ORCID Profile
0000-0003-2884-5622
Current Organisation
Yamaguchi University
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Publisher: Informa UK Limited
Date: 10-12-2022
Publisher: CSIRO Publishing
Date: 2013
DOI: 10.1071/CP13237
Abstract: The majority of rain used by winter grain crops in the Mallee region of Victoria, Australia, falls during the cooler months of the year (April–October). However, rain falling during the summer fallow period (November–March) and stored as soil moisture contributes to grain yield. Strategies to better capture and store summer fallow rain include (i) retention of crop residues on the soil surface to improve water infiltration and evaporation and (ii) chemical or mechanical control of summer fallow weeds to reduce transpiration. Despite the widespread adoption of no-till farming systems in the region, few published studies have considered the benefits of residue management during the summer fallow relative to weed control, and none quantify the impacts or identify the mechanisms by which summer fallow weeds influence subsequent crop yield. Over 3 years (2009–11), identical experiments on adjacent sand and clay soil types at Hopetoun in the southern Mallee were conducted to quantify the effect of residue management (standing, removed, or slashed) and summer fallow weed control (± chemical control) compared with cultivation on soil water and nitrogen (N) accumulation and subsequent crop yield. The presence of residue (2.4–5.8 t/ha) had no effect on soil water accumulation and a small negative effect on grain yield on the clay soil in 2011. Controlling summer weeds (Heliotropium europaeum and volunteer crop species) increased soil water accumulation (mean 45 mm) and mineral N (mean 45 kg/ha) before sowing on both soil types in 2 years of the experiment with significant amounts of summer fallow rain (2010 and 2011). Control of summer weeds increased grain yield of canola by 0.6 t/ha in 2010 and wheat by 1.4 t/ha in 2011. Using the data from these experiments to parameterise the APSIM model, simulation of selected treatments using historical climate data (1958–2011) showed that an extra 40 mm of stored soil water resulted in an average additional 0.4 t/ha yield, most of which was achieved in dry growing seasons. An additional 40 kg/ha N increased yield only in wetter growing seasons (mean 0.4 t/ha on both soil types). The combination of extra water and N that was found experimentally to result from control of summer fallow weeds increased subsequent crop yield in all season types (mean 0.7 t/ha on sand, 0.9 t/ha on clay). The co-limitation of yield by water and N in the Mallee environment means that yield increases due to summer weed control (and thus returns on investment) are very reliable.
Publisher: Elsevier BV
Date: 03-2020
Publisher: Elsevier BV
Date: 08-2014
Publisher: CSIRO Publishing
Date: 2018
DOI: 10.1071/CP17439
Abstract: In the high-rainfall zone of south-eastern Australia, deep incorporation of organic matter has previously been reported to increase crop yields by improving access to subsoil water and nutrients, resulting from the amelioration of subsoil constraints. However, previous experiments did not separate the yield response resulting from nutrients contained in the amendment from yield response due to amelioration of subsoil constraints. In order to separate these effects, eight field experiments were conducted on a range of soil types across the medium- and high-rainfall zones of south-eastern Australia between 2014 and 2016. Grain yield and quality responses of a range of annual crops (canola, wheat, barley and lentil) to surface and deep placement of poultry litter and inorganic fertilisers with matched nutrition were assessed. Over 15 site × year combinations, there was no consistent, significant positive interaction between amendment and incorporation treatments necessary to demonstrate that deep placement of amendment (i.e. subsoil manuring) had advantages over surface application of the same amendment. Differences in crop yield in these experiments are attributed to nutrients (particularly nitrogen) supplied by the amendment, and not to the amelioration of subsoil constraints. Future research, including analysis of subsoil physicochemical properties and plant nutrient concentrations after treatment, is necessary to confirm the role of nitrogen and other nutrients in the crop response to subsoil manuring.
Publisher: Springer Science and Business Media LLC
Date: 26-05-2020
DOI: 10.1038/S41437-020-0320-1
Abstract: Wheat is a major food crop, with around 765 million tonnes produced globally. The largest wheat producers include the European Union, China, India, Russia, United States, Canada, Pakistan, Australia, Ukraine and Argentina. Cultivation of wheat across such erse global environments with variation in climate, biotic and abiotic stresses, requires cultivars adapted to a range of growing conditions. One intrinsic way that wheat achieves adaptation is through variation in phenology (seasonal timing of the lifecycle) and related traits (e.g., those affecting plant architecture). It is important to understand the genes that underlie this variation, and how they interact with each other, other traits and the growing environment. This review summarises the current understanding of phenology and developmental traits that adapt wheat to different environments. Ex les are provided to illustrate how different combinations of alleles can facilitate breeding of wheat varieties with optimal crop performance for different growing regions or farming systems.
Publisher: Elsevier BV
Date: 05-2011
Publisher: Elsevier BV
Date: 12-2019
Publisher: CSIRO Publishing
Date: 2009
DOI: 10.1071/CP09052
Abstract: Crop simulation models relevant to real-world agriculture have been a rationale for model development over many years. However, as crop models are generally developed and tested against experimental data and with large systematic gaps often reported between experimental and farmer yields, the relevance of simulated yields to the commercial yields of field crops may be questioned. This is the third paper in a series which describes a substantial effort to deliver model-based decision support to Australian farmers. First, the performance of the cropping systems simulator, APSIM, in simulating commercial crop yields is reported across a range of field crops and agricultural regions. Second, how APSIM is used in gaining farmer credibility for their planning and decision making is described using actual case studies. Information was collated on APSIM performance in simulating the yields of over 700 commercial crops of barley, canola, chickpea, cotton, maize, mungbean, sorghum, sugarcane, and wheat monitored over the period 1992 to 2007 in all cropping regions of Australia. This evidence indicated that APSIM can predict the performance of commercial crops at a level close to that reported for its performance against experimental yields. Importantly, an essential requirement for simulating commercial yields across the Australian dryland cropping regions is to accurately describe the resources available to the crop being simulated, particularly soil water and nitrogen. Five case studies of using APSIM with farmers are described in order to demonstrate how model credibility was gained in the context of each circumstance. The proposed process for creating mutual understanding and credibility involved dealing with immediate questions of the involved farmers, contextualising the simulations to the specific situation in question, providing simulation outputs in an iterative process, and together reviewing the ensuing seasonal results against provided simulations. This paper is distinct from many other reports testing the performance and utility of cropping systems models. Here, the measured yields are from commercial crops not experimental plots and the described applications were from real-life situations identified by farmers. A key conclusion, from 17 years of effort, is the proven ability of APSIM to simulate yields from commercial crops provided soil properties are well characterised. Thus, the ambition of models being relevant to real-world agriculture is indeed attainable, at least in situations where biotic stresses are manageable.
Publisher: CSIRO Publishing
Date: 28-02-2023
DOI: 10.1071/CP22370
Abstract: Context Herbicide-resistant annual ryegrass (Lolium rigidum ARG) is a major weed of commercial significance globally, including no-till wheat-based production systems in south-eastern Australia. Aims To compare the cost-effectiveness of different crop sequences and intensities of weed management to control ARG in rainfed grain production. Methods Two on-farm studies in southern New South Wales, Australia, compared the effect of combinations of 3-year crop-sequence options (continuous wheat, 1- or 2-years of break crops), conservative or aggressive weed-control measures, hay cuts, legume brown manure (BM), and/or weed-free winter fallow on in-crop ARG infestations and soil seedbanks. Gross margins were calculated for each combination of treatments to compare system economic performance. Key results Double-breaks consisting of two consecutive broadleaf crops, or canola–cereal hay, were frequently the most profitable and effective ARG control strategies. Single canola or lupin crops, BM, cereal hay, and fallow all significantly reduced subsequent in-crop ARG and seedbank numbers compared with continuous wheat. Aggressive in-crop control measures in wheat were more expensive than those applied to break crops. Gains in ARG control could be lost by a single year of poor weed control. Conclusions High levels of control ( %) over three consecutive seasons are required to reduce ARG seedbanks, and this is most cost-effectively achieved with erse crop sequences. Implications Farmers with high populations of ARG can reduce seedbanks by growing three crops sequentially that achieve complete weed seed control. This must be followed with ongoing high levels of control in subsequent years to keep ARG seedbanks low.
Publisher: CSIRO Publishing
Date: 2015
DOI: 10.1071/CP14230
Abstract: Interest is growing in the potential to expand cropping into Australia’s high-rainfall zone (HRZ). Dual-purpose crops are suited to the longer growing seasons in these environments to provide both early grazing for livestock and later regrow to produce grain. Grain yield and grazing potential of wheats of four different maturity types were simulated over 50 years at 13 locations across Australia’s HRZ, and sowing date, nitrogen (N) availability and crop density effects were explored. Potential grazing days on wheat were obtained by simulating sheep grazing crops to Zadoks growth stage Z30 at 25 dry sheep equivalents (DSE)/ha. Optimal sowing dates for each maturity type at each location were matched to the flowering window during which risk of frost and heat stress was lowest. Overall, we found significant national potential for dual-purpose use of winter wheat cultivars across Australia’s HRZ, with opportunities identified in all regions. Simulated mean wheat yields exceeded 6 t/ha at most locations, with highest mean grain yields (8–10 t/ha) in southern Victoria, and lower yields (5–7 t/ha) in the south-west of Western Australia (WA) and central and northern New South Wales (NSW). Highest grazing days were from winter cultivars sown early (March–mid-April), which could provide 1700–3000 DSE-days/ha of grazing across HRZ locations this was 2–3 times higher than could be obtained from grazing spring cultivars (200–800 DSE-days/ha). Sowing date was critical to maximise both grazing and grain yield potential from winter cultivars each 1-week delay in sowing after 8 March reduced grazing by 200–250 DSE-days/ha and grain yield by 0.45 t/ha. However, in Mediterranean climates, a lower frequency of early sowing opportunities before mid-April ( % of years) is likely to limit the potential to use winter cultivars. Prospects to graze shorter season spring cultivars that fit later sowing windows require further examination in south-west WA, the slopes of NSW and southern Queensland.
Publisher: Elsevier BV
Date: 03-2012
Publisher: CSIRO Publishing
Date: 2015
DOI: 10.1071/CP14252
Abstract: Wheat crops usually yield more when grown after another species than when grown after wheat. Quantifying the yield increase and explaining the factors that affect the increase will assist farmers to decide on crop sequences. This review quantifies the yield increase, based on comparisons of wheat growing after a break crop with wheat after wheat. The mean increase in wheat yield varied with species of break crop, ranging from 0.5 t ha–1 after oats to 1.2 t ha–1 after grain legumes. Based on overlapping experiments, the observed ranking of break-crop species in terms of mean yield response of the following wheat crop was: oats canola ≈ mustard ≈ flax field peas ≈ faba beans ≈ chickpeas ≈ lentils ≈ lupins. The mean additional wheat yield after oats or oilseed break crops was independent of the yield level of the following wheat crop. The wheat yield response to legume break crops was not clearly independent of yield level and was relatively greater at high yields. The yield of wheat after two successive break crops was 0.1–0.3 t ha–1 greater than after a single break crop. The additional yield of a second wheat crop after a single break crop ranged from 20% of the effect on a first wheat crop after canola, to 60% after legumes. The mean yield effect on a third wheat crop was negligible, except in persistently dry conditions. The variability of the break-crop effect on the yield of a second wheat crop was larger than of a first wheat crop, particularly following canola. We discuss the responses in relation to mechanisms by which break crops affect soil and following crops. By quantifying the magnitude and persistence of break-crop effects, we aim to provide a basis for the decision to grow continuous cereal crops, strategic rotations or tactically selected break crops. In many wheat-growing areas, the large potential yield increases due to break crops are not fully exploited. Research into quantifying the net benefits of break crops, determining the situations where the benefits are greatest, and improving the benefits of break crops promises to improve the efficiency of wheat-based cropping systems.
Publisher: CSIRO Publishing
Date: 2018
DOI: 10.1071/CP18014
Abstract: Growers in the wheatbelt of south-eastern Australia need increases in water-limited potential yield (PYw) in order to remain competitive in a changing climate and with declining terms of trade. In drought-prone regions, flowering time is a critical determinant of yield for wheat (Triticum aestivum L.). Flowering time is a function of the interaction between management (M, establishment date), genotype (G, development rate) and prevailing seasonal conditions. Faced with increasing farm size and declining autumn rainfall, growers are now sowing current fast-developing spring wheat cultivars too early. In order to widen the sowing window and ensure optimum flowering dates for maximum yield, new G × M strategies need to be identified and implemented. This study examined the effect of manipulating genotype (winter vs spring wheat and long vs short coleoptile) and management (sowing date, fallow length and sowing depth) interventions on yield and flowering date in high-, medium- and low-rainfall zones in south-eastern Australia. Twelve strategies were simulated at nine sites over the period 1990–2016. At all sites, the highest yielding strategies involved winter wheats with long coleoptiles established on stored subsoil moisture from the previous rotation, and achieved a mean yield increase of 1200 kg/ha or 42% relative to the baseline strategy. The results show promise for winter wheats with long coleoptiles to widen the sowing window, remove the reliance on autumn rainfall for early establishment and thus stabilise flowering and maximise yield. This study predicts that G × M strategies that stabilise flowering may increase PYw.
Publisher: Elsevier BV
Date: 06-2018
Publisher: Elsevier BV
Date: 02-2023
Publisher: Oxford University Press (OUP)
Date: 03-06-2021
DOI: 10.1093/JXB/ERAB250
Abstract: Crop yield must increase to keep pace with growing global demand. Past increases in crop production have rarely been attributable to an in idual innovation but have occurred when technologies and practices combine to form improved farming systems. Inevitably this has involved synergy between genotypic and management improvements. We argue that research focused on developing synergistic systems that overcome clear production constraints will accelerate increases in yield. This offers the opportunity to better focus and multiply the impact of discipline-focused research. Here we use the rainfed grain production systems of south-eastern Australia as a case study of how transformational change in water productivity can be achieved with research focused on genotype × management synergies. In this region, rainfall is low and variable and has declined since 1990. Despite this, growers have maintained yields by implementing synergistic systems combining innovations in (i) soil water conservation, (ii) crop ersity, (iii) earlier sowing, and (iv) matching nitrogen fertilizer to water-limited demand. Further increases are emerging from synergies between genetic improvements to deliver flowering time stability, adjusted sowing times, and potential dual-purpose use. Collaboration between agronomists, physiologists, and crop breeders has led to development of commercial genotypes with stable flowering time that are in early phases of testing and adoption.
Publisher: Elsevier BV
Date: 02-2021
Publisher: Springer Science and Business Media LLC
Date: 25-02-2019
Publisher: Elsevier BV
Date: 04-2025
Publisher: Wiley
Date: 11-08-2022
DOI: 10.1002/JSFA.12108
Abstract: Understanding how climate change affects the phosphorus (P) nutrition of crops grown on acid soils is important in optimizing the management of P, and to secure future food production on these soils. This study assessed the impact of elevated CO 2 (eCO 2 ) on the P nutrition of wheat ( Triticum aestivum ) grown on Al 3+ ‐toxic and P‐deficient soils or in hydroponics. The aluminium‐resistant near‐isogenic wheat lines EGA‐Burke (malate efflux only) and EGA‐Burke TaMATE1B (malate and citrate efflux) were grown under ambient (400 μmol mol −1 ) and elevated CO 2 (800 μmol mol −1 ) in growth chambers for 4–6 weeks. Elevated CO 2 enhanced shoot growth and total P uptake of both lines at P rates mg kg −1 , which was associated with improved root biomass allocation and thus increased root growth, but these effects were not apparent at lower P rates. Elevated CO 2 decreased specific P uptake (P uptake per unit root length) at P supply mg kg −1 , but did not significantly affect external or internal P requirements. This effect on the specific P uptake was less for EGA‐Burke TaMATE1B than for EGA‐Burke, possibly due to the increased citrate efflux and decreased Al concentration in root tips of EGA‐Burke TaMATE1B . Compared to EGA ‐ Burke, citrate‐exuding EGA ‐ Burke TaMATE1B had greater shoot P concentration and greater specific P uptake. Elevated CO 2 improved root growth, and thus total P uptake and plant production of both lines when high P alleviated Al 3+ toxicity and improved P nutrition in acid soils. The decreased P uptake efficiency under eCO 2 was less for EGA ‐ Burke TaMATE1B than EGA‐Burke . © 2022 Society of Chemical Industry.
Publisher: Royal Society of Chemistry (RSC)
Date: 2018
DOI: 10.1039/C7RA12697B
Abstract: This study reports on the selective separation of scandium (Sc) from other rare earth metals (REMs) using a polymer inclusion membrane (PIM).
Publisher: Elsevier BV
Date: 09-2016
Publisher: Elsevier BV
Date: 03-2019
Publisher: CSIRO Publishing
Date: 2011
DOI: 10.1071/CP11268
Abstract: In southern Australia, summer fallow rain (SFR) has not traditionally been valued for winter crop production. Modern, higher yielding farming practices combined with a decade of below-average growing-season rainfall and a predicted increase in the proportion of summer rain under future climate patterns have stimulated a re-evaluation of this notion. We used a widely validated crop simulation model (APSIM-Wheat) to quantify the potential value of SFR to wheat yield under contemporary farming practices using long-term climatic data at 37 locations throughout southern Australia. The potential value of SFR was high, contributing on average 1.0 t/ha or 33% of water-limited attainable yield. Yield increases were due to both increased water use and increased water-use efficiency through higher harvest index. The contribution to yield varied significantly according to the rainfall distribution and soil type across sites. In central-west New South Wales, the equi-seasonal rainfall pattern, high soil water-holding capacity and variable spring rainfall resulted in SFR contributing up to 2.0 t/ha or 72% of mean simulated wheat yield. In contrast, in the north-western grain belt of Western Australia, SFR contributed as little as 0.1 t/ha or 3% of mean simulated yield due to strong Mediterranean rainfall pattern, low soil water-holding capacity and reliable growing-season rainfall. At all locations there was significant year-to-year variation in the simulated yield contribution of SFR. At a given site, soils with higher water-holding capacity in the surface tended to reduce summer fallow efficiency (proportion of summer rainfall stored at sowing) due to the failure of most summer rain to penetrate below the evaporation zone. Despite seasonal variability in yield contribution, interventions to preserve summer rainfall, such as strict summer weed control generated high return on investment (range 6–1328% mean 733%). Risk of financial loss due to strict summer weed control varied across sites, with failure to achieve a return on investment occurring in 1–70% of years depending on location. The proportion of annual rain falling during the summer fallow period in some locations has increased in the last 10 years and this forecast result of climate change is likely to increase the value of SFR to wheat production in the future.
Publisher: Oxford University Press (OUP)
Date: 13-08-2010
DOI: 10.1093/JXB/ERQ245
Abstract: Improvements in water productivity and yield arise from interactions between varieties (G) and their management (M). Most G×M interactions considered by breeders and physiologists focus on in-crop management (e.g. sowing time, plant density, N management). However, opportunities exist to capture more water and use it more effectively that involve judicious management of prior crops and fallows (e.g. crop sequence, weed control, residue management). The dry-land wheat production system of southern Australia, augmented by simulation studies, is used to demonstrate the relative impacts and interactions of a range of pre-crop and in-crop management decisions on water productivity. A specific case study reveals how a novel genetic trait, long coleoptiles that enable deeper sowing, can interact with different management options to increase the water-limited yield of wheat from 1.6 t ha(-1) to 4.5 t ha(-1), reflecting the experience of leading growers. Understanding such interactions will be necessary to capture benefits from new varieties within the farming systems of the future.
Publisher: CSIRO Publishing
Date: 2014
DOI: 10.1071/CP13426
Abstract: The improvement in grain yield of wheat throughout Australia through both breeding and management has been impressive. Averaged across all farms, there has been an approximate doubling of yield per unit area since ~1940. This has occurred across a broad range of environments with different rainfall patterns. Interestingly, the gain in the driest years (9 kg ha–1 year–1 or 0.81% year–1) has been proportionally greater than in the most favourable years (13.2 kg ha–1 year–1 or 0.61% per year) when expressed as yield relative to 2012. These data from all farms suggest that further yield progress is likely, and evidence is presented that improved management practices alone could double this rate of progress. The yield increases achieved have been without any known compromise in grain quality or disease resistance. As expected, improvements have come from both changed management and from better genetics, as well as from the synergy between them. Yield improvements due to changed management have been dramatic and are easiest to quantify, whereas those from breeding have been important but more subtle. The management practices responsible have largely been driven by advances in mechanisation that enable direct seeding, more timely and flexible sowing and nutrient management, and improved weed and pest control, many of which have been facilitated by improved crop sequences with grain legumes and oilseeds that improve water- and nutrient-use efficiency. Most of the yield improvements from breeding in Australia have come from conventional breeding approaches where selection is almost solely for grain yield (together with grain quality and disease resistance). Improvements have primarily been through increased harvest index (HI), although aboveground biomass has also been important. We discuss future opportunities to further increase Australian rainfed wheat yields. An important one is earlier planting, which increases resource capture. This will require knowledge of the genes regulating phenological development so that flowering still occurs at the optimum time appropriate modifications to sowing arrangements and nutrient management will also be required. To improve yield potential, we propose a focus on physiological traits that increase biomass and HI and suggest that there may be more scope to improve biomass than HI. In addition, there are likely to be important opportunities to combine novel management practices with new breeding traits to capture the synergy possible from variety × management interactions. Finally, we comment on research aimed at adapting agriculture to climate change.
Publisher: CSIRO Publishing
Date: 2009
DOI: 10.1071/CP09064
Abstract: Water-use efficiency (WUE) is defined here as the ratio of grain yield (kg/ha) to crop water use by evapotranspiration (mm). Much of the WUE literature has focussed on either the determination of the boundary of attainable WUE for any amount of available water, or on the practicalities of measurement of the WUE of a crop. While these are important issues for defining the gap between the attained and the potential WUE, little progress has been reported on clarifying the components that contribute to this gap or on how it can be bridged. To address these questions, we analysed 334 wheat fields for which we had the data necessary to both calculate WUE and to simulate crop growth and water use. Simulations were conducted through Yield Prophet®, an on-line version of the APSIM systems model. For this dataset, evapotranspiration accounted for 69% of observed yield variation, although the more commonly used growing-season (April–October) rainfall accounted for 50%. Considering that evapotranspiration efficiency does not account for a wide range of potentially yield-limiting factors including soil and fertiliser nitrogen supply, crop phenology, and sowing dates, or rainfall distribution, these results reinforce the importance of evapotranspiration efficiency as a yield determinant for well managed crops in water-limited environments. WUE attained over the whole dataset was 15.2 kg grain/ha.mm (x-intercept = 67 mm), although this value contained data subsets with important differences in WUE based on soil water-holding capacity and regional ersity. Yield Prophet® simulated commercial wheat yields with RMSDs of 0.80 t/ha (r2 = 0.71), with some systematic error between observed and simulated yields. Simulated crops achieved a higher WUE (16.9 kg grain/ha.mm x-intercept = 72 mm) than the observed crops, probably because APSIM does not account for effects of factors such as weeds, pests and diseases and impacts of severe weather. Simulated ‘what-if’ analysis suggested that further improvement in WUE may be achieved with an early sowing strategy or a higher nitrogen input strategy. A ‘yield maximising’ strategy that included an optimal plant density, early sowing date, and higher nitrogen inputs resulted in an average WUE (21.4 kg grain/ha.mm x-intercept = 80 mm) that is close to the previously reported (French-Schultz) boundary of WUE. This outcome suggests a great deal of scope for Australian wheat growers to adopt strategies that improve their WUE. Yield Prophet® farmers have already demonstrated significant improvement in on-farm WUE compared with previous studies. However, additional improvements will only be partially realised due to considerations of the cost: benefit ratio and risk in a highly variable climate, and the operational feasibility of these strategies with current technologies.
Publisher: CSIRO Publishing
Date: 2009
DOI: 10.1071/CP09020
Abstract: In Australia, a land subject to high annual variation in grain yields, farmers find it challenging to adjust crop production inputs to yield prospects. Scientists have responded to this problem by developing Decision Support Systems, yet the scientists’ enthusiasm for developing these tools has not been reciprocated by farm managers or their advisers, who mostly continue to avoid their use. Preceding papers in this series described the FARMSCAPE intervention: a new paradigm for decision support that had significant effects on farmers and their advisers. These effects were achieved in large measure because of the intensive effort which scientists invested in engaging with their clients. However, such intensive effort is time consuming and economically unsustainable and there remained a need for a more cost-effective tool. In this paper, we report on the evolution, structure, and performance of Yield Prophet®: an internet service designed to move on from the FARMSCAPE model to a less intensive, yet high quality, service to reduce farmer uncertainty about yield prospects and the potential effects of alternative management practices on crop production and income. Compared with conventional Decision Support Systems, Yield Prophet offers flexibility in problem definition and allows farmers to more realistically specify the problems in their fields. Yield Prophet also uniquely provides a means for virtual monitoring of the progress of a crop throughout the season. This is particularly important for in-season decision support and for frequent reviewing, in real time, of the consequences of past decisions and past events on likely future outcomes. The Yield Prophet approach to decision support is consistent with two important, but often ignored, lessons from decision science: that managers make their decisions by satisficing rather than optimising and that managers’ fluid approach to decision making requires ongoing monitoring of the consequences of past decisions.
Publisher: Elsevier BV
Date: 07-2023
Publisher: CSIRO Publishing
Date: 2019
DOI: 10.1071/SR18215
Abstract: A large-scale field experiment was used to investigate the long-term effects of a single application of manure or inorganic fertiliser on microbial communities in the topsoil and subsoil of a cropping field in south-west Victoria. Poultry litter (20 t ha–1) and fertiliser (with equivalent total nutrients to the manure) was either surface broadcast or deep ripped into the subsoil before sowing in 2014. Soil s les were collected from the 0–10 and 25–40cm horizons in each treatment immediately after harvest of the third successive crop in January 2017. Next-generation sequencing of the 16S and ITS rRNA genes was used to characterise the bacterial and fungal communities in the soil. Amendment type and method of placement had a limited effect on soil microbial community structure and ersity, three years after treatments were applied. Fungal communities exhibited weak responses to the poultry litter and fertiliser in comparison to a nil control, but none of the treatments had any detectable effect on bacterial communities. Differences in structure and ersity of microbial communities were overwhelmingly due to their vertical distribution in the soil profile, and not the application of different amendments to the soil by deep ripping or surface broadcasting. The strength and timing of the soil disturbance, plant selection effects and farm management history likely contributed to the lack of measurable response in the soil microbial community.
Publisher: Elsevier BV
Date: 05-2018
Publisher: Elsevier BV
Date: 04-2014
Publisher: Frontiers Media SA
Date: 27-05-2020
Publisher: Springer Science and Business Media LLC
Date: 29-07-2019
Publisher: CSIRO Publishing
Date: 2018
DOI: 10.1071/CP18102
Abstract: Flowering time of wheat (Triticum aestivum L.) is a critical determinant of grain yield. Frost, drought and heat stresses from either overly early or overly late flowering can inflict significant yield penalties. The ability to predict time of flowering from different sowing dates for erse cultivars across environments in Australia is important for maintaining yield as autumn rainfall events become less reliable. However, currently there are no models that can accurately do this when new cultivars are released. Two major Photoperiod1 and three Vernalisation1 development genes, with alleles identified by molecular markers, are known to be important in regulating phasic development and therefore time to anthesis, in response to the environmental factors of temperature and photoperiod. Allelic information from molecular markers has been used to parameterise models that could predict flowering time, but it is uncertain how much variation in flowering time can be explained by different alleles of the five major genes. This experiment used 13 elite commercial cultivars of wheat, selected for their variation in phenology and in turn allelic variation at the major development genes, and 13 near-isogenic lines (NILs) with matching multi-locus genotypes for the major development genes, to quantify how much response in time to flowering could be explained by alleles of the major genes. Genotypes were grown in four controlled environments at constant temperature of 22°C with factorial photoperiod (long or short day) and vernalisation (±) treatments applied. NILs were able to explain a large proportion of the variation of thermal time to flowering in elite cultivars in the long-day environment with no vernalisation (97%), a moderate amount in the short-day environment with no vernalisation (62%), and less in the short-day (51%) and long-day (47%) environments with vernalisation. Photoperiod was found to accelerate development, as observed in a reduction in phyllochron, thermal time to heading, thermal time to flowering, and decreased final leaf numbers. Vernalisation response was not as great, and rates of development in most genotypes were not significantly increased. The results indicate that the alleles of the five major development genes alone cannot explain enough variation in flowering time to be used to parameterise gene-based models that will be accurate in simulating flowering time under field conditions. Further understanding of the genetics of wheat development, particularly photoperiod response, is required before a model with genetically based parameter estimates can be deployed to assist growers to make sowing-time decisions for new cultivars.
Publisher: Frontiers Media SA
Date: 15-05-2020
Publisher: CSIRO Publishing
Date: 2012
DOI: 10.1071/CP12123
Abstract: The amounts of foliage nitrogen (N) fixed by various annual and perennial legumes growing in Australian pastures range from to kg N/ha.year. Differences in N2 fixation result from variations in the proportion of the legume-N derived from atmospheric N2 (%Ndfa) and/or the amount of legume-N accumulated during growth. On-farm surveys of %Ndfa achieved by legumes growing in farmers’ paddocks in Australia indicated that N2 fixation contributed % of the legume’s N requirements in three-quarters of the annual legumes examined, but this decreased to two-thirds of lucerne (Medicago sativa also known as alfalfa), and half of white clover (Trifolium repens) s les. Factors such as low numbers or the poor effectiveness of rhizobial strains in the soil, water stress, high soil concentrations of N, and nutrient disorders contribute to poor nodulation and %Ndfa values %, but there is also evidence that the observed %Ndfa can be dependent on the legume species present, and whether the legume is grown in a pure stand or in a mixed sward. The accumulation of legume-N relates primarily to the legume content and net productivity of the pasture. For many legume species, ~20 kg of shoot-N is fixed on average for every tonne of herbage dry matter produced. Legume productivity can be influenced by (i) sowing and establishment techniques and other strategies that enhance the legume content in pasture swards (ii) the amelioration of soil constraints (iii) the use of new legume species (and host–rhizobial strain combinations) that are more tolerant of hostile soil environments than subterranean clover (T. subterraneum) or annual medics (Medicago spp) and (iv) the inclusion of perennials such as lucerne to offset the year-to-year variability in productivity and N2 fixation that is a common occurrence with annual legumes.
Publisher: Elsevier BV
Date: 02-2023
Publisher: Elsevier BV
Date: 06-2022
Publisher: Elsevier BV
Date: 08-2017
Publisher: CSIRO Publishing
Date: 08-03-2023
DOI: 10.1071/CP22213
Abstract: Context Wheat (Triticum aestivum L.) adaptation is highly dependent on crop lifecycle duration, particularly the time at which flowering occurs in a specific environment. Frost, low solar radiation, heat and drought can significantly reduce yield if a crop flowers too early or late. Wheat genotypes have different lifecycle durations determined by plant responses to temperature (thermal time accumulation and vernalisation) and photoperiod. These responses are largely controlled by five phenology genes (two PPD1 and three VRN1 genes). Advances in crop phenology modelling suggest that flowering time under field conditions could be accurately predicted with parameters derived from photoperiod and vernalisation responses obtained in controlled environments. Aims This study quantified photoperiod and vernalisation responses of 69 Australian wheat genotypes selected for ersity at the PPD1 and VRN1 loci. Methods Spring and winter genotypes were grown in four controlled environments at a constant temperature of 22°C with photoperiod (17 or 8 h) and vernalisation (0 or 8 weeks) treatments as factors. Key results Thermal time from coleoptile emergence to flowering in spring genotypes was typically decreased more by long photoperiod than by vernalisation the opposite was true for winter genotypes. Spring genotypes that were sensitive to vernalisation contained a sensitive allele at the Vrn-A1 locus. Conclusions There is large ersity in phenological responses of wheat genotypes to photoperiod and vernalisation, including among those with matching multi-locus genotype. Implications Data from this study will be used to parameterise and test a wheat phenology model in a future study.
Publisher: American Chemical Society (ACS)
Date: 27-05-2020
Publisher: Elsevier BV
Date: 06-2021
Publisher: American Chemical Society (ACS)
Date: 06-12-2019
Publisher: Wiley
Date: 03-04-2020
DOI: 10.1111/GCB.15082
Publisher: CSIRO Publishing
Date: 2017
DOI: 10.1071/SR16330
Abstract: Nitrogen (N) contributed by legumes is an important component of N supply to subsequent cereal crops, yet few Australian grain-growers routinely monitor soil mineral N before applying N fertiliser. Soil and crop N data from 16 dryland experiments conducted in eastern Australia from 1989–2016 were examined to explore the possibility of developing simple predictive relationships to assist farmer decision-making. In each experiment, legume crops were harvested for grain or brown-manured (BM, terminated before maturity with herbicide), and wheat, barley or canola were grown. Soil mineral N measured immediately before sowing wheat in the following year was significantly higher (P 0.05) after 31 of the 33 legume pre-cropping treatments than adjacent non-legume controls. The average improvements in soil mineral N were greater for legume BM (60 ± 16 kg N/ha n = 5) than grain crops (35 ± 20 kg N/ha n = 26), but soil N benefits were similar when expressed on the basis of summer fallow rainfall (0.15 ± 0.09 kg N/ha per mm), residual legume shoot dry matter (9 ± 5 kg N/ha per t/ha), or total legume residue N (28 ± 11%). Legume grain crops increased soil mineral N by 18 ± 9 kg N/ha per t/ha grain harvested. Apparent recovery of legume residue N by wheat averaged 30 ± 10% for 20 legume treatments in a subset of eight experiments. Apparent recovery of fertiliser N in the absence of legumes in two of these experiments was 64 ± 16% of the 51–75 kg fertiliser-N/ha supplied. The 25 year dataset provided new insights into the expected availability of soil mineral N after legumes and the relative value of legume N to a following wheat crop, which can guide farmer decisions regarding N fertiliser use.
Publisher: Wiley
Date: 25-01-2013
DOI: 10.1111/WRE.12008
No related grants have been discovered for James Hunt.