title: Changes in natural ¹⁵n abundance in pastoral soils receiving differing amounts of superphosphate fertilizer and irrigation for 50 years

authors: Mudge, Paul Lawrence

abstract: Intensification of pastoral agriculture has led to increased N losses to the wider environment. This has led to an emphasis on improving our understanding of soil N dynamics, and development of management practices which mitigate N losses. The natural abundance of the stable isotope δ¹⁵N relative to ¹⁴N (δ¹⁵N) in soils can provide an integrated measure of past N cycle processes, and in particular soil δ15N can reflect past N losses, because during most N transformation processes 14N is preferentially lost. We therefore hypothesized that pastoral soils under intensive management regimes (with high N inputs, cycling, and loss) would become progressively enriched with ¹⁵N relative to soils under less intensive management. To test this hypothesis we analyzed archived surface soils from two long-term grazed field trials in New Zealand, where different rates of irrigation and superphosphate fertilizer had been applied for ∼50 yr. In all treatments except one (a control treatment receiving no fertilizer), δ¹⁵N increased with time and the increase was greater in treatments receiving more superphosphate or irrigation (average increases ranged from ∼0.015–0.034 ‰ yr–1). Pasture production and grazing intensity also increased with increasing fertilizer rate and irrigation frequency, and we found positive correlations between the average rate of change in soil δ¹⁵N, and total pasture production (r² = 0.77, p = 0.02), clover production (r² = 0.95, p < 0.001), and calculated N losses (r² = 0.98, p < 0.001) over ∼50 yr. We suggest that most of the difference in δ¹⁵N observed between treatments was due to the influence fertilizer and irrigation had on pasture production, and the resulting effects this had on isotope fractionating N loss processes. Soil δ¹⁵N could therefore be a useful indicator of past management intensity and N cycling and loss from pastoral systems.

text: Changes in natural ¹⁵n abundance in pastoral soils receiving differing amounts of superphosphate fertilizer and irrigation for 50 years Intensification of pastoral agriculture has led to increased N losses to the wider environment. This has led to an emphasis on improving our understanding of soil N dynamics, and development of management practices which mitigate N losses. The natural abundance of the stable isotope δ¹⁵N relative to ¹⁴N (δ¹⁵N) in soils can provide an integrated measure of past N cycle processes, and in particular soil δ15N can reflect past N losses, because during most N transformation processes 14N is preferentially lost. We therefore hypothesized that pastoral soils under intensive management regimes (with high N inputs, cycling, and loss) would become progressively enriched with ¹⁵N relative to soils under less intensive management. To test this hypothesis we analyzed archived surface soils from two long-term grazed field trials in New Zealand, where different rates of irrigation and superphosphate fertilizer had been applied for ∼50 yr. In all treatments except one (a control treatment receiving no fertilizer), δ¹⁵N increased with time and the increase was greater in treatments receiving more superphosphate or irrigation (average increases ranged from ∼0.015–0.034 ‰ yr–1). Pasture production and grazing intensity also increased with increasing fertilizer rate and irrigation frequency, and we found positive correlations between the average rate of change in soil δ¹⁵N, and total pasture production (r² = 0.77, p = 0.02), clover production (r² = 0.95, p < 0.001), and calculated N losses (r² = 0.98, p < 0.001) over ∼50 yr. We suggest that most of the difference in δ¹⁵N observed between treatments was due to the influence fertilizer and irrigation had on pasture production, and the resulting effects this had on isotope fractionating N loss processes. Soil δ¹⁵N could therefore be a useful indicator of past management intensity and N cycling and loss from pastoral systems.

year: 2013

title: A Study on Supported Metal Catalysts Prepared from Colloidal Precursors

authors: Jaine, Jacob Evan

subjects: catalyst

abstract: When metal nanoparticles are supported on the surface of an inert carrier, the resulting materials can become powerful heterogeneous catalysts capable of accelerating a diverse range of chemical reactions. Though there are a wide variety of synthetic routes by which these materials can be prepared, many offer little control over the textural properties of the resulting catalyst. Conversely, methods using pre-formed colloidal nanoparticles as a metal source offer the potential for precise control of properties like particle size and shape. This is both a topical class of syntheses, and the subject of the current body of work. Three different types of colloids were therefore prepared using different stabilising agents, and subsequently used to produce an array of different catalysts.

As support materials for the catalysts, a series of four commercially available materials were obtained, including silica, alumina, hydroxyapatite, and microcrystalline cellulose. Four novel analogues were also obtained, including halloysite, perlite, bioapatite, and macrofibrillar cellulose. In order to understand their physicochemical properties, they were characterised by a combination of Fourier transform infrared microspectroscopy, solid-state ¹H, ¹³C, ²⁷Al, ²⁹Si, and ³¹P nuclear magnetic resonance spectroscopy, x-ray diffraction, x-ray fluorescence spectroscopy, scanning and transmission electron microscopy, laser diffraction analysis, and zeta potential measurements. Additional experiments were performed to investigate the wetting properties of the materials using the Washburn capillary rise method, which was shown to be a valuable method for rationalising solvent choice for reactions involving these materials.

An initial batch of catalysts was produced by immobilising electrostatically-stabilised rhodium, palladium, and platinum colloids onto these support materials. Instrumental characterisation of the catalysts showed no major perturbation to the chemistry of the materials following the immobilisation, though some subtle surface effects were observed. These catalysts were tested in the hydrogenation of several olefins, and were found to have excellent catalytic activity, up to 64,400 hr⁻¹, under standard conditions. 
A second batch of catalysts was produced by immobilising polymer-stabilised metal colloids onto the supports. Characterisation of the materials showed the polymers and the nanoparticles they contained were associated strongly with the support materials, though the spatial distribution varied significantly between systems. Activation of the catalysts by calcination was shown to initiate their thermal decomposition and oxidation, which in turn affected their catalytic activity. The catalysts containing supported rhodium or platinum were inactive, while those containing supported palladium showed good activity, up to 41,900 hr⁻¹.
A third batch of catalysts was produced by immobilising solvent-stabilised metal colloids onto the supports. Amide-type solvents were shown to be the most effective for this purpose, though spectroscopic evidence suggested the samples contained residual solvent and related decomposition products. These catalysts displayed modest activities of up to 8,100 hr⁻¹.
Finally, a method was developed for quantifying the amount of metal in the catalysts using laser-induced breakdown spectroscopy. A series of matrix-matched standards were prepared, and their elemental compositions measured accurately using neutron activation analysis. The method was shown to be rapid and inexpensive to implement, with linearity up to 2.0 wt% metal and a precision of over 95%.

text: A Study on Supported Metal Catalysts Prepared from Colloidal Precursors When metal nanoparticles are supported on the surface of an inert carrier, the resulting materials can become powerful heterogeneous catalysts capable of accelerating a diverse range of chemical reactions. Though there are a wide variety of synthetic routes by which these materials can be prepared, many offer little control over the textural properties of the resulting catalyst. Conversely, methods using pre-formed colloidal nanoparticles as a metal source offer the potential for precise control of properties like particle size and shape. This is both a topical class of syntheses, and the subject of the current body of work. Three different types of colloids were therefore prepared using different stabilising agents, and subsequently used to produce an array of different catalysts.

As support materials for the catalysts, a series of four commercially available materials were obtained, including silica, alumina, hydroxyapatite, and microcrystalline cellulose. Four novel analogues were also obtained, including halloysite, perlite, bioapatite, and macrofibrillar cellulose. In order to understand their physicochemical properties, they were characterised by a combination of Fourier transform infrared microspectroscopy, solid-state ¹H, ¹³C, ²⁷Al, ²⁹Si, and ³¹P nuclear magnetic resonance spectroscopy, x-ray diffraction, x-ray fluorescence spectroscopy, scanning and transmission electron microscopy, laser diffraction analysis, and zeta potential measurements. Additional experiments were performed to investigate the wetting properties of the materials using the Washburn capillary rise method, which was shown to be a valuable method for rationalising solvent choice for reactions involving these materials.

An initial batch of catalysts was produced by immobilising electrostatically-stabilised rhodium, palladium, and platinum colloids onto these support materials. Instrumental characterisation of the catalysts showed no major perturbation to the chemistry of the materials following the immobilisation, though some subtle surface effects were observed. These catalysts were tested in the hydrogenation of several olefins, and were found to have excellent catalytic activity, up to 64,400 hr⁻¹, under standard conditions. 
A second batch of catalysts was produced by immobilising polymer-stabilised metal colloids onto the supports. Characterisation of the materials showed the polymers and the nanoparticles they contained were associated strongly with the support materials, though the spatial distribution varied significantly between systems. Activation of the catalysts by calcination was shown to initiate their thermal decomposition and oxidation, which in turn affected their catalytic activity. The catalysts containing supported rhodium or platinum were inactive, while those containing supported palladium showed good activity, up to 41,900 hr⁻¹.
A third batch of catalysts was produced by immobilising solvent-stabilised metal colloids onto the supports. Amide-type solvents were shown to be the most effective for this purpose, though spectroscopic evidence suggested the samples contained residual solvent and related decomposition products. These catalysts displayed modest activities of up to 8,100 hr⁻¹.
Finally, a method was developed for quantifying the amount of metal in the catalysts using laser-induced breakdown spectroscopy. A series of matrix-matched standards were prepared, and their elemental compositions measured accurately using neutron activation analysis. The method was shown to be rapid and inexpensive to implement, with linearity up to 2.0 wt% metal and a precision of over 95%.

year: 2016

title: Inside the Resource Management Act:  A Tainui Case Study

authors: Greensill, Angeline Ngahina

subjects: Maori

abstract: Under the Resource Management Act (RMA) 1991 councils are required to promote the sustainable management of physical and natural resources within their respective areas.    In carrying out their duties, councils are obliged to recognise and provide for the relationship of Māori with their culture, traditions, lands, waters and other taonga.  They are also required to have regard to kaitiakitanga, and to take into account the principles of te Tiriti o Waitangi when making decisions.    
This thesis focuses on the RMA experiences of Tainui, a hapū in Whaingaroa. It sets out to prove that in the last 19 years, since the enactment of the RMA, Waikato councils have failed to honour these obligations to Tainui.  While the RMA specifically provides for Māori interests, in reality those interests are contested and eroded by decision makers who write and enforce rules which inequitably affect Māori relationships with land and other taonga. 
The thesis engages multiple theories and methodologies including Kaupapa Māori, critical theory, autobiography, and a longitudinal case study to expose personal experiences that   bring the realities of planning impacts on Tainui to life.    The fact that Tainui has successfully appealed several council decisions to the Environment Court indicates that councils are failing to meet their obligations as laid out in the legislation.

text: Inside the Resource Management Act:  A Tainui Case Study Under the Resource Management Act (RMA) 1991 councils are required to promote the sustainable management of physical and natural resources within their respective areas.    In carrying out their duties, councils are obliged to recognise and provide for the relationship of Māori with their culture, traditions, lands, waters and other taonga.  They are also required to have regard to kaitiakitanga, and to take into account the principles of te Tiriti o Waitangi when making decisions.    
This thesis focuses on the RMA experiences of Tainui, a hapū in Whaingaroa. It sets out to prove that in the last 19 years, since the enactment of the RMA, Waikato councils have failed to honour these obligations to Tainui.  While the RMA specifically provides for Māori interests, in reality those interests are contested and eroded by decision makers who write and enforce rules which inequitably affect Māori relationships with land and other taonga. 
The thesis engages multiple theories and methodologies including Kaupapa Māori, critical theory, autobiography, and a longitudinal case study to expose personal experiences that   bring the realities of planning impacts on Tainui to life.    The fact that Tainui has successfully appealed several council decisions to the Environment Court indicates that councils are failing to meet their obligations as laid out in the legislation.

year: 2010