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Context Eggs, a dietary staple, are a low environmental-impact animal protein, although no quantified analysis has been published for the Australian egg industry. Aims This study determined baseline greenhouse-gas (GHG) emissions, fossil energy use, freshwater consumption, water stress, and land-occupation impacts for the Australian egg for 2020 and identified hotspots. Methods To understand the environmental credentials of the industry, an attributional life-cycle assessment was conducted using primary data collected from all major Australian production regions. Impacts were reported per kilogram of table eggs and per kilogram of shell- and protein-corrected eggs for cage (C), cage-free (CF) and free-range (FR) production. Monte Carlo analysis was used to assess uncertainty, and results are presented using the means and standard deviations. Key results Statistically significant (P

The effect of drying air temperature and relative humidity on the rate of drying and damage to navy beans was investigated. A thin-layer apparatus was developed to dry beans from an initial moisture content of around 25% to 14% wet basis (w.b.) using temperatures between 328 and 62° C and relative humidities between 7.5% and 45%.

PigBal is a mass balance model that uses pig diet, digestibility and production data to predict the manure solids and nutrients produced by pig herds. It has been widely used for designing piggery effluent treatment systems and sustainable reuse areas at Australian piggeries. More recently, PigBal has also been used to estimate piggery volatile solids production for assessing greenhouse gas emissions for statutory reporting purposes by government, and for evaluating the energy potential from anaerobic digestion of pig effluent. This paper has compared PigBal predictions of manure total, volatile, and fixed solids, and nitrogen (N), phosphorus (P) and potassium (K), with manure production data generated in a replicated trial, which involved collecting manure from pigs housed in metabolic pens. Predictions of total, volatile, and fixed solids and K in the excreted manure were relatively good (combined diet R2 ≥ 0.79, modelling efficiency (EF) ≥ 0.70) whereas predictions of N and P, were generally less accurate (combined diet R2 0.56 and 0.66, EF 0.19 and –0.22, respectively). PigBal generally under-predicted lower N values while over-predicting higher values, and generally over-predicted manure P production for all diets. The most likely causes for this less accurate performance were ammonium-N volatilisation losses between manure excretion and sample analysis, and the inability of PigBal to account for higher rates of P uptake by pigs fed diets containing phytase. The outcomes of this research suggest that there is a need for further investigation and model development to enhance PigBal’s capabilities for more accurately assessing nutrient loads. However, PigBal’s satisfactory performance in predicting solids excretion demonstrates that it is suitable for assessing the methane component of greenhouse gas emission and the energy potential from anaerobic digestion of volatile solids in piggery effluent. The apparent overestimation of N and P excretion may result in conservative nutrient application rates to land and the over-prediction of the nitrous oxide component of greenhouse gas emissions.

Artificially drying lucerne immediately after cutting eliminates quality losses during field drying and minimizes the number of field operations. The average potential saving, calculated over a 20-year period for southeast Queensland, is about $40 (Australian)/t of hay, minus drying costs. The optimum technique of hay drying (immediately after cutting) in a solar-supplemented, step-flow dryer was investigated. A computer model was developed to minimize the cost of drying and to define the optimum drying parameters. Sensitivity analyses were carried out for drying air temperatures in tiie range of 30 to 70° C. The results show that there is an optimum number of hours of operation per day (8 h/d) for any combination of the other variables. The most critical factors affecting annual savings are the temperature of drying air, the length of the drying season, the cost of fuel, and the specific cost of the collector. An economic analysis showed that an average annual increase in profit of about $16/t of dried hay (at 12% w.b.) could be attained under optimum sets of operating conditions.