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1
Armstrong, D. P. "Water use efficiency and profitability on an irrigated dairy farm innorthern Victoria: a case study." Australian Journal of Experimental Agriculture 44, no. 2 (2004): 137. http://dx.doi.org/10.1071/ea02123.
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A study was conducted to look at water use efficiency and profitability on an irrigated dairy farm in northern Victoria. For this case study farm, an economic evaluation was performed for various development options that could result in higher water use efficiency, increased profit, and meet the farm owners' objectives. Water use efficiency was defined as the amount of milk (kg milk fat plus protein) produced from pasture per megalitre of water (irrigation plus effective rainfall).The case study farm data indicated that between 1995–96 and 1998–99 there was no simple, direct association between water use efficiency and profitability. The development options considered included building a new dairy and increasing herd size and either increasing the area of irrigated pasture or intensifying on the existing irrigated area. The likely water use efficiency and economic efficiency were estimated for the various development options. The development budgets suggested that intensifying on the existing irrigated land was the most attractive option, if the predicted improvements in water use efficiency were achieved. This option had an internal rate of return of 64%, broke even after 5 years and was compatible with the objectives of the farm owners.Options that resulted in simultaneous increases in water use efficiency, profitability and labour efficiency appear to be more likely to be adopted than options that focus solely on increasing water use efficiency.
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Linehan, C. J., D. P. Armstrong, P. T. Doyle, and F. Johnson. "A survey of water use efficiency on irrigated dairy farms in northern Victoria." Australian Journal of Experimental Agriculture 44, no. 2 (2004): 131. http://dx.doi.org/10.1071/ea02234.
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Water use efficiency (WUE) in irrigated dairy systems has been defined, in this paper, as the amount of milk (kg milk fat plus protein) produced from pasture per megalitre of water (irrigation plus effective rainfall). A�farm survey was conducted for the 1997–98 and 1998–99 seasons in the Goulburn Irrigation System (GIS) and Murray Irrigation System (MIS) when the irrigation water allocated to irrigators in the GIS was low (100–120% of water right compared with the MIS which was 130 and 200% of water right). These data were analysed in conjunction with information collected on the same farms in the 1994–95 and 1995–96 seasons when the irrigation water allocated to irrigators in both systems was above 150% of water right (Armstrong et al. 1998, 2000). The aim of the survey was to determine if the management decisions made by dairy farmers in seasons of low irrigation water allocations had an impact on WUE.Milk production averaged across the 2 irrigation systems increased significantly over the 5-year period (57 540–75 040 kg milk fat + protein per farm). Over the same period the amount of irrigation water applied (GIS�7.6 ML/ha, MIS 9.2 ML/ha) and the milking area (GIS 72 ha, MIS 73 ha) remained constant. The amount of concentrates fed per cow (GIS 650–1100 kg DM, MIS 480–860 kg DM) and per farm (GIS 119–228 t DM, MIS�72–157 t DM) increased, but pasture consumption (GIS 8.9–9.5 t DM/ha, MIS 9.1–9.7 t DM/ha) did not increase significantly over the survey period. Therefore, the increase in milk production appeared to come primarily from an increase in supplementary feeding rather than an increase in pasture consumption, resulting in no significant change in WUE in either system (GIS 66 kg milk fat + protein/ML, MIS 61 kg milk fat + protein/ML).The survey results indicate that despite varying water allocations in the 2 major irrigation systems in northern Victoria, milk production on farms in both systems increased while changes in WUE could not be detected by the methods used. This suggests tactical options to increase WUE in response to short-term changes in water allocation were either difficult to implement or not a priority in a business sense.
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Crawford, R. H., V. Paton-Cole, R. Turnbull, E. Fitzgerald, A. Michalewicz, and J. Garber. "Trends in residential sustainability measures in the state of Victoria." IOP Conference Series: Earth and Environmental Science 1101, no. 2 (November 1, 2022): 022018. http://dx.doi.org/10.1088/1755-1315/1101/2/022018.
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Abstract Buildings require a significant quantity of energy and water during their operation. Solar water heaters and rainwater tanks have become increasingly common to reduce the demand for fossil-fuel based energy and mains water within buildings. Since 2006, the Victorian Building Authority has required either a rainwater tank or solar water heater to be installed in any new house built in Victoria, Australia. This research analyses the trend in adoption of these two systems using data from building permits issued from 2006 to 2019. This shows that despite an initial preference for rainwater tanks, solar water heaters have been the preferred choice. This preference was found to be greatest for projects costing from $200k-$600k and for allotment areas smaller than 500 m2. Preference for rainwater tanks tended to increase in line with an increase in project cost and allotment area, and this preference was found to be most common in metropolitan areas. This study provides insight into the opportunities for further adoption of solar water heaters and rainwater tanks, including using information at the LGA level to develop specific business opportunities or to inform policy, such as alternative water efficiency solutions for households where allotment area may limit rainwater tank adoption.
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Armstrong, D. P., J. E. Knee, P. T. Doyle, K. E. Pritchard, and O. A. Gyles. "Water-use efficiency on irrigated dairy farms in northern Victoria and southern New South Wales." Australian Journal of Experimental Agriculture 40, no. 5 (2000): 643. http://dx.doi.org/10.1071/ea99132.
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A survey of 170 randomly selected, irrigated, dairy farms in northern Victoria and 9 in southern New South Wales was conducted to examine and benchmark the key factors influencing water-use efficiency. Water-use efficiency was defined as the amount of milk (kg milk fat plus protein) produced from pasture per megalitre of water (irrigation plus effective rainfall). Information on water-use, milk production, supplementary feeding, farm size and type, pasture management, and irrigation layout and management was collected for each farm by personal interview for the 1994–95 and 1995–96 seasons. The farms were ranked in the order of water-use efficiency with the average farm compared with the highest and lowest 10% of farms. The range in water-use efficiency was 25–115 kg milk fat plus protein/ML, with the highest 10% averaging 94 kg/ML and the lowest 10% averaging 35 kg/ML. The large range in water-use efficiency indicated potential for substantial improvement on many farms. The high water-use efficiency farms, when compared with the low group: (i) produced a similar amount of milk from less water (387 v. 572 ML) (P<0.05), less land (48 v. 83 ha) (P< 0.05) and a similar number of cows (152 v. 143 cows); (ii) had higher estimated pasture consumption per hectare (11.5 v. 5.5 t DM/ha) (P<0.01) and per megalitre (1.0 v. 0.5 t DM/ML) (P<0.01); (iii) had higher stocking rates (3.2 v. 1.8 cows/ha) (P<0.01); (iv) used higher rates of nitrogen fertiliser (59 v. 18 kg N/ha.year) (P<0.05) and tended to use more phosphorus fertiliser (64 v. 34 kg P/ha.year) (P<0.10); (v) used similar levels of supplementary feed (872 v. 729 kg concentrates/cow); (vi) had higher milk production per cow (396 v. 277 kg fat plus protein) (P<0.05); and (vii) directed a higher proportion of the estimated energy consumed by cows into milk production (53 v. 46%) (P<0.05). The survey data confirmed that irrigated dairy farm systems are complex and variable. For example, the amount of feed brought in from outside the milking area varied from 0 to 74% of the estimated total energy used by a milking herd. There was a large range in the level of supplement input amongst the farms in the high water-use efficiency group, and in the low water-use efficiency group. This indicates that the management of the farming system has a greater impact on the efficiency of water-use on irrigated dairy farms, than the type of system. The data from the survey provide information for individual farms, a measure of the water-use efficiency of the industry, and an indication of the quality of regional land and water resources.
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Harris, Edwyna. "The Impact of Institutional Path Dependence on Water Market Efficiency in Victoria, Australia." Water Resources Management 25, no. 15 (July 27, 2011): 4069–80. http://dx.doi.org/10.1007/s11269-011-9884-0.
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Maher, Michelle, and Emer Campbell. "Demonstrating environmental water needs in a climate of change." Proceedings of the Royal Society of Victoria 122, no. 2 (2010): 70. http://dx.doi.org/10.1071/rs10016.
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Efficient and accountable management of water resources in Northern Victoria has become a critical issue for the future of irrigation, communities and the environment, both north and south of the Great Dividing Range. To increase efficiencies and enhance accountability for water resource use, the Victorian Government is investing $1 billion through the Northern Victoria Irrigation Renewal Project (NVIRP) to upgrade ageing irrigation infrastructure across the Goulburn-Murray Irrigation District. The upgrade is expected to generate an additional 225 GL of water that will be distributed equally between irrigators, the environment and Melbourne. Whilst there are significant potential benefits for the environment as a whole from the water savings initiatives, there may also be adverse impacts from altering the hydrology of the diverse array of wetlands and rivers which are directly linked to the irrigation delivery network. The NVIRP Environmental Referrals process has investigated these potential impacts and identified ten wetlands and four rivers of high environmental value that require the development of environmental watering plans. These plans are the primary means by which the NVIRP commitment to ‘no net environmental loss’ will be achieved and assets of high environmental value will be protected. Three Environmental Watering Plans (EWPs) were completed prior to the operation of NVIRP works in the 2009-2010 irrigation season. These are for Johnson Swamp, Lake Elizabeth and Lake Murphy. The paper will describe the development of the Lake Elizabeth EWPs by the North Central Catchment Management Authority (NCCMA), within the context of uncertain climatic conditions, the recent long drought and the need to demonstrate accountability and efficiency in the use of a scarce and finite resource.
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Glenn, D. Michael, Nicola Cooley, Rob Walker, Peter Clingeleffer, and Krista Shellie. "Impact of Kaolin Particle Film and Water Deficit on Wine Grape Water Use Efficiency and Plant Water Relations." HortScience 45, no. 8 (August 2010): 1178–87. http://dx.doi.org/10.21273/hortsci.45.8.1178.
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Water use efficiency (WUE) and response of grape vines (Vitis vinifera L. cvs. ‘Cabernet Sauvignon’, ‘Merlot’, and ‘Viognier’) to a particle film treatment (PFT) under varying levels of applied water were evaluated in Victoria, Australia, and southwestern Idaho. Vines that received the least amount of water had the warmest canopy or leaf surface temperature and the lowest (more negative) leaf water potential, stomatal conductance (gS), transpiration (E), and photosynthesis (A). Vines with plus-PFT had cooler leaf and canopy temperature than non-PFT vines; however, temperature difference resulting from irrigation was greater than that resulting from PFT. In well-watered vines, particle film application increased leaf water potential and lowered gS. Point-in-time measurements of WUE (A/E) and gS did not consistently correspond with seasonal estimates of WUE based on carbon isotope discrimination of leaf or shoot tissue. The response of vines with particle film to undergo stomatal closure and increase leaf water potential conserved water and enhanced WUE under non-limiting soil moisture conditions and the magnitude of response differed according to cultivar.
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Byrnes, Joel, Lin Crase, Brian Dollery, and Renato Villano. "The relative economic efficiency of urban water utilities in regional New South Wales and Victoria." Resource and Energy Economics 32, no. 3 (August 2010): 439–55. http://dx.doi.org/10.1016/j.reseneeco.2009.08.001.
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Pawsey, Nicholas, Jayanath Ananda, and Zahirul Hoque. "Rationality, accounting and benchmarking water businesses." International Journal of Public Sector Management 31, no. 3 (April 9, 2018): 290–315. http://dx.doi.org/10.1108/ijpsm-04-2017-0124.
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Purpose The purpose of this paper is to explore the sensitivity of economic efficiency rankings of water businesses to the choice of alternative physical and accounting capital input measures. Design/methodology/approach Data envelopment analysis (DEA) was used to compute efficiency rankings for government-owned water businesses from the state of Victoria, Australia, over the period 2005/2006 through 2012/2013. Differences between DEA models when capital inputs were measured using either: statutory accounting values (historic cost and fair value), physical measures, or regulatory accounting values, were scrutinised. Findings Depending on the choice of capital input, significant variation in efficiency scores and the ranking of the top (worst) performing firms was observed. Research limitations/implications Future research may explore the generalisability of findings to a wider sample of water utilities globally. Future work can also consider the most reliable treatment of capital inputs in efficiency analysis. Practical implications Regulators should be cautious when using economic efficiency data in benchmarking exercises. A consistent approach to account for the capital stock is needed in the determination of price caps and designing incentives for poor performers. Originality/value DEA has been widely used to explore the role of ownership structure, firm size and regulation on water utility efficiency. This is the first study of its kind to explore the sensitivity of DEA to alternative physical and accounting capital input measures. This research also improves the conventional performance measurement in water utilities by using a bootstrap procedure to address the deterministic nature of the DEA approach.
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Bethune, M., and Q. J. Wang. "A lysimeter study of the water balance of border-check irrigated perennial pasture." Australian Journal of Experimental Agriculture 44, no. 2 (2004): 151. http://dx.doi.org/10.1071/ea03049.
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The dairy industry is a major user of water in northern Victoria and southern New South Wales. Water is typically applied to pasture using the border-check irrigation system. The border-check system is largely gravity driven and thus energy efficient. However, deep drainage can potentially be high because the system allows only limited control over the depth of water applied in each irrigation event. For this reason, heavy soils are regarded as the most suitable for border-check irrigation. This study quantified net deep drainage (deep drainage less capillary rise) under border-check irrigated pasture on a Goulburn clay loam soil. Additionally, the study investigated the extent to which irrigation frequency and watertable conditions influence water use, dry matter production and deep drainage. The water balance and dry matter production were monitored over 2.5 years in a lysimeter facility in northern Victoria. The Goulburn clay loam is representative of the heavier textured soils used for border-check irrigation of pasture in northern Victoria. The average measured net deep drainage was 4 mm/year. This indicates that relatively small levels of net deep drainage can be achieved under well-managed border-check irrigation on a Goulburn clay loam soil. Net deep drainage losses were greatest following winter, when rainfall exceeded pasture water use for an extended period. Increasing the interval between irrigation events resulted in reduced plant water use, infiltration of irrigation water, rainfall runoff and pasture production. However, increasing the interval did not impact on net deep drainage or water use efficiency. Depth of watertable had a relatively minor impact on the water balance.
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Sommerville, Katy E., and Jennifer Read. "Contrasting water-use strategies in two sympatric cool-temperate rainforest species, Nothofagus cunninghamii (Nothofagaceae) and Atherosperma moschatum (Atherospermataceae)." Australian Journal of Botany 56, no. 2 (2008): 109. http://dx.doi.org/10.1071/bt07138.
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Nothofagus cunninghamii (Hook.) Oerst. and Atherosperma moschatum Labill. co-occur in cool-temperate rainforest across the wetter parts of Tasmania and Victoria, Australia, but A. moschatum extends to drier areas than N. cunninghamii. Possible reasons include differential tolerance of drought and fire or dispersal capacity. Here, we compare these species in their responses to water deficits. Differences in seedling survival, leaf tissue damage, shoot water relations, stomatal sensitivity, allocation of biomass and the long-term water-use efficiency of each species in response to water stress were investigated. N. cunninghamii showed traits typical of a high-water-use species, such as high stomatal conductance, a strategy that is not surprising in a rainforest species. However, it also displayed an exceptional ability to draw water from the soil and longer seedling roots, allowing replacement of water lost, at least in the short term. A. moschatum showed a more conservative water-use strategy, surviving greater internal dehydration with less damage, and displaying greater stomatal sensitivity to drought and long-term water-use efficiency in trees. The apparently superior long-term drought resistance of A. moschatum may in part explain its more common occurrence in drier regions than N. cunninghamii, at least in Tasmania, while the capacity of N. cunninghamii to survive short but severe periods of water stress correlates well with its higher position in the canopy and greater exposure to sunlight and desiccating winds. However, there is little evidence to suggest that the absence of N. cunninghamii from the rainforests of eastern Victoria is due to drought. We also suggest that the water-use strategy of N. cunninghamii may relate not just to surviving water deficits, but to maximising annual carbon gain in a temperate climate that is, on average, driest during the warmest time of the year.
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Borstlap, Sylvia, and Martin H. Entz. "Zero-tillage influence on canola, field pea and wheat in a dry subhumid region: Agronomic and physiological responses." Canadian Journal of Plant Science 74, no. 3 (July 1, 1994): 411–20. http://dx.doi.org/10.4141/cjps94-078.
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Field trials were conducted over 4 site-years in southern Manitoba to compare the response of Katepwa wheat, Westar canola and Victoria field pea to zero tillage (ZT). The experimental design was a split plot with tillage system as the mainplot (ZT vs. conventional tillage (CT)) and crop species as the subplot. All crops received protection from insect, weed and disease pests. Tillage system had only a limited impact on crop dry matter accumulation or grain quality. Where differences were observed, crop performance was enhanced under ZT. Seasonal evapotranspiration (ET) was either reduced or unaffected by ZT, while ET efficiency (ETE: kg ha−1 mm−1 ET) was either increased or unchanged by the shift from CT to ZT. Higher ETE under ZT was attributed to less soil water evaporation. Significant tillage system × crop species (T × S) interactions for growth parameters, ET and ETE indicated that field pea often benefitted more than wheat or canola from ZT. A significant T × S interaction at one of the four sites indicated that water extraction between 30 and 90 cm was higher for pea and canola in the ZT compared with CT treatment, while soil water extraction by wheat was reduced under ZT. At a second site, lower ET for all three crops under ZT was attributed to reduced water use between 90 and 130 cm. Despite some effects of ZT on crop growth and water use, no significant tillage, T × S, or site × tillage interactions were observed for grain yield. It was concluded that under the conditions of this study (i.e. precipitation and temperature conditions close to the long-term average), Westar canola, Victoria field pea and Katepwa wheat were, for the most part, equally suited to ZT production. Key words: Soil water extraction, evapotranspiration efficiency, crop quality, grain yield, canopy development
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Schlafrig, J., J. Sturman, G. Ho, and K. Mathew. "Water auditing: the case for statutory requirements." Water Supply 8, no. 6 (December 1, 2008): 597–601. http://dx.doi.org/10.2166/ws.2008.112.
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Drought across swathes of Australia, highlights our need for water conservation in addition to seeking new sources of water (demand and supply-side resource options). Water conservation or efficiency improvement is currently a non-systematic process along the lines of ‘if we do such and such then we will save so much water’. Such an approach is ad-hoc and only has the appearance of being ‘quantitative’. We would class it as qualitative, or maybe advanced qualitative water conservation. True quantitative or structured water auditing of non-domestic water consumption is an iterative, systematic and documented process of obtaining reliable use data, validated by a closure approach. Opportunities are identified for water use reduction, water reuse, recycling and for water resource substitution. Financial assessment of savings in cost against cost of measures will provide a payback period. A water management strategy or Water Management Plan (WMP) as it is known in Victoria, Australia, is devised which is consistent with legal requirements, the enterprise's environmental policy and its movement towards sustainable development. Regulators have legislated for mandatory WMPs and audits in Victoria, but this is the only state so far to do this. Mandatory water auditing should be an uncontested choice as it can only provide a win:win situation regulation to the private sector. We argue that only the systematic process provided by structural water auditing constitutes quantitative water conservation. Further, statutory obligation for water users to engage in the water auditing process will give the broad, systematic quantitative information, and based upon which optimal water management strategies or WMPs can be devised. This will ensure a rational approach to our future water needs and the needs of our environment. It is anticipated that voluntary auditing in the arenas not mandated will increase in the long term if this is done.
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Collett, Brent, and Nicola Henry. "Water justice: exploring the social dimensions of new irrigation technologies in northern Victoria, Australia." Water Policy 16, S2 (November 1, 2014): 155–73. http://dx.doi.org/10.2166/wp.2014.102.
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Water resource management is one of the most pressing human and environmental challenges of the 21st century. Technological approaches to improving the management of water feature prominently, with technology positioned as the solution to issues of competing interests and the achievement of water savings. This paper analyses the social dimensions of a regional-level irrigation technology, examining the piloting of Total Channel Control™ technology in northern Victoria, Australia, as a case study. Water savings, organisational efficiency, on-demand ordering, occupational health and safety improvements, and many other benefits were anticipated to flow from this ‘world first’ technology. Drawing on semi-structured interviews with stakeholders and participant observation of an irrigation committee, this paper examines stakeholder accounts regarding piloting of the technology. We argue that in order to achieve justice and fairness in implementing regional irrigation technology, three essential criteria must be met: genuine consultation, participation and negotiation; responsive and respectful dialogue and communication; and mutual information exchange. As society shifts towards greater reliance on technological intervention to solve some of the most pressing dilemmas of the modern era, a more holistic approach focusing on the complexity of human interaction with the technology is vital.
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Wood, M. L., and L. Finger. "Influence of irrigation method on water use and production of perennial pastures in northern Victoria." Australian Journal of Experimental Agriculture 46, no. 12 (2006): 1605. http://dx.doi.org/10.1071/ea05197.
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The irrigation of pasture for the dairy industry accounts for a large proportion of Australia’s total irrigation water use, particularly in the Murray–Darling Basin. Most pasture is irrigated using the border-check method. The dairy industry is under increasing pressure to use water more efficiently in response to water market reforms and restrictions on future irrigation water availability, creating interest in the potential of alternative irrigation methods. A field experiment was conducted at Tatura, Victoria, Australia between July 2000 and July 2002 to quantify the differences in water use, perennial pasture production and pasture composition under border-check, surge, sprinkler and subsurface drip irrigation. The experiment aimed to assess each irrigation method as it would perform under farm best management practices. Measurements included applied water, tailwater runoff, soil water status, dry matter production and botanical composition. This experiment found that sprinkler and subsurface drip irrigation used on average 2 ML/ha.year (17–23%) less water than border-check irrigation while maintaining or increasing pasture production, consequently having a significantly higher water use efficiency. Surface runoff was significantly reduced under sprinkler and subsurface drip irrigation. Surge irrigation had no advantages over border-check. Although some differences in pasture composition were observed between irrigation treatments, the trends were inconsistent from one season to the next. The high water use by gravity fed irrigation methods is attributed to a combination of higher evaporation and groundwater accessions.
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Watson, D. J., and G. Drysdale. "Irrigation practices on north-east Victorian dairy farms: a survey." Australian Journal of Experimental Agriculture 45, no. 12 (2005): 1539. http://dx.doi.org/10.1071/ea03231.
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The north-east region of Victoria is an important water-harvesting catchment for gravity-fed irrigators downstream of Lake Mulwala. Dairy farmers are significant users of irrigation water in north-east Victoria but little was known about their irrigation practices and attitudes. A survey undertaken in 2000 collected data on irrigation practices and attitudes from 92% of the irrigating dairy farmers in the region. It found diversity in many aspects of irrigation amongst the region’s irrigated dairy farms, ranging from the proportion of the farm irrigated to the irrigation system used, and identified areas where improvements to irrigation practices could be made. More than 8 different irrigation systems were used in the region, and flood irrigation was the most commonly used. However, a large proportion (37%) of flood irrigators were contemplating changing to spray irrigation, mostly to long lateral hand move sprinkler irrigation, in an effort to improve water use efficiency. More than 50% of respondents did not meter irrigation water use, and 83% pumped water directly from rivers or creeks, with dams and dragline holes the next most common sources. Irrigation scheduling (when to start irrigating and the frequency of irrigation thereafter) and the amount of water to apply were generally based on knowledge and experience rather than on soil moisture monitoring equipment or use of evaporation rates. Most survey respondents recognised that their irrigation practices could improve and said that they would be interested in information to help them make more informed decisions about irrigation practices.
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Kaine, G., D. Bewsell, A. Boland, and C. Linehan. "Using market research to understand the adoption of irrigation management strategies in the stone and pome fruit industry." Australian Journal of Experimental Agriculture 45, no. 9 (2005): 1181. http://dx.doi.org/10.1071/ea01183.
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Market research was conducted to develop an extension program targeting the specific irrigation management needs of growers in the stone and pome fruit industry within the Goulburn Valley, Victoria. The process of integrating market research with extension practice proved challenging, as it required the development of an extension program that was fundamentally different from what was originally envisaged. However, it was essential to achieve this integration in order to meet the original objectives for the extension program as set by the funding body. We found, in most cases, that the motivation for stone and pome fruit growers in the Goulburn Valley to change orchard irrigation management practices was not because they needed to save water, or to increase water use efficiency. Instead, growers were changing practices in order to save time irrigating, improve the scope for managerial flexibility in the orchard, or when redeveloping their orchard to a closer planting design. These findings suggest that growers in the Goulburn Valley are more likely to respond to an extension program consistent with these motivations rather than a program promoting water use efficiency.
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Olalde G., Víctor M., J. Alberto Escalante E., and Angel A. Mastache L. "PHENOLOGY, YIELD AND WATER USE EFFICIENCY OF SUNFLOWER IN FUNCTION OF ENVIRONMENT AND NITROGEN / FENOLOGIA, RENDIMIENTO Y EFICIENCIA EN EL USO DEL AGUA EN FUNCION DEL AMBIENTE Y NITRÓGENO / PHÉNOLOGIE, RENDEMENT ET EFFICACITÉ DE L’UTILISATION DE L’EAU EN FONCTION DES ENVIRONS ET DE L’AZOTE CHEZ LE TOURNESOL." HELIA 24, no. 35 (December 2001): 111–28. http://dx.doi.org/10.1515/helia.2001.24.35.111.
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SUMMARYDuring the rainy season of 1998, a field experiment was established in Cocula, Guerrero (hot subhumid climate, Awo) and in Montecillo, México (semiarid climate, BS1), to evaluate the effect of nitrogen (0, 10 and 20 g m-2) and environment on phenology, yield and its components, water use efficiency (WUE), and crop evapotranspiration (ETc) and heat units (HU) accumulated during the growth cycle of sunflower (Helianthus annuus L.) cv. Victoria. The crop was planted on June 1 at a density of 7.5 pl m-2 in both climates. In Cocula, maximum and minimum temperatures were more extreme and rainfall was more intense, while soil was poor in total nitrogen, compared with Montecillo. Crop growth, yield and its components, and water use efficiency were affected significantly by the environment, nitrogen and the interaction environment * nitrogen. The crop cycle in the hot environment was 36 days shorter, with a greater accumulation of HU and ETc. Yield and its components and water use efficiency were significantly higher in Cocula. Nitrogen positively affected the evaluated variables. The interactive effect of environment * nitrogen was observed clearly, since in Cocula there was response to the application of nitrogen in most of the variables evaluated, while in Montecillo there was not.
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Zafari, Najibullah, Ashok Sharma, Dimuth Navaratna, Varuni M. Jayasooriya, Craig McTaggart, and Shobha Muthukumaran. "A Comparative Evaluation of Conceptual Rainfall–Runoff Models for a Catchment in Victoria Australia Using eWater Source." Water 14, no. 16 (August 16, 2022): 2523. http://dx.doi.org/10.3390/w14162523.
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Hydrological modelling at a catchment scale was conducted to investigate the impact of climate change and land-use change individually and in combination with the available streamflow in the Painkalac catchment using an eWater Source hydrological model. This study compares the performance of three inbuilt conceptual models within eWater Source, such as the Australian water balance model (AWBM), Sacramento and GR4J for streamflow simulation. The three-model performance was predicted by bivariate statistics (Nash–Sutcliff efficiency) and univariate (mean, standard deviation) to evaluate the efficiency of model runoff predictions. Potential evapotranspiration (PET) data, daily rainfall data and observed streamflow measured from this catchment are the major inputs to these models. These models were calibrated and validated using eight objective functions while further comparisons of these models were made using objective functions of a Nash–Sutcliffe efficiency (NSE) log daily and an NSE log daily bias penalty. The observed streamflow data were split into three sections. Two-thirds of the data were used for calibration while the remaining one-third of the data was used for validation of the model. Based on the results, it was observed that the performance of the GR4J model is more suitable for the Painkalac catchment in respect of prediction and computational efficiency compared to the Sacramento and AWBM models. Further, the impact of climate change, land-use change and combined scenarios (land-use and climate change) were evaluated using the GR4J model. The results of this study suggest that the higher climate change for the year 2065 will result in approximately 45.67% less streamflow in the reservoir. In addition, the land-use change resulted in approximately 42.26% less flow while combined land-use and higher climate change will produce 48.06% less streamflow compared to the observed flow under the existing conditions.
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Kanda, Edwin K., Job R. Kosgei, and Emmanuel C. Kipkorir. "Simulation of organic carbon loading using MIKE 11 model: a case of River Nzoia, Kenya." Water Practice and Technology 10, no. 2 (June 1, 2015): 298–304. http://dx.doi.org/10.2166/wpt.2015.035.
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River Nzoia is the largest river draining into the Kenyan portion of Lake Victoria. This river receives both point sources of pollution from industrial and municipal wastes, and non-point sources from agricultural runoff in the catchment. The objective of this study was to simulate dissolved oxygen (DO) and biochemical oxygen demand (BOD) of the middle section of River Nzoia using MIKE 11 model. The model was calibrated using discharge and water quality data for 2009 and validated with March–April 2013 data. The model performance was good with coefficient of determination (R2) values of between 0.845 and 0.995, Nash–Sutcliffe efficiency values of between 0.748 and 0.993 and percent bias of less than 10 for both calibration and validation of electrical conductivity (EC), DO and BOD. EC and BOD values were lower for April compared to March which could be attributed to dilution during high flows. DO values were above the recommended minimum level of 4 mg/l in all the sections of the river in the wet period but some sections had lower than 4 mg/l during low flow period. The government agencies such as Water Resources Management Authority and National Environment Management Authority should enforce the effluent standards to ensure that industries and wastewater treatment plants adhere to the maximum allowable limit for BOD and also improve their treatment efficiencies of wastewater plants so as to improve the quality of River Nzoia which is important in the overall management of the Lake Victoria basin.
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Jacobs, J. L., G. N. Ward, F. R. McKenzie, and G. Kearney. "Irrigation and nitrogen fertiliser effects on dry matter yield, water use efficiency and nutritive characteristics of summer forage crops in south-west Victoria." Australian Journal of Experimental Agriculture 46, no. 9 (2006): 1139. http://dx.doi.org/10.1071/ea05122.
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Summer forage crops form an integral component of feed rations to meet the dietary requirements of dairy cows in south-west Victoria. Irrigation of such crops has the potential to increase the availability of feed of high nutritive value. The effect of irrigation strategies and nitrogen (N) fertiliser on forage crop accumulation rates, dry matter yield, water use efficiency and nutritive characteristics was determined at each harvest over 2 summers. The crops used were Hunter (Brassica campestris L. × Brassica napus L.), Graza (a complex hybrid of Raphanus sativus L. with introgression from Raphanus maritimus L. and Brassica oleracea L.) and Shirohie millet (Echinochloa utilis Ohwi & Yabuno). Irrigation treatments were dryland control, weekly irrigation to 100% of estimated requirements, weekly irrigation to 50% of estimated requirements and 25% of estimated requirements every second week. Following sowing and after each harvest, N was applied at either 50 or 100 kg N/ha (brassica crops, 3 applications; millet, 2 applications). In both years, fully irrigated crops produced higher dry matter yields than the dryland crops for all species. For Hunter and Graza, full irrigation also resulted in higher dry matter yields than irrigating every second week. Nitrogen at the higher application rate led to higher dry matter yields for Graza in both years and for millet in year 1. Irrigation had inconsistent effects on the nutritive characteristics of all species. Metabolisable energy content ranged from 10.1 to 13.6, 9.8 to 13.3 and 8.2 to 11.3 MJ/kg dry matter for Hunter, Graza and millet, respectively. Nitrogen application at 100 kg N/ha resulted in higher crude protein content for Hunter and Graza at the second and third harvests and for millet at the second harvest at 50 kg N/ha in both years. Water use efficiencies (irrigation plus effective rainfall) varied according to species with all dryland crops having higher water use efficiencies than the irrigated crops. Total water use efficiencies ranged from 21 to 55, 17 to 39 and 28 to 86 kg dry matter/ha.mm for Hunter, Graza and millet, respectively. In contrast, water use efficiencies from applied irrigation water ranged from 0 to 18 kg dry matter/ha.mm for Hunter, 5 to 18 kg dry matter/ha.mm for Graza and 3 to 33 kg dry matter/ha.mm for millet. Economic assessments indicated average costs for dryland Hunter, Graza and millet to be AU$94, $124 and $76/t dry matter and average costs for fully irrigated crops to be $57, $67 and $51/t dry matter, respectively. This study indicates there is potential to economically irrigate these species to provide additional dry matter of medium to high nutritional value to feed lactating dairy cows through late spring and summer. The data also indicate that for the irrigation of summer forage crops in this environment, the most efficient use of limited water supplies is likely to be a weekly application of water at 50% of the estimated perennial pasture requirements.
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Mkuna, Eliaza, and Lloyd J. S. Baiyegunhi. "Analysis of the technical efficiency of Nile perch (Lates niloticus ) fishers in the Tanzanian portion of Lake Victoria: A stochastic frontier analysis." Lakes & Reservoirs: Research & Management 24, no. 3 (July 25, 2019): 228–38. http://dx.doi.org/10.1111/lre.12274.
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Ho, C. K. M., B. Malcolm, and P. T. Doyle. "Supplementary feeding options to alleviate the impacts of decreased water availability on dairy-farm economic performance in northern Victoria." Animal Production Science 55, no. 2 (2015): 194. http://dx.doi.org/10.1071/an14287.
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The anticipated effects of climate change, competing demands from the environment, industry and urban users, and changes in water policy are likely to reduce the amount and increase the variability of water allocations to dairy farmers in northern Victoria. The way two irrigated dairy farms that differed in feedbase characteristics, herd size and farm area, would operate and perform with reduced and more variable water allocations was examined over 10 years. Strategies to manage the impact of changed water availability were tested; namely, increasing milk production by feeding more supplementary feed, changing the feed system to present supplements in a partial mixed ration (PMR), and increasing milk production by using a PMR. Neither farm was profitable under medium climate change, or if the conditions that generated the low inflows of water into irrigation supply dams between 1996–97 and 2006–07 prevailed, unless changes were made to the farm system. Feeding supplements in a well formulated mixed ration have the potential to increase the efficiency of metabolisable energy use and offers the opportunity to increase feed intake and milk production. A PMR system enabled one of the farms to maintain and increase profit under medium climate change conditions; however, risk, measured as variability in profit, also increased. Under more severe reductions in water availability, neither of the farms examined was profitable over the run of years. Changes to the farm system other than feeding additional supplementary feed to increase milk production and/or using a PMR system, would be needed to counteract the effects of reduced and more variable water availability and maintain profit.
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Jacobs, J. L., G. N. Ward, and G. Kearney. "Effects of irrigation strategies and nitrogen fertiliser on turnip dry matter yield, water use efficiency, nutritive characteristics and mineral content in western Victoria." Australian Journal of Experimental Agriculture 44, no. 1 (2004): 13. http://dx.doi.org/10.1071/ea03054.
Full textAbstract:
The effect of different irrigation strategies on turnip forage crop growth rates, dry matter (DM) yield, water use efficiency (WUE), changes in soil volumetric water content, nutritive characteristics and mineral content was determined on different soil types at different sites (site 1 and 2) over 2 years. Treatments were: (A) a dryland control; (B) fully watered to soil field capacity each week; (C) 75% of full watering; (D) 50% of full watering; (E) 25% of full watering; (F) a single watering to soil field capacity or to a maximum of 50 mm between weeks 0–6; (G) a single watering between weeks 6–8; (H) a single watering between weeks 8–10; and (I) a single watering between weeks 10–12 after sowing. In addition, each irrigation treatment received either 0 or 50 kg N/ha applied 5 weeks after sowing. Responses to applied irrigation water were different at each site and also within one year. At site 1, responses to irrigation were adversely affected by insect damage and delayed sowing, particularly in year 1. However, there were significant increases in DM yield to weekly irrigation regimes in both years, with responses greater in year 2, and responses in both years were greater where nitrogen was applied. At site 2, there were significant responses to weekly irrigation regimes in year 1 with DM yields from fully irrigated plots almost double that of the dryland treatment. In year 2, DM yields from all treatments were similar and it is proposed that lower summer temperatures may have contributed to the improved DM yield observed with the dryland treatment. In both years, at site 2, there were generally higher DM yields with nitrogen application irrespective of irrigation regime. Turnip metabolisable energy values were consistently above 11.5 and 13 MJ/kg DM for leaves and roots respectively, with crude protein contents for leaves ranging from 11 to 20% and 13 to 24% and roots from 6 to 14% and 9 to 17% at sites 1 and 2, respectively. Water use efficiencies varied according to irrigation treatment with higher efficiencies observed at site 2 in both years. In year 1 and 2, total WUE at site 1 varied from 5 to 11 kg DM/ha.mm while at site 2 the range was 20–48�kg�DM/ha.mm with higher values being observed in year 2. As with DM yields it is likely that the observed higher WUE in year 2 was due to lower summer temperatures. At site 2, the dryland treatments produced the highest efficiencies in both years. In contrast, WUE from applied irrigation water ranged from 0 to 35 kg DM/ha.mm at site�1 and from 0 to 23 kg DM/ha.mm at site 2. This study suggests that there is potential to economically irrigate turnips to provide additional DM of high nutritional value for lactating dairy cows, however, issues such as sowing dates, soil type, and insect damage will also influence final yields. In particular, summer temperatures influence both dryland growth potential and growth responses to irrigation. Also single irrigations during the growing period will not significantly increase DM yields over a crop grown under dryland conditions.
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Khan, S. I., P. Adhikari, Y. Hong, H. Vergara, R. F Adler, F. Policelli, D. Irwin, T. Korme, and L. Okello. "Hydroclimatology of Lake Victoria region using hydrologic model and satellite remote sensing data." Hydrology and Earth System Sciences 15, no. 1 (January 14, 2011): 107–17. http://dx.doi.org/10.5194/hess-15-107-2011.
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Abstract. Study of hydro-climatology at a range of temporal scales is important in understanding and ultimately mitigating the potential severe impacts of hydrological extreme events such as floods and droughts. Using daily in-situ data over the last two decades combined with the recently available multiple-years satellite remote sensing data, we analyzed and simulated, with a distributed hydrologic model, the hydro-climatology in Nzoia, one of the major contributing sub-basins of Lake Victoria in the East African highlands. The basin, with a semi arid climate, has no sustained base flow contribution to Lake Victoria. The short spell of high discharge showed that rain is the prime cause of floods in the basin. There is only a marginal increase in annual mean discharge over the last 21 years. The 2-, 5- and 10- year peak discharges, for the entire study period showed that more years since the mid 1990's have had high peak discharges despite having relatively less annual rain. The study also presents the hydrologic model calibration and validation results over the Nzoia basin. The spatiotemporal variability of the water cycle components were quantified using a hydrologic model, with in-situ and multi-satellite remote sensing datasets. The model is calibrated using daily observed discharge data for the period between 1985 and 1999, for which model performance is estimated with a Nash Sutcliffe Efficiency (NSCE) of 0.87 and 0.23% bias. The model validation showed an error metrics with NSCE of 0.65 and 1.04% bias. Moreover, the hydrologic capability of satellite precipitation (TRMM-3B42 V6) is evaluated. In terms of reconstruction of the water cycle components the spatial distribution and time series of modeling results for precipitation and runoff showed considerable agreement with the monthly model runoff estimates and gauge observations. Runoff values responded to precipitation events that occurred across the catchment during the wet season from March to early June. The spatially distributed model inputs, states, and outputs, were found to be useful for understanding the hydrologic behavior at the catchment scale. The monthly peak runoff is observed in the months of April, May and November. The analysis revealed a linear relationship between rainfall and runoff for both wet and dry seasons. Satellite precipitation forcing data showed the potential to be used not only for the investigation of water balance but also for addressing issues pertaining to sustainability of the resources at the catchment scale.
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Kelly, K. B., C. R. Stockdale, and W. K. Mason. "The productivity of irrigated legumes in northern Victoria. 1. Effect of irrigation interval." Australian Journal of Experimental Agriculture 45, no. 12 (2005): 1567. http://dx.doi.org/10.1071/ea03212.
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An experiment was undertaken to determine the production and water use of pure swards of white clover (Trifolium repens L. cv. Haifa), red clover (Trifolium pratense L. cv. Redquin) and lucerne (Medicago sativa L. cv. Validor) between December 1987 and December 1990. The experiment was a split plot design with 3 irrigation interval treatments, which were the main plots, and 3 legume species, which were the subplots, all of which were replicated 4 times. Irrigation frequency was determined by evaporation minus rainfall (E-R) and was scheduled to occur at intervals of about 40, 80 or 120 mm of cumulative E-R. Annual amounts of harvested dry matter (DM) ranged from 8 to 22 t/ha depending on irrigation and species treatment. There was an interaction (P<0.05) between irrigation interval and species during each irrigation season. White clover DM harvested was reduced (P<0.05) by an average of 23 and 41%, respectively, as irrigation intervals were extended beyond 40 mm E-R (where up to 12 t DM/ha was recorded in an irrigation season). The decline in white clover growth in the less frequently irrigated treatments, relative to the 40 mm E-R irrigation treatment, was most pronounced between December and February, the months of highest evaporative demand, when these swards were 30 and 52% less productive (80 and 120 mm E-R, respectively). This compared with reductions of 16 and 32%, respectively, for red clover and 1 and 4%, respectively, for lucerne during the same period. Red clover, a dense productive stand initially, lost vigour and density in the second summer of this experiment, and from February in the second year was not harvested. However, for the period during which it was harvested, red clover production was reduced (P<0.05) by 21%, on average, when the irrigation interval was 120 mm E-R compared with the 40 and 80 mm E-R irrigation treatments. The production of lucerne was not affected (P>0.05) by the range of irrigation frequencies used in this experiment, although its crown density in the most frequent irrigation treatment was 30% less than in the 2 less frequently irrigated treatments when measurements were terminated in December 1990. However, after the first year, the lucerne swards were all highly productive, producing up to 21 t DM/ha in an irrigation season. For white clover to be productive, frequent irrigation is essential. However, all the indices of plant and sward performance measured during intensive studies showed that frequent irrigation of white clover resulted in earlier onset of water stress relative to the less frequent irrigation intervals. Despite this earlier onset of water stress, the yield advantage of frequent irrigation was large. Red clover and lucerne were less reliant on frequent irrigations to maintain productivity than white clover. However, red clover may need to be re-sown on a regular basis in the northern Victorian environment because of its failure to persist beyond 2 years. It is suggested that lucerne should be considered in preference to white clover because of its greater water use efficiency and its less critical reliance on irrigation management to maintain productivity.
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Sadras, Víctor, David Roget, and Garry O'Leary. "On-farm assessment of environmental and management constraints to wheat yield and efficiency in the use of rainfall in the Mallee." Australian Journal of Agricultural Research 53, no. 5 (2002): 587. http://dx.doi.org/10.1071/ar01150.
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The responses of wheat grain yield to soil properties, weather, root diseases, and management practices were investigated in 75 grower-managed crops in the Mallee region of South Australia, Victoria, and New South Wales during 3 growing seasons. Fourteen cultivars were represented in the sampled crops, with Frame being the most common (56%). The most widespread crop sequence was wheat after pasture (43% of wheat crops), followed by wheat after fallow or cereal (both about 20%); 12% of the wheat was sown after legumes. Wheat after cereal was more common in drier sites, and wheat after fallow in wetter sites. Wheat yield was proportional to Fischer’s photothermal coefficient around flowering, and ranged from nil to 4.7 t/ha. On average, wheat crops sown after cereals yielded 0.4 t/ha less than their counterparts sown after fallow, and 0.7 t/ha less than those after legumes. Sowing date ranged from 24 April to 21 July; yield declined with delayed sowing at an average rate of 17 kg/ha.day. Growing season rainfall (April–October) ranged from 111 to 266 mm, and accounted for 27% of the variation in grain yield. Soil water content at sowing (0–1 m) ranged from 32 to 330 mm; yield increased with initial soil water at an average rate of 6 kg/ha.mm. Grain yield per unit growing season rainfall was generally low, with 75% of crops producing <12 kg grain/ha.mm; the maximum ratio was 21 kg/ha.mm. Soil constraints, including sodicity, alkalinity, salinity, and boron toxicity, reduced yield in part by reducing availability of stored soil water. Owing to severity of chemical constraints increasing with soil depth, grain yield and yield per unit growing season rainfall were both inversely related to the proportion of water stored deeper in the soil (0.5–1 m). Yield was unrelated to nitrogen, both initial and applied. Larger amounts of nitrogen accumulated in soils with more severe constraints partially accounted for the lack of association between yield and nitrogen.
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Jacobs, J. L., G. N. Ward, A. M. McDowell, and G. Kearney. "Effect of seedbed cultivation techniques, variety, soil type and sowing time, on brassica dry matter yields, water use efficiency and crop nutritive characteristics in western Victoria." Australian Journal of Experimental Agriculture 42, no. 7 (2002): 945. http://dx.doi.org/10.1071/ea01133.
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Effect of cultivation practice and sowing time on soil moisture retention at sowing, growth rates, dry matter yield, water use efficiency and nutritive characteristics (metabolisable energy, crude protein, neutral detergent fibre, water-soluble carbohydrates and starch) of turnip, pasja and rape was determined on 2 soil types (site A and B) over 2 years. Cultivation treatments were: optimum full inversion, an optimum non-inversion cultivation and over cultivated. At each site, cultivation treatments were imposed at 2 different times (early and late).Results showed few differences in soil moisture at sowing between the 3 cultivation systems. Where seedbeds were prepared earlier rather than later, soil moisture at sowing was higher. Given that there was relatively little difference in soil moisture between cultivation treatments within a sowing time, it is likely that rainfall events may have confounded cultivation effects.Apart from year 2 at site A, the water use efficiency of turnip was higher than for pasja and rape. It is proposed that the lower value in year 2 may be due to root development being retarded by low moisture availability, particularly at the later sowing date, thus leading to a lower dry matter yield.Despite no cultivation effects on soil moisture at sowing, there appeared to be clear advantages for the full inversion technique in terms of subsequent weed germination. Generally, weed numbers post germination were lower for this cultivation method compared with both non-inversion techniques. In conclusion, the cultivation techniques used had little effect on soil moisture at sowing and subsequent dry matter yields, provided the resultant seedbed was well-prepared, fine, firm and weed free. Full inversion cultivation techniques in areas where broad-leaved weeds are a problem may substantially reduce subsequent weed burdens. Early sowing where possible may reduce the likelihood of crop failure through the provision of adequate soil moisture at sowing and increase the incidence of rain during the growing period. Timing of sowing will vary according to paddock requirements during early spring (e.g. grazing or forage conservation), soil type, and trafficability for cultivation.
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Baskaran, K., L. M. Palmowski, and B. M. Watson. "Wastewater reuse and treatment options for the dairy industry." Water Supply 3, no. 3 (June 1, 2003): 85–91. http://dx.doi.org/10.2166/ws.2003.0012.
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Milk-processing plants generate significant quantities of wastewater with relatively high organic matter concentrations on a daily basis. In addition to environmental damage that can result from the discharge of these wastewaters into the natural waterways, the presence of products such as milk solids into wastewater streams represents a loss of valuable product for the plants. This paper presents a review of wastewater management practices employed by six milk-processing plants in Victoria, Australia. In all six plants investigated, milk powder represents a major product. During the milk powder production, water is evaporated, condensed and can be reused for various purposes with a significant impact on water usage. Other major products are anhydrous milk fat, cheese, butter, and UHT milk. The effectiveness of the practices was assessed through two main criteria: first through the water to milk intake ratio, and the waste volume coefficient. Both parameters characterise the plant efficiency in regard of water consumption and water reuse. Information on cleaning chemical usage and recovery was also assessed as part of the review. Significant discrepancies emerge between the plants first due to the products manufactured and water reuse possibilities available in each plant. Second the type of treatment technologies used for condensate and cleaning solution influences the figures. One of the investigated plants is almost self-sufficient for water, emphasising the benefits gained from the use of technologies like membrane separations for condensate and cleaning solution treatment. In some cases, less cost-intensive technologies such as a clarifier are successful to improve cleaning agent recovery.
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Rodriguez, D., and V. O. Sadras. "The limit to wheat water-use efficiency in eastern Australia. I. Gradients in the radiation environment and atmospheric demand." Australian Journal of Agricultural Research 58, no. 4 (2007): 287. http://dx.doi.org/10.1071/ar06135.
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In the wheatbelt of eastern Australia, rainfall shifts from winter dominated in the south (South Australia, Victoria) to summer dominated in the north (northern New South Wales, southern Queensland). The seasonality of rainfall, together with frost risk, drives the choice of cultivar and sowing date, resulting in a flowering time between October in the south and August in the north. In eastern Australia, crops are therefore exposed to contrasting climatic conditions during the critical period around flowering, which may affect yield potential, and the efficiency in the use of water (WUE) and radiation (RUE). In this work we analysed empirical and simulated data, to identify key climatic drivers of potential water- and radiation-use efficiency, derive a simple climatic index of environmental potentiality, and provide an example of how a simple climatic index could be used to quantify the spatial and temporal variability in resource-use efficiency and potential yield in eastern Australia. Around anthesis, from Horsham to Emerald, median vapour pressure deficit (VPD) increased from 0.92 to 1.28 kPa, average temperature increased from 12.9 to 15.2°C, and the fraction of diffuse radiation (FDR) decreased from 0.61 to 0.41. These spatial gradients in climatic drivers accounted for significant gradients in modelled efficiencies: median transpiration WUE (WUEB/T) increased southwards at a rate of 2.6% per degree latitude and median RUE increased southwards at a rate of 1.1% per degree latitude. Modelled and empirical data confirmed previously established relationships between WUEB/T and VPD, and between RUE and photosynthetically active radiation (PAR) and FDR. Our analysis also revealed a non-causal inverse relationship between VPD and radiation-use efficiency, and a previously unnoticed causal positive relationship between FDR and water-use efficiency. Grain yield (range 1–7 t/ha) measured in field experiments across South Australia, New South Wales, and Queensland (n = 55) was unrelated to the photothermal quotient (Pq = PAR/T) around anthesis, but was significantly associated (r2 = 0.41, P < 0.0001) with newly developed climatic index: a normalised photothermal quotient (NPq = Pq . FDR/VPD). This highlights the importance of diffuse radiation and vapour pressure deficit as sources of variation in yield in eastern Australia. Specific experiments designed to uncouple VPD and FDR and more mechanistic crop models might be required to further disentangle the relationships between efficiencies and climate drivers.
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Mundy, G. N., K. L. Greenwood, K. B. Kelly, S. M. Austin, and K. E. Dellow. "Improved soil and irrigation management for forage production 3. Plant - soil - water relationships." Australian Journal of Experimental Agriculture 46, no. 3 (2006): 327. http://dx.doi.org/10.1071/ea04097.
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A field experiment was conducted from January 2000 for 2.5 years, at the Department of Primary Industries, Kyabram, in northern Victoria. The experiment determined the effect of soil modification, with and without subsurface drainage, on the yield and water use of tall fescue (Festuca arundinacea), lucerne (Medicago sativa), phalaris (Phalaris aquatica) and perennial ryegrass (Lolium perenne) under 2 irrigation frequencies. The soil was a red-brown earth. The forages were spray irrigated from August to May when evaporation minus rainfall (E – R) reached 45–50 mm (frequent) or 90–100 mm (infrequent). The depth of irrigation water applied was equal to the soil water deficit (SWD) of each treatment, measured before each irrigation. Soil modification did not change the plant available water content of the soil (about 115 mm). The apparent depth of water extraction was initially different between soil management treatments but, over time, these differences disappeared. There were consistent differences between the forage species in the apparent depth of soil water extraction. Lucerne extracted water from deeper in the soil than phalaris followed by tall fescue and then perennial ryegrass. In general, the infrequently irrigated forages extracted water from deeper in the soil than did the frequently irrigated forages. The frequently irrigated treatments received slightly more water than did the infrequent treatments. The depth of water applied to the control and modified soil was similar, whereas the drained soils received more water than did the undrained treatments. There were differences between the forages in the depth of water applied, with lucerne receiving up to about 1500 mm/year and the grasses about 1100 to 1300 mm/year. Water use efficiency [kg dry matter (DM)/ha.mm] of the forages ranged from 14 to 18 kg DM/ha.mm in 2000–01 and up to 24 kg DM/ha.mm in 2001–02. The relatively high water use efficiencies were largely due to the high yields achieved, as water use was similar to that of district farms.
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O'Leary, GJ, DJ Connor, and DH White. "Effect of sowing time on growth, yield and water-use of rain-fed wheat in the Wimmera, Vic." Australian Journal of Agricultural Research 36, no. 2 (1985): 187. http://dx.doi.org/10.1071/ar9850187.
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Crops of wheat (Triticum aestivum cv. Olympic) were sown after a 10-month fallow at three times in both 1979 and 1980 in the Wimmera district of Victoria. Total above-ground plant material (biomass) and soil water content were measured for each crop at monthly intervals from sowing to anthesis and thereafter every 2 weeks. The duration of the phenophase, sowing to anthesis, varied from 88 to 163 days, but the maximum difference between anthesis date for the early (May) and late (August) sown crops was only 21 days. The duration of this phenophase was best described by a photothermal unit of 6846 day-degree-hours (>2�C, >6 h). The pattern of biomass accumulation varied markedly between crops, with biomass ranging from 9 to 13 t ha-1 and yield between 3 and 4 t ha-1. Total wateruse efficiency in the production of biomass to anthesis ranged from 30.5 to 19.8 kg ha-1 mm-1 and in the seasonal production of grain from 8.6 to 6.6 kg ha-' mm-'. Whilst the data include only one early sown crop, it was possible to identify an optimum balance between pre- and post-anthesis growth in crops sown in June to produce 9 t ha-1 of biomass at anthesis in early November, a yield sink of 12500 grains m-2 and in the 2 years of the experiment a grain yield of 4 t ha-1.
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Chapman, D. F., B. R. Cullen, I. R. Johnson, and D. Beca. "Interannual variation in pasture growth rate in Australian and New Zealand dairy regions and its consequences for system management." Animal Production Science 49, no. 12 (2009): 1071. http://dx.doi.org/10.1071/an09054.
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The profitability of dairy farms in Australia and New Zealand is closely related to the amount of pasture dry matter consumed per hectare per year. There is variability in the pasture growth curve within years (seasonal variation) and between years (interannual variation) in all dairy regions in both countries. Therefore, the biological efficiency of production systems depends on the accuracy and timeliness of the many strategic and tactical decisions that influence the balance between feed supply and demand over an annual cycle. In the case of interannual variation, decisions are made with only limited quantitative information on the range of possible pasture growth outcomes. To address this limitation, we used the biophysical simulation model ‘DairyMod’ to estimate mean monthly herbage accumulation rates of annual or perennial ryegrass-based pastures in 100 years (1907–2006) for five Australian sites (Kyabram in northern Victoria, Terang in south-west Victoria, Ellinbank in Gippsland, Elliott in north-west Tasmania and Vasse in south-west Western Australia) and in 35 years (1972–2006) for three sites in New Zealand (Hamilton in the Waikato, Palmerston North in the Manawatu and Winchmore in Canterbury). The aim was to evaluate whether or not a probabilistic approach to the analysis of pasture growth could provide useful information to support decision making. For the one site where annual ryegrass was simulated, Vasse, the difference between the 25th and 75th percentile years was 20 kg DM/ha.day or less in all months when pasture growth occurred. Irrigation at Kyabram and Winchmore also resulted in a narrow range of growth rates in most months. For non-irrigated sites, the 25th–75th percentile range was narrow (10–15 kg DM/ha.day) from May or June through to September or October, because plant available soil water was adequate to support perennial ryegrass growth, and the main source of interannual variability was variation in temperature. Outside of these months, however, variability in growth was large. There was a positive relationship between total annual herbage accumulation rate and mean stocking for four southern Australian regions (northern Victoria, south-west Victoria, Gippsland and Tasmania), but there was evidence of a negative relationship between the co-efficient of variation in pasture growth and stocking rate. The latter suggests that farmers do account for risk in pasture supply in their stocking rate decisions. However, for the one New Zealand region included in this analysis, Waikato, stocking rate was much higher than would be expected based on the variability in pasture growth, indicating that farmers in this region have well defined decision rules for coping with feed deficits or surpluses. Model predictions such as those presented here are one source of information that can support farm management decision making, but should always be coupled with published data, direct experience, and other relevant information to analyse risk for individual farm businesses.
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Hirth, J. R., P. J. Haines, A. M. Ridley, and K. F. Wilson. "Lucerne in crop rotations on the Riverine Plains. 2. Biomass and grain yields, water use efficiency, soil nitrogen, and profitability." Australian Journal of Agricultural Research 52, no. 2 (2001): 279. http://dx.doi.org/10.1071/ar00006.
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In a field experiment in north-eastern Victoria (average annual rainfall 598 mm), the impact of 2–4 years of lucerne growth on the following 3–4 crops was assessed. Controls of continuous lucerne, annual pasture, and continuous crop were compared with 5 lucerne–crop rotations. Above-ground biomass and water use efficiency of lucerne, annual pasture, and crops were assessed, as were the soil N status, grain yields, and profitability of crops after lucerne. Lucerne grew more slowly over the autumn–spring growing season (20 kg DM/ha.day) than did annual pastures and crops (41 and 58 kg DM/ha.day, respectively), while over the spring–autumn period, it grew at a mean 26 kg DM/ha.day. The summer growth rates of lucerne were, however, highly variable (1–52 kg DM/ha.day). Despite large changes in temperature and water availability over the year, the biomass water use efficiency (WUEB) of lucerne was similar over the winter and summer growth seasons (16 and 10 kg DM/ha.mm, respectively) and averaged 13 kg DM/ha.mm for the whole year. In contrast, the WUEB of wheat, canola, and annual pasture over their respective growth seasons averaged 36, 38, and 26 kg DM/ha.mm. When calculated over a whole year, however, they were much closer to lucerne at 23, 14, and 17 kg DM/ha.mm, respectively. Autumn removal of lucerne left soils initially low in mineral N (mean 82 kg N/ha.m depth in April) for the establishment of the first crop, but this was not reflected in the subsequent N contents of crop biomass and grain. Autumn mineral N concentrations peaked 1–2 years after lucerne removal (mean 141 kg N/ha.m depth). Yields of first crops after lucerne were strongly dependent on growing season rainfall. When sowing commenced in a wet year, they were similar to, or greater than, the control, but when sown in a dry year, were substantially lower. When sowing commenced in a wet year, lucerne supplied additional N for a minimum of 2 crops. At least 3 crops were supplied with lucerne N when cropping commenced in a dry year. The inclusion of 2–3 years of lucerne into a continuous cropping sequence only decreased annual profitability by $AU40/ha. This work shows that short phases of lucerne (minimum of 3 years) followed by 3–4 crops can provide economically viable options for farmers and produce better hydrological outcomes than current annual-plant based cropping systems.
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McCaskill, M. R., M. C. Raeside, S. G. Clark, C. MacDonald, B. Clark, and D. L. Partington. "Pasture mixes with lucerne (Medicago sativa) increase yields and water-use efficiencies over traditional pastures based on subterranean clover (Trifolium subterraneum)." Crop and Pasture Science 67, no. 1 (2016): 69. http://dx.doi.org/10.1071/cp14179.
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Pastures sown to lucerne (Medicago sativa L.) with a perennial non-legume could increase feed supply relative to traditional pastures based on subterranean clover (Trifolium subterraneum L.). Such mixtures might also be preferable to pure lucerne pastures, which are prone to weed invasion. Yield and water-use efficiency (harvested dry matter per unit evapotranspiration) of mixtures with lucerne or subterranean clover were compared a field experiment established under rainfed conditions at Hamilton, Victoria. Soil moisture and dry matter production were measured over 2 years. Treatments included chicory (Cichorium intybus L.), cocksfoot (Dactylis glomerata L.) and tall fescue (Festuca arundinacea Shreb.) with either lucerne or subterranean clover; pure lucerne; and phalaris (Phalaris aquatica L.) and perennial ryegrass (Lolium perenne L.) with only subterranean clover. In the second year, dry matter production from lucerne mixtures exceeded that of equivalent mixtures with subterranean clover in spring, summer and winter. In spring, the lucerne component continued producing for longer than the clover component through its use of deeper stored soil water, and in summer, lucerne continued to grow slowly after the grass component had entered a drought-induced dormancy. In winter, the contribution from the lucerne component complemented, rather than competed with, that from the non-legume component. Water-use efficiencies during winter–spring ranged from 4 kg ha–1 mm–1 for chicory–clover to 27 kg ha–1 mm–1 for a fescue–lucerne mixture, and during summer–autumn from nil for cocksfoot–clover to 13 kg ha–1 mm–1 for a fescue–lucerne mixture. This study demonstrates that lucerne-based mixtures can increase forage supply per unit water use relative to traditional pastures based on subterranean clover.
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Guinaldo, Thibault, Simon Munier, Patrick Le Moigne, Aaron Boone, Bertrand Decharme, Margarita Choulga, and Delphine J. Leroux. "Parametrization of a lake water dynamics model MLake in the ISBA-CTRIP land surface system (SURFEX v8.1)." Geoscientific Model Development 14, no. 3 (March 10, 2021): 1309–44. http://dx.doi.org/10.5194/gmd-14-1309-2021.
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Abstract. Lakes are of fundamental importance in the Earth system as they support essential environmental and economic services, such as freshwater supply. Streamflow variability and temporal evolution are impacted by the presence of lakes in the river network; therefore, any change in the lake state can induce a modification of the regional hydrological regime. Despite the importance of the impact of lakes on hydrological fluxes and the water balance, a representation of the mass budget is generally not included in climate models and global-scale hydrological modeling platforms. The goal of this study is to introduce a new lake mass module, MLake (Mass-Lake model), into the river-routing model CTRIP to resolve the specific mass balance of open-water bodies. Based on the inherent CTRIP parameters, the development of the non-calibrated MLake model was introduced to examine the influence of such hydrological buffer areas on global-scale river-routing performance. In the current study, an offline evaluation was performed for four river networks using a set of state-of-the-art quality atmospheric forcings and a combination of in situ and satellite measurements for river discharge and lake level observations. The results reveal a general improvement in CTRIP-simulated discharge and its variability, while also generating realistic lake level variations. MLake produces more realistic streamflows both in terms of daily and seasonal correlation. Excluding the specific case of Lake Victoria having low performances, the mean skill score of Kling–Gupta efficiency (KGE) is 0.41 while the normalized information contribution (NIC) shows a mean improvement of 0.56 (ranging from 0.15 to 0.94). Streamflow results are spatially scale-dependent, with better scores associated with larger lakes and increased sensitivity to the width of the lake outlet. Regarding lake level variations, results indicate a good agreement between observations and simulations with a mean correlation of 0.56 (ranging from 0.07 to 0.92) which is linked to the capability of the model to retrieve seasonal variations. Discrepancies in the results are mainly explained by the anthropization of the selected lakes, which introduces high-frequency variations in both streamflows and lake levels that degraded the scores. Anthropization effects are prevalent in most of the lakes studied, but they are predominant for Lake Victoria and are the main cause for relatively low statistical scores for the Nile River However, results on the Angara and the Neva rivers also depend on the inherent gap of ISBA-CTRIP process representation, which relies on further development such as the partitioned energy budget between the snow and the canopy over a boreal zone. The study is a first step towards a global coupled land system that will help to qualitatively assess the evolution of future global water resources, leading to improvements in flood risk and drought forecasting.
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Das, Sushil K., Amimul Ahsan, Md Habibur Rahman Bejoy Khan, Muhammad Atiq Ur Rehman Tariq, Nitin Muttil, and Anne W. M. Ng. "Impacts of Climate Alteration on the Hydrology of the Yarra River Catchment, Australia Using GCMs and SWAT Model." Water 14, no. 3 (February 1, 2022): 445. http://dx.doi.org/10.3390/w14030445.
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A rigorous evaluation of future hydro-climatic changes is necessary for developing climate adaptation strategies for a catchment. The integration of future climate projections from general circulation models (GCMs) in the simulations of a hydrologic model, such as the Soil and Water Assessment Tool (SWAT), is widely considered as one of the most dependable approaches to assess the impacts of climate alteration on hydrology. The main objective of this study was to assess the potential impacts of climate alteration on the hydrology of the Yarra River catchment in Victoria, Australia, using the SWAT model. The climate projections from five GCMs under two Representative Concentration Pathway (RCP) scenarios—RCP 4.5 and 8.5 for 2030 and 2050, respectively—were incorporated into the calibrated SWAT model for the analysis of future hydrologic behaviour against a baseline period of 1990–2008. The SWAT model performed well in its simulation of total streamflow, baseflow, and runoff, with Nash–Sutcliffe efficiency values of more than 0.75 for monthly calibration and validation. Based on the projections from the GCMs, the future rainfall and temperature are expected to decrease and increase, respectively, with the highest changes projected by the GFDL-ESM2M model under the RCP 8.5 scenario in 2050. These changes correspond to significant increases in annual evapotranspiration (8% to 46%) and decreases in other annual water cycle components, especially surface runoff (79% to 93%). Overall, the future climate projections indicate that the study area will become hotter, with less winter–spring (June to November) rainfall and with more water shortages within the catchment.
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Wiedemann, S. G., M. J. Yan, and C. M. Murphy. "Resource use and environmental impacts from Australian export lamb production: a life cycle assessment." Animal Production Science 56, no. 7 (2016): 1070. http://dx.doi.org/10.1071/an14647.
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This study conducted a life cycle assessment (LCA) investigating energy, land occupation, greenhouse gas (GHG) emissions, fresh water consumption and stress-weighted water use from production of export lamb in the major production regions of New South Wales, Victoria and South Australia. The study used data from regional datasets and case study farms, and applied new methods for assessing water use using detailed farm water balances and water stress weighting. Land occupation was assessed with reference to the proportion of arable and non-arable land and allocation of liveweight (LW) and greasy wool was handled using a protein mass method. Fossil fuel energy demand ranged from 2.5 to 7.0 MJ/kg LW, fresh water consumption from 58.1 to 238.9 L/kg LW, stress-weighted water use from 2.9 to 137.8 L H2O-e/kg LW and crop land occupation from 0.2 to 2.0 m2/kg LW. Fossil fuel energy demand was dominated by on-farm energy demand, and differed between regions and datasets in response to production intensity and the use of purchased inputs such as fertiliser. Regional fresh water consumption was dominated by irrigation water use and losses from farm water supply, with smaller contributions from livestock drinking water. GHG emissions ranged from 6.1 to 7.3 kg CO2-e/kg LW and additional removals or emissions from land use (due to cultivation and fertilisation) and direct land-use change (due to deforestation over previous 20 years) were found to be modest, contributing between –1.6 and 0.3 kg CO2-e/kg LW for different scenarios assessing soil carbon flux. Excluding land use and direct land-use change, enteric CH4 contributed 83–89% of emissions, suggesting that emissions intensity can be reduced by focussing on flock production efficiency. Resource use and emissions were similar for export lamb production in the major production states of Australia, and GHG emissions were similar to other major global lamb producers. The results show impacts from lamb production on competitive resources to be low, as lamb production systems predominantly utilised non-arable land unsuited to alternative food production systems that rely on crop production, and water from regions with low water stress.
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Gray, S., and N. Booker. "Wastewater services for small communities." Water Science and Technology 47, no. 7-8 (April 1, 2003): 65–71. http://dx.doi.org/10.2166/wst.2003.0672.
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Connection to centralised regional sewage systems has been too expensive for small-dispersed communities, and these townships have traditionally been serviced by on-site septic tank systems. The conventional on-site system in Australia has consisted of an anaerobic holding tank followed by adsorption trenches. This technique relies heavily on the uptake of nutrients by plants for effective removal of nitrogen and phosphorus from the effluent, and is very seasonal in its efficiency. Hence, as these small communities have grown in size, the environmental effects of the septic tank discharges have become a problem. In locations throughout Australia, such as rural Victoria and along the Hawkesbury-Nepean River, septic tanks are being replaced with the transport of sewage to regional treatment plants. For some isolated communities, this can mean spending $20,000-$40,000/household, as opposed to more common connection prices of $7,000/household. This paper explores some alternative options that might be suitable for these small communities, and attempts to identify solutions that provide acceptable environmental outcomes at lower cost. The types of alternative systems that are assessed in the paper include local treatment systems, separate blackwater and greywater collection and treatment systems both with and without non-potable water recycling, a small township scale treatment plant compared to either existing septic tank systems or pumping to a remote regional treatment facility.The work demonstrated the benefits of a scenario analysis approach for the assessment of a range of alternative systems. It demonstrated that some of the alternatives systems can achieve better than 90% reductions in the discharge of nutrients to the environment at significantly lower cost than removing the wastewater to a remote regional treatment plant. These concepts allow wastewater to be retained within a community allowing for local reuse of treated effluent.
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Masso, Cargele, Fredrick Baijukya, Peter Ebanyat, Sifi Bouaziz, John Wendt, Mateete Bekunda, and Bernard Vanlauwe. "Dilemma of nitrogen management for future food security in sub-Saharan Africa – a review." Soil Research 55, no. 6 (2017): 425. http://dx.doi.org/10.1071/sr16332.
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Food security entails having sufficient, safe, and nutritious food to meet dietary needs. The need to optimise nitrogen (N) use for nutrition security while minimising environmental risks in sub-Saharan Africa (SSA) is overdue. Challenges related to managing N use in SSA can be associated with both insufficient use and excessive loss, and thus the continent must address the ‘too little’ and ‘too much’ paradox. Too little N is used in food production (80% of countries have N deficiencies), which has led to chronic food insecurity and malnutrition. Conversely, too much N load in water bodies due mainly to soil erosion, leaching, limited N recovery from wastewater, and atmospheric deposition contributes to eutrophication (152 Gg N year–1 in Lake Victoria, East Africa). Limited research has been conducted to improve N use for food production and adoption remains low, mainly because farming is generally practiced by resource-poor smallholder farmers. In addition, little has been done to effectively address the ‘too much’ issues, as a consequence of limited research capacity. This research gap must be addressed, and supportive policies operationalised, to maximise N benefits, while also minimising pollution. Innovation platforms involving key stakeholders are required to address N use efficiency along the food supply chain in SSA, as well as other world regions with similar challenges.
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Azzaro, Maurizio, Theodore T. Packard, Luis Salvador Monticelli, Giovanna Maimone, Alessandro Ciro Rappazzo, Filippo Azzaro, Federica Grilli, Ermanno Crisafi, and Rosabruna La Ferla. "Microbial metabolic rates in the Ross Sea: the ABIOCLEAR Project." Nature Conservation 34 (May 3, 2019): 441–75. http://dx.doi.org/10.3897/natureconservation.34.30631.
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The Ross Sea is one of the most productive areas of the Southern Ocean and includes several functionally different marine ecosystems. With the aim of identifying signs and patterns of microbial response to current climate change, seawater microbial populations were sampled at different depths, from surface to the bottom, at two Ross Sea mooring areas southeast of Victoria Land in Antarctica. This oceanographic experiment, the XX Italian Antarctic Expedition, 2004-05, was carried out in the framework of the ABIOCLEAR project as part of LTER-Italy. Here, microbial biogeochemical rates of respiration, carbon dioxide production, total community heterotrophic energy production, prokaryotic heterotrophic activity, production (by3H-leucine uptake) and prokaryotic biomass (by image analysis) were determined throughout the water column. As ancillary parameters, chlorophylla, adenosine-triphosphate concentrations, temperature and salinity were measured and reported. Microbial metabolism was highly variable amongst stations and depths. In epi- and mesopelagic zones, respiratory rates varied between 52.4–437.0 and 6.3–271.5 nanol O2l-1h-1; prokaryotic heterotrophic production varied between 0.46–29.5 and 0.3–6.11 nanog C l-1h-1; and prokaryotic biomass varied between 0.8–24.5 and 1.1–9.0 µg C l-1, respectively. The average heterotrophic energy production ranged between 570 and 103 mJ l-1h-1in upper and deeper layers, respectively. In the epipelagic layer, the Prokaryotic Carbon Demand and Prokaryotic Growth Efficiency averaged 9 times higher and 2 times lower, respectively, than in the mesopelagic one. The distribution of plankton metabolism and organic matter degradation was mainly related to the different hydrological and trophic conditions. In comparison with previous research, the Ross Sea results, here, evidenced a relatively impoverished oligotrophic microbial community, throughout the water column.
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Chauhan, Moondeep, Navneet Kaur, Pratibha Bansal, Rajeev Kumar, Sesha Srinivasan, and Ganga Ram Chaudhary. "Proficient Photocatalytic and Sonocatalytic Degradation of Organic Pollutants Using CuO Nanoparticles." Journal of Nanomaterials 2020 (June 10, 2020): 1–15. http://dx.doi.org/10.1155/2020/6123178.
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In recent years, due to the advancement in nanotechnology, advanced oxidation processes (AOPs), especially sonocatalysis and photocatalysis, have become a topic of interest for the elimination of pollutants from contaminated water. In the research work reported here, an attempt has been made to study and establish a physicochemical mechanism for the catalytic activity of copper oxide nanoparticles (CuO NPs) in AOPs using the degradation of dyes as model contaminants. CuO NPs exhibited brilliant sonocatalytic and photocatalytic activities for the degradation of a cationic dye (Victoria Blue) as well as an anionic dye (Direct Red 81). The degradation efficiency of CuO NPs was calculated by analysing the variation in the absorbance of dye under a UV-Vis spectrophotometer. The influence of different operating parameters on the catalytic activity of CuO NPs, such as the amount of catalysts dose, pH of the solution, and the initial dye concentration, was thoroughly investigated. In addition, the kinetic process for the degradation was also examined. It was observed that both dyes exhibited and followed the pseudo-first-order kinetics relation. The rate constant for sonocatalysis was high as compared to photocatalysis. The rate constant for both sonocatalysis and photocatalysis was successfully established, and reusability tests were done to ensure the stability of the used catalysts. To get an insight into the degradation mechanism, experiments were performed by using ⋅OH radical scavengers. The efficacy of CuO NPs for dye decolorization was found to be superior for the sonocatalyst than the photocatalyst.
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Massawe, Ezrael J., Richard Kimwaga, and Fredrick Mwanuzi. "Modelling Transport of Nitrogen Compounds in Geita Wetland along Mtakuja River." Tanzania Journal of Engineering and Technology 37, no. 2 (June 30, 2018): 89–106. http://dx.doi.org/10.52339/tjet.v37i2.486.
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The impacts of excessive nitrogen loading to streams in a watershed occur in the receiving waters such as rivers at the outlet of the watershed. To quantify the impacts of land use and management practices on the nitrogen loading at the watershed outlet, simulation models are needed that can both predict the nitrogen loading at the edge of individual fields and predict the fate of nitrogen as it moves through the river network to the watershed outlet. This paper presents the results of a model analysis for describing the processes governing transformations and transport of nitrogen compounds (NO3-N and NH4-N) through Mtakuja River in the Geita wetland. The model was made in Soil and Water Assessment Tool (SWAT), a watershed model developed to assess the impact of land management practices on water, sediment and agricultural chemical yields with varying soils, land use and management conditions. Two monitoring stations namely MTSP1 and MTSP2 were established along Mtakuja River. A set of SWAT model inputs representative of the water conditions was collected from the established monitoring stations. The model was calibrated and validated for the prediction of flow and nitrogen compounds (NO3-N and NH4-N) transport, against a set of measured mean monthly monitoring data. Sensitive model parameters were adjusted within their feasible ranges during calibration to minimize model prediction errors. At the gauging station MTSP2, the calibration results showed that the model predicted mean monthly flow within 18% of the measured mean monthly flow with the r2 coefficient and Nash-Sutcliffe (NSE) were 0.84 and 0.82, respectively. At the water quality monitoring station MTSP2, the calibration results showed the model predicted nitrogen compounds (NO3-N and NH4-N) loadings within 21% and 23% of their respective measured mean monthly loadings. The mean monthly comparisons of r 2 values for nitrogen compounds ranged from 0.77 to 0.81 while the Nash-Sutcliffe Efficiency (NSE) values were between 0.72 and 0.73. The model results and field measurements demonstrated that about 70% of the annual nitrogen compounds loadings which would otherwise reach Lake Victoria are retained in the wetland. The Mtakuja river model can therefore be used for prediction of nitrogen compounds (NO3-N and NH4-N) transformation processes in the Geita wetland.
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Lei, Thomas. "Environmental preferences and constraints of Daphne laureola, an invasive shrub in western Canada." Canadian Journal of Forest Research 44, no. 11 (November 2014): 1462–67. http://dx.doi.org/10.1139/cjfr-2014-0261.
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Daphne laureola L. is an evergreen forest understory shrub native to the Mediterranean regions of Europe and North Africa that has invaded parts of western North America, including coastal British Columbia (BC) and the states of Washington and Oregon. It can form dense thickets that are likely to prevent the establishment and growth of native plants. Despite its expanding range in the west coast regions, not much is known about its environmental preferences and the ecophysiological attributes associated with its presence and distribution. A 2-year study conducted in Victoria, BC, found that D. laureola attained higher densities in forests with moderate shade at 12%–15% canopy gap opening, whereas densities decreased at higher and lower levels of canopy openness. Specifically, variation in patch density was significantly associated with the level of diffuse light (UOC, uniform overcast sky) and sunfleck duration in the summer, but many leaf-level properties such as photosynthetic rate, leaf dry mass per unit area (LMA), and long-term water use efficiency (as indicated by δ13C) were similar between patches. Taken together, highest plant densities were achieved in forest understory that received less direct but more diffuse sunlight in summer, suggesting that the best growing condition is a compromise between reduced drought stress through lower sunfleck exposure and increased carbon gain under brighter canopies. In future, the high fruit output combined with the readily available seed dispersers seems to ensure that D. laureola will continue to spread, particularly into mainland areas where milder summers may offer a wider range of potential sites for occupation.
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Khan, Muhammad Jamal, Graham Brodie, and Dorin Gupta. "Potential of microwave soil heating for weed management and yield improvement in rice cropping." Crop and Pasture Science 70, no. 3 (2019): 211. http://dx.doi.org/10.1071/cp18515.
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Herbicide-resistant weeds have prompted the development of non-chemical weed-control techniques for sustainable crop production. We examined the potential of pre-emergence microwave (MW) soil treatment to suppress weeds and enhance grain yield in rice (Oryza sativa L.) cropping in two agro-ecological zones of Australia. An experimental MW weed killer, which has four, independently controlled, 2-kW MW generators operating at 2.45 GHz, was used to treat the soil before cropping under field conditions. A once-off MW soil treatment (duration 60 s) and an untreated control were assigned in a randomised complete block design with five replicates at two study locations: Dookie (Victoria) and Jerilderie (New South Wales). Simpson’s numerical surface integral approximation estimated the applied energy density of ~500 J cm–2. This energy increased the soil’s temperature up to 70–75°C in top soil horizon (0–6 cm) as depicted by infrared thermal imaging. No statistically significant difference was detected for weed control between MW and untreated control plots at either study location. At Dookie, grain yield did not significantly increase in response to MW soil treatment, whereas at Jerilderie, grain yield was 20% higher (P < 0.05) with MW soil treatment than in control plots. At Jerilderie, the irrigation water use efficiency (t ML–1) was 21% higher in MW plots than control plots. In summary, MW exposure of 60 s appeared to be an insufficient heating duration for seedbank depletion. This suggests further treatment modification followed by rigorous testing under different soils conditions using the MW prototype.
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Thompson, A. N., A. J. Kennedy, J. Holmes, and G. Kearney. "Arrowleaf clover improves lamb growth rates in late spring and early summer compared with subterranean clover pastures in south-west Victoria." Animal Production Science 50, no. 8 (2010): 807. http://dx.doi.org/10.1071/an09100.
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The profitable production of lamb from pasture-based systems is dependent on high levels of pasture production being efficiently utilised by sheep of superior genetic merit. Pastures that can extend the pasture-growing season and provide high quality feed in late spring and summer have the potential to increase production efficiency and the proportion of lambs that meet market specifications. In this paper we tested the hypothesis that arrowleaf clover (cv. Arrotas), a cultivar selected for late maturity, would supply feed of higher nutritive value than conventional annual legumes and perennial ryegrass mixtures during December and January and this would improve lamb growth rates over this period. Two experiments were conducted to compare the nutritive value of pasture and growth rates of lambs grazing arrowleaf clover, subterranean clover (cv. Leura) or subterranean clover/perennial ryegrass mixtures at different stocking rates during late spring and early summer in south-west Victoria. In the second experiment an arrowleaf clover/perennial ryegrass treatment was also included. Lambs were removed from the plots when they could no longer maintain liveweight. Arrowleaf clover extended the growing season by 4–6 weeks and provided feed of significantly higher digestibility than subterranean clover during December and January. The digestibility of arrowleaf and perennial ryegrass was comparable, but arrowleaf had significantly higher crude protein content during this period. Lambs grazing arrowleaf clover at stocking rates up to 24 lambs/ha grew at or above 100 g/day until the end of January, whereas lambs grazing subterranean clover and perennial ryegrass mixed pastures could not maintain weight by mid-to-late December in both years and were removed from the pastures. At the highest stocking rates total lamb production from arrowleaf clover monoculture pastures in late spring and early summer was ~400 kg liveweight/ha, and was more than double that achieved from the subterranean clover and perennial ryegrass/subterranean clover mixed pastures. The perennial ryegrass/arrowleaf clover mixed pastures in the second experiment produced a similar quantity of lamb per hectare as the arrowleaf clover monoculture pastures at the same stocking rate. In this paper we demonstrated that late-maturing arrowleaf clover can be a profitable, special purpose lamb-finishing pasture. Arrowleaf clover was most suited to more elevated parts of the landscape where estimated carrying capacity was 20 to 40% greater than that from lower lying parts of the landscape that were more subject to water logging and weed infestation. The risks of including arrowleaf clover pastures into the farming system could be reduced by direct drilling arrowleaf clover, which has relatively poor winter production, into existing perennial ryegrass pastures.
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Shukla, Anoop, Chandra Ojha, Rajendra Singh, Lalit Pal, and Dafang Fu. "Evaluation of TRMM Precipitation Dataset over Himalayan Catchment: The Upper Ganga Basin, India." Water 11, no. 3 (March 25, 2019): 613. http://dx.doi.org/10.3390/w11030613.
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Satellite based rainfall estimation techniques have emerged as a potential alternative to ground based rainfall measurements. The Tropical Rainfall Measuring Mission (TRMM) precipitation, in particular, has been used in various climate and hydrology based studies around the world. While having wide possibilities, TRMM rainfall estimates are found to be inconsistent with the ground based rainfall measurements at various locations such as the southwest coast and Himalayan region of India, northeast parts of USA, Lake Victoria in Africa, La Plata basin in South America, etc. In this study, the applicability of TRMM estimates is evaluated over the Upper Ganga Basin (Himalayan catchment) by comparing against gauge-based India Meteorological Department (IMD) gridded precipitation records. Apart from temporal evaluation, the ability of TRMM in capturing spatial distribution is also examined using three statistical parameters namely correlation coefficient (r), mean absolute error (MAE) and relative bias (RBIAS). In the results, the dual nature of bias is evident in TRMM precipitation with rainfall magnitude falling in the range from 100 to 370 mm representing positive bias, whereas, rainfall magnitude above 400 mm, approximately, representing negative bias. The Quantile Mapping (QM) approach has been used to correct the TRMM dataset from these biases. The raw TRMM precipitation is found to be fairly correlated with IMD rainfall for post-monsoon and winter season with R2 values of 0.65 and 0.57, respectively. The R2 value of 0.41 is obtained for the monsoon season, whereas least correlation is found for the pre-monsoon season with an R2 value of 0.24. Moreover, spatial distribution of rainfall during post-monsoon and winter season is captured adequately; however, the limited efficiency of TRMM is reflected for pre-monsoon and monsoon season. Bias correction has satisfactorily enhanced the spatial distribution of rainfall obtained from TRMM for almost all the seasons except for monsoon. Overall, the corrected TRMM precipitation dataset can be used for various climate analyses and hydrological water balance based studies in the Himalayan river basins.
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Incerti, M., and GJ O'Leary. "Rooting depth of wheat in the Victorian Mallee." Australian Journal of Experimental Agriculture 30, no. 6 (1990): 817. http://dx.doi.org/10.1071/ea9900817.
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In 1986 and 1987 wheat was sown in an experiment at the Mallee Research Station, Walpeup, at 2 times of sowing and with 3 rates of applied nitrogen. Soil cores were taken and trenches excavated to 1.5 m to measure wheat root growth and depth of rooting. Wheat roots penetrated to a maximum depth of 104 cm in crops sown in May, the optimum time of sowing for maximum yield, while delayed sowing reduced total root biomass and limited rooting depth to 73-83 cm. The application of nitrogen fertiliser did not affect either the rooting depth or growth and yield. Significant changes in total soil water content between sowing and harvest only occurred in 1987 with the early and late sown crops reducing the total soil water content by 47 and 99 mm respectively. In 1986, above average rainfall during the growing season caused the early sown crop to accumulate more water below 50 cm than the late sown crop. While total water use was increased only in 1986 with early sowing, crop water use efficiency and yield was greater in both years. The addition of nitrogen had no effect on crop water use or water use efficiency. A survey of wheat crops carried out in 1988 on 10 Mallee farms also found that shallow rooting is widespead. The field experiment and survey data show that, irrespective of sowing time, roots did not penetrate as far down the profile as might be expected, given reported rooting depths commonly in excess of 200 cm on similarly textured soils. This was shown to be associated with high soil pH and salt content. Poor rooting depth of wheat in this environment will restrict the use of stored water and accordingly, calls the practice of fallowing into question.
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Davies, C. M., S. M. Petterson, C. Kaucner, N. J. Ashbolt, V. G. Mitchell, G. D. Taylor, and J. Lewis. "Microbial challenge-testing of treatment processes for quantifying stormwater recycling risks and management." Water Science and Technology 57, no. 6 (March 1, 2008): 843–47. http://dx.doi.org/10.2166/wst.2008.194.
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Pathogenic microorganisms have been identified as the main human health risks associated with the reuse of treated urban stormwater (runoff from paved and unpaved urban areas). As part of the Smart Water initiative (Victorian Government, Australia), a collaborative evaluation of three existing integrated stormwater recycling systems, and the risks involved in non-potable reuse of treated urban stormwater is being undertaken. Three stormwater recycling systems were selected at urban locations to provide a range of barriers including biofiltration, storage tanks, UV disinfection, a constructed wetland, and retention ponds. Recycled water from each of the systems is used for open space irrigation. In order to adequately undertake exposure assessments, it was necessary to quantify the efficacy of key barriers in each exposure pathway. Given that none of the selected treatment systems had previously been evaluated for their treatment efficiency, experimental work was carried out comprising dry and wet weather monitoring of each system (for a period of 12 months), as well as challenging the barriers with model microbes (for viruses, bacteria and parasitic protozoa) to provide input data for use in Quantitative Microbial Risk Assessment.
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Norton, R. M., and N. G. Wachsmann. "Nitrogen use and crop type affect the water use of annual crops in south-eastern Australia." Australian Journal of Agricultural Research 57, no. 3 (2006): 257. http://dx.doi.org/10.1071/ar05056.
Full textAbstract:
The effect of management and crop selection on water use and profile drying was investigated using 2 series of experiments conducted in the Victorian Wimmera. The effect of applied nitrogen on growth and water use of canola was assessed from 3 field experiments on a Vertosol soil. Across these sites, 140 kg N/ha increased crop water use by a mean of 30 mm, and the biological response averaged 3.68 t/ha of shoot dry matter and seed yield increased by 73% from 1.46 to 2.52 t/ha. The additional nitrogen enabled roots to go deeper into the soil and also to extract water to higher tensions, but the increases in water use were far less than the growth and yield responses. Estimated average soil evaporation was 120 mm across these experiments, but ranged from 26 to 57% of total water use. It was concluded that increased crop vigour in response to applied nitrogen does increase total water use, but the main way that water-use efficiency increases is through reduced soil evaporation. In a second series of experiments, the growth, yield, and water use of wheat, canola, linseed, mustard, and safflower were compared across 4 sites with differing soil moisture contents. Wheat was the highest yielding crop at all sites. Mustard and canola produced similar amounts of biomass and seed yields, whereas linseed produced seed yields that were generally less than the brassica oilseeds. Safflower grew well and produced large amounts of biomass at all sites, but this increased growth did not necessarily translate into increased seed yields. Safflower yielded less seed than all other crops at the 2 dry sites, but yields were similar to canola at the wetter sites. On 2 drier sites, soil water extraction occurred to approximately 1 m for all crops, and all available water was used within that zone by all crops. Where the soil was wet beyond 1 m, safflower was able to extract water from deeper in the profile than the other crops and generated a soil water deficit of about 100 mm more than the other crops at maturity. This deficit persisted into the subsequent autumn–winter period. The potential of using safflower as a management option to extract water from deep in the profile, and so create a soil buffer, is discussed.