Resource use and greenhouse gas emissions from grain-finishing beef cattle in seven Australian feedlots: a life cycle assessment

Grain finishing of cattle has become increasingly common in Australia over the past 30 years. However, interest in the associated environmental impacts and resource use is increasing and requires detailed analysis. In this study we conducted a life cycle assessment (LCA) to investigate impacts of the grain-finishing stage for cattle in seven feedlots in eastern Australia, with a particular focus on the feedlot stage, including the impacts from producing the ration, feedlot operations, transport, and livestock emissions while cattle are in the feedlot (gate-to-gate). The functional unit was 1 kg of liveweight gain (LWG) for the feedlot stage and results are included for the full supply chain (cradle-to-gate), reported per kilogram of liveweight (LW) at the point of slaughter. Three classes of cattle produced for different markets were studied: short-fed domestic market (55–80 days on feed), mid-fed export (108–164 days on feed) and long-fed export (>300 days on feed). In the feedlot stage, mean fresh water consumption was found to vary from 171.9 to 672.6 L/kg LWG and mean stress-weighted water use ranged from 100.9 to 193.2 water stress index eq. L/kg LWG. Irrigation contributed 57–91% of total fresh water consumption with differences mainly related to the availability of irrigation water near the feedlot and the use of irrigated feed inputs in rations. Mean fossil energy demand ranged from 16.5 to 34.2 MJ lower heating values/kg LWG and arable land occupation from 18.7 to 40.5 m2/kg LWG in the feedlot stage. Mean greenhouse gas (GHG) emissions in the feedlot stage ranged from 4.6 to 9.5 kg CO2-e/kg LWG (excluding land use and direct land-use change emissions). Emissions were dominated by enteric methane and contributions from the production, transport and milling of feed inputs. Linear regression analysis showed that the feed conversion ratio was able to explain >86% of the variation in GHG intensity and energy demand. The feedlot stage contributed between 26% and 44% of total slaughter weight for the classes of cattle fed, whereas the contribution of this phase to resource use varied from 4% to 96% showing impacts from the finishing phase varied considerably, compared with the breeding and backgrounding. GHG emissions and total land occupation per kilogram of LWG during the grain finishing phase were lower than emissions from breeding and backgrounding, resulting in lower life-time emissions for grain-finished cattle compared with grass finishing.

Shelf life of minimally processed honeydew, kiwifruit, papaya, pineapple and cantaloupe

Shelf life of minimally processed (peeled, deseeded, and diced) honeydew melon, kiwifruit, papaya, pineapple, and cantaloupe stored at 4°C was studied. Sensory assessments were carried out at 3-day intervals by highly trained panels until the end of shelf life. Microbiological counts were made immediately after dicing fruit and at the end of shelf life. Results indicated that both the length of shelf life and type of spoilage were related to fruit species. Minimally processed fruit had longer shelf life at 4°C than at temp. recommended for whole fruit when these were >4°C. Spoilage of 4°C-stored kiwifruit, papaya, and pineapple pieces was found to be not as a consequence of microbial growth

The life history of Phalacrognathus Muelleri (Macleay) (Coleoptera: Lucanidae)

The life history of Phalacrognathus muelleri (Macleay) is described and aspects of its biology discussed. The species is restricted to the wet tropics of northern Queensland where it breeds in rotting wood in rainforest. Larvae have been extracted from the wood of 27 tree species in 13 families. All larvae found were in wood attacked by white rot fungi. The final instar larva is described. Larva, pupa, and parasites are figured.

Developments in termite management in Queensland, Australia: Life after Cyclodienes (Isoptera)

The highly persistent cyclodiene (organochlorine) insecticides (aldrin, dieldrin, chlordane and heptachlor), the main termiticides used in Australia for 30 years, were withdrawn from use in most of Australia on 30 June 1995. Alternative strategies for subterranean termite management in buildings and other structures had been under development, well before this withdrawal. Here we focus on these and subsequent developments in subterranean termite management, relevant to Queensland, including a national survey, relevant building regulations, approvals and changes in the Australian Standards on termite management. Developments including a national training and competency-based-licensing system for pest managers, insurance of dwellings against termite damage and several alternative termite management strategies are discussed. An integrated approach to termite management is the likely direction for the future in Australia, minimising reliance on chemical sprays and drenches. There will be an increased need for physical barriers in improved building design and reliable preventative and remedial treatments involving bait technology. The need for research on termite biology and, in particular, foraging behavior is emphasized yet again.

Designing better on-farm research in Australia using a participatory workshop process

There are renewed calls for end-user participation and the integration of local knowledge in agricultural research. In Australia, the response has included an increased emphasis on participatory on-farm research with farmers and commercial agronomists that tests accepted principals to answer practical local farming questions. However, this pursuit of greater relevance has often led to compromises in research designs, unclear results and frustration amongst farmers, commercial agronomists and Research Development and Extension (RDE) agency researchers. This paper reports on a series of pre-season planning workshops from `Doing successful on-farm research', a workshop-based initiative that provides guidelines and a series of interactive activities to plan better participatory on-farm research. The workshop approach helps people design on-farm research that is appropriate to their own needs and local conditions. It assists them to clearly identify their issues, develop specific research questions and decide the best approach to answer those questions with the appropriate rigour for their own situations. These `Doing successful on-farm research' workshops address four potential deficiencies in on-farm research and farming systems RDE more generally in Australia: (1) variable participation of scientists and farmers in on-farm research; (2) the lack of clear guidelines for effective participatory practice and on-farm research; (3) limited support for on-farm research beyond the intensive investigations conducted by RDE agencies and (4) limited support for industry and farmers to contextualise information and research outcomes for specific individual circumstances and faster adaptation of technology. This may be a valuable contribution to balancing the demands for both relevance and rigour in on-farm research in Australia. In "Ground–breaking Stuff’- Proceedings of the 13th Australian Society of Agronomy Conference, 10-14 September 2006, Perth, Western Australia.

The environmental fate of diuron under a conventional production regime in a sugarcane farm during the plant cane phase

BACKGROUND: Field studies of diuron and its metabolites 3-(3,4-dichlorophenyl)-1-methylurea (DCPMU), 3,4-dichlorophenylurea (DCPU) and 3,4-dichloroaniline (DCA) were conducted in a farm soil and in stream sediments in coastal Queensland, Australia. RESULTS: During a 38 week period after a 1.6 kg ha^-1 diuron application, 70-100% of detected compounds were within 0-15 cm of the farm soil, and 3-10% reached the 30-45 cm depth. First-order t1/2 degradation averaged 49 ± 0.9 days for the 0-15, 0-30 and 0-45 cm soil depths. Farm runoff was collected in the first 13-50 min of episodes lasting 55-90 min. Average concentrations of diuron, DCPU and DCPMU in runoff were 93, 30 and 83-825 µg L^-1 respectively. Their total loading in all runoff was >0.6% of applied diuron. Diuron and DCPMU concentrations in stream sediments were between 3-22 and 4-31 µg kg^-1 soil respectively. The DCPMU/diuron sediment ratio was >1. CONCLUSION: Retention of diuron and its metabolites in farm topsoil indicated their negligible potential for groundwater contamination. Minimal amounts of diuron and DCMPU escaped in farm runoff. This may entail a significant loading into the wider environment at annual amounts of application. The concentrations and ratio of diuron and DCPMU in stream sediments indicated that they had prolonged residence times and potential for accumulation in sediments. The higher ecotoxicity of DCPMU compared with diuron and the combined presence of both compounds in stream sediments suggest that together they would have a greater impact on sensitive aquatic species than as currently apportioned by assessments that are based upon diuron alone.

Salmonella and on-farm risk factors in healthy slaughter-age cattle and sheep in eastern Australia

To examine healthy slaughter-age cattle and sheep on-farm for the excretion of Salmonella serovars in faeces and to identify possible risk factors using a questionnaire. The study involved 215 herds and flocks in the four eastern states of Australia, 56 with prior history of salmonellosis. Production systems examined included pasture beef cattle, feedlot beef cattle, dairy cattle, prime lambs and mutton sheep and animals were all at slaughter age. From each herd or flock, 25 animals were sampled and the samples pooled for Salmonella culture. All Salmonella isolated were serotyped and any Salmonella Typhimurium isolates were phage typed. Questionnaires on each production system, prepared in Epi Info 6.04, were designed to identify risk factors associated with Salmonella spp excretion, with separate questionnaires designed for each production system. Salmonellae were identified in all production systems and were more commonly isolated from dairies and beef feedlots than other systems. Statistical analysis revealed that dairy cattle were significantly more likely to shed Salmonella in faeces than pasture beef cattle, mutton sheep and prime lambs (P < 0.05). A wide diversity of Salmonella serovars, all of which have been isolated from humans in Australia, was identified in both cattle and sheep. Analysis of the questionnaires showed access to new arrivals was a significant risk factor for Salmonella excretion on dairy properties. For beef feedlots, the presence of large numbers of flies in the feedlot pens or around stored manure were significant risk factors for Salmonella excretion. Dairy cattle pose the highest risk of all the slaughter-age animals tested. Some of the identified risk factors can be overcome by improved management practices, especially in relation to hygiene.

Using a supply chain approach to guide R&D

Consumers today are presented with an increasing array of products. The growing competition for consumer expenditure requires a whole of supply chain approach to maintain market share for existing cultivars and to successfully commercialise new cultivars. The supply chain needs to deliver value and satisfaction to the end customer and profitability to their members. Critical to getting the product right is developing inherent robustness into the cultivar, and developing processes and systems through the whole supply chain that maintain product quality and add value. This paper describes the approach we have used in working with supply chains in Australia and Indonesia to identify priority areas for improvement. Our experience demonstrates the need for a champion in the supply chain with significant influence and a desire to improve. The paper also describes our approach towards improving a specific supply chain to achieve successful commercialisation of a new cultivar. The cultivar was primarily selected for good production characteristics and attractive visual appeal. The performance of the fruit is being monitored from farm to retail shelf to identify points where quality is lost and practices can be improved. A targeted R&D program is investigating ways of improving production efficiency (nutrition, flowering and canopy management), maturity standards to optimise flavour, harvesting and packing practices to reduce skin damage, and ripening and handling practices to optimise shelf life. This integrated approach is based on similar approaches used to improve the performance of existing mango and avocado cultivars.

Stakeholder expectations for environmental assurance in agriculture: Lessons from the pastoral industry

This paper outlines the expectations of a wide range of stakeholders for environmental assurance in the pastoral industries and agriculture generally. Stakeholders consulted were domestic consumers, rangeland graziers, members of environmental groups, companies within meat and wool supply chains, and agricultural industry, environmental and consumer groups. Most stakeholders were in favour of the application of environmental assurance to agriculture, although supply chains and consumers had less enthusiasm for this than environmental and consumer groups. General public good benefits were more important to environmental and consumer groups, while private benefits were more important to consumers and supply chains. The 'ideal' form of environmental assurance appears to be a management system that provides for continuous improvement in environmental, quality and food safety outcomes, combined with elements of ISO 14024 eco-labelling such as life-cycle assessment, environmental performance criteria, third-party certification, labelling and multi-stakeholder involvement. However, market failure prevents this from being implemented and will continue to do so for the foreseeable future. In the short term, members of supply chains (the people that must implement and fund environmental assurance) want this to be kept simple and low cost, to be built into their existing industry standards and to add value to their businesses. As a starting point, several agricultural industry organisations favour the use of a basic management system, combining continuous improvement, risk assessment and industry best management practice programs, which can be built on over time to meet regulator, market and community expectations.

Losses of nitrogen in surface runoff from a plantation horticulture farm in coastal Queensland, Australia.

Surface losses of nitrogen from horticulture farms in coastal Queensland, Australia, may have the potential to eutrophy sensitive coastal marine habitats nearby. A case-study of the potential extent of such losses was investigated in a coastal macadamia plantation. Nitrogen losses were quantified in 5 consecutive runoff events during the 13-month study. Irrigation did not contribute to surface flows. Runoff was generated by storms at combined intensities and durations that were 20–40 mm/h for >9 min. These intensities and durations were within expected short-term (1 year) and long-term (up to 20 years) frequencies of rainfall in the study area. Surface flow volumes were 5.3 ± 1.1% of the episodic rainfall generated by such storms. Therefore, the largest part of each rainfall event was attributed to infiltration and drainage in this farm soil (Kandosol). The estimated annual loss of total nitrogen in runoff was 0.26 kg N/ha.year, representing a minimal loading of nitrogen in surface runoff when compared to other studies. The weighted average concentrations of total sediment nitrogen (TSN) and total dissolved nitrogen (TDN) generated in the farm runoff were 2.81 ± 0.77% N and 1.11 ± 0.27 mg N/L, respectively. These concentrations were considerably greater than ambient levels in an adjoining catchment waterway. Concentrations of TSN and TDN in the waterway were 0.11 ± 0.02% N and 0.50 ± 0.09 mg N/L, respectively. The steep concentration gradient of TSN and TDN between the farm runoff and the waterway demonstrated the occurrence of nutrient loading from the farming landscapes to the waterway. The TDN levels in the stream exceeded the current specified threshold of 0.2–0.3 mg N/L for eutrophication of such a waterway. Therefore, while the estimate of annual loading of N from runoff losses was comparatively low, it was evident that the stream catchment and associated agricultural land uses were already characterised by significant nitrogen loadings that pose eutrophication risks. The reported levels of nitrogen and the proximity of such waterways (8 km) to the coastline may have also have implications for the nearshore (oligotrophic) marine environment during periods of turbulent flow.

Collation, analysis and research of thermal benefits of green life in the urban landscapes

This project reviewed international research conducted on the possible role of plants in alleviating high temperatures in our living spaces. The literature review served to identify the work that has already been carried out in the area and to highlight the gaps to be filled by experimental research. A pilot study then investigated the thermal properties of six of the most common landscaping materials. This project clearly shows that plants can play a significant role in modifying the thermal conditions of urban environments. Tall trees can shade nearby buildings and allow for reductions in cooling costs. In addition to basic shading, the dispersal of heat via the plant’s natural transpiration stream has long been recognised as an important component of the urban energy balance. It has been shown that urban temperatures can be up to 7°C higher than nearby rural areas, illustrating the impact of plants on their environment. These benefits argue against the idea of removing plants from landscapes in order to save on water in times of drought. Similarly, the idea of switching to artificial turf is questionable, since artificial turf still requires watering and can reach temperatures that far exceed the safe range for players. While vegetation offers evaporative cooling, non-vegetative, impervious surfaces such as concrete do not, and can therefore cause greater surface and soil temperatures. In addition, the higher temperatures associated with these impervious surfaces can negatively affect the growth of plants in surrounding areas. Permeable surfaces, such as mulches, have better insulating properties and can prevent excessive heating of the soil. However, they can also lead to an increase in reflected longwave radiation, causing the leaves of plants to close their water-conducting pores and reducing the beneficial cooling effects of transpiration. The results show that the energy balance of our surroundings is complicated and that all components of a landscape will have an impact on thermal conditions.

Polychaete-assisted sand filters – prawn farm wastewater remediation trial

Medium bedding sand which is commonly available in coastal sedimentary deposits, and a marine polychaete-worm species from Moreton Bay recently classified as Perinereis helleri (Nereididae), were deployed in a simple low-maintenance sand filter design that potentially has application at large scale. Previous work had shown that this physical and biological combination can provide a new option for saline wastewater treatment, since the worms help to prevent sand filter blocking with organic debris and offer a profitable by-product. To test the application of this new concept in a commercial environment, six 1.84 m2 Polychaete-assisted sand filters were experimentally tested for their ability to treat wastewater from a semi-intensive prawn culture pond. Polychaetes produced exclusively on the waste nutrients that collected in these gravity-driven sand filters were assessed for their production levels and nutritional contents. Water parameters studied included temperature, salinity, pH, dissolved oxygen (DO), oxidation/ reduction potential (redox), suspended solids, chlorophyll a, biological oxygen demand (BOD), and common forms of nitrogen and phosphorus. Pond water which had percolated through the sand bed had significantly lower pH, DO and redox levels compared with inflow water. Suspended solids and chlorophyll a levels were consistently more than halved by the process. Reductions in BOD appeared dependant on regular subsurface flows. Only marginal reductions in total nitrogen and phosphorus were documented, but their forms were altered in a potentially useful way: dissolved forms (ammonia and orthophosphate) were generated by the process, and this remineralisation also seemed to be accentuated by intermittent flow patterns. Flow rates of approximately 1,500 L m-2 d-1 were achieved suggesting that a 1 ha polychaete bed of this nature could similarly treat the discharge from a 10 ha semi-intensive prawn farm. Sixteen weeks after stocking sand beds with one-month-old P. helleri, over 3.6 kg of polychaete biomass (wet weight) was recovered from the trial. Production on a sand bed area basis was 328 g m-2. Similar (P>0.05) overall biomass production was found for the two stocking densities tested (2000 and 6000 m-2; n = 3), but survival was lower and more worms were graded as small (<0.6 g) when produced at the higher density (28.2 ± 1.5 % and approx. 88 %, respectively) compared with the lower density (46.8 ± 4.4 % and approx. 76 %, respectively). When considered on a weight for weight basis, about half of the worm biomass produced was generally suitable for use as bait. The nutritional contents of the worms harvested were analysed for different stocking densities and graded sizes. These factors did not significantly affect their percentages of dry matter (DM) (18.23 ± 0.57 %), ash (19.77 ± 0.80 % of DM) or gross energy 19.39 ± 0.29 MJ kg-1 DM) (n = 12). Although stocking density did not affect the worms’ nitrogen and phosphorus contents, small worms had a higher mean proportion of nitrogen and phosphorus (10.57 ± 0.17 % and 0.70 ± 0.01 % of DM, respectively) than large worms (9.99 ± 0.12 % and 0.65 ± 0.01 % of DM, respectively) (n = 6). More lipid was present in large worms grown at the medium density (11.20 ± 0.19 %) compared with the high density (9.50 ± 0.31 %) and less was generally found in small worms (7.1-7.6 % of DM). Mean cholesterol and total phospholipid levels were 5.24 ± 0.15 mg g-1 and 13.66 ± 2.15 mg g-1 DM, respectively (n = 12). Of the specific phospholipids tested, phosphatidyl-serine or sphingomyelin were below detection limits (<0.05 mg g-1), whilst mean levels of phosphatidyl-ethanolamine, phosphatidyl-inositol, phosphatidyl-choline and lysophosphatidyl-choline were 6.89 ± 1.09, 0.89 ± 0.26, 4.04 ± 1.17 and 1.84 ± 0.37 mg g-1, respectively (n = 12). Culture density generally had a more pronounced effect on phospholipid contents than did size of worms. By contrast, worm size had a more pronounced effect on total fatty acid contents, with large worms containing significantly higher (P<0.001) levels on a DM basis (46.88 ± 2.46 mg g-1) than smaller worms (27.76 ± 1.28 mg g-1). A very broad range of fatty acids were detected with palmitic acid being the most heavily represented class (up to 14.23 ± 0.49 mg g-1 DM or 27.28 ± 0.22 % of total fatty acids). Other heavily represented classes included stearic acid (7.4-8.8 %), vaccenic acid (6.8-7.8 %), arachidonic acid (3.5-4.4 %), eicosapentaenoic acid (9.9-13.8 %) and docosenoic acid (5.7-7.0 %). Stocking density did not affect (P>0.05) the levels of amino acids present in polychaete DM, but there was generally less of each amino acid tested on a weight per weight basis in large worms than in small worms. This difference was significant (P<0.05) for the most heavily represented classes being glutamic acid (73-77 mg g-1), aspartic acid (50-54 mg g-1), and glycine (46-53 mg g-1). These results demonstrate how this polychaete species can be planted and sorted at harvest according to various strategies aimed at providing biomass with specific physical and nutritional qualities for different uses.

Effects of secondary crops on bacterial growth and nitrogen removal in shrimp farm effluent treatment systems

Secondary crops provide a means of assimilating some effluent nitrogen from eutrophic shrimp farm settlement ponds. However, a more important role may be their stimulation of beneficial bacterial nitrogen removal processes. In this study, bacterial biomass, growth and nitrogen removal capacity were quantified in shrimp farm effluent treatment systems containing vertical artificial substrates and either the banana shrimp Penaeus merguiensis (de Man) or the grey mullet, Mugil cephalus L. Banana shrimp were found to actively graze biofilm on the artificial substrates and significantly reduced bacterial biomass relative to a control (24.5 ± 5.6mgCm−2 and 39.2 ± 8.7mgCm−2, respectively). Bacterial volumetric growth rates, however, were significantly increased in the presence of the shrimp relative to the control 45.2±11.3mgCm−2 per day and 22.0±4.3mgCm−2 per day, respectively). Specific growth rate, or growth rate per cell, of bacteria was therefore appreciably stimulated by the banana shrimp. Nitrate assimilation was found to be significantly higher on grazed substrate biofilm relative to the control (223±54 mgNm−2 per day and 126±36 mg Nm−2 per day, respectively), suggesting that increased bacterial growth rate does relate to enhanced nitrogen uptake. Regulated banana shrimp feeding activity therefore can increase the rate of newbacterial biomass production and also the capacity for bacterial effluent nitrogen assimilation. Mullet had a negligible influence on the biofilm associated with the artificial substrate but reduced sediment bacterial biomass (224 ± 92 mgCm−2) relative to undisturbed sediment (650 ± 254 mgCm−2). Net, or volumetric bacterial growth in the sediment was similar in treatments with and without mullet, suggesting that the growth rate per cell of bacteria in grazed sediments was enhanced. Similar rates of dissolved nitrogen mineralisation werefound in sediments with and without mullet but nitrificationwas reduced. Presence of mullet increased water column suspended solids concentrations, water column bacterial growth and dissolved nutrient uptake. This study has shown that secondary crops, particularly banana shrimp, can play a stimulatory role in the bacterial processing of effluent nitrogen in eutrophic shrimp effluent treatment systems.

Treatment of shrimp farm effluent with omnivorous finfish and artificial substrates

Long-term environmental sustainability and community acceptance of the shrimp farming industry in Australia requires on-going development of efficient cost-effective effluent treatment options. In this study, we aimed to evaluate the effectiveness of a shrimp farm treatment system containing finfish and vertical artificial substrates (VAS). This was achieved by (1) quantifying the individual and collective effects of grey mullet (Mugil cephalus L.) and VASs on water and sediment quality, and (2) comparing the retention of N in treatment systems with and without the presence of finfish (M. cephalus and the siganid Siganus nebulosus (Quoy & Gaimard)), where light was selectively removed. Artificial substrates were found to significantly improve the settlement of particulate material, regardless of the presence of finfish. Mullet actively resuspended settled solids and reduced the production of nitrate when artificial substrates were absent. However, appreciable nitrification was observed when mullet were present together with artificial substrates. The total quantity of N retained by the mullet was found to be 1.8– 2.4% of the incoming pond effluent N. It was estimated that only 21% of the pond effluent N was available for mullet consumption. When S. nebulosus was added, total finfish N retention increased from 1.8% to 3.9%, N retention by mullet also improved (78±16 to 132±21-mg N day−1 before and after siganid addition respectively). Presence of filamentous macroalgae (Enteromorpha spp.) was found to improve the removal of N from pond effluent relative to treatments where light was excluded. Denitrification was also a significant sink for N (up to 24% N removed). Despite the absence of algal productivity and greater availability of nitrate, denitrification was not higher in treatments where light was excluded. Mullet were found to have no effect on the rates of denitrification but significantly reduced macroalgal growth on the surface of the water. When mullet were absent, excessive macroalgal growth led to reduced dissolved oxygen concentrations and nitrification. This study concludes that the culture of mullet alone in shrimp farm effluent treatment systems does not result in significant retention of N but can contribute to the control of macroalgal biomass. To improve N retention and removal, further work should focus on polyculturing a range of species and also on improving denitrification.

International advances in prawn farm recirculation technology

This report provides details of visits and investigations conducted during an international study tour by the author.