Nitrogen and phosphorus exports from high rainfall zone cropping in Australia: issues and opportunities for research

Cropping is one of the many industries contributing to the excessive loading of nitrogen (N) and phosphorus (P) to rivers and lakes in Australia. Nitrogen and P exports from cropping systems have not been systematically investigated to the same extent as those from other agricultural sectors, such as dairy pastures. Therefore, this review relies heavily on information derived from agronomy and other fundamental studies on soil-nutrient interactions to determine the potential for nutrient export from high rainfall zone (HRZ) cropping. There is a great deal of variation in environmental and management strategies across cropping in the HRZ, which suggests that nutrient exports could occur under a range of scenarios. The potential for exports is therefore discussed within a conceptual framework of nutrient sources, mechanisms for mobilization, and transport pathways in HRZ cropping. Transport refers to nutrient movement by flowing water after it has been mobilized, and export refers to the transfer of nutrients from one landscape compartment (e.g., a soil) to another (e.g., a stream or lake). The transport of nutrients from HRZ cropping can occur through surface and/or subsurface pathways depending on factors such as landform and infiltration and nutrient sorption characteristics of the soil profile. Surface pathways are likely to be more significant for phosphorus. For N, subsurface movement is likely to be as significant as surface movement because nitrates are generally not bound by most soils. Information about mechanisms of nutrient mobilization is essential for developing management strategies to control nutrient exports from HRZ cropping.     

A simple method to predict dissolved phosphorus in runoff from surface-applied manures

Computer models are a rapid, inexpensive way to identify agricultural areas with a high potential for P loss, but most models poorly simulate dissolved P release from surface-applied manures to runoff. We developed a simple approach to predict dissolved P release from manures based on observed trends in laboratory extraction of P in dairy, poultry, and swine manures with water over different water to manure ratios. The approach predicted well dissolved inorganic (R2 = 0.70) and organic (R2 = 0.73) P release from manures and composts for data from leaching experiments with simulated rainfall. However, it predicted poorly (R2 = 0.18) dissolved inorganic P concentrations in runoff from soil boxes where dairy, poultry, and swine manures had been surface-applied and subjected to simulated rainfall. Multiplying predicted runoff P concentrations by the ratio of runoff to rainfall improved the relationship between measured and predicted runoff P concentrations, but runoff P was still overpredicted for dairy and swine manures. We attributed this overprediction to immediate infiltration of dissolved P in the freely draining water of dairy and swine manure slurries upon their application to soils. Further multiplying predicted runoff dissolved inorganic P concentrations by 0.35 for dairy and 0.60 for swine manures resulted in an accurate prediction of dissolved P in runoff (R2 = 0.71). The ability of our relatively simple approach to predict dissolved inorganic P concentrations in runoff from surface-applied manures indicates its potential to improve water quality models, but field testing of the approach is necessary first.     

Tree species for recovering nitrogen from dairy-farm effluent in New Zealand

Land treatment of dairy-farm effluent is being widely adopted as an alternative to disposal into surface waters in New Zealand. This study investigated water balances and associated N leaching from short-rotation forest (SRF) species irrigated with dairy-farm effluent. Single trees were grown in lysimeters filled with Manawatu fine sandy loam (mixed mesic Dystric Eutrochrept). Dairy-farm effluent was applied during two irrigation periods at 21.5 mm wk(-1) with a total loading equivalent to 870 kg N ha(-1) occurring over 17 mo. Following tree harvest in April 1997, measurements continued until August 1997 to monitor tree reestablishment. Cumulative N leached did not differ between lysimeters in which evergreen Sydney blue gum (Eucalyptus saligna Sm.) and shining gum [Eucalyptus nitens (H. Deane & Maiden) Maiden] and deciduous kinu-yanagi (Salix kinuyanagi Kimura) were grown. Leachate N concentrations of all treatments were on average higher than the New Zealand drinking water standard of 11.3 mg N L(-1). The E. nitens and S. kinuyanagi treatments leached 33 and 35 kg N ha(-1) yr(-1) in 1996 following application of 236 kg N ha(-1) during the first irrigation season. Leaf area was strongly correlated to evapotranspiration, drainage volume, and nitrogen leached. The majority of leaching in the tree treatments occurred after harvest. Reducing the leaching in the regrowth phase may be achieved through timing harvest in the spring when growth rates are higher and leaching potential is lower. Based on N uptake rates observed in this study and average pond discharge, a plantation of 5.4 ha would be required for N recovery on a typical dairy farm in New Zealand.     

A land management history for central Queensland,Australia as determined from land-holder questionnaire and aerial photography

Features of the land management history over a 125,755 km(2) area of central Queensland, Australia were determined from a variety of sources. A random sample of 205 site locations provided the basis for determining trends in land use. Trends in vegetation clearing were determined using sequential aerial photography for the sample sites, revealing a steady rate averaging nearly 1% of the region per annum over 41 years. This measure of sustained clearing over a large region is higher than recently published clearing rates from South America. Land types have been selectively cleared with over 90% of the Acacia on clay land type having been cleared. A land-holder questionnaire pertaining to the random sites yielded a response rate of 71% and provided information on vegetation clearing, ploughing, tree killing (ring-barking or tree poisoning), and fire frequency, season and intensity. The land-holder responses were compared with independent data sources where possible and revealed no mis-information. However, land-holders may have been marginally less likely to respond if the sample area had been cleared, although this effect was not statistically significant. Ploughing and tree killing are variable depending on land type, but the former has affected about 40% of the Acacia on clay land type, effectively eliminating options for natural regrowth. The proportion of decade-site combinations that were reported as having no fires increased from 22% in the 1950s to an average of 42% for subsequent decades, although the reporting of more than one fire per decade has been relatively constant through the study period. The reporting of at least one fire per decade varies from 46% for the Acacia on sand land type to 77% for the Eucalypt on sand land type for decade-site combinations. Fires are more intense when associated with clearing than in uncleared vegetation, but the proportion of cool and hot fires is relatively constant between land types in uncleared vegetation. Nearly all fires reported were either in spring or summer and this seasonally restricted regime is probably at variance with Aboriginal fire regimes. This study describes the rapid transformation of central Queensland. This has yielded substantially increased agricultural production but may also result in a range of negative impacts and these are discussed.     

Environmental accounting for waste management: A study of local governments in Australia

Local governments in Australia, especially in large urban areas, have faced a challenge of the growing quantity of waste generated and the diminishing space for waste disposal in recent years. The central government has demonstrated the importance of developing strategies to make full environmental costs and impacts of waste disposal and material recovery accountable for waste management decision-making. However, research into this field is limited. This paper investigates environmental accounting practices in local government waste management. From a survey conducted with local government authorities in New South Wales (NSW) Australia, it is found that overall the level of direct waste flow and activity accounting is higher than the level of hidden and external environmental cost accounting, though local governments tend to identify and use more physical information associated with waste flows and activities than relevant monetary information. External environmental impacts of waste disposal are often overlooked and show the lowest level of practices. The survey results also indicate that urban local governments have taken more environmental information into account than rural local governments, but such difference is not significant between local governments of different sizes. The complexity of waste technical services and operations is confirmed to have a positive and significant effect on the level of environmental accounting for waste management across local governments surveyed.     

Optimisation of rainwater tank design from large roofs: A case study in Melbourne, Australia

Rainwater tanks for larger roof areas need optimisation of tank size, which is often not carried out before installation of these tanks. This paper presents a case study of rainwater tank evaluation and design for large roof areas, located in Melbourne, Australia, based on observed daily rainfall data representing three different climatic regimes (i.e. dry average, and wet years). With the aim of developing a comprehensive Decision Support Tool for the performance analysis and design of rainwater tanks, a simple spreadsheet based daily water balance model is developed using daily rainfall data, contributing roof area, rainfall loss factor, available storage volume, tank overflow and irrigation water demand. In this case study, two (185 m³ and 110 m³) underground rainwater tanks are considered. Using the developed model, effectiveness of each tank under different climatic scenarios are assessed. The analysis shows that both the tanks are quite effective in wet and average years, however less effective in dry years. A payback period analysis of the tanks is preformed which reveals that the total construction cost of the tanks can be recovered within 15-21 years time depending on tank size, climatic conditions and future water price increase rates. For the tanks, a relationship between water price increase rates and payback periods is developed. The study highlights the need for detailed optimisation and financial analysis for large rainwater tanks to maximise the benefits.     

Evaluation of alternative water sources for commercial buildings: A case study in Brisbane,Australia

Commercial buildings are central to cities and contribute significantly to the urban demand for natural resources, including freshwater. Green building benchmarking tools include more efficient water use as key indicator of sustainability. This paper explores options for substituting mains drinking water with an alternative, non-potable water source on a fit for purpose basis. The research findings are based on a monitoring study of a commercial building in Brisbane, Australia that is harvesting rainwater for meeting non-potable water demand. The results demonstrated that the system is only achieving moderate reliability in meeting demand due to operational problems. The case study analysis has highlighted the need to include validation and monitoring to ensure the system is operating as per design intent. The paper also investigates the potential of other local, non-potable water sources for high-rise commercial buildings, in particular air conditioning condensate and groundwater inflow to a basement wet well. The paper concludes by comparing the advantages and disadvantages of different local water sources which highlights the need to undertake a site specific investigation to identify a suitable alternative water source, which considers O&M complexity and the capacity of facilities management.     

A comparison of in situ methods for measuring net nitrogen mineralization rates of organic soil amendments

In situ incubation methods may help provide site-specific estimates of N mineralization from land-applied wastes. However, there are concerns about the reliability of the data generated by the various methods due to containment artifacts. We amended a sandy soil with either poultry manure, biosolids, or yard-waste compost and incubated the mixtures using four in situ methods (buried bags, covered cylinders, standard resin traps, and "new" soil-resin traps) and a conventional laboratory technique in plastic bags. Each incubation device was destructively sampled at 45-d intervals for 180 d and net N mineralization was determined by measuring the amount of inorganic N that accumulated in the soil or soil plus resin traps. Containment effects were evaluated by comparing water content of the containerized soil to a field-reference soil column. In situ incubation methods provided reasonable estimates of short-term (< 45 d) N mineralization, but long-term (> 45 d) mineralization data were not accurate due to a variety of problems specific to each technique. Buried bags and covered cylinders did not retain mineralized N due to water movement into and out of the containers. Neither resin method captured all of the mineralized N that leached through the soil columns, but the new soil-resin trap method tracked field soil water content better than all other in situ methods evaluated. With further refinement and validation, the new soil-resin trap method may be a useful in situ incubation technique for measuring net N mineralization rates of organic soil amendments.     

Revegetation Strategies for Bauxite Refinery Residue: A Case Study of Alcan Gove in Northern Territory, Australia

Alumina extraction from bauxite ore with strong alkali produces waste bauxite refinery residue consisting of residue sand and red mud. The amount and composition of refinery residue depend on the purity of the bauxite ore and extraction conditions, and differs between refineries. The refinery residue is usually stored in engineered disposal areas that eventually have to be revegetated. This is challenging because of the alkaline and sodic nature of the residue. At Alcan Gove’s bauxite refinery in Gove, Northern Territory, Australia, research into revegetation of bauxite residue has been conducted since the mid-1970s. In this review, we discuss approaches taken by Alcan Gove to achieve revegetation outcomes (soil capping of refinery residue) on wet-slurry disposal areas. Problems encountered in the past include poor drainage and water logging during the wet season, and salt scalding and capillary rise during the dry season. The amount of available water in the soil capping is the most important determinant of vegetation survival in the seasonally dry climate. Vegetation cover was found to prevent deterioration of the soil cover by minimising capillary rise of alkalinity from the refinery residue. The sodicity and alkalinity of the residue in old impoundments has diminished slightly over the 25 years since it was deposited. However, development of a blocky structure in red mud, presumably due to desiccation, allows root penetration, thereby supplying additional water to salt and alkali-tolerant plant species. This has led to the establishment of an ecosystem that approaches a native woodland.     

A hybrid scheme for comparing the effects of bird diversity conservation approaches on landscape patterns and biodiversity in the Shangan sub-watershed in Taiwan

This work utilizes bird survey data, regression modeling, land-use modeling and landscape metrics to evaluate the effects of various spatial bird diversity conservation approaches on land-use allocation, land-use patterns, and biodiversity in the Shangan sub-watershed in central Taiwan. A survey of the distribution of species revealed that bird species are concentrated in the central and western parts of the sub-watershed. The results obtained using a Shannon-Weaver diversity regression model suggest that diversity of land-use increases the diversity of bird species. Logistic regression results verify that socio-economic factors determine the potential advantages of designating a particular type of land-use in certain parts of the study area. The results of land-use simulation modeling indicate that the eastern and southwestern areas of the sub-watershed will change most frequently between 2007 and 2017. Additionally, increasing the areas to protect bird diversity will effectively increase the patch size, habitat core area, edge effect and habitat connectivity. The Shannon-Weaver diversity regression model shows that protecting bird species diversity in large areas increases bird diversity. The proposed modeling approach is an effective tool that provides useful information for ecological planning and policymaking related to watersheds.     

A review of the cost-effectiveness and suitability of mitigation strategies to prevent phosphorus loss from dairy farms in New Zealand and Australia

The loss of phosphorus (P) from land to water is detrimental to surface water quality in many parts of New Zealand and Australia. Farming, especially pasture-based dairying, can be a source of P loss, but preventing it requires a range of fully costed strategies because little or no subsidies are available and the effectiveness of mitigation strategies varies with different farm management systems, topography, stream density, and climate. This paper reviews the cost-effectiveness of mitigation strategies for New Zealand and Australian dairy farms, grouping strategies into (i) management (e.g., decreasing soil test P, fencing streams off from stock, or applying low-water-soluble P fertilizers), (ii) amendments (e.g., alum or red mud [Bauxite residue]), and (iii) edge-of-field mitigations (e.g., natural or constructed wetlands). In general, on-farm management strategies were the most cost-effective way of mitigating P exports (cost range, $0 to $200 per kg P conserved). Amendments, added to tile drains or directly to surface soil, were often constrained by supply or were labor intensive. Of the amendments examined, red mud was cost effective where cost was offset by improved soil physical properties. Edge-of-field strategies, which remove P from runoff (i.e., wetlands) or prevent runoff (i.e., irrigation runoff recycling systems), were generally the least cost effective, but their benefits in terms of improved overall resource efficiency, especially in times of drought, or their effect on other contaminants like N need to be considered. By presenting a wide range of fully costed strategies, and understanding their mechanisms, a farmer or farm advisor is able to choose those that suit their farm and maintain profitability. Further work should examine the potential for targeting strategies to areas that lose the most P in time and space to maximize the cost-effectiveness of mitigation strategies, quantify the benefits of multiple strategies, and identify changes to land use that optimize overall dairy production, but minimize catchment scale, as versus farm scale, nutrient exports.     

A cost-effective microbial slurry technology for rapid composting of municipal solid wastes in waste dump sites in India and its feasibility for use in Australia

This short article reports on commercial composting slurry now available in India. The slurry culture containing active decomposer bacteria and enzymes is spread on the surface of the garbage and inside the heaps in windrows constructed at waste dump sites. The microbes produce hydrolysing enzymes to break down the long chain complexes of the organic substrates. About 1 kg of slurry culture in the colloidal emulsion form mixed with 20 litres of water is sprayed on about 3 m of solid waste. For one tonne of waste 200 litres of slurry water are needed. The waste heaps are turned once in 7 to 10 days for proper aeration and the inoculant slurry is sprayed at each turning to enhance decomposition and to maintain the proper moisture level which is usually 45–55 percent. The process is exothermic and the windrows reach a temperature of 70°–75°C within 24–36 hours, killing many harmful pathogens and repelling all birds, stray animals, flies and mosquitos from the dump site. The entire process is completed within 4–6 weeks and as the decomposition is completed the temperature falls to normal. About 40–45 percent of the undecomposed matter is of recyclable materials, and of the rest about 25–30 percent requires safe disposal in adjacent land-fill sites. The problem of emission from tip gases and of leachate and discharge of effluents is greatly reduced. The foul odor of the tip also disappears within 2–3 days of sanitization. The compost produced is rich in sodium, potassium and phosphorous as well as certain trace elements, and contains active nitrogen fixing and phosphate solubulising bacteria.     

A simple high performance liquid chromatography method for analyzing paraquat in soil solution samples

A high performance liquid chromatography (HPLC) method with UV detection was developed to analyze paraquat (1,1'-dimethyl-4,4'-dipyridinium dichloride) herbicide content in soil solution samples. The analytical method was compared with the liquid scintillation counting (LSC) method using 14C-paraquat. Agreement obtained between the two methods was reasonable. However, the detection limit for paraquat analysis was 0.5 mg L(-1) by the HPLC method and 0.05 mg L(-1) by the LSC method. The LSC method was, therefore, 10 times more precise than the HPLC method for solution concentrations less than 1 mg L(-1). In spite of the high detection limit, the UC (nonradioactive) HPLC method provides an inexpensive and environmentally safe means for determining paraquat concentration in soil solution compared with the 14C-LSC method.     

Adaptive management for mitigating Cryptosporidium risk in source water: A case study in an agricultural catchment in South Australia

Water-borne pathogens such as Cryptosporidium pose a significant human health risk and catchments provide the first critical pollution ‘barrier’ in mitigating risk in drinking water supply. In this paper we apply an adaptive management framework to mitigating Cryptosporidium risk in source water using a case study of the Myponga catchment in South Australia. Firstly, we evaluated the effectiveness of past water quality management programs in relation to the adoption of practices by landholders using a socio-economic survey of land use and management in the catchment. The impact of past management on the mitigation of Cryptosporidium risk in source water was also evaluated based on analysis of water quality monitoring data. Quantitative risk assessment was used in planning the next round of management in the adaptive cycle. Specifically, a pathogen budget model was used to identify the major remaining sources of Cryptosporidium in the catchment and estimate the mitigation impact of 30 alternative catchment management scenarios. Survey results show that earlier programs have resulted in the comprehensive adoption of best management practices by dairy farmers including exclusion of stock from watercourses and effluent management from 2000 to 2007. Whilst median Cryptosporidium concentrations in source water have decreased since 2004 they remain above target levels and put pressure on other barriers to mitigate risk, particularly the treatment plant. Non-dairy calves were identified as the major remaining source of Cryptosporidium in the Myponga catchment. The restriction of watercourse access of non-dairy calves could achieve a further reduction in Cryptosporidium export to the Myponga reservoir of around 90% from current levels. The adaptive management framework applied in this study was useful in guiding learning from past management, and in analysing, planning and refocussing the next round of catchment management strategies to achieve water quality targets.     

Responses of community to the possible use of recycled water for washing machines: A case study in Sydney, Australia

Recycled water is a valuable resource that has potential to free up potable water supplies and recharge systems while improving the environment. Recycled water for washing machine could be one of the options as new end use of recycled water to alleviate the demand on existing and limited water supplies. This paper summarizes the findings of a research survey in Sydney, Australia to explore the attitudes and opinions of community towards the use of recycled water for different purposes, especially for the washing machine. The survey showed that 97% of the respondents were aware of the persisting water shortage problem while more than 60% of the respondents supported the use of recycled water for washing clothes. This paper exposes the basic concern of participants for using recycled water in washing machine. Health issue was found as the most concerns of the community. The survey also presents the further conditions to be considered for using recycled water for washing machine according to the participants’ opinions. Correlation between knowledge and attitudes of respondents was also found in this survey.     

特高含硫油气田废水中阴离子（F－、Cl－、Br－、SO）的离子色谱测定

论述了用国产的低压离子色谱仪、电导检测器作为测定特高含硫油气田废水中Ｆ－、Ｃｌ－、Ｂｒ－、ＳＯ离子的可行性，并讨论了分析条件、最低检出限、精密度、准确度以及干扰等，及对国家标样及实际样品进行了测定。结果表明该法简单、快速、灵敏、准确，是目前较为理想的测定特高含硫油气田废水中无机阴离子的方法。     

Environmental culture change in local government: a practised perspective from the international council for local environmental initiatives—Australia/New Zealand>

Environmental culture change, a seemingly intangible concept, is fast becoming an important indicator of success for organisations delivering sustainable development around the globe. This article provides an analysis of local government's ability to affect culture change within its organisations and communities, and the role the International Council for Local Environmental Initiatives—Australia/New Zealand (ICLEI-A/NZ) has in assisting local government with this process. While the impact ICLEI-A/NZ has had on the culture change movement is difficult to define, the methodologies adopted by the organisation have been designed to institutionalise the integration of environmental decision-making concepts and practices in local government. This article discusses the degree to which ICLEI-A/NZ's capacity-building campaigns and other performance-focused initiatives have instilled core environmental values in local government.     

A well to wire LCA model development and sensitivity analysis for carbon footprint of combined cycle power plants in Iranian electricity network

The present research introduces a well to wire pseudo comprehensive carbon footprint model for combined cycle power plants. The mentioned model integrates land use change model, operational model and transmission and distribution model into one comprehensive model. The parameters which their effects are considered in the integrated model are: fuel type, fuel transmission type, emission for fuel extraction and processing, own consumption of the plant, degradation, site ambient condition, transmission and distribution losses. For quantifying the effectiveness of each parameter, sensitivity analyses based on different life cycle scenarios are performed. The result shows that the effect of land use change is negligible. The carbon footprint of electrical energy produced in combined cycle plant until it is delivered to the end users varies from 321 to 522 g CO₂ eq/kWh.     

A hybrid model based on smooth transition periodic autoregressive and Elman artificial neural network for wind speed forecasting of the Hebei region in China

Wind energy, one of the most promising renewable and clean energy sources, is becoming increasingly significant for sustainable energy development and environmental protection. Given the relationship between wind power and wind speed, precise prediction of wind speed for wind energy estimation and wind power generation is important. For proper and efficient evaluation of wind speed, a smooth transition periodic autoregressive (STPAR) model is developed to predict the six-hourly wind speeds. In addition, the Elman artificial neural network (EANN)-based error correction technique has also been integrated into the new STPAR model to improve model performance. To verify the developed approach, the six-hourly wind speed series during the period of 2000–2009 in the Hebei region of China is used for model construction and model testing. The proposed EANN-STPAR hybrid model has demonstrated its powerful forecasting capacity for wind speed series with complicated characteristics of linearity, seasonality and nonlinearity, which indicates that the proposed hybrid model is notably efficient and practical for wind speed forecasting, especially for the Hebei wind farms of China.