ORCID Profile
0000-0002-4152-7699
Current Organisations
University of Western Australia
,
CSIRO Adelaide
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Publisher: Springer Science and Business Media LLC
Date: 11-03-2020
Publisher: Elsevier BV
Date: 06-2021
Publisher: CSIRO Publishing
Date: 2020
DOI: 10.1071/SR19161
Abstract: Sandy soils make up a substantial fraction of cropping land in low rainfall (& mm p.a.) south and south-eastern Australia. In this paper we review the possible soil constraints to increased production on these soils in this region. Many of these soils have a very low (& %) clay content and suffer from severe water repellency, making crop establishment and weed control problematic. Crops which do emerge are faced with uneven soil wetting and poor access to nutrients, with crop nutrition constraints exacerbated by low fertility (soil organic matter & 1%) and low cation exchange capacity. Zones of high penetration resistance appear common and have multiple causes (natural settling, cementation and traffic induced) which restrict root growth to & cm. Crop water use and grain yield are therefore likely to be well below the water-limited potential. Water repellency is readily diagnosed and where apparent should be the primary management target. Repellency can be mitigated through the use of furrow and other sowing technologies, along with soil wetting agents. These techniques appear to be affected by site and soil nuances and need to be refined for local soils and conditions. Once crop establishment on water repellent soils has been optimised, attention could be turned to opportunities for improving crop rooting depth through the use of deep tillage or deep ripping techniques. The required ripping depth, and how long the effects may last, are unclear and need further research, as do the most effective and efficient machinery requirements to achieve sustained deeper root growth. Crop nutrition matched to the water-limited crop yield potential is the third pillar of crop production that needs to be addressed. Low soil organic matter, low cation exchange capacity, low biological activity and limited nutrient cycling perhaps make this a greater challenge than in higher rainfall regions with finer textured soils. Interactions between nutrients in soils and fertilisers are likely to occur and make nutrient management more difficult. While amelioration (elimination) of water repellency is possible through the addition of clay to the soil surface, the opportunities for this may be restricted to the ~30% of the sandy soils of the region where clay is readily at hand. The amounts of clay required to eliminate repellency (~5%) are insufficient to significantly improve soil fertility or soil water holding capacity. More revolutionary soil amelioration treatments, involving additions and incorporation of clay and organic matter to soils offer the possibility of a more elevated crop yield plateau. Considerable research would be required to provide predictive capacity with respect to where and when these practices are effective.
Publisher: Elsevier BV
Date: 06-2012
Publisher: No publisher found
Date: 2018
Publisher: CSIRO Publishing
Date: 2014
DOI: 10.1071/CP13413
Abstract: Plantings of forage shrubs such as saltbush (Atriplex spp.) in the drier part of the crop–livestock zone of southern Australia have the potential to help fill feed autumn gaps, provide valuable feed during drought periods, and provide year-round groundcover, shelter for livestock and options for management of saline soils. However, the proportion of farms with forage shrub plantings and the extent of those plantings remain relatively low, with the rate of new plantings slowing over the past decade. Development of new forage-shrub options has been occurring with the aim of improving the feed value and adoption of forage shrubs. Using a whole-farm bio-economic optimisation model for a crop–livestock farming system in the low-rainfall Mallee region of southern Australia (Mallee MIDAS—model of an integrated dryland agricultural system), we explored how key attributes of forage-shrub plantings and the associated pasture understorey, such as biomass growth, digestibility and ease of establishment, can make forage shrub plantings economically more attractive to farmers. We found that saltbush types and forage-shrub options with improved feed quality characteristics will offer the opportunity for improved economic returns and increased profitability from larger plantings compared with existing options. Improving feed quality was more important than increasing the growth rates of saltbush plants. Results still indicate only a niche role in farming systems, with profit typically being greatest when using relatively small areas ( % of farm area) on the less productive soils of the farm. The results suggest that the profitability of forage shrubs will be greatest for those growers with larger areas of marginal cropping soils and greater reliance on livestock than cropping. Furthermore, the results demonstrate that, if cereal prices or yields fall significantly and/or lamb prices rise, the value of a forage shrub planting can increase substantially. The principles revealed have wide application beyond the region, although these need to be adapted on-farm and widely disseminated before potential contribution to Australian agriculture can be realised.
Publisher: CSIRO Publishing
Date: 2014
DOI: 10.1071/CP14109
Abstract: Non-symbiotic nitrogen (N2) fixation by diazotrophic bacteria is a potential source for biological N inputs in non-leguminous crops and pastures. Perennial grasses generally add larger quantities of above- and belowground plant residues to soil, and so can support higher levels of soil biological activity than annual crops. In this study, the hypothesis is tested that summer-active perennial grasses can provide suitable microsites with the required carbon supply for N2 fixation by diazotrophs, in particular during summer, through their rhizosphere contribution. In a field experiment on a Calcarosol at Karoonda, South Australia, during summer 2011, we measured populations of N2-fixing bacteria by nifH-PCR quantification and the amount of 15N2 fixed in the rhizosphere and roots of summer-active perennial grasses. Diazotrophic N2 fixation estimates for the grass roots ranged between 0.92 and 2.35 mg 15N kg–1 root day–1. Potential rates of N2 fixation for the rhizosphere soils were 0.84–1.4 mg 15N kg–1 soil day–1 whereas the amount of N2 fixation in the bulk soil was 0.1–0.58 mg 15N kg–1 soil day–1. Populations of diazotrophic bacteria in the grass rhizosphere soils (2.45 × 106 nifH gene copies g–1 soil) were similar to populations in the roots (2.20 × 106 nifH gene copies g–1 roots) but the ersity of diazotrophic bacteria was significantly higher in the rhizosphere than the roots. Different grass species promoted the abundance of specific members of the nifH community, suggesting a plant-based selection from the rhizosphere microbial community. The results show that rhizosphere and root environments of summer-active perennial grasses support significant amounts of non-symbiotic N2 fixation during summer compared with cropping soils, thus contributing to biological N inputs into the soil N cycle. Some pasture species also maintained N2 fixation in October (spring), when the grasses were dormant, similar to that found in soils under a cereal crop. Surface soils in the rainfed cropping regions of southern Australia are generally low in soil organic matter and thus have lower N-supply capacity. The greater volume of rhizosphere soil under perennial grasses and carbon inputs belowground can potentially change the balance between N immobilisation and mineralisation processes in the surface soils in favour of immobilisation, which in turn contributes to reduced N losses from leaching.
Publisher: Elsevier BV
Date: 04-2014
Publisher: Elsevier BV
Date: 06-2018
Publisher: CSIRO Publishing
Date: 2014
DOI: 10.1071/CP14111
Abstract: Developing new and improved grazing systems for crop–livestock farms where crop production is the major driver of farm management decisions presents a unique research and development challenge. In southern Australia, a substantial proportion of animal production from grazing comes from regions and farms where cropping is the major enterprise. In this paper, we describe a multi-disciplinary farming-systems research approach (EverCrop) aimed at improving farm profitability, risk management and environmental impacts through the development and integration of new grazing options with an emphasis on perennial species. It has been used to analyse and target new opportunities for farmers to benefit from perennial species across dry Mediterranean-type and temperate regions of southern Australia. It integrates field experimentation, on-farm trialling, farmer participatory research, soil–plant–climate biophysical modelling, whole-farm bioeconomic analysis and evaluations of adoptability. Multi-functional roles for summer-active grasses with winter cropping, integration of forage shrubs and establishment of new mixes of perennial grasses in crop rotations to improve farming system performance are identified, along with an analysis of factors likely to affect rate of uptake by farmers.
Publisher: Wiley
Date: 13-04-2016
DOI: 10.1002/FES3.81
Publisher: MDPI AG
Date: 27-02-2018
DOI: 10.3390/ANI8030033
Publisher: DAFF, GRDC & CSIRO
Date: 2014
Publisher: Informa UK Limited
Date: 08-06-2017
Publisher: Elsevier BV
Date: 06-2006
Publisher: Elsevier BV
Date: 07-2005
Publisher: CSIRO Publishing
Date: 2005
DOI: 10.1071/EA04102
Abstract: Early identification of farmer perceptions influencing particular farm management decisions provides the opportunity to more effectively focus investment in research and extension. A survey-based study examining the adoption of integrated weed management by Western Australian grain growers was used to demonstrate how identification of key farmer perceptions can help to guide research and extension priorities. It was found that the adoption of integrated weed management practices was influenced by grower perceptions of herbicide resistance-related factors and of the efficacy and economic value of integrated weed management practices in the farming system. However, there were generally no significant differences between the perceptions of practice efficacy held by users and non-users of the integrated weed management practices. As initial perceptions of efficacy were generally consistent with local field experience, it was expected that extension would not have a major influence on this variable. Consistent with this, participation by growers in a workshop based on the bio-economic farming systems model, resistance integrated management (RIM), did not result in changes in perceptions of practice efficacy. However, changes in the perceived short-term economic value of some weed management practices did occur where the broader value of practices to the farming system, not necessarily relating to weed control, could be demonstrated. This also led to more growers deciding to adopt those practices. For ex le, intended wheat seeding rates were shown to increase by 5 kg/ha as a result of participation in the extension activity. Determining the perceptions influencing adoption, and then identifying the major learning opportunities can be valuable in focusing research and extension. Measures of perceptions also allow learning to be evaluated. In the case study of adoption of the integrated weed management practices in WA, it seems that emphasis on developing and extending the farming-systems impacts beyond just weed and resistance management is likely to be more effective than focusing on the efficacy of the practices for controlling major weeds.
Publisher: Elsevier BV
Date: 09-2017
Publisher: MDPI AG
Date: 20-06-2020
DOI: 10.3390/ANI10061069
Abstract: The eShepherd® virtual fencing system being commercialized for cattle has the potential to exclude cattle from environmentally sensitive areas. Animals are given audio cues to indicate a fence line via a neckband device. An electrical pulse is administered if the animal continues moving forward following an audio cue. A commercial trial was conducted in South Australia to assess whether virtual fencing technology could exclude 20 cattle from an area of regenerating saplings across 44 days using a contoured fence line. The results showed that the cattle were able to rapidly learn the virtual fencing cues responding appropriately to the audio cue for 74.5% of 4378 audio signals and were excluded from the regenerating area for 99.8% of the trial period with the more complex fence line (contoured not straight) in place. IceQube R’s® measuring lying time and bouts showed no consistent increasing or decreasing pattern of change. At the trial conclusion the feed available in the protected zone was double the quantity and quality of the grazed zone. Technical issues occurred with some of the pre-commercial prototype devices but those versions are now obsolete. This study observed a single group of cattle in one paddock further testing of the virtual technology is warranted.
Publisher: MDPI AG
Date: 26-02-2018
DOI: 10.3390/ANI8030031
Publisher: Elsevier BV
Date: 2015
DOI: 10.2139/SSRN.2897229
Publisher: Cambridge University Press (CUP)
Date: 02-2009
DOI: 10.1614/WS-08-067.1
Abstract: The aim of this study was to test whether herbicide resistance in rigid ryegrass has led to increased densities of this weed in Western Australian (WA) cropping fields. A total of 503 wheat fields with previously unknown management history and weed status were visited prior to harvest across 15 agronomic areas of the central WA cropping belt in 1998 and 2003. Rigid ryegrass density was visually assessed and, where possible, seed was collected from the population. Ryegrass was found in 91% of the wheat crops s led. Ryegrass populations were tested in the following year for resistance to chlorsulfuron, sulfometuron, diclofop, and clethodim. With the use of nonparametric and regression statistical methods, resistance status, including multiple-resistance status, was not found to be associated with higher weed density. The results show that growers are generally maintaining low densities in fields with herbicide-resistant rigid ryegrass. The most common rigid ryegrass density at harvest time was less than 1 plant m −2 in both resistant and susceptible populations. Field and model-based studies of weed and herbicide resistance management that allow populations to continue at very high densities are unlikely to reflect common grower practice.
Publisher: Springer Science and Business Media LLC
Date: 30-06-2012
Publisher: Elsevier BV
Date: 04-2012
Publisher: Wiley
Date: 05-02-2020
DOI: 10.1002/AEPP.13007
Publisher: Elsevier BV
Date: 12-2021
Publisher: Elsevier BV
Date: 10-2007
Publisher: CSIRO Publishing
Date: 2023
DOI: 10.1071/CP23157
Publisher: Elsevier BV
Date: 05-2017
Publisher: Wiley
Date: 2007
Publisher: MDPI AG
Date: 29-09-2022
Abstract: Managed plantations of saltbush have the potential to increase the productivity and climate resilience of the farming systems of the low rainfall areas of the world, where livestock are important. The objective was to dynamically simulate the behaviour of grazing saltbush plantations with a new modelling capacity in the APSIM framework to enable the dynamic grazing of forage systems. Scenarios simulated included: the choice of plant species growing in the interrow area between shrub-rows, density of saltbush spatial arrangement, locations with different climates and soils, and grazing strategy by sheep. Comparisons of scenarios across systems were insightful during rainfall years when the shrub systems are of high value (i.e., driest/lowest 20% rainfall years in the simulation period). Overall, the efficient grazing of shrubs by dry sheep with little supplementary feeding, required the availability of a large amount of low quality interrow. Shrub plantations with an interrow of standing oats required least supplementation. Summer grazing was the optimal time for grazing shrub plantations in low rainfall years. Plantations with more shrubs relative to interrow increased the need for supplementary feeding but reduced the variation between years. This is one of the first uses of systems modelling to explore forage shrub system designs that maximise the grazing value of shrub plus interrow.
Publisher: CSIRO Publishing
Date: 2015
DOI: 10.1071/CP14166
Abstract: In low-rainfall environments, a high frequency of cereal crops has been favoured for optimising productivity and risk. However, cereals at high intensity often lead to declining water-use efficiency and increasing inputs to cope with emergent nutritional, disease and weed problems. The value of including breaks in the cropping sequence can involve a high level of uncertainty in low-rainfall areas where non-cereal crops are more risky and profitability is largely determined by the subsequent benefit to cereal productivity. In this study, we aimed to improve understanding of the magnitude and primary source of break benefits such as nutrition, water and disease management in a low-rainfall environment where a high level of within-field soil variability can also contribute to uncertainty about the value of breaks. In on-farm field experiments near Karoonda in the South Australian Mallee, breaks were grown in 2009 or 2010 on four distinct soil types across a dune–swale catena. The effect of these breaks on subsequent cereal production was measured for up to 3 years. In addition, the effect of breaks on nutrition and water available, along with disease infection in subsequent cereal crops, was explored and actual yields were compared with nitrogen and water-limited potential yields. Consistent cumulative benefits to subsequent cereal crops of at least 1 t ha–1 after 3 years accrue from breaks grown on the different soil types. The inclusion of breaks had beneficial effects on the cycling and supply of nutrients along with some short-term impacts on infection by Rhizoctonia solani AG8 in subsequent cereals, whereas there were no conclusive effects of breaks on the supply of water to subsequent crops. This study suggests that the inclusion of both legume and brassica breaks is likely to be beneficial to subsequent cereal production where nitrogen is a factor limiting productivity in low-rainfall, semi-arid environments.
Publisher: No publisher found
Date: 2010
Publisher: Wiley
Date: 06-05-2008
Publisher: Wiley
Date: 24-10-2018
DOI: 10.1002/AGR.21525
Publisher: CSIRO Publishing
Date: 2007
DOI: 10.1071/AR06283
Abstract: In 2003, a random survey was conducted across the Western Australian wheatbelt to establish the frequency and distribution of herbicide resistance in ryegrass populations infesting crop fields. Five hundred cropping fields were visited at crop maturity, and ryegrass seed was collected in 452 of these fields. Subsequently, each crop field population was screened with herbicides of various modes of action that are commonly used for ryegrass control in Australian cropping systems. Most of these ryegrass populations were found to be resistant to the ACCase-inhibitor herbicide diclofop-methyl (68%) and the ALS-inhibitor herbicide sulfometuron (88%). A comparison of resistance levels in the same agronomic zones surveyed 5 years earlier determined that there had been an increase of 20 percentage points in the frequency of resistance over this 5-year period. This survey also determined that the majority (64%) of populations were found to be multiple resistant to both diclofop-methyl and sulfometuron. The distribution patterns of the collected populations indicated that there were higher frequencies of resistant and developing resistance populations occurring in the intensively cropped regions of the wheatbelt, which had greater herbicide selection pressure. Of concern is that 24% and 8% of populations were found to be developing resistance to trifluralin and clethodim, respectively. Currently these herbicides are heavily relied upon for control of ACCase and ALS herbicide resistant ryegrass. Nearly all populations remain susceptible to glyphosate. Ryegrass across the WA wheatbelt now exhibits multiple resistance across many but not all herbicides, posing severe management and sustainability challenges.
Publisher: Elsevier BV
Date: 07-2006
Publisher: Elsevier BV
Date: 02-2022
Publisher: CSIRO Publishing
Date: 2006
DOI: 10.1071/EA05025
Abstract: Adoption of no-tillage sowing systems has increased rapidly in many Australian grain growing regions over the past decade. The extent of herbicide resistant weed populations in these regions has also increased over the same period. A survey of growers in the South and Western Australian cropping regions was conducted to identify opportunities for more effective tillage and weed-related extension. Trends in sowing system use are determined, as are growers’ perceptions of the long-term effects of no-tillage on herbicide costs, herbicide resistance, and soil erosion. The results suggest a major expansion in the adoption of no-tillage sowing in most South Australian cropping regions over the next 5 years, although growers expect increased herbicide costs in no-tillage systems and an increased risk of herbicide resistance. Herbicide resistance and weed control issues are the main reasons given for reducing no-tillage use. A key research and extension challenge is to develop and implement weed management strategies that are able to sustain long-term no-tillage use in a cropping environment where growers place a high value on the soil and production benefits of no-tillage, but over-reliance on herbicides can rapidly lead to resistance in major crop weeds.
Publisher: Elsevier BV
Date: 07-2015
Publisher: Elsevier BV
Date: 04-2004
Publisher: Elsevier BV
Date: 12-2021
Publisher: CSIRO Publishing
Date: 2004
DOI: 10.1071/EA03115
Abstract: Greater adoption of integrated weed management, to reduce herbicide reliance, is an objective of many research and extension programmes. In Australian grain-growing regions, integrated weed management is particularly important for the management of herbicide resistance in weeds. In this study, survey data from personal interviews with 132 Western Australian grain growers are used to characterise the use and perceptions of integrated weed management practices. The main objective was to identify opportunities for improved weed management decision making, through targeted research and extension. The extent to which integrated weed management practices are used on in idual farms was measured. Perceptions of the efficacy and reliability of various weed management practices were elicited for control of annual ryegrass (Lolium rigidum Gaud.), along with perceptions of the economic value of integrated weed management practices relative to selective herbicides. All growers were shown to be using several integrated weed management practices, although the use of some practices was strongly associated with the presence of a herbicide-resistant weed population. In general, both users and non-users were found to have high levels of awareness of integrated weed management practices and their weed control efficacy. Herbicide-based practices were perceived to be the most cost-effective. Opportunities for greater adoption of integrated weed management practices, to conserve the existing herbicide resource, exist where practices can be shown to offer greater shorter-term economic value, not necessarily just in terms of weed control, but to the broader farming system.
Publisher: MDPI AG
Date: 13-01-2021
Abstract: Models can provide a structured way to think about adoption and provide a method to investigate the impacts of different factors in the adoption process. With at least 70 years of research in the adoption of agricultural innovations, there has been a proliferation of adoption models, both conceptual and numerical. This ersity has resulted in a lack of convergence in the way adoption is defined, explained, and measured, causing agricultural extension and policy to rely on a body of literature that is often not able to offer clear recommendations on the variables or mechanisms that can be used to design interventions. We conducted a review of conceptual models to clarify the concepts and approaches used in the practice of modeling adoption in agriculture. We described general adoption conceptual models originating from sociology, psychology, economics, and marketing and reviewed ex les of models specifically defined for the study of adoption in agriculture. We also broadly assessed the ability of conceptual models to support building numerical models. Our review covered a range of modeling approaches for diffusion and in idual adoption, illustrating different perspectives used in the literature. We found that key elements that should be used in adoption models for agriculture include: a way to assess the performance of the proposed new technology (e.g., relative advantage, both economic and non-economic) in relation to the existing technology or practice in place, the process of learning about this advantage, the interaction between in idual decision-making and external influences, and characteristics of potential adopters affecting their attitudes towards the technology. We also detected inconsistencies in how different elements are treated in different conceptual models, particularly behavioral elements such as attitudes, motivations, intentions, and external influences. In terms of modeling, the main implication of these inconsistencies is the difficulty to generate quantitative evidence to support these models since multiple interpretations make it difficult to achieve consistency in the definition of observable, measurable variables that can be used to quantify cause-effect relationships. Suggestions for further research in the field include: questioning whether the adoption of all technologies and practices can be represented by the same adoption or learning process, exploring the dynamics in the relationship between adopters and technology before and after adoption, and questioning the basic assumptions behind the process of in idual decision-making models and the role of collective decision-making. Findings from this review can be considered by adoption researchers and modelers in their work to assist policy and extension efforts to improve the uptake of future beneficial agricultural innovations.
Publisher: Wiley
Date: 05-02-2020
DOI: 10.1002/AEPP.13012
Publisher: PeerJ
Date: 30-09-2020
DOI: 10.7717/PEERJ.10066
Abstract: Early virtual fencing trials have effectively contained small groups of sheep within set areas of a paddock when all animals were wearing manual electronic collars. With sheep farming commonly involving large flocks, a potential cost-effective application of virtual fencing would involve applying equipment to only a proportion of the flock. In this study, we tested the ability of virtual fencing to control a small flock of sheep with differing proportions of the group exposed to the virtual fence (VF). Thirty-six Merino sheep were identified as leaders, middle or followers by moving them through a laneway. The sheep were then allocated to groups balanced for order of movement. The groups ( n = 9 per group) included applying the VF to the following proportions of animals within each group: (1) 100% ( n = 9 VF) (2) 66% ( n = 6 VF n = 3 no VF) (3) 33% ( n = 3 VF n = 6 no VF) (4) 0% (no VF free to roam the paddock). The groups were given access to their own paddock (80 × 20 m) for two consecutive days, six hours per day, with the VF groups prevented from entering an exclusion zone that covered 50% of the north side of the paddock. During these hours, VF interactions, behavioural time budgets, and body temperature were recorded as measures of stress, and location was tracked with GPS. Group 100% VF and Control were tested on the first two days and groups 33% VF and 66% VF were tested on the following two days. During VF implementation the 100% VF and 66% VF group were successfully prevented from entering the exclusion zone. Having only 33% of the flock exposed to the virtual fence was not successful, with the sheep pushing forward through the VF to join flock mates in the exclusion zone. For learning to respond to the audio cue, sheep in the 33% group received more electrical stimuli with a 0.51 proportion for the ratio of electrical stimuli to audio cue, compared to 0.22 and 0.28 for the 100% and 66% groups, respectively. There were small differences in behavioural patterns of standing and lying on both days of testing, with the 100% VF and 66% VF groups spending more time lying. Although stress-induced hyperthermia did not occur in any of the VF groups, body temperature differed in the 33% VF group. There were no differences in temperature measures between the control and 100% VF animals. This study demonstrates that for a short period, controlling two-thirds of the flock was equally as effective as virtually fencing all animals, while controlling one-third of a flock with a virtual fence was not effective. For the short term, it appears that implementing the VF to a proportion of the flock can be an effective method of containment. Due to the limitations of this study, these results warrant further testing with larger flocks and for longer periods.
Publisher: Elsevier BV
Date: 03-2013
Publisher: Cambridge University Press (CUP)
Date: 10-05-2017
DOI: 10.1017/WET.2017.9
Abstract: HWSC systems that target weed seed production during harvest have been in use in Australian crop production systems for over 30 years. Until recently, though, grower adoption of these systems has been relatively low. It is now apparent with the introduction of a range of new weed seed targeting systems that there is renewed grower interest in the use of this approach to weed control. With the aim of determining the current adoption and use of HWSC systems, 600 crop producers from throughout Australia’s cropping regions were interviewed on their adoption and use of these systems. This survey established that 43% of Australian growers are now routinely using HWSC to target weed seed production during grain harvest. The adoption of narrow-windrow burning (30%) was considerably greater than the other currently available techniques of chaff tramlining (7%), chaff carts (3%), bale-direct system (3%), and the Harrington Seed Destructor (HSD) ( %). When growers were asked about their future use of these systems 82% indicated that they would be using some form of HWSC within five years. Grower preferences for future HWSC use were primarily for either narrow-windrow burning (42%) or the HSD (29%). This very high level of current and potential HWSC adoption signifies that HWSC is now considered an established weed control practice by Australian growers.
Publisher: Informa UK Limited
Date: 16-02-2018
Publisher: Informa UK Limited
Date: 29-01-2018
Publisher: CSIRO
Date: 2010
Publisher: CSIRO Publishing
Date: 2015
DOI: 10.1071/CP14136
Abstract: Continuous-cropping systems based on no-till and crop residue retention have been widely adopted across the low-rainfall cereal belt in southern Australia in the last decade to manage climate risk and wind erosion. This paper reports on two long-term field experiments that were established in the late 1990s on texturally different soil types at a time of uncertainty about the profitability of continuous-cropping rotations in low-rainfall environments. Continuous-cereal systems significantly outyielded the traditional pasture–wheat systems in five of the 11 seasons at Waikerie (light-textured soil), resulting in a cumulative gross margin of AU$1600 ha–1 after the initial eight seasons, almost double that of the other treatments. All rotation systems at Kerribee (loam-textured soil) performed poorly, with only the 2003 season producing yields close to 3 t ha–1 and no profit achieved in the years 2004–08. For low-rainfall environments, the success of a higher input cropping system largely depends on the ability to offset the losses in poor seasons by capturing greater benefits from good seasons therefore, strategies to manage climatic risk are paramount. Fallow efficiency, or the efficiency with which rainfall was stored during the period between crops, averaged 17% at Kerribee and 30% at Waikerie, also indicating that soil texture strongly influences soil evaporation. A ‘responsive’ strategy of continuous cereal with the occasional, high-value ‘break crop’ when seasonal conditions are optimal is considered superior to fixed or pasture–fallow rotations for controlling grass, disease or nutritional issues.
Publisher: Cambridge University Press (CUP)
Date: 04-2001
Publisher: Elsevier BV
Date: 12-2022
Publisher: Elsevier BV
Date: 12-2002
Publisher: Wiley
Date: 14-01-2017
DOI: 10.1111/JAC.12159
Publisher: Wiley
Date: 26-07-2019
DOI: 10.1111/JAC.12357
Publisher: Informa UK Limited
Date: 10-2010
Publisher: Wiley
Date: 14-08-2019
Publisher: Cambridge University Press (CUP)
Date: 2012
Abstract: Herbicides are the foundation of weed control in commercial crop-production systems. However, herbicide-resistant (HR) weed populations are evolving rapidly as a natural response to selection pressure imposed by modern agricultural management activities. Mitigating the evolution of herbicide resistance depends on reducing selection through ersification of weed control techniques, minimizing the spread of resistance genes and genotypes via pollen or propagule dispersal, and eliminating additions of weed seed to the soil seedbank. Effective deployment of such a multifaceted approach will require shifting from the current concept of basing weed management on single-year economic thresholds.
Publisher: CSIRO Publishing
Date: 2014
DOI: 10.1071/CP13452
Abstract: Old man saltbush (Atriplex nummularia Lindl.) is a useful forage shrub for livestock in the low-rainfall areas of the world, and particularly in Australia. In these semi-arid and arid environments, saltbush is valuable for increasing the production from otherwise marginal areas of the farm and during drought periods when there are few feed alternatives. The ability to predict the growth and development of perennial forages such as old man saltbush in response to rainfall, soils and farm management is necessary for farming system planning and design purposes. A field experiment was conducted at Waikerie, South Australia, to inform the development of a new forage shrub model for use in the APSIM framework. The model takes into account the common setup of saltbush plantations in alley systems, by simulating light interception and water uptake for interacting shrub and inter-row zones separately. This is done by modelling the canopy and root system development. Field data across three soil types along a landscape catena showed that the model was able to satisfactorily predict daily biomass accumulation, partitioning into leaf and woody biomass, and regrowth after grazing. The model was sensitive to properties associated with the root system, and with limited parameterisation can be tailored to simulate different clonal cultivars. The model can now be used in the APSIM framework to assess temporal and spatial dynamics of forage systems combining shrubs with herbaceous pasture components.
Publisher: Wiley
Date: 20-02-2014
DOI: 10.1093/AEPP/PPU001
Publisher: Cambridge University Press (CUP)
Date: 14-02-2019
DOI: 10.1017/S1742170518000108
Abstract: If the United Nations Sustainable Development Goals are to be achieved, African smallholder farmers will need to embrace new technologies such as conservation agriculture (CA) in order to increase both their productivity and sustainability. Yet farmers have been slow to embrace CA and when they have, they are inclined to do so at limited intensities. Current investigations tend to apply binary frameworks that classify all utilizations as ‘adoption’, and do not consider in depth the farmer perspectives and contextual realities that affect farmer decision-making on the intensity of use. We analyze 57 in-depth, semi-structured interviews with farmers who implement CA to understand why they tend to do so at limited intensities and what is required to intensify their CA activities, both for them and others within their communities. While most farmers reported substantial yield benefits from using CA, this was mainly related to input intensification (particularly herbicides) and was limited by constrained financial resources. Overall, the intensity of CA utilization was constrained due to farmer-identified constraints across their physical, financial, human and informational resources. Because of this, stagnation at low intensities of CA utilization was common, reflecting the assumed transformational adoption pathway for CA and the focus on binary adoption, as opposed to modification and the broader utilization process. To overcome this, we propose a more nuanced transitional approach focused on the intensification of four broader principles of CA over time [i.e., (1) strategic tillage, (2) soil protection, (3) crop ersification and (4) input management] as opposed to the strict packaging of CA practices. Such a change in approach will foster increased positive perceptions within the community and allow farmers to locally adapt CA to build their own way toward complete CA utilization and with less need for subsidization.
Publisher: Informa UK Limited
Date: 04-05-2018
Publisher: MDPI AG
Date: 10-02-2023
DOI: 10.3390/ANI13040619
Abstract: Virtual fencing technology uses on-animal devices to communicate boundaries via a warning audio tone and electrical pulse signals. There is currently limited validation work on sheep. This study used modified cattle eShepherd® virtual fencing neckbands on reduced-wool sheep with clipped necks to enable automated trials with small groups across both day and night. The first 5-day trial with six Dorper crossbred sheep was conducted in an experimental paddock setting, with a second 5-day trial conducted with 10 Ultra White sheep on a commercial farm. The animals across both trials were contained in the inclusion zone for 99.8% and 92.2% of the trial period, with a mean percentage (±SD) of total audio cues as audio only (i.e., not followed by an electrical pulse) being 74.9% ± 4.6 in the first trial, and 83.3% ± 20.6 for the second trial. In the second trial, sheep crossed over into the exclusion zone on the third night and remained there until they were walked out for their daily yard check in the morning. These preliminary trial results are promising for the use of automated technology on sheep, but suitable devices and algorithms still need to be designed specifically for sheep in the long term.
Publisher: Elsevier BV
Date: 04-2018
No related grants have been discovered for Rick Llewellyn.