title: Pasture burning post irrigation of dairy factory effluent at Edgecumbe, New Zealand

authors: Patterson, Kelli Beth

abstract: Pasture “burning” occurs when pasture turns yellow and dies back following irrigation of high strength effluent from the Fonterra Edgecumbe dairy factory. Pasture burning generally occurs intermittently during spring and continues into early summer. The objectives of my thesis are to review literature related to pasture burning and relate literature to potential causes; monitor pasture burning events and activities at Fonterra Edgecumbe dairy factory to endeavour to find potential causes of pasture burning and undertake an experiment(s) to determine the concentration at which components of the effluent cause pasture burning. 

Preliminary observations and a literature review identified multiple potential causes of pasture burning including effluent with high or low pH, high temperature, low osmotic potential/high osmolality as well as UV-radiation damage, excess nutrients, and salt build up in the soil and plant leaves. The weather at the time of irrigation and daily changes in the effluent composition may influence the severity of burning. It is likely that pasture burning is caused by a combination of effects.

The osmolality measures the concentration of a solution. Osmolality was chosen as a measure of pasture burning as the osmolality measure the solute concentration in a solution. Fresh clover (400 - 500 mmol/kg) and ryegrass (500 - 600 mmol/kg) had a similar mean symplasmic osmolality to burnt clover and ryegrass. The high strength effluent had a lower mean osmolality (217 mmol/kg) compared to fresh and burnt clover and ryegrass. If there are spikes in the concentration of effluent, the osmolality of the effluent may exceed that of the pasture causing reverse osmosis and the water in the plant cells to move out of the leaf causing dehydration. 

A pilot trial to determine if there was a relationship between osmolality and pasture burning was undertaken. Effluent was spiked with KCl and lactose solution to increase the osmolality. The pilot trial showed that as the osmolality of the effluent increased, clover and ryegrass burning increased. A main experiment was then designed to determine the cut off point for the osmolality of the effluent to prevent pasture burning. 

The main experiment was also designed to determine if younger growth was more susceptible to pasture burning. One block had progibb and urea applied to enhance the growth of the pasture.  The main experiment however, was unable to determine if new growth was more susceptible to pasture burning as the weather and nutrient content of the soil was optimal for pasture growth in both blocks.

In the pilot trial, there was a positive correlation (R2 > 0.5) between ryegrass and osmolality, pH, electrical conductivity, total magnesium, sulphate, total sulphur, total sodium, total nitrogen, dissolved reactive phosphorus, total kjeldahl nitrogen and the sodium absorption ratio.

In the main experiment, there was a positive correlation (R2 > 0.5) between clover burning and electrical conductivity, exchangeable sodium percentage, total potassium and chloride. However, there was no strong correlation between ryegrass burning and any of the effluent properties. 
When the pilot trial and main experiment results were combined, there was a positive correlation (R2 > 0.5) between clover burning and electrical conductivity, chloride, total potassium and osmolality. 

My results suggest that the effluent osmolality should not exceed 450 mmol/kg and the electrical conductivity should not exceed 1500 mS/m to prevent strong to very strong pasture burning. Effluent that exceeds either 450 mmol/kg and/or 1500 mS/m should be recirculated through the holding tanks to reduce the concentration of the “spike”.
Clover was more susceptible to severe pasture burning than ryegrass. Further research into pasture burning is required to isolate and better understand the exact cause.

text: Pasture burning post irrigation of dairy factory effluent at Edgecumbe, New Zealand Pasture “burning” occurs when pasture turns yellow and dies back following irrigation of high strength effluent from the Fonterra Edgecumbe dairy factory. Pasture burning generally occurs intermittently during spring and continues into early summer. The objectives of my thesis are to review literature related to pasture burning and relate literature to potential causes; monitor pasture burning events and activities at Fonterra Edgecumbe dairy factory to endeavour to find potential causes of pasture burning and undertake an experiment(s) to determine the concentration at which components of the effluent cause pasture burning. 

Preliminary observations and a literature review identified multiple potential causes of pasture burning including effluent with high or low pH, high temperature, low osmotic potential/high osmolality as well as UV-radiation damage, excess nutrients, and salt build up in the soil and plant leaves. The weather at the time of irrigation and daily changes in the effluent composition may influence the severity of burning. It is likely that pasture burning is caused by a combination of effects.

The osmolality measures the concentration of a solution. Osmolality was chosen as a measure of pasture burning as the osmolality measure the solute concentration in a solution. Fresh clover (400 - 500 mmol/kg) and ryegrass (500 - 600 mmol/kg) had a similar mean symplasmic osmolality to burnt clover and ryegrass. The high strength effluent had a lower mean osmolality (217 mmol/kg) compared to fresh and burnt clover and ryegrass. If there are spikes in the concentration of effluent, the osmolality of the effluent may exceed that of the pasture causing reverse osmosis and the water in the plant cells to move out of the leaf causing dehydration. 

A pilot trial to determine if there was a relationship between osmolality and pasture burning was undertaken. Effluent was spiked with KCl and lactose solution to increase the osmolality. The pilot trial showed that as the osmolality of the effluent increased, clover and ryegrass burning increased. A main experiment was then designed to determine the cut off point for the osmolality of the effluent to prevent pasture burning. 

The main experiment was also designed to determine if younger growth was more susceptible to pasture burning. One block had progibb and urea applied to enhance the growth of the pasture.  The main experiment however, was unable to determine if new growth was more susceptible to pasture burning as the weather and nutrient content of the soil was optimal for pasture growth in both blocks.

In the pilot trial, there was a positive correlation (R2 > 0.5) between ryegrass and osmolality, pH, electrical conductivity, total magnesium, sulphate, total sulphur, total sodium, total nitrogen, dissolved reactive phosphorus, total kjeldahl nitrogen and the sodium absorption ratio.

In the main experiment, there was a positive correlation (R2 > 0.5) between clover burning and electrical conductivity, exchangeable sodium percentage, total potassium and chloride. However, there was no strong correlation between ryegrass burning and any of the effluent properties. 
When the pilot trial and main experiment results were combined, there was a positive correlation (R2 > 0.5) between clover burning and electrical conductivity, chloride, total potassium and osmolality. 

My results suggest that the effluent osmolality should not exceed 450 mmol/kg and the electrical conductivity should not exceed 1500 mS/m to prevent strong to very strong pasture burning. Effluent that exceeds either 450 mmol/kg and/or 1500 mS/m should be recirculated through the holding tanks to reduce the concentration of the “spike”.
Clover was more susceptible to severe pasture burning than ryegrass. Further research into pasture burning is required to isolate and better understand the exact cause.

year: 2017

title: The uncertainty contagion: Revealing the interrelated, cascading uncertainties of managed retreat

authors: Hanna, Christina Jane

abstract: Managed retreat presents a dilemma for at-risk communities, and the planning practitioners and decisionmakers working to address natural hazard and climate change risks. The dilemma boils down to the countervailing imperatives of moving out of harm’s way versus retaining ties to community and place. While there are growing calls for its use, managed retreat remains challenging in practice—across diverse settings. The approach has been tested with varied success in a number of countries, but significant uncertainties remain, such as regarding who ‘manages’ it, when and how it should occur, at whose cost, and to where? Drawing upon a case study of managed retreat in New Zealand, this research uncovers intersecting and compounding arenas of uncertainty regarding the approach, responsibilities, legality, funding, politics and logistics of managed retreat. Where uncertainty is present in one domain, it spreads into others creating a cascading series of political, personal and professional risks that impact trust in science and authority and affect people’s lives and risk exposure. In revealing these mutually dependent dimensions of uncertainty, we argue there is merit in refocusing attention away from policy deficits, barrier approaches or technical assessments as a means to provide ‘certainty’, to instead focus on the relations between forms of knowledge and coordinating interactions between the diverse arenas: scientific, governance, financial, political and socio-cultural; otherwise uncertainty can spread like a contagion, making inaction more likely.

text: The uncertainty contagion: Revealing the interrelated, cascading uncertainties of managed retreat Managed retreat presents a dilemma for at-risk communities, and the planning practitioners and decisionmakers working to address natural hazard and climate change risks. The dilemma boils down to the countervailing imperatives of moving out of harm’s way versus retaining ties to community and place. While there are growing calls for its use, managed retreat remains challenging in practice—across diverse settings. The approach has been tested with varied success in a number of countries, but significant uncertainties remain, such as regarding who ‘manages’ it, when and how it should occur, at whose cost, and to where? Drawing upon a case study of managed retreat in New Zealand, this research uncovers intersecting and compounding arenas of uncertainty regarding the approach, responsibilities, legality, funding, politics and logistics of managed retreat. Where uncertainty is present in one domain, it spreads into others creating a cascading series of political, personal and professional risks that impact trust in science and authority and affect people’s lives and risk exposure. In revealing these mutually dependent dimensions of uncertainty, we argue there is merit in refocusing attention away from policy deficits, barrier approaches or technical assessments as a means to provide ‘certainty’, to instead focus on the relations between forms of knowledge and coordinating interactions between the diverse arenas: scientific, governance, financial, political and socio-cultural; otherwise uncertainty can spread like a contagion, making inaction more likely.

year: 2020

title: The perspective of youth leadership through the insight of current Māori leaders

authors: Wairepo, Ngareta

abstract: Within Te Ao Māori, leadership qualities are central to Māori cultural norms and societal structures. In particular, a rich legacy of supporting intergenerational leadership exists, wherein following generations are endorsed into these leadership roles. Yet, little is documented in academic literature regarding first-hand experiences of the relationship between current Māori leader’s opinions, experiences, and perceptions for supporting the development of future and upcoming rangatahi into leadership roles. Therefore, this research project seeks to explore how leadership and the value of intergenerational indigenous wisdom can contribute to the supporting and flourishing of rangatahi into leadership roles and responsibilities in their communities to support intergenerational leadership development. 
A Kaupapa Māori approach was used for the framework to centre Indigenous ways of being and knowing. Eight semi-structured, conversational interviews were conducted with current Māori leaders to understand their perceptions, experiences, and opinions on leadership. These were then analysed using thematic analysis. Three major themes were identified; Mental strategies, Understanding the complexity of Māori leadership, and Intergenerational development. This research affirms the importance of leadership for Māori communities, and in particular, the role of intergenerational knowledge-sharing as key for supporting rangatahi to be well.

text: The perspective of youth leadership through the insight of current Māori leaders Within Te Ao Māori, leadership qualities are central to Māori cultural norms and societal structures. In particular, a rich legacy of supporting intergenerational leadership exists, wherein following generations are endorsed into these leadership roles. Yet, little is documented in academic literature regarding first-hand experiences of the relationship between current Māori leader’s opinions, experiences, and perceptions for supporting the development of future and upcoming rangatahi into leadership roles. Therefore, this research project seeks to explore how leadership and the value of intergenerational indigenous wisdom can contribute to the supporting and flourishing of rangatahi into leadership roles and responsibilities in their communities to support intergenerational leadership development. 
A Kaupapa Māori approach was used for the framework to centre Indigenous ways of being and knowing. Eight semi-structured, conversational interviews were conducted with current Māori leaders to understand their perceptions, experiences, and opinions on leadership. These were then analysed using thematic analysis. Three major themes were identified; Mental strategies, Understanding the complexity of Māori leadership, and Intergenerational development. This research affirms the importance of leadership for Māori communities, and in particular, the role of intergenerational knowledge-sharing as key for supporting rangatahi to be well.

year: 2024