title: The effects of varying intensity cultivation on soil quality in a maize cropping system

authors: McKay, Emily Grace

abstract: Maize is the primary crop grown on arable land in the Waikato region, predominantly established on Allophanic soils due to their well-drained and resilient properties. Full cultivation (FC) is universally adopted in cropping systems and associated with increased soil aeration and successful seed establishment, however, has been shown to reduce soil quality through declines in soil organic matter (SOM) and soil structure. SOM (TC & TN) decline and aggregate stability are considered important indicators of soil quality in cropping systems as they pose the greatest risk to long term productivity and profitability. Soil degradation can be reduced through conservation tillage such as no-till (NT) and strip-till (ST). Previous studies have investigated the effect of cultivation intensity on soil quality and consistently found that NT systems have greater carbon (C) levels and aggregate stability at the soil surface than higher intensity cultivation systems. 

The main aim of this thesis was to determine whether there were significant differences in soil quality between varying intensity cultivation systems (FC, ST, NT) on Allophanic soils in the Hamilton Basin. Further aims were to determine whether differences in the inherent soil properties of the Horotiu silt loam and Bruntwood silt loam would influence the soil quality within the study area, and to identify whether soil quality was influenced by an interaction between cultivation intensity and soil type. 

Twelve plots with four replicates of each cultivation treatment were sampled and soil quality measured using seven soil quality indicators (total C (TC), total nitrogen (TN), mineralisable nitrogen (N), soil pH, Olsen P, bulk density (BD), and macroporosity (MP)) and three additional cropping indicators (aggregate stability, penetration resistance, and visual soil assessment). Mechanically driven cores for TC and TN analysis were taken from 0 – 7.5 cm, 7.5 – 15 cm, and 15 – 30 cm. Significant differences in TC, TN, and aggregate stability in the top 10 cm were detected between cultivation treatments (p < 0.05). NT was shown to be the most beneficial cultivation for a maize cropping system, indicated by significantly greater TC (3.98 %), TN (0.41 %), and aggregate stability (0.97 mm, MWD) at the soil surface than higher intensity cultivation systems (For FC; TC = 3.56 %, TN = 0.37 %, aggregate stability = 0.62 mm). Additionally, significant differences in TC and TN were found between soil types, where Horotiu silt loam had significantly greater TC and TN (e.g. for 0 – 10 cm; Horotiu: TC = 4.02 %, TN = 0.42 %; Bruntwood TC = 3.52 %, TN = 0.36 %). There were also significant differences in aggregate stability, MP, and BD between soil types, where the Horotiu silt loam had higher aggregate stability (0.82 mm, MWD), MP (14 %) and lower BD   (0.96 t m-3) and Olsen P (82.9 μg g-1) than the Bruntwood silt loam (Aggregate stability = 0.73 mm, MP = 12 %, BD = 1.05 t m-3, Olsen P = 105.5 g g-1). Where there were interactions between cultivation intensity and soil type, significant differences were detected in aggregate stability and penetration resistance, where the Horotiu silt loam under NT had higher aggregate stability (1.07 mm, MWD) and penetration resistance (2.00 MPa) than all other combinations. Conversely, the Bruntwood silt loam under FC had the lowest aggregate stability (0.55 mm, MWD) and penetration resistance (1.63 MPa). 

Many of the soil quality values in the study area fell below or exceeded target ranges set for cropping systems, regardless of cultivation treatment or soil type. This is due to the intensive nature of cropping systems, use of heavy machinery, removal during harvest, and poorly defined target ranges. This study highlights how differences in inherent soil properties between two soil types within the same soil order can greatly influence soil quality. Previous data showed cultivation intensity did not significantly influence maize yield at this stage in the trial.  This research therefore suggests NT systems result in higher SOM content and greater aggregate stability and therefore may be a more suitable cultivation system for continuous maize cropping without decreasing productivity or profitability.

text: The effects of varying intensity cultivation on soil quality in a maize cropping system Maize is the primary crop grown on arable land in the Waikato region, predominantly established on Allophanic soils due to their well-drained and resilient properties. Full cultivation (FC) is universally adopted in cropping systems and associated with increased soil aeration and successful seed establishment, however, has been shown to reduce soil quality through declines in soil organic matter (SOM) and soil structure. SOM (TC & TN) decline and aggregate stability are considered important indicators of soil quality in cropping systems as they pose the greatest risk to long term productivity and profitability. Soil degradation can be reduced through conservation tillage such as no-till (NT) and strip-till (ST). Previous studies have investigated the effect of cultivation intensity on soil quality and consistently found that NT systems have greater carbon (C) levels and aggregate stability at the soil surface than higher intensity cultivation systems. 

The main aim of this thesis was to determine whether there were significant differences in soil quality between varying intensity cultivation systems (FC, ST, NT) on Allophanic soils in the Hamilton Basin. Further aims were to determine whether differences in the inherent soil properties of the Horotiu silt loam and Bruntwood silt loam would influence the soil quality within the study area, and to identify whether soil quality was influenced by an interaction between cultivation intensity and soil type. 

Twelve plots with four replicates of each cultivation treatment were sampled and soil quality measured using seven soil quality indicators (total C (TC), total nitrogen (TN), mineralisable nitrogen (N), soil pH, Olsen P, bulk density (BD), and macroporosity (MP)) and three additional cropping indicators (aggregate stability, penetration resistance, and visual soil assessment). Mechanically driven cores for TC and TN analysis were taken from 0 – 7.5 cm, 7.5 – 15 cm, and 15 – 30 cm. Significant differences in TC, TN, and aggregate stability in the top 10 cm were detected between cultivation treatments (p < 0.05). NT was shown to be the most beneficial cultivation for a maize cropping system, indicated by significantly greater TC (3.98 %), TN (0.41 %), and aggregate stability (0.97 mm, MWD) at the soil surface than higher intensity cultivation systems (For FC; TC = 3.56 %, TN = 0.37 %, aggregate stability = 0.62 mm). Additionally, significant differences in TC and TN were found between soil types, where Horotiu silt loam had significantly greater TC and TN (e.g. for 0 – 10 cm; Horotiu: TC = 4.02 %, TN = 0.42 %; Bruntwood TC = 3.52 %, TN = 0.36 %). There were also significant differences in aggregate stability, MP, and BD between soil types, where the Horotiu silt loam had higher aggregate stability (0.82 mm, MWD), MP (14 %) and lower BD   (0.96 t m-3) and Olsen P (82.9 μg g-1) than the Bruntwood silt loam (Aggregate stability = 0.73 mm, MP = 12 %, BD = 1.05 t m-3, Olsen P = 105.5 g g-1). Where there were interactions between cultivation intensity and soil type, significant differences were detected in aggregate stability and penetration resistance, where the Horotiu silt loam under NT had higher aggregate stability (1.07 mm, MWD) and penetration resistance (2.00 MPa) than all other combinations. Conversely, the Bruntwood silt loam under FC had the lowest aggregate stability (0.55 mm, MWD) and penetration resistance (1.63 MPa). 

Many of the soil quality values in the study area fell below or exceeded target ranges set for cropping systems, regardless of cultivation treatment or soil type. This is due to the intensive nature of cropping systems, use of heavy machinery, removal during harvest, and poorly defined target ranges. This study highlights how differences in inherent soil properties between two soil types within the same soil order can greatly influence soil quality. Previous data showed cultivation intensity did not significantly influence maize yield at this stage in the trial.  This research therefore suggests NT systems result in higher SOM content and greater aggregate stability and therefore may be a more suitable cultivation system for continuous maize cropping without decreasing productivity or profitability.

year: 2020

title: Wilspace: Reflections on establishing small significant online network groups (SSONG) to advance knowledge in work-integrated learning

authors: Wilkinson, Helene

subjects: work-integrated learning

abstract: In 2020 during COVID-19 lockdowns, a small group of Australasian Work-Integrated Learning (WIL) practitioners gathered online for semi-regular conversations. The purpose of this small significant network group (SSONG) was to provide support for one another as we navigated WIL education during this time of turmoil.

Reflecting on their SSONG experience two years later, the authors realised these small online group conversations provided the means to engage at a deeper level with likeminded individuals, without restrictions arising from differences in physical location. SSONG members could share alternative viewpoints with ease and interest because they were familiar with one another, yet from diverse perspectives including disciplines, location, experience and background, hence adding to the richness of their conversations. Out of this, and in discussions with a third New Zealand based academic, WILspace was conceptualised.

WILspace is an online international community of practice, comprising of multiple SSONGs. It was launched at World Association of Cooperative Education (WACE) in June 2023, where WIL practitioners were invited to register their interest. The first WIL SSONG conversations were held in November 2023.

We report on our experience in developing and managing this international community of practice. A key aim of the initiative was to facilitate meaningful discussions about WIL related issues, extending conversations beyond the physical environment of an international conference or a WIL-related course. Topics & prompts developed by the WILspace team were used to activate these conversations, after which each SSONG provided feedback on their discussions via an email to the facilitators. These resources were then summarised and shared via the WILspace website. Following each conversation, feedback was also obtained from SSONG members via a short Qualtrics survey. It was important to the authors that we were able to measure the success of this innovative initiative. Ethics approval (AUTEC 22/329) had been gained from both University Ethics Committees prior to the launch of the global conversation platform.

In this paper we identify, examine and reflect on our successes and challenges in maintaining conversations with an international group membership, across multiple time zones. To date, evaluations suggest support for the initiative is strong amongst active participants, however there is evidence of continuing challenges in maintaining these conversations. Strategies are presented to facilitate implementation and management of future online communities of practice, based on the use of SSONGs.

text: Wilspace: Reflections on establishing small significant online network groups (SSONG) to advance knowledge in work-integrated learning In 2020 during COVID-19 lockdowns, a small group of Australasian Work-Integrated Learning (WIL) practitioners gathered online for semi-regular conversations. The purpose of this small significant network group (SSONG) was to provide support for one another as we navigated WIL education during this time of turmoil.

Reflecting on their SSONG experience two years later, the authors realised these small online group conversations provided the means to engage at a deeper level with likeminded individuals, without restrictions arising from differences in physical location. SSONG members could share alternative viewpoints with ease and interest because they were familiar with one another, yet from diverse perspectives including disciplines, location, experience and background, hence adding to the richness of their conversations. Out of this, and in discussions with a third New Zealand based academic, WILspace was conceptualised.

WILspace is an online international community of practice, comprising of multiple SSONGs. It was launched at World Association of Cooperative Education (WACE) in June 2023, where WIL practitioners were invited to register their interest. The first WIL SSONG conversations were held in November 2023.

We report on our experience in developing and managing this international community of practice. A key aim of the initiative was to facilitate meaningful discussions about WIL related issues, extending conversations beyond the physical environment of an international conference or a WIL-related course. Topics & prompts developed by the WILspace team were used to activate these conversations, after which each SSONG provided feedback on their discussions via an email to the facilitators. These resources were then summarised and shared via the WILspace website. Following each conversation, feedback was also obtained from SSONG members via a short Qualtrics survey. It was important to the authors that we were able to measure the success of this innovative initiative. Ethics approval (AUTEC 22/329) had been gained from both University Ethics Committees prior to the launch of the global conversation platform.

In this paper we identify, examine and reflect on our successes and challenges in maintaining conversations with an international group membership, across multiple time zones. To date, evaluations suggest support for the initiative is strong amongst active participants, however there is evidence of continuing challenges in maintaining these conversations. Strategies are presented to facilitate implementation and management of future online communities of practice, based on the use of SSONGs.

year: 2024

title: An Assessment of the Cognitive Ability and the Attitude to Rehabilitation of European and Maori Trainees at a Borstal Institution.

authors: Zimmerman, Malcolm Laird

subjects: Borstal Institution

abstract: The incidence of delinquency in New Zealand has risen and is a cause for serious concern for the future of the nation. "As in all fields of social inquiry it is much easier to specify the problem than it is to account for its occurrence ... In the case of delinquency, it is much easier to record what has occurred as opposed to why - it is even more difficult to prevent delinquency from occurring at all. Why should this be so?" (Blizard, 1967, p.i.)
There are no easy answers: there are no short cuts to understanding: there will never be an easily worked out, or easily administered programme for prevention. The road is hard, costly both in terms of men, money and time.

text: An Assessment of the Cognitive Ability and the Attitude to Rehabilitation of European and Maori Trainees at a Borstal Institution. The incidence of delinquency in New Zealand has risen and is a cause for serious concern for the future of the nation. "As in all fields of social inquiry it is much easier to specify the problem than it is to account for its occurrence ... In the case of delinquency, it is much easier to record what has occurred as opposed to why - it is even more difficult to prevent delinquency from occurring at all. Why should this be so?" (Blizard, 1967, p.i.)
There are no easy answers: there are no short cuts to understanding: there will never be an easily worked out, or easily administered programme for prevention. The road is hard, costly both in terms of men, money and time.

year: 1971