School of Agriculture, Food and Ecosystem Sciences - Research Publications
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ItemNo Preview AvailableThemeda Triandra as a Perennial Seed Crop in South-Eastern Australia: What Are the Agronomic Possibilities and Constraints, and Future Research Needs?(International Grassland Congress 2023, 2023)
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ItemNo Preview AvailableCombining community and technology to turn stormwater into water supply, flood mitigation and provision of environmental flow(Novatech 2023, 2023)Impervious areas and urban stormwater systems radically change streamflows, with larger peak flows, yet typically depleted baseflows, as a result of reduced infiltration. Urban areas are thus often subject to increased risk of flooding, but also periods where flows are inadequate to support instream habitat. In addition, with increasing climate extremes, there is a need to increase the security of urban water supplies whilst maintaining adequate water for the environment. In response to these drivers, we are testing the “Monbulk Creek Smart Water Network”, where 100s of real-time controlled rainwater tanks (installed on homes, businesses and public buildings) are being combined with real-time control of three large urban lakes, to create a “smart network” of stormwater storage and release. This network will (i) provide a supplementary supply of water to households for non-potable needs, (ii) reduce flood risk (by drawing down the storages in the days before large storm events), and (iii) actively release water to protect the health of the local receiving water (Monbulk Creek). The research will investigate the technical feasibility of this concept, but also seek to understand its social feasibility, exploring how household water practices shape and are shaped by this hybrid centralised-decentralised infrastructure approach to stormwater management. The ecological consequences of stream flow regulation will also be measured. In this paper we present the system architecture and control logic, outline its proposed implementation, and highlight key issues for the social sustainability of the approach.
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ItemPotential of Plant-derived Bioactives and Polyphenols to Abate Enteric Methane Emission and Heat Stress in Ruminants(Cornell University, 2023)Climate change has emerged as a critical concern at the global level, impacting animal welfare and productivity, especially in tropical areas. Methane (CH4), a potent greenhouse gas (GHG), is primarily generated by ruminant animals within the livestock sector. Owing to the high global warming potential of CH4, it is crucial to identify the most effective and applicable strategies to abate CH4 emissions from ruminant livestock. The ruminant livestock sector both fuels global warming and suffers from its consequences. Heat stress (HS) is a climate factor that impairs livestock productivity and health, causing financial losses for producers as well as environmental concerns due to increased CH4 emission intensity, a measure of GHG emitted per unit of product (e.g., milk or meat). A consequence of HS is oxidative stress, which has been shown to be at least partially offset by supranutritional supplementation with antioxidants. However, the level of antioxidants required is higher than allowed in many jurisdictions, so alternatives are being sought. This mini-review aims to discuss the potential of plant-derived bioactive compounds in mitigating CH4 emission from enteric fermentation and alleviating the negative effects of HS in ruminant livestock; the frequency of the latter is expected to intensify according to the climate projections (IPCC, 2022). Feeding high-concentrate diets is also briefly discussed as a potential strategy in the context of CH4 emission and HS abatement and how plant bioactives could modulate the rumen fermentation perturbations.
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ItemEffects of body weight and age at first kidding on milk yield and composition in primiparous dairy goats.(International Goat Association, 2022)This study aimed to characterize the effects of BW at kidding (KBW) and age at first kidding (AFK) on the likelihood of achieving 270d in milk (LK270), total milk yield at 270d (TMY), and milk components in primiparous dairy goats. Lactation data was collected from 2882 Saanen goats, from three different farms, from Mar/17 to Oct/19. Our results show that TMY increased with increasing KBW and AFK. The LK270 increased with increasing KBW but was not affected by AFK. Increasing AFK increased fat and decreased protein in early lactation, with no significant effects in mid and late-lactation. Our findings attest for the importance of monitoring BW and bringing goats as close as possible to their optimum BW before kidding, as KBW is likely to have a significant impact on lactation length, milk yield and milk composition in first-lactation goats.
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ItemNo Preview AvailableTamanu (Calophyllum inophyllum) growth performance on different types of degraded peatlands in Central Kalimantan(IOP Publishing, 2021-11-26)Abstract To achieve its national goals in climate and landscape resilience, including bioenergy production, the Government of Indonesia has launched an initiative to restore 14 million hectares of degraded land, including 2 million hectares of peatlands, by 2030. Here we present early findings on tamanu adaptability and tree growth (height, diameter and branches) on two types of degraded peatlands in Central Kalimantan. The paper reports peatland type and tamanu tree growth and adaptability in a 3-ha plantation trial plot over three years and a 2-ha plot over two years in Kalampangan and Buntoi villages. Results show survival rates of 82% in the plot on ombrogenous peat in Kalampangan and 81% on topogenous peat in Buntoi. Furthermore, the growth performance of 2-year-old tamanu trees on topogenous peat in Buntoi with an average height of 1.74 m and diameter of 3.97 cm at 5 cm above ground level and 15 branches was better than on ombrogenous peat in Kalampangan with an average height of 0.68 m and diameter of 1.43 cm at 5cm above ground level and five branches. While initial survival and tree growth results are promising, further monitoring of flowering and fruiting is necessary to determine tamanu’s viability for biodiesel production on degraded peatlands.
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ItemGrowth performance of Calophyllum inophyllum at a bioenergy trial plot in Bukit Soeharto Research and Education Forest, East Kalimantan(IOP Publishing, 2021-05-17)Abstract The Indonesian government has committed to providing its entire population with energy through the National Energy Policy, which highlights the importance of diversification, environmental sustainability, and enhanced deployment of domestic energy resources. The contribution of new and renewable energy (NRE) to the nation’s energy supply is mandated to reach 23% by 2025, with bioenergy an important NRE alternative. If developed and deployed appropriately, bioenergy plantations have potential to restore degraded land and enhance biodiversity and environmental services while supporting rural livelihoods. As a potential biofuel tree species suited to the tropics, Calophyllum inophyllum (nyamplung) is being tested across wide-ranging degraded forest conditions in Indonesia. Nyamplung is a potential biodiesel alternative as it grows well in harsh environmental conditions, produces non-edible seed oil, has high amounts of kernel oil and fruits profusely. Here we report growth performance in a plantation trial plot established in February 2018, on previously burned land in Mulawarman University’s Bukit Soeharto Research and Educational Forest. Growth of this two-year-old plantation is strong compared to other Indonesian sites, with average survival rate above 90% on Ultisol soil, which is classified as low fertility and acidic. The findings reveal that different doses of fertilizer applications and slope gradient have no significant effects on growth performance. In addition, trees have already started to flower and fruit, and are colonized by bird species and insects, including bees and butterflies. The study indicates that nyamplung adapts well to different land and soil types. Bioenergy plantations on degraded land are a promising approach for land restoration, and enhance native biodiversity and environmental services while providing a source of renewable energy.
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ItemUsing milk tanker pickup and weather data to quantify the impacts of heat stress on milk production in Australia(Modelling and Simulation Society of Australia and New Zealand, 2021-12-16)Due to high metabolic heat production, dairy cows are more sensitive to heat stress than other livestock. This has consequences on the animal’s welfare and productivity. Reductions in milk production can occur from relatively mild temperatures with the degree of impact increasing with increasing severity of heat exposure. The degree to which heat stress impacts milk production, farm income, and milk supply is becoming increasingly important as the duration and frequency of heat waves increases. This analysis aims to provide estimates of the sensitivity of milk production on Australian dairy farms under heat stress situations. The milk tanker pickup data from three dairy companies was used to investigate the on-farm impacts of heat stress on milk production in three regions of Australia. Milk production and weather data were matched based on the postcode of the farm and Bureau of Meteorology weather station. Weather data were used to calculate the temperature-humidity index (THI) using a formula typically used in Australian studies. The THI is commonly used to quantify the effects of heat stress by combining the effects of temperature and relative humidity. Data that did not meet pre-defined quality criteria were eliminated from the analysis. For instance, records that occurred three or more days since the previous milk pickup, data from farms with less than one year of observations, and years in which more than 10 records were missing between October and April, inclusive, were excluded. Over 960,000 records from 1,286 farms are included in the regional analysis. Linear mixed effect models were fitted to the data from each of three regions using R. The estimated response of milk volume (L) and milk solids (kg) and associated 95% confidence intervals (CIs) are summarised in Table 1. Models using THI values averaged over 7-days, consistently performed better than those averaged over shorter periods. THI values based on minimum and average temperatures performed slightly, but consistently, better than those based on maximum temperature.
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ItemInsects: A Sustainable Feed Protein Source for Animal Nutrition(Proceedings MDPI, 2021)Animal products are a valuable source of nutrients and fibre for humans. Modern consumers are increasingly concerned with the environmental impact of animal production. Thus, a key agenda for agricultural production systems is to improve and develop more sustainable practices whereby food and feed can be produced in an environmentally efficient manner. One such process is the bioconversion of organic waste into insects in a no waste system, leading to the development of what is termed a ‘circular economy’. Insects are highly efficient and can rapidly convert substrates (such as feed/food waste and manure) into high value products high in protein and fat. Numerous production animal species, such as monogastric species and fish, naturally consume insects. Insect production is also estimated to be lower in Green House Gas emissions and have low land and water requirements compared to traditional animal and animal feed production systems. Insect species currently investigated for mass production include black soldier fly larvae (BSFL), mealworms, and crickets. Research into insect production on a mass scale for use as a food or feed source is receiving increased global attention, with multiple companies both in Australia and overseas working to scale up insect production to meet consumer needs. This presentation will introduce the current knowledge of insect rearing for food and feed production.