title: Rates of accumulation of cadmium and uranium in a New Zealand hill farm soil as a result of long-term use of phosphate fertilizer

authors: Schipper, Louis A.

subjects: pasture

abstract: In New Zealand, phosphate (P) fertilisers used in agriculture are the main sources of the potentially toxic elements cadmium (Cd) and uranium (U), which occur as unwanted contaminants. New Zealand is developing draft soil guideline values (SGV) for maximum concentrations of Cd. To assess when soils under pasture for sheep production might reach a particular SGV, we analysed archived soil samples from a 23 yr P fertiliser trial. The pasture sites were at Whatawhata, North Island, New Zealand, and had received P fertiliser at the rates of 0, 30, 50 and 100 kg P ha⁻¹ yr⁻¹. From 1983 to 1989, P was applied as single superphosphate, from 1989 to 2006, P was applied as triple superphosphate. Soils from replicate paddocks were sampled annually to a depth of 75 mm on easy (10–20°) and steep (30–40°) slope classes. Total P, Cd and U were analysed by ICP-MS after acid digestion. Data were analysed by fitting trend lines using linear mixed models for two slope classes and for two sampling periods 1983–1989 and 1989–2006 when the soil sampling method and fertiliser type had been changed.

The changes in total P, Cd and U were directly related to the type and amount of P fertiliser applied, the control treatment showed no significant change in P, Cd or U. At 50 and 100 kg P ha⁻¹ yr⁻¹ there were generally linear increases in total P and total U, and the same trend line applied to both time periods, but the rate of increase in P was greater on the easy slope class. For Cd, a “broken stick” model was needed to explain the data. Pre-1989, Cd increased in the 50 and 100 kg P ha⁻¹ yr⁻¹ treatment (0.036–0.045 mg kg⁻¹ yr⁻¹, respectively): post 1988 the rate of increase declined markedly on those two treatments (0.005–0.015 mg kg⁻¹ yr⁻¹, respectively), and declined absolutely in the 30 kg P ha⁻¹ yr⁻¹ treatments. The maximum content of Cd was in the 100 kg P ha⁻¹ yr⁻¹ treatment which reached 0.931 mg Cd kg⁻¹ on the easy slope. For U there were steady linear increases for the 30, 50 and 100 kg P ha⁻¹ treatments, and no significant difference between the steep and easy slopes, nor the two sampling periods, the maximum concentration obtained was 2.80 mg U kg⁻¹ on the 100 kg P ha⁻¹ treatment. The results suggest that at rates of P fertiliser likely to be applied to hill farms (<50 kg P ha⁻¹ yr⁻¹ ), and using P fertiliser with low Cd content, then the Cd concentration in this soil will never reach a SGV of 1 mg kg⁻¹.

text: Rates of accumulation of cadmium and uranium in a New Zealand hill farm soil as a result of long-term use of phosphate fertilizer In New Zealand, phosphate (P) fertilisers used in agriculture are the main sources of the potentially toxic elements cadmium (Cd) and uranium (U), which occur as unwanted contaminants. New Zealand is developing draft soil guideline values (SGV) for maximum concentrations of Cd. To assess when soils under pasture for sheep production might reach a particular SGV, we analysed archived soil samples from a 23 yr P fertiliser trial. The pasture sites were at Whatawhata, North Island, New Zealand, and had received P fertiliser at the rates of 0, 30, 50 and 100 kg P ha⁻¹ yr⁻¹. From 1983 to 1989, P was applied as single superphosphate, from 1989 to 2006, P was applied as triple superphosphate. Soils from replicate paddocks were sampled annually to a depth of 75 mm on easy (10–20°) and steep (30–40°) slope classes. Total P, Cd and U were analysed by ICP-MS after acid digestion. Data were analysed by fitting trend lines using linear mixed models for two slope classes and for two sampling periods 1983–1989 and 1989–2006 when the soil sampling method and fertiliser type had been changed.

The changes in total P, Cd and U were directly related to the type and amount of P fertiliser applied, the control treatment showed no significant change in P, Cd or U. At 50 and 100 kg P ha⁻¹ yr⁻¹ there were generally linear increases in total P and total U, and the same trend line applied to both time periods, but the rate of increase in P was greater on the easy slope class. For Cd, a “broken stick” model was needed to explain the data. Pre-1989, Cd increased in the 50 and 100 kg P ha⁻¹ yr⁻¹ treatment (0.036–0.045 mg kg⁻¹ yr⁻¹, respectively): post 1988 the rate of increase declined markedly on those two treatments (0.005–0.015 mg kg⁻¹ yr⁻¹, respectively), and declined absolutely in the 30 kg P ha⁻¹ yr⁻¹ treatments. The maximum content of Cd was in the 100 kg P ha⁻¹ yr⁻¹ treatment which reached 0.931 mg Cd kg⁻¹ on the easy slope. For U there were steady linear increases for the 30, 50 and 100 kg P ha⁻¹ treatments, and no significant difference between the steep and easy slopes, nor the two sampling periods, the maximum concentration obtained was 2.80 mg U kg⁻¹ on the 100 kg P ha⁻¹ treatment. The results suggest that at rates of P fertiliser likely to be applied to hill farms (<50 kg P ha⁻¹ yr⁻¹ ), and using P fertiliser with low Cd content, then the Cd concentration in this soil will never reach a SGV of 1 mg kg⁻¹.

year: 2011

title: Understanding the properties of low-cost iron-containing powder metallurgy titanium alloys

authors: Bolzoni, Leandro

abstract: The high production costs of titanium in comparison to other structural metals is the main limiting factor for the wide employment of titanium. Cost reduction can be addressed considering creative fabrication methods and/or formulating new chemical compositions. In this work the fabrication of low-cost iron-containing powder metallurgy titanium alloys is studied by using a spherical 85Fe/15Ni powder whose small particle size and spherical morphology favours both the densification of the material and the diffusion of the alloying elements. The designed composition are obtained by the blending elemental approach and processed by means of the conventional powder metallurgy route. The high vacuum sintered α + β alloys show homogeneous microstructure and the formation of brittle intermetallic phases is prevented as checked by XRD and DTA analysis. Similar physical and mechanical behaviour to wrought-equivalent structural titanium alloys is obtained for these new low-cost alloys which, therefore, are potential materials for cheaper structural titanium components.

text: Understanding the properties of low-cost iron-containing powder metallurgy titanium alloys The high production costs of titanium in comparison to other structural metals is the main limiting factor for the wide employment of titanium. Cost reduction can be addressed considering creative fabrication methods and/or formulating new chemical compositions. In this work the fabrication of low-cost iron-containing powder metallurgy titanium alloys is studied by using a spherical 85Fe/15Ni powder whose small particle size and spherical morphology favours both the densification of the material and the diffusion of the alloying elements. The designed composition are obtained by the blending elemental approach and processed by means of the conventional powder metallurgy route. The high vacuum sintered α + β alloys show homogeneous microstructure and the formation of brittle intermetallic phases is prevented as checked by XRD and DTA analysis. Similar physical and mechanical behaviour to wrought-equivalent structural titanium alloys is obtained for these new low-cost alloys which, therefore, are potential materials for cheaper structural titanium components.

year: 2016-11-15

title: Te Puea Herangi: an ethno-biographical study

authors: King, Michael

abstract: Early explanations of Maori leadership (for example Buck 1950) tended to emphasize the principle of male primogeniture - the expectation that community leadership would in the normal course of affairs pass to the eldest sons of lines of first-born males. Later studies of Western-educated leaders and those with a non-traditional power base (see Butterworth 1969, Cody 1953, Condliffe 1971, and Henderson 1972) continued to emphasize male primacy. Against the tenor of these studies, however, is the fact that in the first half of the twentieth century the Maori King Movement was dominated and welded together by a woman who preached male primogeniture though her life seemed to contradict the principle; Te Puea Herangi was not of a senior descent line and neither compensated for its absence by a substantial degree of European education nor consolidated her position by marriage. Nor was she simply a forceful leader in Maori terms only: Professor J.G.A. Pocock (in The Maori and New Zealand Politics) called her “possibly the most influential woman in our political history”.

This study examines Te Puea's leadership role: how she came to assume it, how she exercised it, and its consequences. Analytical concepts like Max Weber's distinctions between charismatic, traditional and rational-legal authority, have been avoided. The danger of adopting them is that the themes and emphases of research material can be easily and unintentionally warped to fit the model, in the interests of tidiness and intelligibility. Instead, this study proceeds by way of a detailed and chronological examination of the major events of Te Puea's life, and an evaluation of actions and statements as they occur and in the context in which they occur. It is, in other words, a consideration of Te Puea's life in terms of her own concepts, and in relation to the Maori and wider public affairs of her day. Explanations for her behaviour are sought within the boundaries of her own life and culture rather than from the imposition of alien models.

text: Te Puea Herangi: an ethno-biographical study Early explanations of Maori leadership (for example Buck 1950) tended to emphasize the principle of male primogeniture - the expectation that community leadership would in the normal course of affairs pass to the eldest sons of lines of first-born males. Later studies of Western-educated leaders and those with a non-traditional power base (see Butterworth 1969, Cody 1953, Condliffe 1971, and Henderson 1972) continued to emphasize male primacy. Against the tenor of these studies, however, is the fact that in the first half of the twentieth century the Maori King Movement was dominated and welded together by a woman who preached male primogeniture though her life seemed to contradict the principle; Te Puea Herangi was not of a senior descent line and neither compensated for its absence by a substantial degree of European education nor consolidated her position by marriage. Nor was she simply a forceful leader in Maori terms only: Professor J.G.A. Pocock (in The Maori and New Zealand Politics) called her “possibly the most influential woman in our political history”.

This study examines Te Puea's leadership role: how she came to assume it, how she exercised it, and its consequences. Analytical concepts like Max Weber's distinctions between charismatic, traditional and rational-legal authority, have been avoided. The danger of adopting them is that the themes and emphases of research material can be easily and unintentionally warped to fit the model, in the interests of tidiness and intelligibility. Instead, this study proceeds by way of a detailed and chronological examination of the major events of Te Puea's life, and an evaluation of actions and statements as they occur and in the context in which they occur. It is, in other words, a consideration of Te Puea's life in terms of her own concepts, and in relation to the Maori and wider public affairs of her day. Explanations for her behaviour are sought within the boundaries of her own life and culture rather than from the imposition of alien models.

year: 1977