Carbon losses in terrestrial hydrological pathways in sugarcane cropping systems of Australia

Climate change and carbon (C) sequestration are a major focus of research in the twenty-first century. Globally, soils store about 300 times the amount of C that is released per annum through the burning of fossil fuels (Schulze and Freibauer 2005). Land clearing and introduction of agricultural systems have led to rapid declines in soil C reserves. The recent introduction of conservation agricultural practices has not led to a reversing of the decline in soil C content, although it has minimized the rate of decline (Baker et al. 2007; Hulugalle and Scott 2008). Lal (2003) estimated the quantum of C pools in the atmosphere, terrestrial ecosystems, and oceans and reported a “missing C” component in the world C budget. Though not proven yet, this could be linked to C losses through runoff and soil erosion (Lal 2005) and a lack of C accounting in inland water bodies (Cole et al. 2007). Land management practices to minimize the microbial respiration and soil organic C (SOC) decline such as minimum tillage or no tillage were extensively studied in the past, and the soil erosion and runoff studies monitoring those management systems focused on other nutrients such as nitrogen (N) and phosphorus (P).

The physiological and metabolic impacts on sheep and cattle of feed and water deprivation before and during transport

Sheep and cattle are frequently subjected to feed and water deprivation (FWD) for about 12 h before, and then during, transport to reduce digesta load in the gastrointestinal tract. This FWD is marked by weight loss as urine and faeces mainly in the first 24 h but continuing at a reduced rate subsequently. The weight of rumen contents falls although water loss is to some extent masked by saliva inflow. FWD is associated with some stress, particularly when transportation is added. This is indicated by increased levels of plasma cortisol that may be partly responsible for an observed increase in the output of water and N in urine and faeces. Loss of body water induces dehydration that may induce feelings of thirst by effects on the hypothalamus structures through the renin-angiotensin-aldosterone system. There are suggestions that elevated cortisol levels depress angiotensin activity and prevent sensations of thirst in dehydrated animals, but further research in this area is needed. Dehydration coupled with the discharge of Na in urine challenges the maintenance of homeostasis. In FWD, Na excretion in urine is reduced and, with the reduction in digesta load, Na is gradually returned from the digestive tract to the extracellular fluid space. Control of enteropathogenic bacteria by normal rumen microbes is weakened by FWD and resulting infections may threaten animal health and meat safety. Recovery time is required after transport to restore full feed intake and to ensure that adequate glycogen is present in muscle pre-slaughter to maintain meat quality.

Growing organic prawns - in inland saline waters

This report details the results of research into organic production of prawns in Australia. This has involved activities and experiments over two years at several sites and using a multidisciplinary approach. This includes farm trials at an inland demonstration prawn farm which solely utilises saline bore water, sample collection from two commercial prawn farms in coastal regions of south-eastern Queensland, replicated feed trials at one of DPI&F’s aquaculture research stations, specified feed manufacture at the laboratories of University of Queensland, and packaging and product storage trials and food analyses at two of DPI&F’s food technology laboratories. This work was designed to investigate and assist in the possible adoption of organic procedures by the Australian prawn farming industry. The import from Asia of cheaply produced prawns has forced all Australian prawn farmers to review their marketing procedures. Additionally investors are becoming increasingly concerned at the prospects for the expansion of this industry in Australia. Since the competition of seafood products in the marketplace is increasing on a global basis, alternate products are being investigated by those wishing to maintain and/or grow their market share. The premium paid for organic food products would hopefully provide an economic incentive for farmers to convert to organic production systems, with an added advantage that the standards that apply have beneficial implications also for the social and environmental practices of industry.