School of Agriculture, Food and Ecosystem Sciences - Research Publications
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ItemOpportunities to improve nitrogen use efficiency in an intensive vegetable system without compromising yield(WILEY, 2021-05)Intensive vegetable cropping systems rely heavily on nitrogen (N) inputs from multiple synthetic and organic fertilizer applications. The majority of applied N is lost to the environment through numerous pathways, including as nitrous oxide (N2 O). A field trial was conducted to examine the opportunities to reduce N input in an intensive vegetable system without compromising yield. Treatments applied were control (no N), manure (M, 408 kg N ha-1 from chicken manure), grower practice (GP, 408 kg N ha-1 from chicken manure + 195 kg N ha-1 from fertilizer), and 2/3 GP (two-thirds of the total N input in GP), all with and without 3,4-dimethylpyrazole phosphate (DMPP). Nitrogen recovery in the GP treatment was determined using 15 N-labeled fertilizer. Using only manure significantly lowered celery (Apium graveolens L.) yield and apparent N use efficiency (ANUE) compared with GP. Reducing N input by one-third did not affect yield or ANUE. Use of DMPP increased ANUE despite no yield improvement. More than 50% of the applied N in the GP treatment was lost to the environment, with almost 10 kg N ha-1 emitted as N2 O over the season, which was 67 times more than from the control. Reducing the N input by one-third or using manure only reduced N2 O emissions by more than 70% relative to GP. This study shows that there is a clear opportunity to reduce N input and N2 O emissions in high-fertilizer-input vegetable systems without compromising vegetable yield.
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ItemAn empirical analysis of the use of agricultural mobile applications among smallholder farmers in Myanmar(WILEY, 2021-03)Abstract Mobile phone applications (apps) designed to assist smallholder farmers improve decision‐making have been revolutionizing the agriculture sector. These apps offer solutions to farmer information needs by providing weather information, crop market trends, pest and disease damage identification, and advice on pesticide and fertilizer use. They also facilitate interaction with fellow farmers, extension workers and other stakeholders in the value chain who are interested in information exchange. Much previous research has investigated the contribution of mobile apps to agricultural production. This study explored the agricultural mobile apps available in Myanmar, analyzed factors affecting their use and assessed the potential for farm‐based decision support. Our findings indicate that when introducing mobile‐based tools, focus should be given to younger, more educated farmers growing more specialized crops. The main constraints to adopt agricultural apps are lack of access to smartphone and/or internet (63%) and lack of digital knowledge (20%). However, smallholder farmers in Myanmar were optimistic and positive toward agricultural apps for effective utilization. We also found that majority of the surveyed farmers were familiar with information received through Facebook groups. Incorporating useful information and functions from an agricultural mobile app to a Facebook Page could have a more useful and sustainable impact.
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ItemSolid-State Encapsulation of Urea via Mechanochemistry-Driven Engineering of Metal-Phenolic Networks(AMER CHEMICAL SOC, 2023-09-07)Controlled-release fertilizers (CRFs) are sustainable alternatives as they can increase crop yield and minimize environmental contamination associated with conventional fertilizers. However, there remains a demand for the development of CRFs with high biocompatibility, and tunable morphologies and mechanical properties. Herein, a solvent-free mechanochemical method is developed for synthesizing urea-encapsulated metal-phenolic networks (urea-MPN matrices) as CRFs. The matrices exhibit tunable mechanical resistance, crystallinity, stiffness, and wettability properties via rearranging the internal structure of the MPNs and their subsequent interaction with the encapsulated urea crystals. Sample aging (7 days) leads to a higher degree of complexation of the MPNs, resulting in a material with increased elasticity and melting point relative to the as-synthesized sample. Thermal treatment (60 °C for 6 h) instigates structural reorganization of the urea crystals within the matrix, generating a more robust material with a 51-fold increase in Young’s modulus. As CRFs, the urea-MPN matrices can be tuned to prolong the release of urea for up to 9 days depending on the treatment applied. As the mechanochemical synthesis of MPNs facilitates the tuning of physiochemical properties and has greater practicability for inclusion within large-scale processing, it has potential implementation within a broad range of industries.
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ItemNo Preview AvailableSUSTAINABLE NITROGEN MANAGEMENT IN AUSTRALIAN AGROECOSYSTEMS: CHALLENGES AND OPPORTUNITIES(HIGHER EDUCATION PRESS, 2022-09)
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ItemNo Preview AvailableCosts and benefits of ammonia abatement in Australia(ELSEVIER, 2022-07-01)The abatement of ammonia (NH3) emissions has attracted much attention globally given its increasingly dominant roles in ecosystem sustainability and human health. The potential, costs and benefits of NH3 abatement in Australia, the driest inhabited continent in the world, are less known. We mapped the latest spatial-temporal NH3 emissions in Australia and assessed the feasibility of NH3 abatement. Results show that annual NH3 emissions in Australia ranged 1.2–1.4 Tg N yr-1 in response to agricultural activities and climate variability during 2014–2019. Intensive animal and cropping systems occupy ∼13% of Australia's land but contribute 60% of NH3 emissions. The mitigation potential of Australian agricultural NH3 emissions is 32% (21–47%), with implementation cost estimated at 0.3 (0.1–0.9) billion US dollars (USD), equivalent to only one-tenth of the total mitigation benefit at 3.1 (0.5–7.6) billion USD. The societal benefits of mitigating NH3 emissions in terms of ecosystem sustainability (0.6–6.2 billion USD) are higher than human health benefits (0.8–1.9 billion USD) due to the small human population and the uniqueness and significance of Australia's biodiversity. Mitigating NH3 emissions in Australia should be prioritized to the animal and cropping systems to achieve the low-hanging fruit. Cost-effectiveness mitigation of NH3 will require integration with the current climate policy.
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ItemNo Preview AvailableNitrous oxide production pathways in Australian forest soils(ELSEVIER, 2022-08-15)
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ItemMajor Soilborne Pathogens of Field Processing Tomatoes and Management Strategies(MDPI, 2023-02)Globally, tomato is the second most cultivated vegetable crop next to potato, preferentially grown in temperate climates. Processing tomatoes are generally produced in field conditions, in which soilborne pathogens have serious impacts on tomato yield and quality by causing diseases of the tomato root system. Major processing tomato-producing countries have documented soilborne diseases caused by a variety of pathogens including bacteria, fungi, nematodes, and oomycetes, which are of economic importance and may threaten food security. Recent field surveys in the Australian processing tomato industry showed that plant growth and yield were significantly affected by soilborne pathogens, especially Fusarium oxysporum and Pythium species. Globally, different management methods have been used to control diseases such as the use of resistant tomato cultivars, the application of fungicides, and biological control. Among these methods, biocontrol has received increasing attention due to its high efficiency, target-specificity, sustainability and public acceptance. The application of biocontrol is a mix of different strategies, such as applying antagonistic microorganisms to the field, and using the beneficial metabolites synthesized by these microorganisms. This review provides a broad review of the major soilborne fungal/oomycete pathogens of the field processing tomato industry affecting major global producers, the traditional and biological management practices for the control of the pathogens, and the various strategies of the biological control for tomato soilborne diseases. The advantages and disadvantages of the management strategies are discussed, and highlighted is the importance of biological control in managing the diseases in field processing tomatoes under the pressure of global climate change.
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ItemCost-effective mitigation of nitrogen pollution from global croplands(NATURE PORTFOLIO, 2023-01-05)Cropland is a main source of global nitrogen pollution1,2. Mitigating nitrogen pollution from global croplands is a grand challenge because of the nature of non-point-source pollution from millions of farms and the constraints to implementing pollution-reduction measures, such as lack of financial resources and limited nitrogen-management knowledge of farmers3. Here we synthesize 1,521 field observations worldwide and identify 11 key measures that can reduce nitrogen losses from croplands to air and water by 30-70%, while increasing crop yield and nitrogen use efficiency (NUE) by 10-30% and 10-80%, respectively. Overall, adoption of this package of measures on global croplands would allow the production of 17 ± 3 Tg (1012 g) more crop nitrogen (20% increase) with 22 ± 4 Tg less nitrogen fertilizer used (21% reduction) and 26 ± 5 Tg less nitrogen pollution (32% reduction) to the environment for the considered base year of 2015. These changes could gain a global societal benefit of 476 ± 123 billion US dollars (USD) for food supply, human health, ecosystems and climate, with net mitigation costs of only 19 ± 5 billion USD, of which 15 ± 4 billion USD fertilizer saving offsets 44% of the gross mitigation cost. To mitigate nitrogen pollution from croplands in the future, innovative policies such as a nitrogen credit system (NCS) could be implemented to select, incentivize and, where necessary, subsidize the adoption of these measures.