albany on similar sands have shown that up to 80 per cent of the bicarb extractable P may be lost after only 150 mm of rain. Phosphorus rundown trials. 82HA14, 82HA15, 82HA16, 82HA17, 82HA18. Soil test calibration curve trials. 82HA20, 82HA21, 82HA22, 82HA23, 82HA24, 82HA25, 82HA26, 82HA27, 82HA28, 82HA29, 82HA30. P sources x rates x times of application trials. 82HA31, 82HA32. P sources leaching trials. 82HA33, same site as 82HA31, 82HA34, same site as 82HA32. Lime rates with + P. 82HA36, 82HA37, 82HA38, Old land same site as 82HA28. Overall summary. The reverted superphosphates are at least as good as normal superphosphate as far as pasture yield and P uptake are concerned, however bicarb P results indicate considerably less leaching. The very insoluble phosphate areas do not leach to any degree but are less efficient than superphosphate in pasture nutrition. The performance of these less leachable sources is expected to improve relative to superphosphate in subsequent years. The two leaching trials show that there is little difference in P leaching on new and old land sites, however the build-up of organic material on old land appears to have a marked effect on Potassium retention. In 1983 all treatments in the soil test calibration curve trials should have different residual values of P and splitting each plot into untreated and adequately supplied halves should give many points for the soil test calibration curves. From the three trials reported here it would appear that there is no interaction between P nutrition and added lime, however improved pasture management on these trials in 1983 should give more data

Chemical speciation and flyash stabilization of arsenic, barium, chromium, and lead in drilling fluid wastes /

Another laboratory study was conducted to determine the behavior of metals within drilling fluid wastes stabilized by the addition of flyash. Drilling fluid wastes were mixed with varying proportions of flyash ranging from 10 to 30 percent. After allowing the mixtures to set for 1 week or 5 weeks, EP Toxicity Extractions were performed and the resultant liquid analyzed for arsenic, barium, chromium, lead, and zinc. The behavior of these elements was not significantly affected in the mixtures, beyond that expected by the physical processes involved. No chemical reactions appear to be taking place which might result in a significant release of metals to the environment. Therefore, with respect to the metals tested, flyash stabilization appears to be an acceptable treatment method for drilling fluid wastes.A laboratory study was conducted to determine the influence of pH and ionic strength on the distribution of arsenic, barium, chromium and lead in three different drilling fluid wastes. Samples were obtained in the field and equilibrated in the laboratory under controlled conditions. A sequential extraction procedure was then used to fractionate the heavy metals into the designated forms of exchangeable, adsorbed, organically bound, carbonate, and residual phases, thus providing insight into the potential availability of the heavy metals for possible remobilization effects into ground or surface waters. The majority of each of the metals studied was found in the organically bound, carbonate, or residual forms, with the relative distribution among these forms depending on the pH and type of drilling fluid. Generally, decreasing pH caused a shift from the more stable (residual) form toward less stable (carbonate, organic) forms of the heavy metals. Changes in the ionic strength of the equilibrating solution, by diluting to 0.5 and 0.1 times field strength, had no significant influence on the distribution of the heavy metals within the solid phase. The occurrence of the metals in the more stable organic, carbonate, and residual forms in the waste drilling fluids, coupled with no significant release to the aqueous phase upon varying pH and/or ionic strength, indicated the resistance of these waste metals to remobilization from waste drilling fluids

Exploring the ‘wicked’ problem of student dissatisfaction with assessment and feedback in higher education

tudent dissatisfaction with assessment and feedback is a significant challenge for most UK Higher Education Institutions according to a key national survey. This paper explores the meaning, challenges and potential opportunities for enhancement in assessment and feedback within the authors' own institution as illustrative of approaches that can be taken elsewhere. Using a qualitative design, a review of assessment and feedback, which included an exploration of students' perceptions, was made in one College of the University. The findings highlighted variations in assessment and feedback practice across the College with dissatisfaction typically being due to misunderstanding or miscommunication between staff and students. Drawing on the review, we assert in this paper that students' dissatisfaction with assessment and feedback is not a 'tame' problem for which a straightforward solution exists. Instead, it is a 'wicked' problem that requires a complex approach with multiple interventions

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

Phosphorus Leaching in Sandy Soils. I. Short-term Effects of Fertilizer Applications and Environmental Conditions

The consequences of previous as well as current environmental conditions and management practices on the potential for phosphorus (P) to be lost by drainage from sandy soils in the short term (\u3c 1 year) were studied in the laboratory and the field. The potential for P losses by drainage was estimated by measuring soil solution P levels and rapidly released P. Rapidly released P was measured by determining the concentration of dissolved inorganic P contained in filtered (µm) soil solutions after incubating soil at saturation for 15 min at ambient temperature. In the laboratory, sandy soils were incubated with ordinary superphosphate, coastal superphosphate (a granulated mixture of equal parts of superphospate, rock phosphate and elemental sulfur) or lime-superphosphate (a lime-reverted superphosphate with 18% kiln dust) and sequentially desorbed with deionized water. The effects of the extent of leaching, fertilizer type, application rate and the time of contact with the soil on soil solution P levels were investigated. The influence of annual pasture death and summer rainfall on rapidly released P in soils that had been pre-treated by leaching were also investigated. Phosphorus concentrations decreased logarithmically in the successive supernatants of the sequentially desorbed soils. More P was desorbed from soils incubated with superphosphate and lime-superphosphate than soil incubated with coastal superphosphate. At each level of pre-leaching, the P concentrations in the soil solution increased with increasing time. The level, to which the P concentration in the soil solution increased at each time, decreased with increased extent of pre-leaching. The addition of P fertilizers increased the concentration of P in the soil solution. The concentrations increased with increasing application rate and were much higher for superphosphate than for coastal superphosphate; however, there was little effect of contact time on soil solution P levels. Rapidly released P levels after leaching increased during a period of no further leaching. Additional moisture or plant material during this period of no further leaching increased the rate and extent to which rapidly released P increased. Monitoring of rapidly released P in the 0-2, 2-5, 5-10 and 10-20 cm layers of field plots, with and without applications of superphosphate, showed that sampling depth, water flow path, fertilizer management, rainfall pattern and background P levels would affect the estimate of short-term P losses. Rapidly released P in the 0-2 cm layer varied markedly with time and was higher (P \u3c 0.05) than that in lower soil layers. Rapidly released P increased after the winter and spring rains diminished and then decreased after the rains commenced again at the end of the summer. A possible annual cycle of P in sandy soils in a mediterranean climate is postulated by considering the laboratory and field data in combination

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

The relationship between different types of dissociation and psychosis-like experiences in a non-clinical sample

This study investigates whether detachment-type dissociation, compartmentalisation-type dissociation or absorption was most strongly associated with psychosis-like experiences in the general population. Healthy participants (N=215) were tested with the Dissociative Experiences Scale (DES, for detachment-related dissociative experiences); the Harvard Group Scale of Hypnotic Susceptibility (HGSHS:A, for dissociative compartmentalisation); the Tellegen Absorption Scale (TAS, for non-clinical ‘functional’ dissociative experience); and two measures of psychotic-like experiences, the 21-item Peters et al. Delusions Inventory (PDI-21) and the Cardiff Anomalous Perceptions Scale (CAPS). In multiple regression analyses, DES and TAS but not HGSHS: A scores were found to be significantly associated with PDI-21 and CAPS overall scores. A post-hoc hierarchical cluster analysis checking for cluster overlap between DES and CAPS items, and the TAS and CAPS items showed no overlap between items on the DES and CAPS and minimal overlap between TAS and CAPS items, suggesting the scales measure statistically distinct phenomena. These results show that detachment-type dissociation and absorption, but not compartmentalisation-type dissociation are significantly associated with psychosis-like experiences in a non-clinical population