title: Effect of Phosphorus Fertiliser on Soil Organic Matter Composition of Hill Country Pasture

authors: Binoka, Danfung Teresa

subjects: soil organic matter

abstract: Soil organic matter is important as storage for carbon and nutrients, supporting soil structure, and as a filter for pollutants entering the soil ecosystem. The recovery of soil organic matter in depleted soils can take decades, or even hundreds of years. It has been assumed that in non-eroding pasture, soil carbon levels either increase or not change over time. However, some recent studies have suggested that fertiliser addition to pasture soils may contribute to decreases in soil carbon content. My hypotheses were:
1. As P fertiliser loadings increase the soil carbon content and C:N ratio will decrease.
2. Changes in C pools will be greater in the more active pool (readily available carbon, and microbial biomass carbon) within the soil total carbon

The study was undertaken at a long term fertiliser trial, established in 1980, at the Whatawhata Hill Country Research Station west of Hamilton, New Zealand. The fertiliser trial has P fertiliser application rates maintained since 1984. Olsen P, total C, total N, labile carbon, respirable carbon, specific respiration rate, microbial biomass C, microbial quotient, mineralised N, microbial biomass N, microbial N quotient, and mineralised N per microbial biomass nitrogen, C:N ratio, and soil pH were measured on soil samples collected from 12 paddocks with six P fertiliser loading (0, 10, 20, 30, 50, 100 kg P ha⁻¹ yr⁻¹).

As expected, the available P (Olsen P) increased significantly (P less than 0.001) with increasing P fertiliser application rate. Total carbon, labile carbon, and total nitrogen all decreased significantly (P less than 0.05) with increasing P fertiliser application. No significant relationships were found between P fertiliser and respirable carbon, microbial carbon, microbial (C) quotient, microbial specific respiration, microbial nitrogen, microbial (N) quotient, mineralised N, or C:N ratio. The first hypothesis was rejected as the C:N ratio did not change with increased P fertiliser application. However, both C and N decreased with increased P fertiliser application. The second hypothesis was, therefore, accepted in part because there was a decrease in labile carbon (readily available carbon) and total carbon, with P fertiliser application, but no relationship was evident for the respirable carbon and microbial biomass.

text: Effect of Phosphorus Fertiliser on Soil Organic Matter Composition of Hill Country Pasture Soil organic matter is important as storage for carbon and nutrients, supporting soil structure, and as a filter for pollutants entering the soil ecosystem. The recovery of soil organic matter in depleted soils can take decades, or even hundreds of years. It has been assumed that in non-eroding pasture, soil carbon levels either increase or not change over time. However, some recent studies have suggested that fertiliser addition to pasture soils may contribute to decreases in soil carbon content. My hypotheses were:
1. As P fertiliser loadings increase the soil carbon content and C:N ratio will decrease.
2. Changes in C pools will be greater in the more active pool (readily available carbon, and microbial biomass carbon) within the soil total carbon

The study was undertaken at a long term fertiliser trial, established in 1980, at the Whatawhata Hill Country Research Station west of Hamilton, New Zealand. The fertiliser trial has P fertiliser application rates maintained since 1984. Olsen P, total C, total N, labile carbon, respirable carbon, specific respiration rate, microbial biomass C, microbial quotient, mineralised N, microbial biomass N, microbial N quotient, and mineralised N per microbial biomass nitrogen, C:N ratio, and soil pH were measured on soil samples collected from 12 paddocks with six P fertiliser loading (0, 10, 20, 30, 50, 100 kg P ha⁻¹ yr⁻¹).

As expected, the available P (Olsen P) increased significantly (P less than 0.001) with increasing P fertiliser application rate. Total carbon, labile carbon, and total nitrogen all decreased significantly (P less than 0.05) with increasing P fertiliser application. No significant relationships were found between P fertiliser and respirable carbon, microbial carbon, microbial (C) quotient, microbial specific respiration, microbial nitrogen, microbial (N) quotient, mineralised N, or C:N ratio. The first hypothesis was rejected as the C:N ratio did not change with increased P fertiliser application. However, both C and N decreased with increased P fertiliser application. The second hypothesis was, therefore, accepted in part because there was a decrease in labile carbon (readily available carbon) and total carbon, with P fertiliser application, but no relationship was evident for the respirable carbon and microbial biomass.

year: 2008

title: Importance of environmental factors over habitat connectivity in shaping bacterial communities in microbial mats and bacterioplankton in an Antarctic freshwater system.

authors: Ramoneda, Josep

subjects: 16S rRNA gene

abstract: Freshwater ecosystems are considered hotspots of biodiversity in Antarctic polar deserts. Anticipated warming is expected to change the hydrology of these systems due to increased meltwater and reduction of ice cover, with implications for environmental conditions and physical connectivity between habitats. Using 16S rRNA gene sequencing, we evaluated microbial mat and planktonic communities within a connected freshwater system in the McMurdo Wright Valley, Antarctica, to determine the roles of connectivity and habitat conditions in controlling microbial assemblage composition. We examined communities from glacial Lake Brownworth, the perennially ice-covered Lake Vanda and the Onyx River, which connects the two. In Lake Vanda, we found distinct microbial assemblages occupying sub-habitats at different lake depths, while the communities from Lake Brownworth and Onyx River were structurally similar. Despite the higher physical connectivity and dispersal opportunities between bacterial communities in the shallow parts of the system, environmental abiotic conditions dominated over dispersal in driving community structure. Functional metabolic pathway predictions suggested differences in the functional gene potential between the microbial mat communities located in shallower and deeper water depths. The findings suggest that increasing temperatures and meltwater due to future climate change will affect bacterial diversity and functioning in Antarctic freshwater ecosystems.

text: Importance of environmental factors over habitat connectivity in shaping bacterial communities in microbial mats and bacterioplankton in an Antarctic freshwater system. Freshwater ecosystems are considered hotspots of biodiversity in Antarctic polar deserts. Anticipated warming is expected to change the hydrology of these systems due to increased meltwater and reduction of ice cover, with implications for environmental conditions and physical connectivity between habitats. Using 16S rRNA gene sequencing, we evaluated microbial mat and planktonic communities within a connected freshwater system in the McMurdo Wright Valley, Antarctica, to determine the roles of connectivity and habitat conditions in controlling microbial assemblage composition. We examined communities from glacial Lake Brownworth, the perennially ice-covered Lake Vanda and the Onyx River, which connects the two. In Lake Vanda, we found distinct microbial assemblages occupying sub-habitats at different lake depths, while the communities from Lake Brownworth and Onyx River were structurally similar. Despite the higher physical connectivity and dispersal opportunities between bacterial communities in the shallow parts of the system, environmental abiotic conditions dominated over dispersal in driving community structure. Functional metabolic pathway predictions suggested differences in the functional gene potential between the microbial mat communities located in shallower and deeper water depths. The findings suggest that increasing temperatures and meltwater due to future climate change will affect bacterial diversity and functioning in Antarctic freshwater ecosystems.

year: 2021

title: An integral rite of passage: embedding the aesthetic in adventure education in the pursuit of wellbeing

authors: Wagstaff, Ruth

subjects: wellbeing

abstract: The context for this study was the implementation of an arts integrated unit examined through the lenses of wellbeing, adventure education, children’s spirituality and aesthetic experience. The author’s personal experiences as a holistic educator, connecting theory and practice in educational settings, informed the devising of the learning experiences incorporated into this contemporary ‘Rites of Passage’, arts integrated unit. They also informed the qualitative methods selected for this research. Students reported on their own and others’ perceived state of “wholeness” and completeness of experience and the New Zealand Maori concepts of “hauora” – mental and emotional, physical, social and spiritual wellbeing were examined. Qualitative analysis of the data revealed that a holistic, integrative approach to learning was valued by the students and contributed significantly to their experience of wellbeing and wholeness. The coded data was considered in terms of a heuristic clustering of responses around the relational categories of Self, Others and the Environment. Connection, Relationship and Belonging emerged as the most important themes and, unexpectedly, Inclusion emerged as an important consideration to the participants in this study. Creative and resilience-building learning activities, as within this ‘Rites of Passage” unit and the integral “Wilderness Camp”, are supportive of the health and wellbeing of young learners. Such learning opportunities provide for intra-personal and inter-personal development, and contribute to their sense of self, place, meaning and purpose.

text: An integral rite of passage: embedding the aesthetic in adventure education in the pursuit of wellbeing The context for this study was the implementation of an arts integrated unit examined through the lenses of wellbeing, adventure education, children’s spirituality and aesthetic experience. The author’s personal experiences as a holistic educator, connecting theory and practice in educational settings, informed the devising of the learning experiences incorporated into this contemporary ‘Rites of Passage’, arts integrated unit. They also informed the qualitative methods selected for this research. Students reported on their own and others’ perceived state of “wholeness” and completeness of experience and the New Zealand Maori concepts of “hauora” – mental and emotional, physical, social and spiritual wellbeing were examined. Qualitative analysis of the data revealed that a holistic, integrative approach to learning was valued by the students and contributed significantly to their experience of wellbeing and wholeness. The coded data was considered in terms of a heuristic clustering of responses around the relational categories of Self, Others and the Environment. Connection, Relationship and Belonging emerged as the most important themes and, unexpectedly, Inclusion emerged as an important consideration to the participants in this study. Creative and resilience-building learning activities, as within this ‘Rites of Passage” unit and the integral “Wilderness Camp”, are supportive of the health and wellbeing of young learners. Such learning opportunities provide for intra-personal and inter-personal development, and contribute to their sense of self, place, meaning and purpose.

year: 2011