title: Cost-effective mitigation of greenhouse gas emissions from different dairy systems in the Waikato region of New Zealand

authors: Adler, Alfredo A.

subjects: dairy production

abstract: The New Zealand dairy industry produces approximately 17% of this country's total greenhouse gas emissions (GHG-e) and it is also this nation's largest export industry. The industry needs to reduce GHG-e under proposed policy directives and for ongoing market security. Given these pressures, there is the need to identify cost-effective management strategies to reduce on-farm GHG-e. The objective of this study was to investigate how the management of dairy farms in the Waikato region of New Zealand could change to minimise the abatement costs associated with GHG-e mitigation. Three typical farm systems importing low (less than 10%), medium (10–20%), and high (more than 20%) amounts of supplement are modelled using a non-linear optimisation model.

A reduction in nitrogen fertiliser application was the production factor that changed the most to achieve the cap in all of the simulated systems, followed by a reduction in stocking rate. With the prices used in this study, decreasing farming intensity by reducing nitrogen fertiliser by 21–42% and stocking rate by 8–10% represented a cost of $68–$119/ha and a production reduction of 54–117 kg MS/ha for the three systems studied. Improving reproductive performance proved to be effective in reducing GHG-e, allowing for fewer replacement cows to be supported. However, it did not have a significant effect on profit when emissions were unconstrained. Nitrification inhibitors and stand-off pads were not identified as useful mitigation options, given their high cost relative to de-intensification.

text: Cost-effective mitigation of greenhouse gas emissions from different dairy systems in the Waikato region of New Zealand The New Zealand dairy industry produces approximately 17% of this country's total greenhouse gas emissions (GHG-e) and it is also this nation's largest export industry. The industry needs to reduce GHG-e under proposed policy directives and for ongoing market security. Given these pressures, there is the need to identify cost-effective management strategies to reduce on-farm GHG-e. The objective of this study was to investigate how the management of dairy farms in the Waikato region of New Zealand could change to minimise the abatement costs associated with GHG-e mitigation. Three typical farm systems importing low (less than 10%), medium (10–20%), and high (more than 20%) amounts of supplement are modelled using a non-linear optimisation model.

A reduction in nitrogen fertiliser application was the production factor that changed the most to achieve the cap in all of the simulated systems, followed by a reduction in stocking rate. With the prices used in this study, decreasing farming intensity by reducing nitrogen fertiliser by 21–42% and stocking rate by 8–10% represented a cost of $68–$119/ha and a production reduction of 54–117 kg MS/ha for the three systems studied. Improving reproductive performance proved to be effective in reducing GHG-e, allowing for fewer replacement cows to be supported. However, it did not have a significant effect on profit when emissions were unconstrained. Nitrification inhibitors and stand-off pads were not identified as useful mitigation options, given their high cost relative to de-intensification.

year: 2013

title: Seagrass resilience to waterfowl grazing in a temperate estuary: A multi-site experimental study

authors: Dos Santos, Virginie

subjects: Cygnus atratus

abstract: In New Zealand, black swans have been observed to graze a moderate to large proportion of the biomass of intertidal seagrass (Zostera muelleri) meadows. To evaluate the resilience of seagrass meadows to swan grazing, we performed a grazing simulation experiment at four sites in a large temperate estuary (Tauranga Harbour). In late summer, when swan grazing pressure typically peaks, we established control (0% biomass removed), low grazing intensity (~ 40% biomass removed) and high grazing intensity (~ 100% biomass removed) plots (0.25 m2) to mimic the grazing scars created by black swans. For one year, percentage seagrass above-ground cover of plots and a wider area surrounding the plots (0.75 m2) was monitored monthly. Seagrass biomass and leaf size were measured at the start and end of the experiment. Results showed no significant grazing treatment effect on seagrass leaf size (length and width). The low grazing intensity treatment had no detectable effect on seagrass cover or biomass relative to controls. For the high grazing intensity plots at all sites seagrass cover was restored within 8 months but biomass was not fully restored (only 25–42% of controls) one year later. This suggests that it may take several years (2.4–4.0, assuming a constant recovery rate) for seagrass below-ground biomass and leaf layering to regenerate completely in the grazing scars created by swans.

text: Seagrass resilience to waterfowl grazing in a temperate estuary: A multi-site experimental study In New Zealand, black swans have been observed to graze a moderate to large proportion of the biomass of intertidal seagrass (Zostera muelleri) meadows. To evaluate the resilience of seagrass meadows to swan grazing, we performed a grazing simulation experiment at four sites in a large temperate estuary (Tauranga Harbour). In late summer, when swan grazing pressure typically peaks, we established control (0% biomass removed), low grazing intensity (~ 40% biomass removed) and high grazing intensity (~ 100% biomass removed) plots (0.25 m2) to mimic the grazing scars created by black swans. For one year, percentage seagrass above-ground cover of plots and a wider area surrounding the plots (0.75 m2) was monitored monthly. Seagrass biomass and leaf size were measured at the start and end of the experiment. Results showed no significant grazing treatment effect on seagrass leaf size (length and width). The low grazing intensity treatment had no detectable effect on seagrass cover or biomass relative to controls. For the high grazing intensity plots at all sites seagrass cover was restored within 8 months but biomass was not fully restored (only 25–42% of controls) one year later. This suggests that it may take several years (2.4–4.0, assuming a constant recovery rate) for seagrass below-ground biomass and leaf layering to regenerate completely in the grazing scars created by swans.

year: 2013

title: He aha te mea nui o te ao? He tāngata! (What is the most important thing in the world? It is people!)

authors: Masters-Awatere, Bridgette

subjects: chronic disease prevention

abstract: This paper highlights the importance of people as a central factor in improving health for M aori (Indigenous people of New Zealand). How wh anau (family) relationships, connections, values and inspiration are integral to achieving Indigenous health goals is explained. Descriptions of how community researchers, healthcare staff, consumers and academics worked together to design interventions for two health services (in the Waikato and Bay of Plenty regions) is included. Through highlighting the experiences of health consumers, the potential for future interventions to reduce the advancement of pre-diabetes among wh anau is described. Evidence from the study interviews reinforces the importance of wh anau and whakapapa (heritage) as enabling factors for Indigenous people to improve health. Specifically, the positive effect of wh anau enhancing activities that support peoples’ aspirations of tino rangatiratanga (self-determination) in their lives when engaging with health care has been observed. This study highlights the many positives that have emerged, and offers an opportunity for taking primary health to the next level by placing wh anau alongside Indigenous primary care providers at the centre of change strategies.

text: He aha te mea nui o te ao? He tāngata! (What is the most important thing in the world? It is people!) This paper highlights the importance of people as a central factor in improving health for M aori (Indigenous people of New Zealand). How wh anau (family) relationships, connections, values and inspiration are integral to achieving Indigenous health goals is explained. Descriptions of how community researchers, healthcare staff, consumers and academics worked together to design interventions for two health services (in the Waikato and Bay of Plenty regions) is included. Through highlighting the experiences of health consumers, the potential for future interventions to reduce the advancement of pre-diabetes among wh anau is described. Evidence from the study interviews reinforces the importance of wh anau and whakapapa (heritage) as enabling factors for Indigenous people to improve health. Specifically, the positive effect of wh anau enhancing activities that support peoples’ aspirations of tino rangatiratanga (self-determination) in their lives when engaging with health care has been observed. This study highlights the many positives that have emerged, and offers an opportunity for taking primary health to the next level by placing wh anau alongside Indigenous primary care providers at the centre of change strategies.

year: 2019