title: Modelling New Zealand dairy farm systems to design greenhouse gas mitigation strategies

authors: Adler, Alfredo A.

subjects: mitigaiton cost

abstract: Dairy cattle in New Zealand account for about 17% of the country’s total greenhouse gas (GHG) load. As the nation progresses in its efforts to reduce these emissions, is likely that the dairy industry will face physical constraints and/or financial costs associated with their mitigation. For this study, a non-linear optimization model was developed to analyse the cost-effectiveness of diverse mitigation strategies for reducing GHG loads between 10–30% within systems of different production intensity in the main dairy farming regions of New Zealand: Waikato and Canterbury. Pastoral dairy farms, as found in New Zealand, are complex farming systems with many interdependent management variables and any change in one of these variables in order to reduce GHG emissions will inevitably affect the system as a whole, generating changes in its physical and economic outputs. Computer modelling is thus highly suited to evaluate alternative strategies, given its capacity to represent and consider these interdependencies simultaneously.
De-intensification, by reducing any combination of stocking rate, nitrogen fertiliser and supplement use, was a key strategy in reducing GHG emissions in an economic manner across the whole range of farming systems and regions considered in this study, as well as for all levels of emissions constraints tested. The mean farm profit reduction found under this level of mitigation across all studied systems was 6%, when no other mitigation strategies were available. To achieve this, the mean reduction in stocking rate was 8.8% and the mean nitrogen fertilizer reduction was 36%. Nitrogen fertiliser usage increases GHG emissions by increasing the available mineral nitrogen in soil and thus increasing denitrification and also by increasing enteric methane emissions as more fibrous feed is available to be consumed. The mean profit reduction was 6.9% and 4.9% for the Waikato and Canterbury regions, respectively.
The Canterbury medium-input system had a lower cost of mitigation than the other systems, associated with the use of more supplements with high embedded GHG emissions in the baseline. Accordingly, the use of this kind of supplement was quickly reduced by the optimization model in the mitigation scenarios. At the other end, the Canterbury high input system had the highest cost of mitigation, arising from a combination of larger GHG-e reductions required in absolute terms and the low profitability of the baseline plan, given its high use of imported supplement. In contrast, the abatement cost in the Waikato systems was intermediate between these two extremes.
Improved reproductive performance and improved genetic merit of the herd were selected as optimal in all cases where specific mitigation strategies were available. Profit was reduced by 1.6%, on average, in this case when 10% GHG emissions reductions were imposed. To adapt to this constraint, stocking rate was reduced by 8.1%, while N fertilizer was reduced by 30.7%, on average. Thus, although the availability of specific mitigation strategies was valuable in reducing the profit losses arising from mitigation, these were not sufficient to reduce emissions without some degree of de-intensification. 
Other mitigation strategies, like removing cows from pasture or the use of denitrification inhibitors, were not always cost effective and only entered the optimal solution when higher levels of mitigation were imposed. This demonstrates that the high cost of adopting these specific mitigation strategies is only warranted when systems are exposed to larger profit reductions associated with higher levels of de-intensification. A quick calculation using average reduction in milksolids production found in this study shows that the loss of revenue of the dairy industry if 30% mitigation of GHG is imposed can represent as much as half the export earnings of the entire beef industry of the nation.

text: Modelling New Zealand dairy farm systems to design greenhouse gas mitigation strategies Dairy cattle in New Zealand account for about 17% of the country’s total greenhouse gas (GHG) load. As the nation progresses in its efforts to reduce these emissions, is likely that the dairy industry will face physical constraints and/or financial costs associated with their mitigation. For this study, a non-linear optimization model was developed to analyse the cost-effectiveness of diverse mitigation strategies for reducing GHG loads between 10–30% within systems of different production intensity in the main dairy farming regions of New Zealand: Waikato and Canterbury. Pastoral dairy farms, as found in New Zealand, are complex farming systems with many interdependent management variables and any change in one of these variables in order to reduce GHG emissions will inevitably affect the system as a whole, generating changes in its physical and economic outputs. Computer modelling is thus highly suited to evaluate alternative strategies, given its capacity to represent and consider these interdependencies simultaneously.
De-intensification, by reducing any combination of stocking rate, nitrogen fertiliser and supplement use, was a key strategy in reducing GHG emissions in an economic manner across the whole range of farming systems and regions considered in this study, as well as for all levels of emissions constraints tested. The mean farm profit reduction found under this level of mitigation across all studied systems was 6%, when no other mitigation strategies were available. To achieve this, the mean reduction in stocking rate was 8.8% and the mean nitrogen fertilizer reduction was 36%. Nitrogen fertiliser usage increases GHG emissions by increasing the available mineral nitrogen in soil and thus increasing denitrification and also by increasing enteric methane emissions as more fibrous feed is available to be consumed. The mean profit reduction was 6.9% and 4.9% for the Waikato and Canterbury regions, respectively.
The Canterbury medium-input system had a lower cost of mitigation than the other systems, associated with the use of more supplements with high embedded GHG emissions in the baseline. Accordingly, the use of this kind of supplement was quickly reduced by the optimization model in the mitigation scenarios. At the other end, the Canterbury high input system had the highest cost of mitigation, arising from a combination of larger GHG-e reductions required in absolute terms and the low profitability of the baseline plan, given its high use of imported supplement. In contrast, the abatement cost in the Waikato systems was intermediate between these two extremes.
Improved reproductive performance and improved genetic merit of the herd were selected as optimal in all cases where specific mitigation strategies were available. Profit was reduced by 1.6%, on average, in this case when 10% GHG emissions reductions were imposed. To adapt to this constraint, stocking rate was reduced by 8.1%, while N fertilizer was reduced by 30.7%, on average. Thus, although the availability of specific mitigation strategies was valuable in reducing the profit losses arising from mitigation, these were not sufficient to reduce emissions without some degree of de-intensification. 
Other mitigation strategies, like removing cows from pasture or the use of denitrification inhibitors, were not always cost effective and only entered the optimal solution when higher levels of mitigation were imposed. This demonstrates that the high cost of adopting these specific mitigation strategies is only warranted when systems are exposed to larger profit reductions associated with higher levels of de-intensification. A quick calculation using average reduction in milksolids production found in this study shows that the loss of revenue of the dairy industry if 30% mitigation of GHG is imposed can represent as much as half the export earnings of the entire beef industry of the nation.

year: 2014

title: Language challenges in mathematics education: A literature review

authors: Jourdain, Laura Violet

subjects: Mathematics education

abstract: Traditionally, the difficulties associated with mathematics were largely seen as coming from the cognitive demands of mathematics itself. It is now accepted that language and mathematics are connected in mathematics learning and teaching, and, the potential challenges of language in mathematics have been investigated by a number of researchers. This paper reviews research by applied linguists and mathematics educators to highlight the linguistic challenges of mathematics and suggests pedagogical strategies to help learners in mathematics classrooms. The linguistic challenges include the linguistic features that may make mathematical texts hard to understand, vocabulary in academic mathematics, and reading and writing in facilitating the learning of mathematics. Research on pedagogical practices supports developing mathematics knowledge through attention to the way language is used, suggesting strategies for moving students from informal, everyday ways of talking about mathematics into the registers that construe more technical and precise meanings.

text: Language challenges in mathematics education: A literature review Traditionally, the difficulties associated with mathematics were largely seen as coming from the cognitive demands of mathematics itself. It is now accepted that language and mathematics are connected in mathematics learning and teaching, and, the potential challenges of language in mathematics have been investigated by a number of researchers. This paper reviews research by applied linguists and mathematics educators to highlight the linguistic challenges of mathematics and suggests pedagogical strategies to help learners in mathematics classrooms. The linguistic challenges include the linguistic features that may make mathematical texts hard to understand, vocabulary in academic mathematics, and reading and writing in facilitating the learning of mathematics. Research on pedagogical practices supports developing mathematics knowledge through attention to the way language is used, suggesting strategies for moving students from informal, everyday ways of talking about mathematics into the registers that construe more technical and precise meanings.

year: 2016

title: Māori and kava: New drug fashion or re-engagement with 'kawa'?

authors: Aporosa, S. 'Apo'

subjects: kava

abstract: The Pacific “cultural keystone species” (Garibaldi & Turner, 2004, pp.1,5) kava is uniquely linked with notions of mana (spiritual power) and used to infuse efficacy into celebrations and life events. The drink, made from this potent icon of identity, brings on feelings of relaxation without marked euphoria, aiding clear-minded talanoa (discussion) to facilitate important and/or contentious dialogue. The sharing and drinking of kava as part of host/guest formalities is used in bringing about mutuality and unity (Aporosa, 2019). It is estimated there are more than 20,000 kava users in Aotearoa/New Zealand on an average Friday or Saturday night, with increasing interest and uptake of this indigenous drink by Māori. Crowley (1994) reports that the Māori word ‘kawa’, literally meaning ‘marae protocol’, has its linguistic foundations in ‘kava’ and the practices associated with this cultural keystone species. This paper explores that linguistic union to ask whether increased kava use by Māori has greater significance than simply a new interaction with a foreign drug substance. Further, due to the use of kava in facilitating talanoa (discussion), the possibility of kava playing a similar role for Māori is considered, one linked to ancestral Pacific connections aimed at assisting kōrero (talanoa), cultural connectedness and practice.

text: Māori and kava: New drug fashion or re-engagement with 'kawa'? The Pacific “cultural keystone species” (Garibaldi & Turner, 2004, pp.1,5) kava is uniquely linked with notions of mana (spiritual power) and used to infuse efficacy into celebrations and life events. The drink, made from this potent icon of identity, brings on feelings of relaxation without marked euphoria, aiding clear-minded talanoa (discussion) to facilitate important and/or contentious dialogue. The sharing and drinking of kava as part of host/guest formalities is used in bringing about mutuality and unity (Aporosa, 2019). It is estimated there are more than 20,000 kava users in Aotearoa/New Zealand on an average Friday or Saturday night, with increasing interest and uptake of this indigenous drink by Māori. Crowley (1994) reports that the Māori word ‘kawa’, literally meaning ‘marae protocol’, has its linguistic foundations in ‘kava’ and the practices associated with this cultural keystone species. This paper explores that linguistic union to ask whether increased kava use by Māori has greater significance than simply a new interaction with a foreign drug substance. Further, due to the use of kava in facilitating talanoa (discussion), the possibility of kava playing a similar role for Māori is considered, one linked to ancestral Pacific connections aimed at assisting kōrero (talanoa), cultural connectedness and practice.

year: 2019