Sediment and nutrient losses from exotic Pinus plantation management operations under simulated rainfall

Rainfall simulation experiments were carried out to measure runoff and soil water fluxes of suspended solids, total nitrogen, total phosphorus, dissolved organic carbon and total iron from sites in Pinus plantations on the coastal lowlands of south-eastern Queensland subjected to various operations (treatments). The operations investigated were cultivated and nil-cultivated site preparation, fertilised site preparation, clearfall harvesting and prescribed burning; these treatments were compared with an 8-y-old established plantation. Flow-weighted mean concentrations of total nitrogen and total phosphorus in surface runoff from the cultivated and nil-cultivated site-preparation, clearfall harvest, prescribed burning and 8-y-old established plantation treatments were very similar. However, both the soil water and the runoff from the fertilised site preparation treatment contained more nitrogen (N) and phosphorus (P) than the other treatments - with 3.10 mg N L-1 and 4.32 mg P L-1 (4 and 20 times more) in the runoff. Dissolved organic carbon concentrations in runoff from the nil-cultivated site-preparation and prescribed burn treatments were elevated. Iron concentrations were highest in runoff from the nil-cultivated site-preparation and 8-y-old established plantation treatments. Concentrations of suspended solids in runoff were higher from cultivated site preparation and prescribed burn treatments, and reflect the great disturbance of surface soil at these sites. The concentrations of all analytes were highest in initial runoff from plots, and generally decreased with time. Total nitrogen (mean 7.28, range 0.11-13.27 mg L-1) and total phosphorus (mean 11.60, range 0.06-83.99 mg L-1) concentrations in soil water were between 2 and 10 times greater than in surface runoff, which highlights the potential for nutrient fluxes in interflow (i.e. in the soil above the water table) through the general plantation area. Implications in regard to forest management are discussed, along with results of larger catchment-scale studies.

Weed spread prevention: simple activities for field operations.

This paper discusses how spread of weeds can be minimised by improved knowledge of the weed’s ecology and dispersal, and by better surveillance and treatment methods. Undertaking simple prevention activities reduces the risk of spreading weeds with minimal costs to projects and they noted that field staff and researchers can inadvertently become vectors of weed spread if they do not take adequate precautions. The authors describe several techniques that can be adopted and reference their observations to the eradication program for Siam weed, Chromolaena odorata.

Cat's claw creeper leaf-mining jewel beetle Hylaeogena jureceki Obenberger (Coleoptera: Buprestidae), a host-specific biological control agent for Dolichandra unguis-cati (Bignoniaceae) in Australia

Cat's claw creeper, Dolichandra unguis-cati (L.) L.G. Lohman (syn: Macfadyena unguis-cati (L.) A.H. Gentry) (Bignoniaceae), a major environmental weed in Queensland and New South Wales, is a Weed of National Significance and an approved target for biological control. A leaf-mining jewel beetle, Hylaeogena jureceki Obenberger (Coleoptera: Buprestidae), first collected in 2002 from D. unguis-cati in Brazil and Argentina, was imported from South Africa into a quarantine facility in Brisbane in 2009 for host-specificity testing. H. jureceki adults chew holes in leaves and lay eggs on leaf margins and the emerging larvae mine within the leaves of D. unguis-cati. The generation time (egg to adult) of H. jureceki under quarantine conditions was 55.4 ± 0.2 days. Host-specificity trials conducted in Australia on 38 plant species from 11 families supplement and support South African studies which indicated that H. jureceki is highly host-specific and does not pose a risk to any non-target plant species in Australia. In no-choice tests, adults survived significantly longer (>32 weeks) on D. unguis-cati than on non-target test plant species (<3 weeks). Oviposition occurred on D. unguis-cati and one non-target test plant species, Citharexylum spinosum (Verbenaceae), but no larval development occurred on the latter species. In choice tests involving D. unguis-cati, C. spinosum and Avicennia marina (Avicenniaceae), feeding and oviposition were evident only on D. unguis-cati. The insect was approved for field release in Australia in May 2012.

A framework for optimising capital investment and operations in livestock logistics

Despite the longevity, scale and importance of northern Australia's beef industry, recent disruptions to external markets have demonstrated a degree of vulnerability to shocks in the supply chain. Matching the industry's long-evident resilience to climatic variability with resilience to changes in markets and supply chains requires careful planning. One component of this is how investments in infrastructure will need to be planned to facilitate adaptive responses to market changes. This paper provides an outline of a modelling framework that links strategic and operational dynamic models of logistics along the supply chain from the property to the abattoir or port. A novelty of the methodology is that it takes into account the high granularity of individual livestock transport vehicle movements and the ability to scale up to an almost complete view of logistics costs across the entire beef industry of northern Australia. The paper illustrates how the methodology could be used to examine the effects of changes in logistics infrastructure on efficiency and costs using examples from the states of Northern Territory, Western Australia and Queensland.

Quantitative effects of in-line operations on Campylobacter and Escherichia coli through two Australian broiler processing plants

Campylobacter is an important food borne pathogen, mainly associated with poultry. A lack of through-chain quantitative Campylobacter data has been highlighted within quantitative risk assessments. The aim of this study was to quantitatively and qualitatively measure Campylobacter and Escherichia coli concentration on chicken carcasses through poultry slaughter. Chickens (n = 240) were sampled from each of four flocks along the processing chain, before scald, after scald, before chill, after chill, after packaging and from individual caeca. The overall prevalence of Campylobacter after packaging was 83% with a median concentration of 0.8 log10 CFU/mL. The processing points of scalding and chilling had significant mean reductions of both Campylobacter (1.8 and 2.9 log10 CFU/carcase) and E. coli (1.3 and 2.5 log10 CFU/carcase). The concentration of E. coli and Campylobacter was significantly correlated throughout processing indicating that E. coli may be a useful indicator organism for reductions in Campylobacter concentration. The carriage of species varied between flocks, with two flocks dominated by Campylobacter coli and two flocks dominated by Campylobacter jejuni. Current processing practices can lead to significant reductions in the concentration of Campylobacter on carcasses. Further understanding of the variable effect of processing on Campylobacter and the survival of specific genotypes may enable more targeted interventions to reduce the concentration of this poultry associated pathogen.

A crop productivity research protocol for long wall mining

Springsure Creek Coal (SCC) intends to develop a coal mine using the long wall mining process under grain farming land near Emerald in Central Queensland (CQ). While this technology will result in some subsidence of the land surface, SCC wishes to maintain productivity of the grain cropping land in the precinct after coal mining. However, the impact of the surface subsidence resulting from that mining process on productivity of cropping land in any Australian landscape is currently unclear. A research protocol to investigate the impacts of subsidence on grain productivity for when the SCC project becomes operational is proposed. The protocol has wider application for other similar mining projects throughout the country. A copy of the full report is accessible on www.aginstitute.com.au.