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Factors controlling shallow subsurface dissolved reactive phosphorus concentration and loss kinetics from poorly drained saturated grassland soils
No full textShallow subsurface pathways dominate dissolved reactive phosphorus (DRP) losses in grassland soils that are: poorly drained, shallow, or have a perched water table in wetter months causing saturation-excess runoff. Saturated conditions can lead to anoxia, which can accelerate phosphorus (P) loss. Two scales of investigation were utilized in this study. First, at the field scale, soil cores were extracted to 2.5 m, subdivided and samples extracted using water extractable P (WEP) and sodium-bicarbonate-dithionite extractable P (NaBD-P). Second, at the laboratory scale, detailed incubation studies using field-moist grassland topsoils from sites in Ireland and New Zealand examined the kinetics of WEP under anoxic (WEPanox) and oxic (WEPox) conditions with imposed temperature and soil P fertilizer input treatments. Results from soil-core samples showed that redox-sensitive NaBD-P concentrations were depleted where artificial drainage lines were installed (100 cm deep), but WEP concentrations available to shallow flow were enriched in topsoil. The laboratory scale incubation experiment investigated the influence of temperature (3 vs. 18 °C), anoxia (designed to simulate saturation following a rainfall event), and superphosphate fertilizer (10 to 60 kg P ha¯¹ yr¯¹) on WEP concentrations over 24 h in three grassland topsoils (clay, silt, and sandy loam textures). Concentrations increased with fertilizer rate, temperature, and—in two soils—anoxic conditions. This was commensurate with nitrate (NO3¯) depletion and the reductive dissolution of iron and manganese. The release of P during anoxia was complete within 24 h. The results highlighted late winter to spring as the riskiest period for topsoil P losses in shallow subsurface flow due to wet soil conditions, increasing temperatures, and low soil NO3¯ concentrations. This knowledge highlights the necessity to consider and refine tests used to assess topsoil P loss risk, where in the landscape P losses are likely, and what strategies can be used to mitigate losses
Nitrous oxide emission factors for fertiliser ammonium sulphate, diammonium phosphate, and urea
No full textThis study determined the nitrous oxide emission factors (EF₁, the percentage of N₂O emitted as a proportion of fertiliser N applied) for fertilisers ammonium sulphate (AS), diammonium phosphate (DAP), and urea under the same field conditions. Trials were conducted on pasture soils across four sites (Waikato, Manawatu, Canterbury and Otago) in New Zealand during late autumn and spring of 2022. The average EF₁ values for urea across all four sites were 0.128% (95% C.I., 0.023% and 0.249%) in late autumn and 0.136% (95% C.I., 0.031% and 0.259%) in spring. The corresponding EF₁ values for AS were 0.125% (95% C.I., - 0.021% and 0.246%) in late autumn and 0.083% (95% C.I., 0.015% and 0.197%) in spring, while for DAP, they were 0.049% (95% C.I., - 0.044% and 0.157%) in late autumn and 0.090% (95% C.I., -0.009% and 0.205%) in spring. The mean EF₁ values across all four sites and two seasons were calculated as 0.132% (95% C.I., 0.016% and 0.269%) for urea, 0.104% (95% C.I., - 0.008% and 0.235%) for AS, and 0.069% (95% C.I., - 0.036 and 0.194) for DAP. No significant differences in EF₁ were observed between the three fertilisers (P > 0.05) at individual sites or when considering all four sites collectively
Livelihood goals, livelihood strategy selection and household welfare in rural China: A utility maximization perspective : A thesis submitted in partial fulfilment of the requirements for the Degree of Doctor of Philosophy at Lincoln University
No full textChina has the world’s second largest rural population and dramatic development in the rural economy. Rural households’ livelihoods have changed with economic transformation and face challenges from income equality, relative poverty, climate change and the continuing influence of COVID-19. In this situation, how to realize inclusive, sustainable and resilient livelihoods for rural residents is an urgent problem.
Rural households’ livelihood decision largely results from unobserved heterogeneous goals and intentions and directly observable, different rural household characteristics. Previous studies explored the factors influencing rural households’ choice of a livelihood strategy and livelihood outcome but mainly focused on the impacts of external macro factors. However, livelihood goals are emphasized as the main base for rural households to allocate livelihood assets and are the critical orientations of livelihood strategy selection. To date, it is still poorly understood how rural households’ livelihood goals influence their livelihood strategy selection and whether different livelihood goals and their potential interaction effect with livelihood strategy selection influence rural household welfare.
Using the panel data from the 2010-2018 China Family Panel Studies, this study explores the relationship between livelihood goals, livelihood strategy selection and rural household welfare. After deleting cases with missing values in the main and control variables, 23,967 rural cases are used for analysis in the study.
To explore the linkages between livelihood goals and livelihood strategy selection, this study constructs measurements of three livelihood goals (the survival, security and self-respect goals) and then calculates an index for each goal. Livelihood strategies are divided into three groups (agricultural, non-agricultural, and diversification) based on rural households’ income sources. The multinomial logit model with fixed effects empirically estimates the relationship between livelihood goal indices and livelihood strategy selection. The random effects and the correlated random effects models are used to check the robustness. The two-step instrumental probit regression model is used to address the endogeneity problem. The results show that rural households with a survival goal are more likely to choose the diversification and agricultural strategies but less likely to select the non-agricultural strategy. In contrast, the non-agricultural strategy is the priority when rural households pursue security or self-respect maximization.
To address potential endogeneity in the dynamic panel model, the generalized method of moments model is used to investigate the impact of livelihood goals and strategy selection on rural household welfare. The unconditional quantile regression with fixed effects model is employed to analyse the heterogeneous effects on household welfare. The results show that rural households with a higher livelihood goal do not obtain higher welfare. Rural households adopting the non-agricultural and diversification strategies have higher welfare than other strategies. The interaction effects show that rural households can get higher welfare if their livelihood goals and livelihood strategy selection match. The unconditional quantile regression result shows that households’ livelihood goals and livelihood strategy selection affect household welfare across different quantiles
The effects of corporate governance on firm performance in the Association of Southeast Asian Nations (ASEAN): A comparative analysis : A thesis submitted in partial fulfilment of the requirements for the Degree of Doctor of Philosophy at Lincoln University
No full textIncreasing dependence on corporate governance (CG) raises questions about whether corporate governance positively impacts firm performance and whether other variables can change the relationship between corporate governance and firm performance. We investigate the relationship between corporate governance features, including board effectiveness, block ownership, and national governance, on the firm performance of ASEAN-6 non-financial listed firms. We use the fundamental features of CG, such as board size, board independence, gender diversity, CEO duality, institution ownership, foreign ownership, insider ownership, government effectiveness, the rule of law and regulatory quality to analyse their impact on firm performance as measured by return on equity and Tobin’s Q.
We use 265 ASEAN-6 non-financial listed firms (2385 firm-year observations) from 2010-2019 and uses OLS estimation and System-GMM estimator to control for the endogeneity issue. The results show that, except for CEO duality and insider ownership, that have no significant impact on performance, the other governance mechanisms significantly influence the performance of ASEAN-6 non-financial listed firms. Specifically, board independence, board gender diversity, governance effectiveness, the rule of law, and regulatory quality significantly positively influence ASEAN-6 non-financial listed firms. The results show a significant negative relationship between block ownership variables and the performance of ASEAN-6 non-financial listed firms. From a theoretical perspective, we emphasise how CG impacts firm performance and uncover the importance of CG systems in ASEAN-6 non-financial listed firms. From a practical perspective, we not only explain the optimal structure of CG that can enhance performance but also identify the moderating impact on board effectiveness, block ownership, national governance and the performance of ASEAN-6 non-financial listed firms
Impacts of marketing contract choices on technical efficiency: Insights from citrus production
No full textFarmers seeking marketing contracts for product sales need to adjust their production behaviour in advance to meet the product attributes required by market buyers. However, little is known about whether marketing contract users are more efficient in farm production than non-users. This study contributes to the literature by examining the impacts of marketing contracts (written contracts, verbal contracts, and no contracts) on technical efficiency, taking citrus production in Jiangxi Province, China, as an example. We first use a stochastic production frontier (SPF) model to calculate the technical efficiency scores of citrus production at the individual level. Then, we use a multinomial endogenous switching regression (MESR) model, which mitigates selection bias issues arising from observed and unobserved factors, to estimate the treatment effects of marketing contract choices on technical efficiency. The SPF model estimates show that the mean technical efficient score of citrus production is 0.626, ranging between 0.021 and 0.892. The MESR model estimates reveal that the average technical efficiency scores for written and verbal contract users are 14% and 2% higher than those for no-contract users. The average technical efficiency score for written contract users is 8% higher than for verbal contract users. Our findings highlight the importance of helping citrus farmers use marketing contracts, especially formal written contracts when selling their products, which can help increase technical efficiency and farm productivity
Do capital markets reward corporate climate change actions? Evidence from the cost of debt
No full textAs a result of recurring natural disasters caused by climate change, firms are under enormous pressure to reconsider their environmental footprints. However, whether or not investors reward firms' climate change actions remains a topic of considerable debate. Using a sample of S&P 500 companies over the period 2005–2020, we hypothesise and find a significant negative relationship between climate change actions and the cost of debt, indicating that investors indeed reward corporate climate efforts in the form of lower cost funds. This relationship exists in both environmentally sensitive and non‐sensitive industries and remains negative and statistically significant even after controlling for the impact of the ongoing pandemic (COVID‐19). The findings are robust to the use of alternative measures for our variables, alternative estimation methods and after controlling for endogeneity issues. We interpret our findings within the decision‐usefulness and stakeholder‐agency theories that suggest that non‐financial information on firms' environmental performance is becoming increasingly important when borrowers' creditworthiness is assessed. Our study offers important regulatory and academic policy implications
Osmotic stress responses, cell wall integrity, and conidiation are regulated by a histidine kinase sensor in Trichoderma atroviride
No full textTrichoderma atroviride responds to various environmental stressors through the mitogen-activated protein kinase (MAPK) Tmk3 and MAPK-kinase Pbs2 signaling pathways. In fungi, orthologues to Tmk3 are regulated by a histidine kinase (HK) sensor. However, the role of T. atroviride HKs remains unknown. In this regard, the function of the T. atroviride HK Nik1 was analyzed in response to stressors regulated by Tmk3. The growth of the Δnik1 mutant strains was compromised under hyperosmotic stress; mycelia were less resistant to lysing enzymes than the WT strain, while conidia of Δnik1 were more sensitive to Congo red; however, ∆pbs2 and ∆tmk3 strains showed a more drastic defect in cell wall stability. Light-regulated blu1 and grg2 gene expression was induced upon an osmotic shock through Pbs2-Tmk3 but was independent of Nik1. The encoding chitin synthases chs1 and chs2 genes were downregulated after an osmotic shock in the WT, but chs1 and chs3 expression were enhanced in ∆nik1, ∆pbs2, and ∆tmk3. The vegetative growth and conidiation by light decreased in ∆nik1, although Nik1 was unrequired to activate the light-responsive genes by Tmk3. Altogether, Nik1 regulates responses related to the Pbs2-Tmk3 pathway and suggests the participation of additional HKs to respond to stress
Marine fish-derived lysophosphatidylcholine: Properties, extraction, quantification, and brain health application
No full textLong-chain omega-3 fatty acids esterified in lysophosphatidylcholine (LPC-omega-3) are the most bioavailable omega-3 fatty acid form and are considered important for brain health. Lysophosphatidylcholine is a hydrolyzed phospholipid that is generated from the action of either phospholipase PLA₁ or PLA₂. There are two types of LPC; 1-LPC (where the omega-3 fatty acid at the sn-2 position is acylated) and 2-LPC (where the omega-3 fatty acid at the sn-1 position is acylated). The 2-LPC type is more highly bioavailable to the brain than the 1-LPC type. Given the biological and health aspects of LPC types, it is important to understand the structure, properties, extraction, quantification, functional role, and effect of the processing of LPC. This review examines various aspects involved in the extraction, characterization, and quantification of LPC. Further, the effects of processing methods on LPC and the potential biological roles of LPC in health and wellbeing are discussed. DHA-rich-LysoPLs, including LPC, can be enzymatically produced using lipases and phospholipases from wide microbial strains, and the highest yields were obtained by Lipozyme RM-IM®, Lipozyme TL-IM®, and Novozym 435®. Terrestrial-based phospholipids generally contain lower levels of long-chain omega-3 PUFAs, and therefore, they are considered less effective in providing the same health benefits as marine-based LPC. Processing (e.g., thermal, fermentation, and freezing) reduces the PL in fish. LPC containing omega-3 PUFA, mainly DHA (C22:6 omega-3) and eicosapentaenoic acid EPA (C20:5 omega-3) play important role in brain development and neuronal cell growth. Additionally, they have been implicated in supporting treatment programs for depression and Alzheimer’s. These activities appear to be facilitated by the acute function of a major facilitator superfamily domain-containing protein 2 (Mfsd2a), expressed in BBB endothelium, as a chief transporter for LPC-DHA uptake to the brain. LPC-based delivery systems also provide the opportunity to improve the properties of some bioactive compounds during storage and absorption. Overall, LPCs have great potential for improving brain health, but their safety and potentially negative effects should also be taken into consideration
Impact of ryegrass cover crop inclusion on soil phosphorus and pqqC- and phoD-harboring bacterial communities
No full textItalian ryegrass (Lolium multiflorum L.) is widely used as a cover crop with rice to promote soil fertility and reduce nutrient loss, although the specific impacts on phosphorus (P) dynamics and bioavailability are not clear. Soil samples were taken from a 4-year field experiment that included fertilized fallow-rice and ryegrass cover crop-rice rotations, together with an unfertilized fallow-rice control. Soil analyses included pH, total carbon (C) and nitrogen (N), together with soil P fractionations, acid and alkaline phosphatase enzyme activities, and assessment of the diversity and community of bacterial genes associated with inorganic P solubilization (pqqC) and organic P mineralization (phoD). Results showed that inclusion of the ryegrass cover crop enhanced biological P cycling in soil by significant increases in soil organic P and phosphatase enzyme activities compared with the fertilized fallow. The ryegrass cover crop was shown to reinforce the connection between soil P fractions and pqqC- and phoD-harboring bacterial communities, especially for the genus Rubrobacter. Cover crop inclusion also affected pqqC-harboring bacterial community composition by increasing the relative abundance of Actinobacteria, which reflected changes in the ratios of total P to total carbon and nitrogen in soil. In addition, the pqqC-harboring bacterial community was more affected by the ryegrass cover crop than the corresponding phoD-harboring community. The findings of this study demonstrated that the inclusion of ryegrass as a cover crop with rice significantly impacted biological P cycling in soil which may contribute to improved long-term P use efficiency
The wellbeing experience within a New Zealand township. New Zealand Treasury’s Living Standards Framework in a hyper-local context : A thesis submitted in partial fulfilment of the requirements for the Degree of Master of Applied Science at Lincoln University
No full textThe New Zealand Treasury published ‘Te Tai Waiora’, its first wellbeing report in November 2022. The report presents data on how wellbeing has changed, how wellbeing is distributed and the sustainability of wellbeing in Aotearoa New Zealand. The data collected are analysed using the Living Standards Framework, which provides New Zealand Treasury with a systematic approach to offer policy advice and identify the implications of policy, based on a range of evidence gathered over time.
This research tests the Treasury’s Living Standards Framework at a hyper-local scale (focusing on matters within a small community or specific geographic location), to understand the extent to which a central government approach to measuring wellbeing is appropriate at a local scale. This study found that indicators that provide data for analysis require context and are most relevant when applied ‘at scale’ to identify the wellbeing experience of individuals and communities.
Using a mixed methods approach, the data from the quantitative research showed individuals are significantly more satisfied with various aspects of wellbeing at a local scale than at a national scale. These aspects include the natural environment, safety, housing affordability and political voice. In the qualitative data, it was found that, through a series of processes an individual generates their own wellbeing depending upon capabilities, financial security, locality and employment mobility opportunities. Individuals improved their wellbeing by making deliberate choices within the context of those capabilities. Home ownership was associated with employment mobility and individuals made trade-offs between dimensions of wellbeing as a function of personal value. Both research methods revealed that ‘local matters.’
The findings from this study will contribute to the growing literature on wellbeing. This thesis demonstrates that measuring the wellbeing experience of a small community in a specific geographic location can result in significant differences in wellbeing experiences between the national and local scale. Therefore, adopting an ‘at scale’ approach is more appropriate for policy development if central government is concerned with the wellbeing of all New Zealanders, irrespective of their locality