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Interaction of rice root Fe plaque with radial oxygen loss enhances paddy-soil N₂O emission by increasing •OH production and subsequently inhibiting N₂O reduction
No full textAmorphous iron (Fe) oxides are commonly deposited on rice roots, forming a distinctive Fe plaque, which has been observed as a notable hotspot for increased nitrous oxide (N₂O) emission from paddy fields. However, the precise mechanisms underlying this phenomenon have remained uncertain. We hypothesized that the interaction between Fe plaque and rice root radial oxygen losses (ROL) leads to the generation of hydroxyl radical (•OH), thereby inhibiting N₂O reduction and increasing N₂O emission. To test this hypothesis, we transplanted rice seedlings with induced Fe plaque coating alongside those without Fe plaque coating into the same paddy soil. The results showed that paddy soil with Fe plaque-coated rice seedlings exhibited significantly higher concentrations of •OH and increased N₂O emission rates, but a reduced abundance of the microbial N₂O reduction gene (nosZ), compared to paddy soil with Fe plaque-free rice seedlings. These observed differences in N₂O emission disappeared when we introduced an •OH scavenger into the paddy soil or shaded the rice leaves to reduce ROL. Furthermore, the supplementation of Fe (II) into the paddy soil with Fe plaque-free rice seedlings markedly increased •OH concentrations and N₂O emissions. Our results demonstrate that Fe plaque, in conjunction with rice root ROL, facilitates •OH generation through the Fenton reaction. This •OH production effectively inhibits microbial N₂O reduction, ultimately leading to increased N₂O emissions from paddy soils. Our study uncovers a new mechanism whereby Fe plaque enhances N₂O emissions from paddy soil. Minimizing Fenton reactions on Fe plaque may offer a promising strategy for reducing N₂O emissions from paddy fields
Preface
No full textThese proceedings, presented in five volumes, contain the papers from the 21st Pacific Rim International Conference on Artificial Intelligence (PRICAI 2024), held from November 18 to 24, 2024, in Kyoto, Japan. The papers in these volumes reflect the richness and diversity of the discussions held during the conference, encompassing topics such as machine learning, computer vision, generative artificial intelligence (AI), large language models, and innovative applications of AI in various domains
Litigation risk and the cost of debt financing in M&As
No full textIn this paper, we use a semi-supervised machine learning technique, the word2vec word embedding model, to measure litigation risk for fixed-income issuers that use bond financing in primary market for mergers and acquisitions (M&As) in 28 countries. We investigate the relationship between the litigation risk and the offering yield of these securities, demonstrating that increased litigation risk increases financing costs. We analyze several ways to mitigate adverse effects, including the employment of more M&A advisors and assessing the legal environment in the issuing country. Our results are robust to an instrumental variable approach and alternative measures
Investigations of soil aluminium and legumes for pastoral farming in the Central Otago high country : A thesis submitted in partial fulfilment of the requirements for the Degree of Doctor of Philosophy at Lincoln University
No full textSoil acidity and associated high concentrations of exchangeable aluminium (Al) present significant challenges to the success of legume species and farm sustainability in the high country of Central Otago, Aotearoa New Zealand. Such grasslands rely heavily on legumes for soil nitrogen (N) and quality livestock feed. However, traditional legume species are limited by the district's edaphic and climatic conditions. To address these challenges, this PhD investigated soil chemistry, Al solubility and legumes to support sustainable pastoral farming in the high country.
Understanding the mechanisms controlling Al solubility, soil acidity, and buffering capacity is imperative in addressing the challenges of farming on acid soils. The chemistry of acidic grassland soil was investigated to assess Al fractions and associated properties. The low base saturation (< 10%) and very acidic soil pH (pHKCl 2.9–4.1) indicated that the soil had likely shifted beyond the Al-base cation exchange buffering system into hydroxy Al dissolution or organic Al dissolution pH buffering systems. Statistical modelling showed Al solubility in the A horizon soil was controlled by organically bound Al. This finding underscored the importance of the saturation of Al to carbon (C), in addition to soil pH, in predictive models of exchangeable Al. The equation: logAlKCl = 0.74 – 0.49pHKCl + 0.57log(AlCu/C) effectively predicted exchangeable Al in the A horizon of the investigated soil. Moreover, the low pH coefficient indicated that the A horizon was weakly buffered by the exchange of Al3+ and H+ on soil organic matter binding sites. Conversely, no unequivocal explanation of Al solubility was determined in the B and C horizons. Nevertheless, the linear relationship between exchangeable Al and pH indicated pH can be used to predict exchangeable Al in the B and C horizons by the equation: logA
Thirteen forage legume species were assessed across three field experiments in Central Otago. Plant survival varied among species, with local climate emerging as the pivotal determinant of legume survival and yields. Lotus (Lotus pedunculatus Cav.) exhibited 100% survival over 18 months at a high altitude, acidic, cool climate site, whereas other perennial legume species showed limited persistence (0–55% survival). At two hotter, drier sites, crimson clover (Trifolium incarnatum L.) had the greatest Year 1 establishment and yields of assessed annual legume species. Moreover, strong Year 1 seed set and subsequent regeneration in Year 2 were observed for crimson clover, striated clover (Trifolium striatum L.), and subterranean clover (Trifolium subterraneum L.) (cv.s Denmark and Narrikup). The differences in survival among these legume species underscore the detrimental effect of climate on many legumes and highlight lotus and crimson clover as key species of interest for farms in high country environments.
Following strong survival rates in Year 1 at the high altitude, acidic, cool climate experimental site, lotus and Russell lupin (Lupinus polyphyllus Lindl.) were selected for a glasshouse experiment to investigate potential mechanisms of Al tolerance associated with root growth in acid soil. Shoot and root biomass and root morphology were quantified in response to lime treatments in 0–9 cm and 9–18 cm horizons of 20 cm deep pots. The soil pH was 4.4, 4.9 and 5.4; the exchangeable Al concentrations were 24, 2.5 and 1.5 mg kg-1 for 0, 4.5, and 6.7 g lime L-1 treatments. No response to lime was shown in the mean total shoot and root biomass of lotus (13.2 g DM plant-1) nor Russell lupin (2.9 g DM plant-1). Furthermore, lotus plants did not differ in root length or surface area between the 0–9 and 9–18 cm horizons. However, within 0–9 and 9–18 cm horizons, Russell lupin showed increased root biomass, length, and surface area when lime was not added or was added at a low rate. Greater root biomass in lotus and Russell lupin was associated with a 50% reduction in soil exchangeable Al in the 0–9 cm horizon (16 mg kg-1), compared with the 9–18 cm horizon (32 mg kg-1) and the control soil (27 mg kg-1) in the 0 g lime L-1 treatment, suggesting that this reduction in exchangeable Al concentration is a key mechanism for Al tolerance in these legume species
Does warming erode network stability and ecosystem multifunctionality?
No full textEnvironmental warming is thought to alter food web stability and functioning, but whether warming reduces food web resistance and resilience to further climatic events remains surprisingly unexplored. Warming experiments that superimpose acute disturbances are urgently needed to understand how extreme events further threaten the stability and multifunctionality of ecological networks
Innovative institutional arrangements and shareholding schemes adopted by producer groups servicing smallholders in Myanmar
No full textSmallholder producer groups are vulnerable to institutional problems when they pursue value-adding enterprises requiring capital and predictable deliveries. This paper provides insights into effective shareholding arrangements introduced by two producer groups to upgrade their business strategies from ‘transactional’ to ‘value-adding’ status. The first group planned to offer machinery services to reduce production costs and improve the quality of smallholder paddy. The second group intended to take advantage of a domestic niche market for non-traditional, high-value, paddy varieties. Members and directors of these producer organisations were wary of free-rider problems that undermine collective efforts to finance assets and meet supply contracts. This study draws on the New Institutional Economics concepts of ill-defined ownership rights to analyse the innovative shareholding schemes devised by these groups to prevent free-riding. It treats the producer groups as case studies, and the research is both exploratory and applied set within the framework of action research. Both groups issued non-redeemable, tradable, class B shares. Class B shares are appreciable but confer no (or limited) voting rights, allowing members to benefit as investors and as patrons while maintaining democratic control of their organisation. The key, however, is to align investment with patronage as this prevents free-riding and mitigates conflicts of interest that discourage member investment and compliance with supply contracts. The first group linked member investment to progressive discounts on the cost of machinery services, thereby creating a strong incentive for larger patrons to buy more shares. The second group treated each share as a tradable obligation to deliver a specific quantity of high-value paddy, thereby requiring larger patrons to invest in more shares. This research adds to a small pool of literature that examines the attributes of well-defined ownership rights in smallholder organisations that pursue value-adding business strategies
Valuing nature: constructing “value” and representing interests in environmental decision making
No full textThis chapter begins by acknowledging that environmental values underscore almost every aspect of environmental decision making. Using the case of trout in Aotearoa New Zealand, the chapter highlights the variegated and power-infused perspectives and values that shape how nature matters to people. The chapter describes how political ecologists have rendered environmental values and processes of environmental valuation political through critiques associated with commensurability metrics, such as monetary value, and the power-laden ways values are prioritized and actualized (and also marginalized and suppressed) in environmental governance. This analysis underscores how the valuation process is often presented as merely “technical” or “administrative,” despite actually being subjective, non-neutral and severely constrained in both its development and application. This chapter will be useful to researchers interested in the politics and practices of values-based environmental decision making
Advancements in civet coffee production and analytical techniques: From aroma profiling to market dynamics and ethical considerations
Get PDFBackground: Civet coffee is produced from coffee beans that have been consumed and excreted by civets. However, its production raises several ethical concerns. The increasing cases of adulteration create significant challenges in verifying the authenticity of civet coffee. Currently, there is no comprehensive review addressing alternative and sustainable production methods for civet coffee. This manuscript aims to fill this knowledge gap and serve as a reference for improving civet coffee fermentation.
Scope and approach: This paper explores innovative techniques for producing civet coffee while considering ethical and sustainability issues. It examines market trends and authentication methods, focusing on technologies such as electronic nose (E-Nose) technology, proton-transfer-reaction time-of-flight mass spectrometry (PTR-ToF-MS), UV–visible spectroscopy, infrared spectroscopy (NIR and FTIR), and nuclear magnetic resonance (NMR). Additionally, it discusses the health-promoting effects of civet coffee.
Key findings and conclusions: Alternative methods to the in vivo fermentation of civet coffee, using isolated bacteria (i.e., Bacillus subtilis), yeast, and fungi from the civet's gastrointestinal tract or excreta in glass jars or bioreactors, have significantly enhanced the fermentation process. These methods resulted in improved and consistent coffee quality, flavor, and nutritional value. Technologies like e-nose PTR-ToF-MS effectively distinguish civet coffee from non-civet variants through aroma and marker profiling. Additionally, UV–Vis, NIR, FTIR, NMR, GC/MS, and GC/FID, combined with chemometrics, have demonstrated significant efficacy in distinguishing farmed and wild types of civets. Despite its high price, civet coffee continues to see a growing global demand as consumers increasingly prioritize quality, health benefits and authenticity. Innovative analytical techniques are essential for maintaining the integrity of civet coffee. However, addressing animal welfare concerns in civet coffee production is crucial to meet the expectations of ethically and sustainability-conscious consumers
Predicting future adoption of early-stage innovations for smart farming: A case study investigating critical factors influencing use of smart feeder technology for potential delivery of methane inhibitors in pasture-grazed dairy systems
Get PDFGlobally, livestock farmers are challenged with reducing greenhouse gas emissions to mitigate climate change. A potential option for pasture-based dairy farmers involves including methane-inhibiting compounds in the diet. A novel approach to deliver these compounds with the required frequency and precision is via smart-feeders, an existing smart farming technology used to feed supplements automatically to animals in-paddock. For this innovation to be successful, however, it must integrate with farm systems and provide farmers with a positive value proposition. The aim of this study was to examine the farm system and technology factors influencing potential uptake of in-paddock smart technologies for delivering methane inhibitors in pasture-grazed systems. We utilized an adoption prediction tool (ADOPT) to model the adoption outcomes of smart-feeders as methane inhibitor delivery mechanisms on dairy farms, with input from industry experts and farmers via focus groups. The results indicated low adoption of smart-feeders in a pasture-based system context. This was further explored with a sensitivity analysis of seven critical ADOPT factors which were identified as influential through the farmer focus groups. We modelled the impact of the seven critical ADOPT factors for two smart-feeder concepts to evaluate their relative adoption potential. The adoption modelling showed that while factors such as technology cost and function were important, adoption would also be highly influenced by future regulation settings, innovation uncertainty, and the alignment with farmer values and worldviews about their farm system. This research highlighted that in-paddock delivery technology, and processes for its use on-farm, represents an early-stage innovation and therefore is vital that farmers and other stakeholders are involved in further development to ensure adoption factors are addressed
Preliminary survey of plant-parasitic nematodes associated with grapevines in Blenheim, New Zealand
Get PDFPlant-parasitic nematodes threaten horticultural crops, causing damage by feeding on plant roots, reducing yields, and affecting global food security. We present preliminary results on nematode genera found in soil around two varieties of grapevine (Sauvignon blanc and Pinot noir) with different rootstocks (101-14, SO4, 5C, Riparia Gloire, 3309, Schwarzmann) in ten vineyards located in Blenheim, part of the largest grape-growing area in New Zealand. Soil samples were collected, and nematodes were extracted using a modified centrifugal-flotation technique. Nematode counting and morphological identification to genus level was conducted based on characteristics such as stylet size and overall body shape. Soil texture analysis was performed, and the influences of grape variety and rootstock as well as soil type on nematode diversity were assessed. Four genera of plant-parasitic nematodes, including Pratylenchus, Paratylenchus, Helicotylenchus, and Criconomella, were recovered from the vineyard soils and a snapshot of relative abundance was determined. Differences in the nematode genera and their relative abundance among varieties and rootstocks were found, which suggests potential interactions between nematode genera and grapevine rootstocks/scions. This preliminary survey provides updated information on nematodes since the last survey conducted 20 years ago in New Zealand. This work indicates the presence of various genera of plant-parasitic nematodes in soils around grapevines grown around Blenheim, New Zealand. These findings highlight the need for further research to understand the interactions between nematodes, grape varieties, and rootstocks. The importance of addressing this knowledge gap for biosecurity measures and potential implications on grapevine growth and vineyard productivity is discussed