Australian Journal of Experimental Agriculture

Published by CSIRO Publishing
Print ISSN: 0816-1089
Publications
Location of principal Landcare sites in Mindanao, Southern Philippines.  
‘Landcare’ is a group-based approach to the promotion of conservation farming. A case study of the Landcare program in Lantapan in the southern Philippines is presented to assess the farm-level impacts of this approach. The program was successful in promoting the formation of Landcare groups and a m unicipal Landcare association, resulting in rapid and widespread adoption of conservation practices, particularly among maize farmers. This in turn significantly reduced soil erosion, though the impact on crop yield and income was somewhat delayed. Adoption was thus not motivated primarily by short-term returns but by a concern to reduce so il erosion and provide a basis for diversification into agroforestry.
 
This paper reports on the development of 4 new instruments to measure impacts of an extension program on farming family participants. A case study approach within an action research framework incorporating qualitative and quantitative domains was adopted to explore the impact on Queensland farmers of FutureProfit, a farm business management extension program. Two of these new measures, Management Constructs Change index and Management Objectives Change index, provided evidence of statistically significant changes in participant beliefs about, and attitudes towards farm business management. Although highly correlated with each other, these changes were unrelated statistically to any of seven other commonly used biographical or psychometric indices employed, including level of formal education. The third measure, the Bennett Change index, provided statistically significant evidence that attitudinal and behavioural changes were more frequent in participants with less formal education, but also more frequent in participants who had high urbanisation and self-directed learning index scores. A fourth measure, Values Domain Change, derived from the Management Objectives Change index, condensed objectives change data into values domainoriented scales, and showed that attitudinal change occurred across a wide spectrum of the recognized human values domains. Several conclusions are drawn from these findings, chief of which is that the approach used has successfully quantified impressionistic data in a way that offers potential for other researchers to document program impacts in terms other than hard quantitative measures such as changes in profitability.
 
Outline of experiments conducted to assess performance of irradiated Dwarf Parfitt mutant lines
Incidence of fusarium wilt for Williams, Dwarf Parfitt and putative mutants of Dwarf Parfitt (obtained by gamma irradiation) Cultivars and mutant lines were ranked according to the percentage of plants showing symptoms of fusarium wilt in the plant crop. The incidence of external fusarium wilt was assessed on August 1993 using plants established from bits (sections of rhizome) 21 months after planting. The incidence of internal fusarium wilt was assessed on October 1997 using micropropagated plants 11 months from planting
'Dwarf parfitt', an extra-dwarf Cavendish cultivar with resistance to subtropical race 4 fusarium oxysporum f. sp. cubense 9Foc), was gamma irradiated at a dose of 20 Gy and putative mutants were recovered with improved agronomic characteristics. Further screening of putative mutants for improved yield and fruit size, as well as a degree of resistence to fusarium wilt, led to the selection of a line (DPM25) with improved productivity when grown on soils infested with subtropical race 4 Foc. DPM25 was equal to the industry standard, 'Williams', in every agronomic trait measured and it consistently showed a lower incidence of fusarium wilt. Further improvement of field resistance to race 4 Foc is needed in DPM25 and further cycles of mutation induction and selction is an option discussed.
 
Bagging mango fruit during their development on the tree can reduce insect and disease damage. However, it is also possible that bagging can interfere with transpiration and associated calcium accumulation. Low calcium concentrations have been correlated with poor mango fruit quality. This study was conducted to evaluate the influence of bagging at various stages of fruit development on calcium concentration and postharvest quality of 'Kensington Pride' mangoes. Fruits were bagged at 41, 25 or 9 days before harvest. No statistically significant differences in either skin or flesh calcium concentration were found between the bagged (plastic or paper) and unbagged fruits. Postharvest weight loss was enhanced and shelf life reduced in the 'plastic bagged' fruits. In an ancillary study, calcium concentrations in 'Kensington Pride' nubbins (seedless fruit) were compared with those in seeded fruit, since it has been shown with apple fruit that greater seededness is positively correlated with increased flesh calcium concentrations. Conversely, however, calcium concentrations in the flesh of mango nubbins were found to be significantly higher (0.80 mg/g dry weight) than those in seeded fruit (0.58 mg/g dry weight) of similar size.
 
The plant growth regulator abscisic acid induces stomatal closure, which can reduce transpiration rate and extend vase life of cut flowers by maintaining a positive water balance. Analytical-reagent grade abscisic acid is, however, expensive. In this work, the effects of 2 potentially inexpensive synthetic analogues of abscisic acid were studied as to their effects on cut Baccara roses. Abscisic acid and its analogues PBI-365 and PBI-429 reduced transpiration and helped to increase fresh weight during the first few days of vase life. However, the reduction in transpiration rate brought about by abscisic acid and the analogues did not alter vase life. Sucrose in the vase solution at concentrations of 2 and 4% increased vase life of cut Baccara roses. However, the highest sucrose concentration ( 4%) caused leaf crisping, thereby reducing the quality of the flower stems. Abscisic acid and the analogue PBI-365 reduced this phytotoxicity by induction of stomatal closure and reduction of vase solution sucrose flux into the leaves.
 
Geraldton waxflower (Chamelaucium uncinatum Schauer) is Australia's most economically important cut-flower export. Its small, attractive flowers make it particularly suitable as a filler in floral arrangements. However, postharvest bud and flower abscission is a major problem during transport, handling and marketing. Abscission may be caused by wound-induced endogenous ethylene production brought about by flower tissue infection with fungal pathogens such as Botrytis cinerea. Botany and postharvest characteristics are discussed in relation to flower abscission and how resultant postharvest losses may be minimised.
 
Kernel oil content of macadamia cv. A16 fruits harvested from the ground after spraying without ethephon () or with ethephon at 1200 mg/L () at 3 different stages of the harvest season. The first point on each graph indicates the time of spraying. (a-c) Unshaken trees, sprayed 24 March (pre-season), 12 May (early season) or 8 July (mid-season); (d-f) trees shaken 1 week after spraying on 16 April (pre-season), 4 June (early season) or 16 July (mid-season). Means ± s.e. (n = 10 trees). Asterisks indicate significant differences between 2 means (P < 0.05).
Promotion of fruit abscission in macadamia, Macadamia integrifolia (Proteaceae), has potential to reduce costs associated with prolonged harvesting of late-abscising cultivars. Effects of ethephon [(2-chloroethyl) phosphonic acid] on fruit removal force and crop abscission were monitored at 3 stages of the harvest season on both unshaken and mechanically shaken trees of the late-abscising macadamia cultivar A16. Ethephon application, tree shaking, or a combination of the 2 methods, accelerated crop removal from the tree at all stages during harvest. Early harvest before natural abscission resulted in little or no difference in nut-in-shell and kernel weight, kernel recovery and kernel oil content. Delaying ethephon application or tree shaking until commencement of natural abscission resulted in greater crop removal. Fruit removal force declined naturally towards 1 kgf at this stage, and was further reduced by ethephon application. The most effective approach for harvest acceleration was to reduce fruit removal force, before tree shaking, by spraying trees with ethephon.
 
Percentage (mean ± s.e.) of macadamia fruits [cvv. A16 (), 246 (), 344 () and 741 ()] remaining on the trees from March to October 1998 at Winfield, Queensland, and Victoria Park, New South Wales (n = 5 trees).
Nut-in-shell weights, kernel weights, kernel recoveries and kernel oil contents of macadamia fruits [cvv. A16 (), 344 () and 741 ()] sampled from the ground (a-d) or from the tree (e-h) from March to June 1998 at Winfield, Queensland. Significant differences between means (± s.e.) for a cultivar are indicated by different letters (A16: a, b; 344: c, d, e; 741: f, g) (P < 0.05, n = 5 trees).
Nut-in-shell weights, kernel weights, kernel recoveries and kernel oil contents of macadamia fruits [cvv. 246 (), 344 () and 741 ()] sampled from the ground (a-d) or from the tree (e-h) from March to June 1998 at Victoria Park, New South Wales. Significant differences between means (± s.e.) for a cultivar are indicated by different letters (246: a, b; 344: c, d; 741: f, g) (P<0.05, n = 5 trees).
Delayed or extended fruit abscission in many cultivars of macadamia, Macadamia integrifolia (Proteaceae), necessitates multiple harvests from the orchard floor. However, it is not known whether there is a link between fruit maturation and timing of abscission. In this study, relationships between kernel oil content, nut size, removal force and abscission were investigated in 2 commercial orchards, one in Queensland (24°S) and one in New South Wales (29°S). Abscission lasted 6 months (March–September) at both sites due to differences in timing of abscission between cultivars and extended abscission within cultivars. Abscission was consistently associated with declines in fruit removal force, from more than 2 kgf in early March towards 1 kgf at the peak of abscission. Later abscission in cvv. A16 and 246, compared with cvv. 344 and 741, was correlated with more gradual declines in removal force. Fruits containing small nuts and kernels tended to possess lower removal forces and these fruits were often heavily represented in the population of fruits that abscised earliest. There was little or no difference in kernel oil content between fruits of different removal force or between sample dates for any cultivar, either for samples taken from the tree or from the orchard floor. Attainment of maximal oil content and onset of fruit abscission are therefore independent processes in macadamia. If abscission can be accelerated, it may be possible to advance the harvest of late-abscising cultivars such as A16 and 246 which retain mature nuts on the tree up to several months after maximal oil accumulation.
 
Two revegetation field trials were undertaken on chronically bare acid sulfate soil scalds on grazing properties in the Hawkesbury and Macleay catchments of New South Wales, Australia. The aim was to test the effectiveness of various low cost and readily accessible techniques to encourage revegetation (via existing seedbank or surrounding vegetation) of the scalded sites. The trial at the more efficiently drained Hawkesbury site used a combined treatment of ridging (R), mulching (M) and liming (L) (i.e. R–M–L) compared with a control, within a fenced area. At the more waterlogged Macleay site, various elements of the combined treatment (i.e. R, M, R–M, R–L, R–M–L) were compared with a control, within a fenced area. Vegetation occurrence, biomass and species were tested, along with pertinent soil parameters (pH, salinity, soil moisture, soluble metals). Soil testing was undertaken at 2 depth levels to represent the seed germination zone (0–1 cm), and the potential root zone (1–10 cm). At the Hawkesbury site, the combined treatment (R–M–L) caused significantly greater vegetation occurrence and biomass, lower salinity, higher pH and increased soil moisture. At the Macleay site, results were more variable, but similar to the Hawkesbury trial as the site dried out. Mulching was the single most important treatment. All mulched sites had significantly more vegetation than the control, reaching 100% coverage in the R–M–L plots. Stock exclusion alone produced minimal results. Ridging alone was counterproductive. Liming without mulching caused proliferation of an insubstantial and transient vegetation species (Isolepis inundata). Most interesting was the different vegetation species encouraged by the different mulch treatments: treatment M was dominated by the sedge, Eleocharis acuta; treatment R–M was an even mix of Eleocharis acuta and native water-tolerant grasses (Paspalum distichum and Pseudoraphis paradoxa); treatment R–M–L was dominated by the aforementioned native grasses. These grasses are highly favoured for both economic (highly palatable to stock) and environmental (thick mulch cover, self seeding) objectives. The results demonstrate that revegetation of acid sulfate soil scalds is possible, and different treatments can influence vegetation species composition.
 
Percentage composition of experimental diets
The present study investigated the potential of dual energy X-ray absorptiometry to determine the effect of dietary protein on live pig body composition compared with the standard methods. The experiment utilised 48 Large White x Landrace gilts, stratified on liveweight at 17 weeks of age (initial liveweight about 60 kg), and allocated within strata to diets containing either 85 or 100% of dietary protein requirements. The diets were fed ad libitum and contained 14.6 or 16.7% protein, respectively. Pigs were housed individually to allow weekly measurement of feed intake and liveweight. A Hologic QDR4500A dual energy X-ray absorptiometer was used to determine lean, fat and ash composition of pigs initially and 4 weeks later at the end of the experiment. Daily gain was increased by about 200 g in pigs fed the protein-adequate diet, but feed intake was not affected. Therefore, pigs fed adequate protein had a lower feed conversion ratio (2.92 v. 3.52 g/g, P < 0.001). Feeding the protein-adequate diet increased lean deposition by about 150 g/day (577 v. 429 g/day, P < 0.001) and ash deposition by about 4 g/day (28.7 v. 25.0 g/day, P < 0.001), but did not affect fat accretion. This resulted in carcasses with a higher lean content (54.0 v. 50.7 kg, P < 0.001) and ash content (2.35 v. 2.28 kg, P < 0.05) but unaltered fat content. Therefore, an inadequate level of dietary protein leads to suboptimal growth in lean tissue and bone mineral, with no pronounced effect on fat. These observations were substantiated by chemical analysis and available corrective equations were useful in correcting differences between dual energy X-ray absorptiometry outputs and chemical values. After correction, dual energy X-ray absorptiometry estimates differed less than 5% from the chemical values for lean, protein, water and ash and 10% for lipid. In addition, reduced standard error of the differences around most dual energy X-ray absorptiometry measurements, relative to chemical analysis, allowed small changes in body composition to be detected with increased confidence. These data support the efficacy of using dual energy X-ray absorptiometry in nutritional studies of pigs.
 
Box plots of species richness across (a) regions, (b) crops and (c) sampling season and species density across (d) regions, (e) crops and ( f ) sampling season (note log scale for weed density). The line within each box is the median, the heavy solid line is the mean, the box demarcates the 25th and 75th percentiles, error bars indicate 10th and 90th percentiles and dots are 'outliers'. L'pool Plains, Liverpool Plains region.
Correspondence analysis showing the first 2 ordination axes using sites as the dependent variable.  
Correspondence analysis showing the first 2 ordination axes using species as the dependent variable. For numbered index of species see Appendix 1. Points without numbers were observed in the Liverpool Plains and Moree regions.  
Box plot of species relative abundance within regions (excluding species not recorded in a region, see Appendix 1). The line within each box is the median, the heavy solid line is the mean, the box demarcates the 25th and 75th percentiles, error bars indicate 10th and 90th percentiles and dots are 'outliers'. Note log scale. L'pool Plains, Liverpool Plains region.  
Weed management is one of the most important economic and agronomic issues facing farmers in Australia's grain regions. Weed species occurrence and abundance was monitored between 1997 and 2000 on 46 paddocks (sites) across 18 commercial farms located in the Northern Grain Region. The sites generally fell within 4 disjunct regions, from south to north: Liverpool Plains, Moree, Goondiwindi and Kingaroy. While high species richness was found (139 species or species groups), only 8 species occurred in all 4 regions and many (56 species) only occurred at 1 site or region. No species were observed at every site but 7 species (Sonchus spp., Avena spp., Conyza spp., Echinochloa spp., Convolvulus erubescens, Phalaris spp. and Lactuca serriola) were recorded on more than 70% of sites. The average number of species observed within crops after treatment and before harvest was less than 13. Species richness tended to be higher in winter pulse crops, cotton and in fallows, but overall was similar at the different sampling seasons (summer v. winter). Separate species assemblages associated with the Goondiwindi and Kingaroy regions were identified by correspondence analysis but these appeared to form no logical functional group. The species richness and density was generally low, demonstrating that farmers are managing weed populations effectively in both summer and winter cropping phases. Despite the apparent adoption of conservation tillage, an increase in opportunity cropping and the diversity of crops grown (13) there was no obvious effect of management practices on weed species richness or relative abundance. Avena spp. and Sonchus spp. were 2 of the most dominant weeds, particularly in central and southern latitudes of the region; Amaranthus spp. and Raphanus raphanistrum were the most abundant species in the northern part of the region. The ubiquity of these and other species shows that continued vigilance is required to suppress weeds as a management issue.
 
Experimental procedure for recording images of animals moving down a 900-mm wide, 3-m long laneway.
Invasive vertebrate pests together with overabundant native species cause significant economic and environmental damage in the Australian rangelands. Access to artificial watering points, created for the pastoral industry, has been a major factor in the spread and survival of these pests. Existing methods of controlling watering points are mechanical and cannot discriminate between target species. This paper describes an intelligent system of controlling watering points based on machine vision technology. Initial test results clearly demonstrate proof of concept for machine vision in this application. These initial experiments were carried out as part of a 3-year project using machine vision software to manage all large vertebrates in the Australian rangelands. Concurrent work is testing the use of automated gates and innovative laneway and enclosure design. The system will have application in any habitat throughout the world where a resource is limited and can be enclosed for the management of livestock or wildlife.
 
A knowledge-based decision support system called DAIRYPRO was applied to farm survey data to provide estimates of the achievable milk production for dairy farms in Queensland. The survey data were obtained from personal interviews conducted in 1994-95 involving 37-86% of farmers in 4 dairying districts in Queensland. Farms that had higher levels of milk production and a history of adopting proven management aids such as herd recording had production levels closer to achievable milk production. Measured milk yield relative to achievable milk production for 2 regions was significantly different from the other 2, while the age of the main decision maker was also a significant factor, with farmers aged 30-59 years producing closer to achievable milk production than any other age group (P<0.05). Seven percent of farms had measured production levels greater than the model's estimation of achievable milk production.
 
Effect of spinosad dose on the mean number of lice on sheep with time after treatment from the dose titration study (, 0.08 mg/kg; , 0.4 mg/kg; N , 2 mg/kg; @BULLET, 10 mg/kg).  
Percentage reduction in lice numbers on sheep treated with a suboptimal spinosad dose of 0.4 mg/kg of liveweight applied along the back-line (B) and back-line and flanks (BF) when housed either singly (S) or in groups of 6 (G). Black bars, B + G; dark grey bars, BF + G; light grey bars, B + S; white bars, BF + S.  
Spinosad, applied as a jetting solution or dip is an efficacious, non-systemic treatment for the control of Bovicola ovis in sheep. This paper describes the effect of back-line treatment width and group housing of animals on the efficacy of spinosad for the control of lice. A 0.4 mg/kg liveweight dose was found to be the suboptimal dose of spinosad for the control of body lice in a dose titration study and was used to investigate application and housing effects in a second study. Lousy Merino sheep were treated with either a narrow 3-cm application of spinosad or with a wider 25-cm swathe. After treatment they were either kept alone or in groups of 6 sheep per pen. Lice were counted at day 0 and every 14 days to 70 days after treatment before estimation of the percentage of lice control and analysis of treatment effects. A much higher percentage of lice control was achieved with 0.4 mg/kg in the second study than in the first, possibly because of differences in formulation used. The wider application width gave significantly higher (P < 0.05) control of lice than the narrow application when sheep were either housed alone or in groups up to day 42 post-treatment. Greater control of lice was seen in group-housed sheep compared with sheep housed individually (P < 0.05) up to day 70. Using broader application widths combined with holding the animals together after treatment with pour-on formulations may optimise the delivery and efficacy of ectoparasiticides for livestock.
 
In both Australia and Brazil there are rapid changes occurring in the macroenvironment of the dairy industry. These changes are sometimes not noticed in the microenvironment of the farm, due to the labour-intensive nature of family farms, and the traditionally weak links between production and marketing. Trends in the external environment need to be discussed in a cooperative framework, to plan integrated actions for the dairy community as a whole and to demand actions from research, development and extension (R, D & E). This paper reviews the evolution of R, D & E in terms of paradigms and approaches, the present strategies used to identify dairy industry needs in Australia and Brazil, and presents a participatory strategy to design R, D & E actions for both countries. The strategy incorporates an integration of the opinions of key industry actors ( defined as members of the dairy and associated communities), especially farm suppliers ( input market), farmers, R, D & E people, milk processors and credit providers. The strategy also uses case studies with farm stays, purposive sampling, snowball interviewing techniques, semi-structured interviews, content analysis, focus group meetings, and feedback analysis, to refine the priorities for R, D & E actions in the region.
 
The distribution of (a) wild dogs and (b) livestock in Australia (from Fleming et al. 2001). Wild dogs above the dashed line are mostly pure dingoes (from Corbett 2001). The solid line is the 'barrier fence'. In (a), wild dogs are present at varying densities from naturally sparse to common (light grey shading) to mostly absent (no shading). In (b), livestock distribution is shown as follows: sheep, cereals and cattle production (dark grey shading); cattle predominant (light grey shading); livestock mostly absent (no shading).
The weak relationship between the density of wild dogs (expressed as a mean monthly index of wild dog sign) and the mean monthly sheep production losses caused by wild dogs (n = 40 sheep properties). Regression forced through the origin.  
Calf production losses and injuries caused by wild dogs for a north Queensland property during 20 years of single property ground baiting (1968–88) and during 9 years of coordinated aerial baiting with neighbours (1989–96) (from Allen and Gonzalez 1998).  
Wild canids (wild dogs and European red foxes) cause substantial losses to Australian livestock industries and environmental values. Both species are actively managed as pests to livestock production. Contemporaneously, the dingo proportion of the wild dog population, being considered native, is protected in areas designated for wildlife conservation. Wild dogs particularly affect sheep and goat production because of the behavioural responses of domestic sheep and goats to attack, and the flexible hunting tactics of wild dogs. Predation of calves, although less common, is now more economically important because of recent changes in commodity prices. Although sometimes affecting lambing and kidding rates, foxes cause fewer problems to livestock producers but have substantial impacts on environmental values, affecting the survival of small to medium-sized native fauna and affecting plant biodiversity by spreading weeds. Canid management in Australia relies heavily on the use of compound 1080-poisoned baits that can be applied aerially or by ground. Exclusion fencing, trapping, shooting, livestock-guarding animals and predator calling with shooting are also used. The new Invasive Animals Cooperative Research Centre has 40 partners representing private and public land managers, universities, and training, research and development organisations. One of the major objectives of the new IACRC is to apply a strategic approach in order to reduce the impacts of wild canids on agricultural and environmental values in Australia by 10%. In this paper, the impacts, ecology and management of wild canids in Australia are briefly reviewed and the first cooperative projects that will address IACRC objectives for improving wild dog management are outlined.
 
Hymenachne amplexicaulis, an exotic grass established in ponded pasture in Central Queensland has the potential to become a weed. A suggested alternative, the native grass H. acutigluma produced little biomass when flooded. This investigation attempted to identify limitations to the growth of H. acutigluma under flooded conditions. A series of experiments compared the characteristics conferring adaptation to flooding of H. acutigluma with those of H. amplexicaulis. Photosynthetic activity of the 2 Hymenachne spp. was compared in response to light and temperature. The distribution of resources in response to reduced photosynthesis and flooding was also determined. When flooded, H. acutigluma had similar structural adaptations to H. amplexicaulis. However, H. acutigluma had a lower photosynthetic rate at reduced temperatures and the photosynthetic leaf area decreased when flooded. The implications of these findings are discussed in terms of limitations to the distribution and productivity of H. acutigluma in ponded pasture.
 
The introduced grass Hymenachne amplexicaulis has been established for use in ponded pastures in Central Queensland. However, its ability to out compete native species and invade wetlands makes it a potential weed. To determine the characteristics that make it a successful ponded pasture species, the adaptation of H. amplexicaulis to flooding has been investigated. The growth and development of H. amplexicaulis under flooded and non-flooded conditions was compared in a series of experiments carried out in three 2 m high galvanised steel tanks. Leaf, stem and root sections were taken to determine the timing and extent of aerenchyma formation. The effect of flooding on the pattern and distribution of growth was also determined. Hymenachne amplexicaulis is adapted to flooding because it has the capacity for rapid elongation of the stem and the formation of adventitious roots. Aerenchyma was present in stem, leaf and root tissues in both flooded and non-flooded plants. The aerenchyma would provide buoyancy as well as aiding the circulation of gases. When the plants were flooded, submerged leaves senesced rapidly and the previously exposed, but now submerged nodes produced adventitious roots. Under flooding, the growth of leaves increased at the expense of the roots, presumably maintaining the effective photosynthetic leaf area. The implications and limitations of these adaptations are discussed.
 
National pastoral producer awareness of quality and environmental accreditation schemes.
Potential benefits of environmental accreditation identified by pastoral producers during the national survey.
This paper describes adoption rates of environmental assurance within meat and wool supply chains, and discusses this in terms of market interest and demand for certified 'environmentally friendly' products, based on phone surveys and personal interviews with pastoral producers, meat and wool processors, wholesalers and retailers, and domestic consumers. Members of meat and wool supply chains, particularly pastoral producers, are both aware of and interested in implementing various forms of environmental assurance, but significant costs combined with few private benefits have resulted in low adoption rates. The main reason for the lack of benefits is that the end user (the consumer) does not value environmental assurance and is not willing to pay for it. For this reason, global food and fibre supply chains, which compete to supply consumers with safe and quality food at the lowest price, resist public pressure to implement environmental assurance. This market failure is further exacerbated by highly variable environmental and social production standards required of primary producers in different countries, and the disparate levels of government support provided to them. Given that it is the Australian general public and not markets that demand environmental benefits from agriculture, the Australian government has a mandate to use public funds to counter this market failure. A national farm environmental policy should utilise a range of financial incentives to reward farmers for delivering general public good environmental outcomes, with these specified and verified through a national environmental assurance scheme.
 
(a) No-till cotton planting, Five Points, CA, 2005; (b) ridge-tillage planting into herbicide-killed barley, Five Points, CA, 2002; (c) strip-tillage corn planting following wheat forage harvest, Tipton, CA, 2005; and (d) CT2004 Conference farm field day at the farm of Andy Rollin, Burrel, CA (9 September 2004).  
Responses of Central Valley farmers polled in a 2002 mail survey, when asked about their familiarity with conservation tillage. Data represent information from 57 respondents.
Responses of Central Valley farmers polled in a 2002 mail survey, when asked to indicate obstacles to broaden adoption of conservation tillage. Data represent information from 105 respondents.
Responses of Central Valley farmers polled in 2002 mail survey when asked (a) about the potential of conservation tillage (63 respondents) and (b) whether they see benefits of conservation tillage with their crops or in their region (56 respondents).  
Locations of Conservation Tillage Workgroup's corn, cotton, tomato and small grain forage research and demonstration evaluation sites (2000–2005).  
While there have been several similarities between the development of cropping systems in Australia and California ( including climate, the need for irrigation and very diverse, highly specialised crop rotations), the historical patterns of conservation tillage development in the two regions have been quite different. Current estimates indicate that conservation tillage ( CT) practices are used on less than 2% of annual crop acreage in California's Central Valley. Tillage management systems have changed relatively little since irrigation and cropping intensification began throughout this region, more than 60 years ago. The University of California ( UC) and United States Department of Agriculture ( USDA) Natural Resource Conservation Service ( NRCS) CT Workgroup is a diverse group of UC, NRCS, farmer, private sector, environmental group and other public agency people. It has provided wide- ranging services aimed at developing information on reduced tillage alternatives for California's production valleys. In a short span of 7 years, the CT Workgroup has grown to over 1000 members and has conducted over 60 demonstration evaluations of CT systems. While CT is still quite new in California, a growing number of farmers has become increasingly interested in it, for both economic and environmental reasons. They are now pursuing a wide range of activities and approaches aimed at developing sustainable CT systems. As successful CT systems continue to be demonstrated, the rate of adoption is expected to increase.
 
Feed intake, liveweight gain, inanition and agonistic behaviour of goats lot fed in enriched and typical pens 
By reducing the stress associated with high stocking density in a feedlot it is likely that goats will utilise their feed more efficiently and suffer fewer health problems. One possible method of reducing stress is to enrich the feedlot environment. In a feedlot of 160 castrated goats (average weight 24.6 +/- 2.6 kg), 2 types of feedlot structures were compared; a typical feedlot and an 'environmentally enriched' feedlot, and goats stocked at 2 densities; a high stocking density (1667 goats/ha) and a relatively low stocking density (897 goats/ha). Over a 42-day period, environmental enrichment (old car/truck tyres and wooden railway sleepers to climb on and PVC piping to mouth and butt) increased weight gain by 83% (P = 0.04) and reduced the occurrence of inanition by 36%. Aggressive behaviour at the feed trough was reduced by 30% (P = 0.03) in pens of lower density when compared with pens of higher density. We conclude that lot feeding goats in environmentally enriched surroundings will increase feed conversion and reduce the number of non-eaters when compared with typically bare pen structures. Doubling in liveweight gain of goats within enriched feedlot surroundings when compared with typical structures shows promise as a cost effective, animal-welfare-orientated practice.
 
Lodscore plot of the LLPF (; lod = 4.93), STADH (■; lod = 3.54) and STC (; lod = 1.29) measures of meat tenderness on bovine chromosome 7.
Primers and probes for DNA microsatellites and single nucleotide polymorphisms
From a study of 3 large half-sib families of cattle, we describe linkage between DNA polymorphisms on bovine chromosome 7 and meat tenderness. Quantitative trait loci (QTL) for Longissimus lumborum peak force (LLPF) and Semitendonosis adhesion (STADH) were located to this map of DNA markers, which includes the calpastatin ( CAST) and lysyl oxidase (LOX) genes. The LLPF QTL has a maximum lodscore of 4.9 and allele substitution of approximately 0.80 of a phenotypic standard deviation, and the peak is located over the CAST gene. The STADH QTL has a maximum lodscore of 3.5 and an allele substitution of approximately 0.37 of a phenotypic standard deviation, and the peak is located over the LOX gene. This suggests 2 separate likelihood peaks on the chromosome. Further analyses of meat tenderness measures in the Longissimus lumborum, LLPF and LL compression (LLC), in which outlier individuals or kill groups are removed, demonstrate large shifts in the location of LLPF QTL, as well as confirming that there are indeed 2 QTL on bovine chromosome 7. We found that both QTL are reflected in both LLPF and LLC measurements, suggesting that both these components of tenderness, myofibrillar and connective tissue, are detected by both measurements in this muscle.
 
The effect of year plus overall mean for cane yield per hectare in the Tully mill area from 1988 to 1999. Vertical bars indicate ± s.e.  
Estimated commercial cane sugar values for the Tully mill area based on the effect of year, month of harvest and the interaction between year and month of harvest, and the overall mean. The average standard error was 0.35 and ranged from 0.32 to 0.47 units.  
The effect of the 17 most popular varieties of sugarcane plus the overall mean on commercial cane sugar in the Tully mill area from 1988 to 1999.
A comparison of calculated sugar yield (t/ha) derived from equation 3 with actual sugar yield (t/ha). Dashed line, actual v. predicted yield (r 2 = 0.80); solid line, 1:1 trend line.
The Tully Sugar Mill has collected information about sugarcane supplied for crushing from every block in the mill district from 1970 to 1999. Data from 1988 to 1999 were analysed to understand the extent of the variation in cane yield per hectare and commercial cane sugar in the Tully mill area. The key factors influencing the variation in cane yield and commercial cane sugar in this commercial environment were identified and the variance components computed using a restricted maximum likelihood methodology. Cane yield was predominantly influenced by the year in which it was harvested, the month when the crop was ratooned (month of harvest in the previous year) and the farm of origin. These variables were relatively more important than variety, age of crop or crop class (plant crop, first ratoon through to fourth or older ratoons) and fallowing practice (fallow or ploughout-replant). The month-of-ratooning effect was relatively stable from year-to-year. Commercial cane sugar was influenced by the year of harvest, the month of harvest and their interaction, in that the influence of the month of harvest varied from year to year. Variety and farm differences were also significant but accounted for a much lower portion of the variation in commercial cane sugar. An empirical model was constructed from the key factors that influenced commercial cane sugar and cane yield to quantify their combined influence on sugar yield (t/ha). This may be used to assist mill personnel to predict their activities more accurately, for example to calculate the impact of a late finish to the current harvest season on the following year's crop.
 
Effect of the experimental diet on methane production, intake, weight gain and the acetate to propionate ratio Values are the mean and standard error (s.e.) of three replicate measurements per animal (10 animals per treatment in Period I and five animals per treatment in Period II) for methane measurements and one replicate per animal for the rest of the parameters. CG, concentrate group; HG, hay group. *,
The aim of this experiment was to investigate whether different diets at weaning determine the microbial populations established in the rumen, together with its methanogenic capacity, and whether these differences are consistent over a longer time period. Twenty ewes with single lambs were used in two periods. Period I: 10 lambs had access only to grass hay whilst with the dam and for 8 weeks after weaning (group H). The other 10 lambs had free access to concentrate and grass hay whilst with the dam and were fed with a 60 : 40 mix of concentrate and grass hay for 8 weeks after weaning (group C). Eight weeks after weaning, methane emissions were measured in polycarbonate chambers over a 3-day period. After methane emission measurements, five lambs from each groupwere randomly selected and slaughtered and samples of rumen content collected for measuring rumen fermentation parameters and for microbial enumeration (total and cellulolytic bacteria and methanogenic archeaea) by most probable number. Period II: the remaining 10 lambs were grouped together and fed the same diet (grass and concentrate) for 4 months. After this period, all animals were fed concentrate and grass hay (60 : 40) for 2 weeks and introduced in to the chambers to measure methane emissions over a 3-day period. After measurements, they were slaughtered and rumen samples collected and analysed as in Period I. Lambs from group H produced more (P=0.04) methane than group C lambs (26.0 v. 22.5 L/kgDM intake) in Period I. Group H lambs also had less total bacteria (10.2×1010 v. 61.6×1010 cells; P=0.284) but more cellulolytic bacteria (40.6×109 v. 10.0 ×109 cells; P=0.098) and methanogenic archaea (37.1×109 v. 19.0×109 cells; P=0.113) than group C lambs in Period I. The acetate to propionate ratio tended to be higher (P=0.089) in group H lambs than in group C lambs (3.00 v. 2.35). In Period II, methane produced was not different (P>0.05) between the groups (26.6. v. 25.7 L/kgDM intake by group C and H lambs, respectively). Microbial numbers and fermentation parameters were also similar in samples collected from both experimental groups in Period II. Our results show that the differences observed as a result of providing different diets at weaning disappear in the long-term. It may be appropriate to study a wider range of dietary treatments to better understand the factors determining the microbial populations establishing in the rumen.
 
Long-term probability of exceeding a given aflatoxin risk index (%) at 15 Oct. (solid black line), 15 Nov. (solid grey line), 15 Dec. (dashed black line), and 15 Jan. (dashed grey line) sowings at (a) Kairi, (b) Emerald, (c) Gayndah and (d) Kingaroy in Queensland. 
(a) Long-term average rainfall and (b) ambient temperature during the reproductive stage and (c) stress index during the last 60 days of crop growth at Gayndah, Emerald, Kairi and Kingaroy in Queensland. 
Long-term probability of exceeding a given aflatoxin risk index in simulated sowings at Gayndah for a slow hybrid under an early sowing (solid black line), for a slow hybrid under a late sowing (dashed black line), for a quick hybrid under an early sowing (solid grey line) and for a quick hybrid under a late sowing (dashed grey line). 
(a) Long-term probability of exceeding a given aflatoxin risk index and (b) grain yield in simulated sowings at Gayndah, Queensland on 15 October under 2.5 plants/m 2 (black line) and 10 plants/m 2 (grey line) density. 
Aflatoxins are highly carcinogenic mycotoxins produced by two fungi, Aspergillus flavus and A. parasiticus, under specific moisture and temperature conditions before harvest and/or during storage of a wide range of crops including maize. Modelling of interactions between host plant and environment during the season can enable quantification of preharvest aflatoxin risk and its potential management. A model was developed to quantify climatic risks of aflatoxin contamination in maize using principles previously used for peanuts. The model outputs an aflatoxin risk index in response to seasonal temperature and soil moisture during the maize grain filling period using the APSIM's maize module. The model performed well in simulating climatic risk of aflatoxin contamination in maize as indicated by a significant R2 (P ? 0.01) between aflatoxin risk index and the measured aflatoxin B1 in crop samples, which was 0.69 for a range of rainfed Australian locations and 0.62 when irrigated locations were also included in the analysis. The model was further applied to determine probabilities of exceeding a given aflatoxin risk in four non-irrigated maize growing locations of Queensland using 106 years of historical climatic data. Locations with both dry and hot climates had a much higher probability of higher aflatoxin risk compared with locations having either dry or hot conditions alone. Scenario analysis suggested that under non-irrigated conditions the risk of aflatoxin contamination could be minimised by adjusting sowing time or selecting an appropriate hybrid to better match the grain filling period to coincide with lower temperature and water stress conditions.
 
Two groups of 108 Angus cross yearling heifers were utilised to determine the effects of growth-promoting agents on behaviour, when utilised under thermoneutral, hot and cold environmental conditions. Pens of heifers were observed throughout the day for feed intake pattern via bunk score, panting (hot), degree of bunching and shivering (cold). For cattle that were exposed to cold stress, feed intake was greater earlier in the day, with the majority of the feed consumed by 1500 hours and little or no feed consumed at night, while the opposite trend occurred under heat stress. Nearly 46% of the pens containing heat-stressed heifers had greater than 50% of their feed remaining in the bunk at 1900 hours. Pens of heifers exposed to thermoneutral conditions had a tendency to show elevated panting scores at 0700 hours, while heifers exposed to hot conditions did not, indicating some acclimation to heat stress had already taken place for the heifers exposed to hot conditions. Panting score did not appear to be affected by growth-promoting treatment. Under cold stress, 100% of the cattle displayed bunching behaviour throughout the day, while under hot and thermoneutral conditions, maximum bunching (25 to 30%) occurred at 1500 hours. Within an environmental condition, trenbolone acetate cattle tended to bunch more under thermoneutral and hot conditions, particularly in the morning, when compared with other treatment groups; control and oestrogen-treated cattle tended to bunch less under the same conditions, regardless of the time of day. Although data were inconclusive as to overall effects of growth promotants on mitigating cold stress, shivering scores were increased with a more aggressive growth-promoting treatment (P < 0.05). These findings suggest that if growth promotants, which are used in feedlot cattle, impact cattle exposed to adverse environmental conditions, then they tend to be more effective at mitigating heat stress than cold stress.
 
This paper reports on a purposive survey study which aimed to identify needs for the development, delivery and evaluation of applied climate education for targeted groups, to improve knowledge and skills to better manage under variable climatic conditions. The survey sample consisted of 80 producers and other industry stakeholders in Australia ( including representatives from consulting, agricultural extension and agricultural education sectors), with a 58% response rate to the survey. The survey included an assessment of (i) knowledge levels of the Southern Oscillation Index and sea surface temperatures, and (ii) skill and ability in interpreting weather and climate parameters. Results showed that despite many of the respondents having more than 20 years experience in their industry, the only formal climate education or training undertaken by most was a 1-day workshop. Over 80% of the applied climate skills listed in the survey were regarded by respondents as essential or important, but only 42% of educators, 30% of consultants and 28% of producers rated themselves as competent in applying such skills. Essential skills were deemed as those that would enable respondents or their clients to be better prepared for the next extended wet or dry meteorological event, and improved capability in identifying and capitalising on key decision points from climate information and a seasonal climate outlook. The complex issue of forecast accuracy is a confounding obstacle for many in the application of climate information and forecasts in management. Addressing this problem by describing forecast 'limitations and skill' can help to overcome this problem. The survey also highlighted specific climatic tactical and strategic information collated from grazing, cropping and agribusiness enterprises, and showed the value of such information from a users perspective.
 
Australian wool and meat supply chain companies interviewed
Industry, environmental and consumer organisations interviewed
Requirements of industry, consumer and environmental groups for agricultural environmental assurance QA, quality assurance
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.
 
A circulated heated-air treatment at 92% RH to achieve and maintain a minimum fruit core temperature of 44°C for 2 h is shown to disinfest tomatoes against Queensland fruit fly, Bactrocera tryoni (Froggatt) for market access quarantine purposes. The efficacy of the treatment exceeded 99.99%, tested at the 95% confidence level. An estimated 78 439 eggs were used for large-scale trials, as the stage of the pest most tolerant of heat at the treatment temperature.
 
Conventional pesticide spraying in citrus crops with low-profile sprayers results in pest management problems because of the poor distribution of pesticide throughout the tree. Pesticide losses, particularly drift, are a concern with this type of sprayer especially in orchards situated in or near urban areas. The spray deposit on citrus leaves and fruit and off-target losses (canopy run-off and drift) were determined for air-assisted low-profile sprayers and air-assisted sprayers fitted with tower air conveyors (air-towers). The air-tower sprayers produced even distribution of leaf spray deposits through the full height of the tree canopy while the low-profile sprayers produced decreasing leaf spray deposits with increasing height in the trees. The Metters tower sprayer and Cropliner low-profile sprayer resulted in increasing deposits from the 0 degrees axis through to the 90 degrees axis to sprayer travel while the Barlow tower sprayer and the Hardi low-profile sprayer produced a more even distribution of deposits through the axes to sprayer travel. Fruit deposits were not significantly different between sprayers. The Barlow tower sprayer produced significantly less canopy spray run-off compared with the low-profile sprayers. The Barlow tower sprayer resulted in a significant reduction in spray drift in the above tree zone compared with the Hardi low-profile sprayer. Better distribution of pesticides in citrus tree canopies will improve pest control especially in the top sections of the tree as this is where the greatest increase in pesticide deposit is achieved with air-tower sprayers. Both ground and air contamination from pesticides can also be reduced by using sprayers fitted with air-tower conveyors designed to produce even airflows for the full height of the citrus trees being sprayed.
 
Dairy farms in subtropical Australia use irrigated, annually sown short-term ryegrass (Lolium multiflorum) or mixtures of short-term ryegrass and white (Trifolium repens) and Persian (shaftal) (T. resupinatum) clover during the winter-spring period in all-year-round milk production systems. A series of small plot cutting experiments was conducted in 3 dairying regions (tropical upland, north Queensland, and subtropical southeast Queensland and northern New South Wales) to determine the most effective rate and frequency of application of nitrogen (N) fertiliser. The experiments were not grazed, nor was harvested material returned to the plots, after sampling. Rates up to 100 kg N/ha.month (as urea or calcium ammonium nitrate) and up to 200 kg N/ha every 2 months (as urea) were applied to pure stands of ryegrass in 1991. In 1993 and 1994, urea, at rates up to 150 kg N/ha.month and to 200 kg N/ha every 2 months, was applied to pure stands of ryegrass; urea, at rates up to 50 kg N/ha.month, was also applied to ryegrass-clover mixtures. The results indicate that applications of 50-85 kg N/ha.month can be recommended for short-term ryegrass pastures throughout the subtropics and tropical uplands of eastern Australia, irrespective of soil type. At this rate, dry matter yields will reach about 90% of their potential, forage nitrogen concentration will be increased, there is minimal risk to stock from nitrate poisoning and there will be no substantial increase in soil N. The rate of N for ryegrass-clover pastures is slightly higher than for pure ryegrass but, at these rates, the clover component will be suppressed. However, increased ryegrass yields and higher forage nitrogen concentrations will compensate for the reduced clover component. At application rates up to 100 kg N/ha.month, build-up of NO3--N and NH4+-N in soil was generally restricted to the surface layers (0-20 cm) of the soil, but there was a substantial increase throughout the soil profile at 150 kg N/ha.month. The build-up of NO3--N and NH4+-N was greater and was found at lower rates on the lighter soil compared with heavy clays. Generally, most of the soil N was in the NO3--N form and most was in the top 20 cm.
 
Heritability estimates for wrinkle score 
A genetic solution to breech strike control is attractive, as it is potentially permanent, cumulative, would not involve increased use of chemicals and may ultimately reduce labour inputs. There appears to be significant opportunity to reduce the susceptibility of Merinos to breech strike by genetic means although it is unlikely that in the short term breeding alone will be able to confer the degree of protection provided by mulesing and tail docking. Breeding programmes that aim to replace surgical techniques of flystrike prevention could potentially: reduce breech wrinkle; increase the area of bare skin in the perineal area; reduce tail length and wool cover on and near the tail; increase shedding of breech wool; reduce susceptibility to internal parasites and diarrhoea; and increase immunological resistance to flystrike. The likely effectiveness of these approaches is reviewed and assessed here. Any breeding programme that seeks to replace surgical mulesing and tail docking will need to make sheep sufficiently resistant that the increased requirement for other strike management procedures remains within practically acceptable bounds and that levels of strike can be contained to ethically acceptable levels.
 
Glasshouse trials were conducted to examine the effect of lime or gypsum amendments on the development of cavity spot disease of carrots in soil artificially infested with Pythium coloratum. Each amendment was applied to soil from the field at 4000 or 8000 kg/ha. Lime at both application rates significantly (P<0.05) reduced the incidence of the disease. In contrast, both gypsum treatments had no effect on the incidence of cavity spot disease. There was no significant (P>0.05) difference in calcium concentration between carrot roots grown in unamended, lime- or gypsum-amended soil with or without the pathogen. Calcium did not appear to play a direct role in the reduction of cavity spot disease. Under the controlled conditions of this glasshouse trial, reduction in the incidence of cavity spot appeared to be related to the increase in soil pH associated with the application of lime. Field trials at the site of soil collection will confirm whether this mechanism is related to field reduction of the disease following liming.
 
Biogenic amines were determined in Australian by-product meals including fish meals, poultry meals, meat meals, feather meals and blood meals. They were extracted with 0.1 mol/L HCl, derivatised with dansyl chloride and analysed using HPLC with UV detection at 254 nm. Median levels of putrescine, cadaverine and histamine were determined in the by-product meals, with the ranges being 13-102 mg/kg, 7-220 mg/kg and 4-570 mg/kg, respectively. High levels of biogenic amines were found particularly in fish meals. The results indicate that further studies are required to determine the maximum limits for biogenic amines in by-product meals that will not impair production when fed to poultry.
 
Diseases and insect pests are major causes of low yields of common bean (Phaseolus vulgaris L.) in Latin America and Africa. Anthracnose, angular leaf spot and common bacterial blight are widespread foliar diseases of common bean that also infect pods and seeds. One thousand and eighty-two accessions from a common bean core collection from the primary centres of origin were investigated for reaction to these three diseases. Angular leaf spot and common bacterial blight were evaluated in the field at Santander de Quilichao, Colombia, and anthracnose was evaluated in a screenhouse in Popayan, Colombia. By using the 15-group level from a hierarchical clustering procedure, it was found that 7 groups were formed with mainly Andean common bean accessions (Andean gene pool), 7 groups with mainly Middle American accessions (Middle American gene pool), while 1 group contained mixed accessions. Consistent with the theory of co-evolution, it was generally observed that accessions from the Andean gene pool were resistant to Middle American pathogen isolates causing anthracnoxe, while the Middle American accessions were resistant to pathogen isolates from the Andes. Different combinations of resistance patterns were found, and breeders can use this information to select a specific group of accessions on the basis of their need.
 
This paper is a foreword to a series of papers commissioned on 'the impact of science on the beef industry', where the Beef CRC-related collaborative scientific work of Professor Bernard Michael Bindon will be reviewed. These papers will be presented in March 2006, as part of a 'festschrift' to recognise his wider contributions to the Australian livestock industries for over 40 years. Bindon's career involved basic and applied research in many areas of reproductive physiology, genetics, immunology, nutrition, meat science and more recently genomics, in both sheep and cattle. Together with his collaborators, he made large contributions to animal science by improving the knowledge of mechanisms regulating reproductive functions and in elucidating the physiology and genetics of high fecundity livestock. His collaborative studies with many colleagues of the reproductive biology and genetics of the Booroola Merino were amongst the most extensive ever conducted on domestic livestock. He was instrumental in the development of immunological techniques to control ovulation rate and in examining the application of these and other techniques to increase beef cattle reproductive output. This paper tracks his investigations and achievements both within Australia and internationally. In the later stages of his career he was the major influence in attracting a large investment in Cooperative Research Centres for the Australian cattle industry, in which he directed a multi-disciplinary approach to investigate, develop and disseminate science and technology to improve commercial cattle productivity.
 
Experiment 1. The average amount (kg) of chaff eaten by goats from the control trough or the trough protected by 1 of 5 repellents (treated) for each day, and the average intake over the 3 days
Experiment 2. Summary of the goat feeding behaviour at the feed troughs containing tiger fecal repellents and their behaviour within 4 m of this protected trough
Under some circumstances it may be desirable to repel herbivorous pests (e. g. goats and wallabies) from plants (e. g. horticultural or forestry seedlings) rather than to kill them. These circumstances may include using these animals as a resource at a later time, and there may also be welfare, public perception or legislative issues where repelling animals from particular plants or area is preferable to killing them. The first experiment tested the efficacy of 5 different materials (tiger fecal extract, maggot brew-the liquid exudate from a flyblown goat, capsaicin, dog urine, and burnt goat hair, skin and carcass+fat) to repel groups of goats in a feedlot pen from 1 trough of feed when another trough of feed was available to them to eat. Each repellent was tested on 5 groups of mixed age female goats for periods of 3 days. All 5 groups were exposed to the 5 repellents. Both tiger fecal extract and maggot brew reduced intake of feed from the 'protected' feed trough and significantly (P < 0.05) delayed 'normal' feeding behaviour by more than 5 h from that trough. The repellents became less effective with repeated use even with different groups of goats. The reduction in effectiveness was indicated by higher intakes of feed and earlier feeding from the protected trough. This habituation to the repellents, where the effectiveness is reduced with repeated exposure, is of concern. In the second experiment, we selected the most effective repellent (tiger fecal extract) and tested its efficacy under similar conditions, after the repellent had been mixed with a carrier (bentonite) in an endeavour to increase the duration of its effectiveness. This repellent was significantly more effective in repelling groups of 3 goats in a feedlot pen from 1 trough of feed for 3 days, when another trough of feed was available to them to eat.
 
Conceptual diagram showing the result of increasing N input (left-hand side); increasing forage production, animal production, emissions of CH 4 , NH 3 and N 2 O, and (possibly) C sequestration in soils.  
Animal production systems are large and complex sources of greenhouse gases (GHG), especially nitrous oxide (N2O) and methane (CH4). Emissions from these systems are expected to rise over the coming decades due to the increasing global population and shifting diets, unless appropriate mitigation strategies are implemented. In this paper, we argue that the main constraints for such implementation are: (i) the complex and often poorly understood controls of GHG sources in animal production systems; (ii) the lack of knowledge on the economic and social costs involved in implementing mitigation strategies; and (iii) the strong political emphasis on mitigating nitrate leaching and ammonia volatilisation, rather than GHG emissions. We further argue that overcoming these three constraints can only be achieved by initiating integrated mitigation strategies, based on modelling and experimental work at three scales. At the `laboratory and field scale¿, basic causal relationships with respect to processes of GHG formation and other detrimental fluxes need to be experimentally established and modelled. As management options are considered at the `farm scale¿, this is the ideal scale to evaluate the cost-effectiveness, feasibility and possible pollution swapping effects of mitigation measures. Finally, at the `national and supra-national scales¿, environmental legislation is implemented, effectiveness of environmental policies and emissions abatement measures are being monitored, and the social costs of various scenarios are being weighed. We illustrate the need for integral measures and working across different scales using our own work on the relationship between nitrogen surplus and fluxes to the environment. At the field scale, a clear positive relation between nitrogen surplus and N2O emission, NO3¿ leaching and NH3 volatilisation was experimentally established. At the farm scale, the model DAIRYWISE was used to evaluate effects of minimising nitrogen surplus on the nutrient flow and economic viability of an average Dutch dairy farm. Even after including trade-off effects of CH4 emissions from cattle and manure storage, there was still a clear positive relationship between farm gate nitrogen surplus and GHG emission. At this scale, the prime issue was balancing environmental gains with economic viability. Finally, at the `national and supra-national scale¿ we developed the MITERRA-EUROPE model, and used it to quantify the effects on GHG emissions of environmental policies aimed at reducing NO3¿ leaching and NH3 volatilisation in the 27 Member States of the European Union (EU-27). This showed the intricate relationship between different environmental goals, with both positive feedback (balanced fertilisation reduced both NO3¿ leaching and N2O emission) and negative feedback (`low-emission¿ manure application reduced NH3 volatilisation but increased N2O emission) possible. At this scale, there is a clear need for an integral approach towards reducing environmental assessment to the environment. Our studies so far suggest that `balanced fertilisation¿ is among the most promising mitigation measures for simultaneously lowering N2O emission, NO3¿ leaching and NH3 volatilisation, without pollution swapping to CH4 emission
 
Diseases of temperate annual pasture legumes in subtropical southern Queensland were surveyed during 1992 and 1993. The following pathogenic organisms were recorded: Colletotrichum trifolii, Stemphylium vesicarium, Oidium sp., Uromyces anthyllidis, Uromyces striatus and Pseudopeziza medicaginis from annual Medicago spp.; Rhizoctonia solani and Colletotrichum destructivum from Ornithopus spp.; and Oidium sp. from Trifolium subterraneum. Three of these disease interactions had not been previously recorded in Queensland and 5 were new reports for Australia. Rust was the most frequently observed and widespread disease on annual medics (44% of M. polymorpha samples). All other diseases of annual medics were found infrequently (2-18% of samples). In contrast, both serradella and subterranean clover were relatively free from any diseases. The years during which the survey was conducted were dry (as low as 31% of mean March-October rainfall) and the expression of disease may have been restricted. Nevertheless, this improved knowledge of diseases of temperate annual legumes in southern Queensland will assist in the future selection and breeding of suitable cultivars for use in the subtropics.
 
This study investigated treatment of mango (Mangifera indica L.) fruit with 2 host defence-promoting compounds for suppression of anthracnose disease (Colletotrichum gloeosporioides). Cultivar 'Kensington Pride' fruit were treated at concentrations of up to 1000 mg/L with either potassium phosphonate or salicylic acid. Applications were by various combinations of pre- and postharvest dips and vacuum infiltration. Postharvest treatments at up to 2000 mg/L salicylic acid were evaluated in a second fruiting season. Fruit were either uninoculated or inoculated with the fungal pathogen. Colour, firmness and disease-severity were assessed during shelf life at 23 degreesC. There were no significant (P>0.05) effects of potassium phosphonate or salicylic acid on anthracnose disease severity in the first season. Moreover, phosphonate or salicylic acid treatment did not significantly affect fruit colour or firmness changes. There were significant (P<0.05) reductions in anthracnose severity in the second season, especially at the highest concentration of 2000 mg/L salicylic acid. Mango fruit skin colour and firmness changes were also slowed down significantly (P<0.05). These effects of salicylic acid were attributed to inhibition of mango fruit skin ripening (senescence).
 
Aphids can cause substantial damage to cereals, oilseeds and legumes through direct feeding and through the transmission of plant pathogenic viruses. Aphid-resistant varieties are only available for a limited number of crops. In Australia, growers often use prophylactic sprays to control aphids, but this strategy can lead to non-target effects and the development of insecticide resistance. Insecticide resistance is a problem in one aphid pest of Australian grains in Australia, the green peach aphid (Myzus persicae). Molecular analyses of field-collected samples demonstrate that amplified E4 esterase resistance to organophosphate insecticides is widespread in Australian grains across Australia. Knockdown resistance to pyrethroids is less abundant, but has an increased frequency in areas with known frequent use of these insecticides. Modified acetylcholinesterase resistance to dimethyl carbamates, such as pirimicarb, has not been found in Australia, nor has resistance to imidacloprid. Australian grain growers should consider control options that are less likely to promote insecticide resistance, and have reduced impacts on natural enemies. Research is ongoing in Australia and overseas to provide new strategies for aphid management in the future.
 
The potential for the ethylene binding inhibitor, 1-methylcyclopropene, to delay ripening of 'Hass' avocado, 'African Pride' custard apple, 'Kensington Pride' mango and 'Solo' papaya was examined. Fruit were gassed with 25 muL/L 1-methylcyclopropene for 14 h at 20 degreesC, followed by treatment with 100 muL/L ethylene for 24 h, and then ripened at 20 degreesC. Ethylene treatment alone generally halved the number of days for fruit to reach the ripe stage, compared with untreated fruit. 1-Methylcyclopropene treatment alone increased the number of days to ripening by 4.4 days (40% increase), 3.4 days (58%), 5.1 days (37%) and 15.6 days (325%) for avocado, custard apple, mango and papaya, respectively, compared with untreated fruit. Applying 1-methylcyclopropene to the fruit before ethylene prevented the accelerated ripening normally associated with ethylene treatment, so that the number of days to ripening for fruit treated with 1-methylcyclopropene plus ethylene was similar to the number of days to ripening for fruit treated with 1-methylcyclopropene alone. 1-Methylcyclopropene treatment was associated with slightly higher severity of external blemishes in papaya and custard apple, slightly higher rots severity in avocado, custard apple and papaya, and at least double the severity of stem rots in mango, relative to fruit not treated with 1-methylcyclopropene. Thus, 1-methylcyclopropene treatment has the potential to reduce the risk of premature ripening of avocado, custard apple, mango and papaya fruit due to accidental exposure to ethylene. However, additional precautions may be necessary to reduce disease severity associated with 1-methylcyclopropene treatment.
 
Over the past 200 years agriculture has expanded throughout Australia. The culmination of clearing and cultivating land at the farm scale has resulted in highly modified landscapes and a perceived loss of ecosystem services from pest control and pollination. We examine the literature: (i) to identify the appropriate spatial scale for managing pests, natural enemies and pollinators; and (ii) for evidence that farm-scale changes (due to agricultural intensification) across a landscape have resulted in a tipping point favouring pests and hindering pollinators. Although there is limited information to draw firm conclusions, the evidence suggests that actions undertaken on individual farms have an impact both on their neighbours and regionally, and that the culmination of these actions can lead to changes in population dynamics of pests, natural enemies and pollinators. For major pest species, there is reasonable evidence that grain growers may benefit from improved management and higher yields by implementing area-wide pest management strategies on a landscape scale in collaboration with growers of other crops that also share these pests. As yet, for natural enemies and pollinators there is little direct evidence that similar area-wide initiatives will have a greater effect than management strategies aimed at the field and farm level. Managing pests, natural enemies and pollinators beyond the scale of the field or farm is technically and socially challenging and will required a well defined research agenda, as well as compromise, balance and trading among stakeholders. We highlight critical knowledge gaps and suggest approaches for designing and managing landscapes for ecosystem services.
 
Dynamics of measured and APSIM-soiltemp simulated soil temperatures, ambient temperature, leaf area index and available soil water in four typical peanut farms in the South Burnett during the 2001–05 seasons. 
Agronomic details of different on-farm trials conducted in Kingaroy and Coalstoun Lakes regions from 2001 to 2005
Linear relationships between measured and APSIM-soiltemp simulated soil temperatures from 30 days (or later in some trials) after sowing for 10 farms in the 2001-02 season, 16 farms in 2002-03 season, five farms in 2003-04 season and four farms in 2004-05 season. The solid line represents the regression line and the dotted line represents the slope line.
Measurement or accurate simulation of soil temperature is important for improved understanding and management of peanuts (Arachis hypogaea L.), due to their geocarpic habit. A module of the Agricultural Production Systems Simulator Model (APSIM), APSIM-soiltemp, which uses input of ambient temperature, rainfall and solar radiation in conjunction with other APSIM modules, was evaluated for its ability to simulate surface 5 cm soil temperature in 35 peanut on-farm trials conducted between 2001 and 2005 in the Burnett region (25°36'S to 26°41'S, 151°39'E to 151°53'E). Soil temperature simulated by the APSIM-soiltemp module, from 30 days after sowing until maturity, closely matched the measured values (R2 ≥ 0.80)in the first three seasons (2001-04). However, a slightly poorer relationship (R2 = 0.55) between the observed and the simulated temperatures was observed in 2004-05, when the crop was severely water stressed. Nevertheless, over all the four seasons, which were characterised by a range of ambient temperature, leaf area index, radiation and soil water, each of which was found to have significant effects on soil temperature, a close 1:1 relationship (R2 = 0.85) between measured and simulated soil temperatures was observed. Therefore, the pod zone soil temperature simulated by the module can be generally relied on in place of measured input of soil temperature in APSIM applications, such as quantifying climatic risk of aflatoxin accumulation.
 
APSIM-ORYZA is a new functionality developed in the APSIM framework to simulate rice production while addressing management issues such as fertilisation and transplanting, which are particularly important in Korean agriculture. To validate the model for Korean rice varieties and field conditions, the measured yields and flowering times from three field experiments conducted by the Gyeonggi Agricultural Research and Extension Services (GARES) in Korea were compared against the simulated outputs for different management practices and rice varieties. Simulated yields of early-, mid- and mid-to-late-maturing varieties of rice grown in a continuous rice cropping system from 1997 to 2004 showed close agreement with the measured data. Similar results were also found for yields simulated under seven levels of nitrogen application. When different transplanting times were modelled, simulated flowering times ranged from within 3 days of the measured values for the early-maturing varieties, to up to 9 days after the measured dates for the mid- and especially mid-to-late-maturing varieties. This was associated with highly variable simulated yields which correlated poorly with the measured data. This suggests the need to accurately calibrate the photoperiod sensitivity parameters of the model for the photoperiod-sensitive rice varieties in Korea.
 
The Darling Downs and Southern Inland Burnett are important geographical subregions of the Queensland dairy industry. The system of dairy farming in these subregions is unique in Australia in that it is based on grazed annual forage crops rather than pastures. When these soils were first cultivated up to 110 years ago they were inherently fertile. However, erosion and fertility decline has reduced their productive capacity and there is a need for the adoption of farming practices that are less exploitative. In February 1997, a survey was conducted to determine dairy farmers' practices and attitudes toward management strategies that were being recommended to grain farmers in the subtropical cereal belt for sustaining the soil resource base. These strategies included greater use of ley pastures, opportunistic double-cropping, zero-till planting and higher fertiliser inputs. We found that dairy farmers were generally familiar with and understanding of the potential benefits of these approaches to their farming enterprises. However, farmers raised a number of issues that need consideration in the transfer of these practices to dairy forage production. These included concerns that an increased emphasis on pastures would result in lower and less-reliable forage production; that double-cropping is practiced more out of necessity than in the belief it is a better way to farm; that zero tillage may not be suitable on clay soils that have been trampled by cattle and that farmers rely primarily on their own observations of crop performance to determine fertiliser use. These findings have particular implications for research and extension activities conducted with dairy farmers and are also relevant to work conducted with other cropping enterprises that incorporate grazing animals in their farming program.
 
Two field experiments using maize (Pioneer 31H50) and three watering regimes [(i) irrigated for the whole crop cycle, until anthesis, (ii) not at all (experiment 1) and (iii) fully irrigated and rain grown for the whole crop cycle (experiment 2)] were conducted at Gatton, Australia, during the 2003–04 season. Data on crop ontogeny, leaf, sheath and internode lengths and leaf width, and senescence were collected at 1- to 3-day intervals. A glasshouse experiment during 2003 quantified the responses of leaf shape and leaf presentation to various levels of water stress. Data from experiment 1 were used to modify and parameterise an architectural model of maize (ADEL-Maize) to incorporate the impact of water stress on maize canopy characteristics. The modified model produced accurate fitted values for experiment 1 for final leaf area and plant height, but values during development for leaf area were lower than observed data. Crop duration was reasonably well fitted and differences between the fully irrigated and rain-grown crops were accurately predicted. Final representations of maize crop canopies were realistic. Possible explanations for low values of leaf area are provided. The model requires further development using data from the glasshouse study and before being validated using data from experiment 2 and other independent data. It will then be used to extend functionality in architectural models of maize. With further research and development, the model should be particularly useful in examining the response of maize production to water stress including improved prediction of total biomass and grain yield. This will facilitate improved simulation of plant growth and development processes allowing investigation of genotype by environment interactions under conditions of suboptimal water supply.
 
Helicoverpa armigera is a serious insect pest of sweet corn in Australia and is becoming increasingly difficult to manage with conventional chemical insecticides due to resistance problems. A number of alternative H. armigera control options were evaluated in sweet corn and compared with deltamethrin and no action (control). The alternative tactics evaluated were: heliothis nuclear polyhedrosis virus plus Trichogramma nr. brassicae releases; Bacillus thuringiensis; and Trichogramma alone. The H. tea nuclear polyhedrosis virus + Trichogramma plots had the lowest cob damage (6.0%), followed by the B. thuringiensis plots (12.0%), Trichogramma alone plots (20.2%), control plots (23.2%) and deltamethrin plots (53.5%). There was no evidence to suggest that the Trichogramma nr. brassicae releases had any impact on H. armigera egg mortality. However, there was a large natural population of Trichogramma pretiosum in all plots. The application of deltamethrin reduced the action of these wasps and predators, resulting in higher larval infestation and significantly more cob damage. The findings indicate that the pathogens heliothis nuclear polyhedrosis virus and B. thuringiensis can effectively control H. armigera when their action complements high natural levels of egg parasitism, and that they have potential for use in integrated pest management programs in sweet corn.
 
Fifty Bos indicus steers, 2–3 years old, were exposed to aspects of a feedlot environment on their home property for 9 days (pre-exposed). A further 50 steers were placed in a holding paddock for the 9 days (naïve). Twenty steers in each group became 'focal animals' for periodic blood sampling and behaviour observations. The cattle were transported for 15 h (950 km) to an experimental feedlot where they were lot-fed for 100 days, with productivity (liveweight, body condition and feed intakes) and flight speeds recorded at intervals. A subjective fear of humans test was conducted on the pre-exposed group during the 9 days in the yards on the home property and carcass traits were measured on all cattle. Both groups lost substantial weight on the property and during transportation. On the property, the pre-exposed steers lost about 12% of their original liveweight and the naïve about 9%. Transit losses were a further 5 and 4% of pre-transport liveweights, respectively. The steers did not reach their initial liveweights until day 41 of feedlotting. The pre-exposure treatment did not affect final liveweight, but feed intakes were lower for the pre-exposed animals than the naïve ones during the first 16 days of feedlotting, and the pre-exposed steers had superior average daily gains and feed conversion efficiencies. These effects were probably due to a combination of compensation and improved feed digestibility, as a result of the pre-exposed animals being under-fed on the property, but receiving concentrated grain supplement. There was no effect of focal status on productivity. Flight speed and the subjective fear of humans test were significantly correlated. Neither treatment nor focal status affected flight speeds, but flight speeds decreased in the latter part of feedlotting, were highly correlated between days and negatively correlated with average daily gain and intakes.
 
Fusarium wilt, caused by Fusarium oxysporum f. sp. vasinfectum, is a new and important disease of cotton in Australia. Some factors affecting either the infection process or the subsequent development of symptoms under glasshouse conditions were examined in this study. The pathogenicity of inocula was significantly affected by the media in which they were produced. The most severe symptoms developed in the plants inoculated with the inoculum produced in Komada-Ezuka liquid medium, in which glucose and L-asparagine were used as the carbon and nitrogen source, respectively. Symptoms were significantly more severe in plants inoculated with the inocula suspended in culture filtrates than in those inoculated with the inocula suspended in distilled water, indicating that fungal metabolites played an important role in the infection process. The disease was enhanced by high conidial concentration (>1.0 x 10(6) conidia/mL), slightly acidic inoculum (pH 4.0-5.5) and longer inoculation period (5-25 min). One-week-old seedlings were most susceptible, regardless of cultivar, and the resistance of plants increased with their age. The development of symptoms was enhanced at a moderate temperature range (18-23 degrees C), but suppressed at a higher temperature range (28-33 degrees C). Based on these results, an optimised procedure of pathogenicity assay is described.
 
Top-cited authors
Frank Vanclay
  • University of Groningen
David J. Pannell
  • University of Western Australia
David L Hopkins
  • Formerly New South Wales Department of Primary Industries, Cowra
Tim A Mcallister
  • Agriculture and Agri-Food Canada, Canada, Lethbridge
David William Pethick
  • Murdoch University