ORCID Profile
0000-0002-2804-0384
Current Organisation
University of Adelaide
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Crop and Pasture Nutrition | Plant Cell and Molecular Biology | Crop and Pasture Production not elsewhere classified | Soil Sciences | Soil Biology | Crop and Pasture Production | Crop and Pasture Biochemistry and Physiology
Wheat | Cotton | Grain Legumes | Soybeans |
Publisher: Elsevier BV
Date: 05-2017
Publisher: CSIRO Publishing
Date: 2011
DOI: 10.1071/CP11039
Abstract: Annual clover species such as Trifolium purpureum Loisel., T. resupinatum L., and T. alexandrinum L. are adapted to alkaline soil conditions and provide certain agronomic advantages over annual medics (Medicago spp.). Annual clovers have not been widely grown in alkaline soils in Australia, and quantifying their dinitrogen (N2) fixation in alkaline soils is important in understanding their potential role in mixed farming systems of southern Australia. Using the 15N natural abundance technique, it was estimated that annual clovers fixed 101–137 kg N/ha at Roseworthy and 59–62 kg N/ha at Mallala, on Calcarosols with soil pH of 8.0 and 8.5, respectively. Species differed in the percentages of fixed N2 estimated in shoot dry matter, which was highest in T. alexandrinum (77–85%), moderate in T. resupinatum (76%), and lowest in T. purpureum (65–74%). Naturally occurring soil rhizobia (Rhizobium leguminosarum bv. trifolii) provided adequate nodulation, as inoculation with different strains of rhizobia had little influence on nodulation or N2 fixation. These results indicate that clovers can provide a significant contribution of fixed N2 to mixed farming systems. Examination of nodules indicated variable nodule occupancy by the inoculant rhizobia and that 69% of shoot N was fixed when clovers were nodulated by the soil populations of rhizobia. A simple model is defined to identify the potential interactions between inoculated legumes and soil rhizobia, and the options for enhancing symbiotic effectiveness are discussed.
Publisher: Informa UK Limited
Date: 07-2008
Publisher: Springer Science and Business Media LLC
Date: 06-01-2021
Publisher: Springer Science and Business Media LLC
Date: 19-12-2010
Publisher: MDPI AG
Date: 29-06-2022
DOI: 10.3390/SOILSYSTEMS6030058
Abstract: Land development is rapidly occurring on sand-dominant soils that cover substantial areas of the Lower Mekong Basin (LMB). Sands are at risk of degradation on sloping uplands where agriculture is expanding and on lowland landscapes where intensification of cropping is occurring. Sandstone and granitic geology explain the prevalence of sand-dominant textures of profiles in the LMB. However, the sand terrains in uplands of Cambodia and Southern Laos mostly have not been mapped in detail and the ersity of their edaphic properties is poorly understood. On high-permeability sands, lowland rainfed rice crops are drought-prone, while nutrient losses from leaching are also a risk. Furthermore, waterlogging, inundation and subsoil hardpans are significant hazards that influence the choice of crops and forages for lowland soils. Soil acidity, low nutrient status, hard-setting and shallow rooting depth are significant constraints for crops and forages on sands in the lowlands. Land use change in the lowlands to alternative field crops and forages on sands is contingent on their profitability relative to rice, the amounts and reliability of early wet season rainfall, and the amounts of stored water available after harvesting rice. Low soil fertility and soil acidity are limitations to the productivity of farming systems on the sand profiles in uplands, while erosion, low soil organic matter levels and water balance are concerns for their sustainable use. Site-/soil-specific fertilizer and lime management, land suitability assessment and the use of conservation agriculture principles (minimum tillage and crop residue retention) can overcome some of these constraints.
Publisher: Springer Science and Business Media LLC
Date: 19-10-2017
Publisher: Wiley
Date: 05-11-2020
DOI: 10.1002/CSC2.20286
Abstract: Tetraploid plants, including those induced from diploid barrel medic ( Medicago truncatula Gaertn.) and the snail medic [ Medicago scutellata (L.) Mill.], have the potential to increase vigor and leaf size to improve adaptation to environments with low and variable rainfall in Mediterranean climates. The growth of tetraploid lines induced from barrel medic cultivar Sultan‐SU was evaluated against the diploid parent line and a natural tetraploid snail medic cultivar Sava in field conditions in Adelaide, South Australia. In field conditions, tetraploid lines had up to 106% greater autumn biomass than Sultan‐SU, 58% larger seed weight, and a 127% increase in leaf area. In a controlled environment experiment, snail medic Sava was the only entry to show improved early season (assessed at 6 wk) shoot biomass and canopy cover under short days and low temperatures that were designed to simulate a late start to the growing season. An examination of fresh flower buds showed that the fertility and stability of induced tetraploid lines varied between lines and generations. Hardseed breakdown patterns differed among tetraploid mutant lines, with two lines having much harder seed than Sultan‐SU. Some tetraploid Medicago spp. produced greater early biomass and larger leaves than diploids. Increasing ploidy level provides plant breeders with a promising tool in the development of new cultivars better suited to future climate scenarios.
Publisher: Elsevier BV
Date: 06-2018
Publisher: Springer Science and Business Media LLC
Date: 29-08-2017
Abstract: Astragalus membranaceus, also known as Huangqi in China, is one of the most widely used medicinal herbs in Traditional Chinese Medicine. Traditional Chinese Medicine formulations from Astragalus membranaceus have been used to treat a wide range of illnesses, such as cardiovascular disease, type 2 diabetes, nephritis and cancers. Pharmacological studies have shown that immunomodulating, anti-hyperglycemic, anti-inflammatory, antioxidant and antiviral activities exist in the extract of Astragalus membranaceus . Therefore, characterising the biosynthesis of bioactive compounds in Astragalus membranaceus , such as Astragalosides, Calycosin and Calycosin-7-O-β- d -glucoside, is of particular importance for further genetic studies of Astragalus membranaceus . In this study, we reconstructed the Astragalus membranaceus full-length transcriptomes from leaf and root tissues using PacBio Iso-Seq long reads. We identified 27 975 and 22 343 full-length unique transcript models in each tissue respectively. Compared with previous studies that used short read sequencing, our reconstructed transcripts are longer, and are more likely to be full-length and include numerous transcript variants. Moreover, we also re-characterised and identified potential transcript variants of genes involved in Astragalosides, Calycosin and Calycosin-7-O-β- d -glucoside biosynthesis. In conclusion, our study provides a practical pipeline to characterise the full-length transcriptome for species without a reference genome and a useful genomic resource for exploring the biosynthesis of active compounds in Astragalus membranaceus .
Publisher: Informa UK Limited
Date: 30-08-2017
Publisher: CSIRO Publishing
Date: 2000
DOI: 10.1071/EA99035
Abstract: The current dissatisfaction with low productivity of annual medic (Medicago spp.) pastures has highlighted the need to seek alternative legumes to provide efficient N2 fixation in low rainfall, alkaline soil environments of southern Australia. Clover species adapted to these environments will have limited N2 fixation if effective rhizobia are not present in sufficient quantities. A survey of 61 sites was conducted across South Australia to determine the size, distribution and effectiveness of Rhizobium leguminosarum bv. trifolii (clover rhizobia) populations resident in these low rainfall, alkaline soil environments. Clover rhizobia were detected at 56 of the sites, with a median density of 230–920 rhizobia/g soil. Most rhizobial populations were poor in their capacity to fix nitrogen. Rhizobial populations from fields provided 11–89% and 10–85% of the shoot biomass of commercial reference strains when inoculated onto host legumes T. purpureum (purple clover) and T. resupinatum (persian clover), respectively. Rhizobial population size was correlated negatively to pH and the percentage of CaCO3 in the soil, and was significantly increased in the rhizospheres of naturalised clover, found at 17 sites. Management options for rhizobial populations to improve legume ersity and productivity are discussed in terms of rhizobial population dynamics and likely soil constraints to successful rhizobial colonisation.
Publisher: Wiley
Date: 05-2017
Publisher: Elsevier BV
Date: 08-2018
Publisher: Springer Science and Business Media LLC
Date: 23-02-2016
Publisher: Oxford University Press (OUP)
Date: 24-07-2020
DOI: 10.1111/JAM.14754
Publisher: Springer Science and Business Media LLC
Date: 06-05-2019
Publisher: CSIRO Publishing
Date: 1994
DOI: 10.1071/MF9941395
Abstract: The response of M. halmaturorum was measured to determine the ability of juvenile plants to survive flooding and to examine how this influenced plant growth. Seedlings and one- and two-year-old plants were flooded to 0% (control), 50% or 100% of their initial height for periods of three to 14 weeks, followed by an eight-week recovery period. Only 22% of seedlings survived five weeks of 100% coverage, but these died during the recovery period. The older plants survived the flooding treatments well, but as duration increased so survival through the recovery period declined. After 100% coverage for six weeks followed by the recovery period, only 29% survived. Stem linear extension rates corresponding to these survival rates were used to predict the survival of juvenile M. halmaturorum in Bool Lagoon, South Australia. The results showed that, with the current water regime, natural recruitment would occur only at the highest elevation but that this could be improved by planting older, taller plants at lower elevations. Indices of growth showed that flooded plants performed poorly compared with the controls as duration and percentage of coverage increased. The data suggested that coverage inhibited plant growth during the flood period, but there was a further, interactive response to duration that became apparent after the post-flood recovery period. An interpretation of these results is that M. halmaturorum in its juvenile stages is intermediate between a flood-sensitive and a flood-tolerant species because it is able to recover from short floods of three weeks or less but performs poorly if floods exceed six to nine weeks.
Publisher: Springer Science and Business Media LLC
Date: 16-11-2018
Publisher: Elsevier BV
Date: 02-2019
Publisher: Elsevier BV
Date: 06-2021
Publisher: Springer Science and Business Media LLC
Date: 15-09-2020
Publisher: MDPI AG
Date: 29-10-2020
DOI: 10.3390/MICROORGANISMS8111687
Abstract: Soil nitrification (microbial oxidation of ammonium to nitrate) can lead to nitrogen leaching and environmental pollution. A number of plant species are able to suppress soil nitrifiers by exuding inhibitors from roots, a process called biological nitrification inhibition (BNI). However, the BNI activity of perennial grasses in the nutrient-poor soils of Australia and the effects of BNI activity on nitrifying microbes in the rhizosphere microbiome have not been well studied. Here we evaluated the BNI capacity of bermudagrass (Cynodon dactylon L.), St. Augustinegrass (Stenotaphrum secundatum (Walt.) Kuntze), saltwater couch (Sporobolus virginicus), seashore paspalum (Paspalum vaginatum Swartz.), and kikuyu grass (Pennisetum clandestinum) compared with the known positive control, koronivia grass (Brachiaria humidicola). The microbial communities were analysed by sequencing 16S rRNA genes. St. Augustinegrass and bermudagrass showed high BNI activity, about 80 to 90% of koronivia grass. All the three grasses with stronger BNI capacities suppressed the populations of Nitrospira in the rhizosphere, a bacteria genus with a nitrite-oxidizing function, but not all of the potential ammonia-oxidizing archaea. The rhizosphere of saltwater couch and seashore paspalum exerted a weak recruitment effect on the soil microbiome. Our results demonstrate that BNI activity of perennial grasses played a vital role in modulating nitrification-associated microbial populations.
Publisher: Springer Science and Business Media LLC
Date: 11-01-2019
Publisher: MDPI AG
Date: 13-10-2022
DOI: 10.3390/SU142013113
Abstract: The participation of youth in agricultural entrepreneurship (agripreneurship) is beneficial for the sustainable development of agrarian societies that are transitioning towards the commercialization of agriculture. Accordingly, we investigated the phenomena that motivate practicing young, small- and medium-scale agripreneurs to pursue their careers, using the Lao People’s Democratic Republic (Laos) as a case study. To achieve this, we applied narrative inquiry techniques to the accounts of 74 young Laotian agripreneurs regarding their entry into agripreneurship. This enabled us to identify and describe common and influential paradigms that were subsequently interpreted from the perspective of entrepreneurship and behavioral studies of career decision making to explain the influence of motivations on the young agripreneurs. Our study has shown that despite the characteristics that set agripreneurship in Laos apart from entrepreneurship in general, commonly identified typologies of entrepreneurial motivation, particularly income, extrinsic benefits and emotional paradigms also motivate Lao youth to become agripreneurs. The application of narrative inquiry has revealed the emphasis some practicing agripreneurs in Laos place on the attainability of their career, which resulted in its practice by both opportunity-driven and necessity-driven entrepreneurs, with implications for the sustainable development of other countries in transition to commercial agriculture.
Publisher: Elsevier BV
Date: 05-2021
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: 17-09-2007
DOI: 10.1111/J.1365-3040.2007.01733.X
Abstract: Banksia species (Proteaceae) occur on some of the most phosphorus (P)-impoverished soils in the world. We hypothesized that Banksia spp. maximize P-use efficiency through high photosynthetic P-use efficiency, long leaf lifespan (P residence time), effective P re-mobilization from senescing leaves, and maximizing seed P concentration. Field and glasshouse experiments were conducted to quantify P-use efficiency in nine Banksia species. Leaf P concentrations for all species were extremely low (0.14-0.32 mg P g(-1) DM) compared with leaf P in other species reported and low relative to other plant nutrients in Banksia spp. however, moderately high rates of photosynthesis (13.8-21.7 micromol CO2 m(-2) s(-1)), were measured. Some of the Banksia spp. had greater P proficiency (i.e. final P concentration in senesced leaves after re-mobilization range: 27-196 microg P g(-1) DM) than values reported for any other species in the literature. Seeds exhibited significantly higher P concentrations (6.6-12.2 mg P g(-1 )DM) than leaves, and species that sprout after fire ('re-sprouters') had significantly greater seed mass and P content than species that are killed by fire and regenerate from seed ('seeders'). Seeds contained only small amounts of polyphosphate (between 1.3 and 6 microg g(-1) DM), and this was not correlated with P concentration or fire response. Based on the evidence in the present study, we conclude that Banksia species are highly efficient in their use of P, explaining, in part, their success on P-impoverished soils, with little variation between species.
Publisher: Springer Science and Business Media LLC
Date: 18-06-2021
Publisher: Springer Science and Business Media LLC
Date: 10-09-2020
Publisher: Springer Science and Business Media LLC
Date: 30-09-2021
DOI: 10.1038/S41597-021-01006-6
Abstract: We introduce the AusTraits database - a compilation of values of plant traits for taxa in the Australian flora (hereafter AusTraits). AusTraits synthesises data on 448 traits across 28,640 taxa from field c aigns, published literature, taxonomic monographs, and in idual taxon descriptions. Traits vary in scope from physiological measures of performance (e.g. photosynthetic gas exchange, water-use efficiency) to morphological attributes (e.g. leaf area, seed mass, plant height) which link to aspects of ecological variation. AusTraits contains curated and harmonised in idual- and species-level measurements coupled to, where available, contextual information on site properties and experimental conditions. This article provides information on version 3.0.2 of AusTraits which contains data for 997,808 trait-by-taxon combinations. We envision AusTraits as an ongoing collaborative initiative for easily archiving and sharing trait data, which also provides a template for other national or regional initiatives globally to fill persistent gaps in trait knowledge.
Publisher: Springer Science and Business Media LLC
Date: 02-2005
Publisher: Springer Science and Business Media LLC
Date: 04-07-2010
Publisher: Wiley
Date: 03-10-2019
Publisher: CSIRO Publishing
Date: 2020
DOI: 10.1071/SR20010
Abstract: Tillage management can influence soil physical properties such as soil strength, moisture content, temperature, nutrient and oxygen availability, which in turn can affect crop growth during the early establishment phase. However, a short-term ‘strategic’ conventional tillage (CT) shift in tillage practice in a continuous no-tillage (NT) cropping system may change the soil-pore and root geometry. This study identifies the impact of a tillage regime shift on the belowground soil-pore and root geometry. Micro X-ray computed tomography (µXCT) was used to quantify, measure and compare the soil-pore and root architecture associated with the impact of tillage shift across different plant growth stages. Soil porosity was 12.2% higher under CT in the top 0–100 mm and 7.4% in the bottom 100–200 mm of the soil core compared with NT. Soil-pore distribution, i.e. macroporosity (& μm), was 13.4% higher under CT, but mesoporosity (30–75 μm) was 9.6% higher under NT. The vertical distributions of root biomass and root architecture measurements (i.e. root length density) in undisturbed soil cores were 9.6% higher under the NT and 8.7% higher under the CT system respectively. These results suggest that low soil disturbance under the continuous NT system may have encouraged accumulation of more root biomass in the top 100 mm depth, thus developing better soil structure. Overall, µXCT image analyses of soil cores indicated that this tillage shift affected the soil total carbon, due to the significantly higher soil-pore (i.e. pore surface area, porosity and average pore size area) and root architecture (i.e. root length density, root surface density and root biomass) measurements under the CT system.
Publisher: Oxford University Press (OUP)
Date: 24-02-2020
DOI: 10.1111/JAM.14602
Publisher: Wiley
Date: 04-10-2020
Publisher: CSIRO Publishing
Date: 2012
DOI: 10.1071/CP12032
Abstract: The population size and symbiotic performance (ability to fix N2) of rhizobia (Rhizobium leguminosarum bv. viciae) capable of nodulating field pea (Pisum sativum) were assessed in 114 soils from Mediterranean-type environments of southern Australia. All soils were collected in autumn, before the growing season, and had a history of crop legumes including field pea, faba bean, lentil, or vetch. The most probable number (MPN) technique, with vetch as a trap plant, was used to estimate the numbers of pea rhizobia in soils. Of the soils tested, 29% had low numbers of pea rhizobia ( rhizobia/g), 38% had moderate numbers (100–1000/g), and the remaining 33% had /g. Soil pH, the frequency of a host crop in the rotation, and the number of summer days with a maximum temperature °C were strongly correlated with the pea rhizobia population size. Symbiotic performance (SP) of pea rhizobia in soils was assessed for soils with a MPN rhizobia/g. An extract of the soils was used to inoculate two field pea cultivars growing in a nitrogen-deficient potting media in the greenhouse. Plants were grown for 5 weeks after inoculation and shoot dry matter was expressed as a percentage of the dry matter of plants grown with a commercial strain R. leguminosarum bv. viciae, SU303. Symbiotic performance ranged from 25 to 125%. One-quarter of the soils assessed had suboptimal SP (i.e. %). Soil and climatic variables were weakly associated with SP, with pH and average annual rainfall accounting for 17% of the variance. This research highlights the complexity of factors influencing population size and symbiotic performance of pea rhizobia in soils. Options for the improved management of populations of pea rhizobia in Mediterranean environments are discussed. Specifically, our data indicate that inoculation of pea crops is likely to be beneficial where pH(H2O) .6, particularly when summers have been hot and dry and when a host has been absent for ≥5 years, as numbers of rhizobia are likely to be below the thresholds needed to optimise nodulation and crop growth. New inoculation technologies and plant breeding will be required to overcome large populations of pea rhizobia with suboptimal SP.
Publisher: Elsevier BV
Date: 02-2007
Publisher: Elsevier BV
Date: 12-2009
Publisher: Springer Science and Business Media LLC
Date: 06-04-2020
DOI: 10.1186/S13059-020-01999-0
Abstract: The soil environment is responsible for sustaining most terrestrial plant life, yet we know surprisingly little about the important functions carried out by erse microbial communities in soil. Soil microbes that inhabit the channels of decaying root systems, the detritusphere, are likely to be essential for plant growth and health, as these channels are the preferred locations of new root growth. Understanding the microbial metagenome of the detritusphere, and how it responds to agricultural management such as crop rotations and soil tillage, is vital for improving global food production. This study establishes an in-depth soil microbial gene catalogue based on the living-decaying rhizosphere niches in a cropping soil. The detritusphere microbiome regulates the composition and function of the rhizosphere microbiome to a greater extent than plant type: rhizosphere microbiomes of wheat and chickpea were homogenous (65–87% similarity) in the presence of decaying root (DR) systems but were heterogeneous (3–24% similarity) where DR was disrupted by tillage. When the microbiomes of the rhizosphere and the detritusphere interact in the presence of DR, there is significant degradation of plant root exudates by the rhizosphere microbiome, and genes associated with membrane transporters, carbohydrate and amino acid metabolism are enriched. The study describes the ersity and functional capacity of a high-quality soil microbial metagenome. The results demonstrate the contribution of the detritusphere microbiome in determining the metagenome of developing root systems. Modifications in root microbial function through soil management can ultimately govern plant health, productivity and food security.
Publisher: CSIRO Publishing
Date: 15-11-2021
DOI: 10.1071/CP21258
Abstract: Context Perennial forage grass species are often grown with limited water following establishment and rely on accessing water deep in the soil profile to survive. Aim This study aimed to characterise bermudagrass (Cynodon spp.) genotypes with rapid vertical root growth associated with post-establishment survival. Methods Twelve bermudagrasses representing genotypes from erse climate zones in Australia were established in rhizotrons to analyse the stability in genotypic variation in root and shoot growth in winter and summer experiments. Genotypic rank of root length, leaf area, and root dry weight were consistent in both seasons. Key results Bermudagrass genotypes exhibited different traits correlated with root vertical growth rate and inconsistency of genotypic rank of shoot growth. During winter establishment, the rate of root depth development (RRDD) (r = −0.64) was correlated with the proportion of root length that became inactive, that was likely due to seasonal root death in winter conditions during summer establishment, RRDD was correlated with tiller appearance rate (r = 0.45) and root distribution to 10 cm depth (r = −0.62). Shoot dry weight was correlated with photosynthesis (r = 0.85) and transpiration (r = 0.79) in summer, but not in winter. RRDD (r = 0.75, winter and r = 0.77, summer) was correlated with drought resistance index, previously analysed under field conditions. Conclusions and implications Genotypes from the Mediterranean climates in Australia showed rapid growth of roots and shoots in both seasons and have the greatest potential for broader application for forage production in variable environments.
Publisher: Informa UK Limited
Date: 12-03-2020
Publisher: Elsevier BV
Date: 08-2003
Publisher: Elsevier BV
Date: 2019
Publisher: Springer Science and Business Media LLC
Date: 24-03-2023
Publisher: MDPI AG
Date: 03-2020
Abstract: An in-depth assessment of plant nutrient resorption can offer insights into understanding ecological processes and functional responses to biotic and abiotic changes in the environment. The legume proportion in a mixed grassland can drive changes in the soil environment and plant relationships, but little information is available regarding how the legume proportion influences plant nutrient resorption in mixed grasslands. In this study, three mixed communities of Leymus chinensis (Trin.) Tzvel. and Medicago sativa L. differing in legume proportion (Low-L, with 25% legume composition Mid-L, with 50% legume composition High-L, with 75% legume composition) were established with four replicates in a degraded grassland. Four years after establishing the mixed grassland, the quantity of biological N2 fixation by M. sativa, the availabilities of water and nitrogen (N) and phosphorus (P) in soil were examined, and the concentrations and resorption of leaf N and P for both species were measured during forage maturation and senescence. The results showed Mid-L had greater biological N2 fixation and soil N availability than Low-L and High-L, while the High-L had lower soil water and P availability, but a greater soil available N:P ratio compared with Low-L and Mid-L. Legume proportion did not alter N or P concentrations of mature leaves. However, in Mid-L N resorption was reduced by 8 to 16% for the two mixed-species compared with Low-L and High-L. High-L enhanced P resorption by 20 to 24% in both plant species compared with Low-L. The L. chinensis and M. sativa responded differently to varied legume proportion in terms of P resorption. It was concluded that legume proportion drove changes in soil nutrient availability of mixed communities, which primarily altered plant nutrient resorption during senescence, but had no influence on the nutrient concentrations of mature plants. A moderate legume proportion reduced N resorption, and increased senesced leaf N concentration of grass and legume species. The difference in P resorption by two mixed-species significantly changed the interspecific difference of senesced leaf P concentration and the N:P ratio with varied legume proportion.
Publisher: CSIRO Publishing
Date: 2002
DOI: 10.1071/AR01138
Abstract: Inoculant rhizobia typically need to compete with naturalised soil populations of rhizobia to form legume nodules. We have used the polymerase chain reaction to test the ability of seed-inoculated rhizobia to compete with naturalised populations of rhizobia and form nodules on clover (Trifolium alexandrinum, T.�purpureum, and T. resupinatum) in alkaline soil. Clover rhizobia, Rhizobium leguminosarum bv. trifolii, were identified at the strain level using either a nif-specific RP01 primer or ERIC primers. Analysis of rhizobia isolated from nodules indicated that strain TA1 competed poorly for nodule occupancy at 2 field sites (Roseworthy and Mallala, South Australia), with the exception that it nodulated T. alexandrinum at a level of 39% at the Roseworthy site in the first year of the trial. Strains CC2483g and WSM409 successfully colonised nodules when inoculated onto a particular clover species (T. resupinatum and T. purpureum, respectively) in the first year of inoculation and persisted in the soil to form nodules in the following year. Nodules frequently contained naturalised strains of rhizobia, distinct from introduced commercial strains. Dominant isolates were specific to a field site and nodulated all 3 clover species in both years of the field trial, with each isolate occupying up to 19% of the total nodules at a field site. It was hypothesised that field isolates had a better alkaline soil tolerance conferring a greater ability to nodulate clovers under these edaphic conditions. The results indicate that soil populations of rhizobia may provide a significant constraint to the introduction of current Australian commercial clover rhizobia into alkaline soils, and a more profitable strategy may be to seek rhizobial inoculants that are adapted to these soils.
Publisher: Wiley
Date: 16-01-2007
DOI: 10.1111/J.1469-8137.2006.01956.X
Abstract: Banksia species (Proteaceae) occur on some of the most phosphorus (P)-impoverished soils in the world. We hypothesized that plasticity in the exudation of P-mobilizing carboxylates would be greater in widespread than in rare Banksia species. Glasshouse experiments were conducted to identify and quantify carboxylate exudation in three widespread and six narrowly distributed Banksia species. High concentrations of carboxylates (predominantly malate, citrate, aconitate, oxalate) were measured in the rhizosphere of all nine species of Banksia on six different soils, but widespread species did not have greater plasticity in the composition of exuded carboxylates. Based on the evidence in the present study, rarity in Banksia cannot be explained by limited phenotypic adjustment of carboxylate exudation.
Publisher: Wiley
Date: 14-05-2019
DOI: 10.1002/9781119312994.APR0697
Abstract: Intensification of agricultural land and the overuse of inorganic fertilisers has led to soil acidification, depletion of organic matter, and environmental pollution. Approaches to protect soil health, including the enhancement of microbial ersity, are integral to improving crop productivity and food security. Metagenomics has rapidly improved our understanding of soil microbial ersity and function, while genetic techniques have helped to dissect the complex signal exchange between microorganisms and plants. This article presents and evaluates reported beneficial effects of plant growth‐promoting bacteria (PGPB), focussing on those capable of mobilising or solubilising nutrients and/or stimulating plant growth when applied to agriculturally important grasses. The agricultural industry has capitalised on these scientific advancements, generating microbial formulations for specific crop responses. However, scientific methodologies must be applied in order to overcome inherent limitations of many PGPBs including their inability to be cultured, their poorly defined or multiple modes of action, a low level of integration with the crop partner, and an unpredictability in translating beneficial plant responses to the field. Novel approaches such as engineered rhizospheres, enhancing endophytic systems, cereal nodule development, and the use of inoculant consortiums will be necessary to sustain growth in the biofertiliser industry.
Publisher: Informa UK Limited
Date: 22-01-2019
Publisher: MDPI AG
Date: 26-02-2023
DOI: 10.3390/SU15054219
Abstract: Efforts to achieve inclusive and sustainable agricultural-sector growth in developing economies will benefit from agricultural entrepreneurship (agripreneurship) by young farmers. However, challenges that hinder transition from subsistence to commercial agriculture remain. A better understanding of enablers and constraints that young farmers experience can facilitate the development of an enabling environment for sustainably transitioning from subsistence into commercial agriculture. We interviewed 74 young agricultural entrepreneurs (agripreneurs) in Laos, a country with a young and highly rural population, to explore their perceptions of institutions and support functions that enable or limit agripreneurship. Respondents reported that institutions and support functions have generally improved to make agripreneurship easier than before, with infrastructure, logistics, and new platforms for information sharing, banking, marketing, and delivery identified as specific improvements. However, agripreneurs identified weaknesses in the nature, scope, and quality of agricultural information and extension services that limit their performance difficulties in accessing loans with favorable conditions, which discourages investment opaque and costly payments and red tape processes that frustrate business establishment, operations, and regulatory compliance and a lack of targeted policy actions towards enabling youth agripreneurship, which leaves youth feeling unsupported. Improvements in infrastructure, promotion of agri-careers, and more transparency of taxation, registration, and administration fees/systems are recommended.
Publisher: CSIRO Publishing
Date: 2011
DOI: 10.1071/CP11229
Abstract: Developing new perennial pasture legumes for low-P soils is a priority for Australian Mediterranean agro-ecosystems, where soil P availability is naturally low. As legumes tend to require higher P inputs than non-legumes, the ability of these plants to fix N2 under varying soil P levels must be determined. Therefore, the objective of this study was to investigate the influence of soil P supply on plant N status and nodule formation in 11 perennial legumes, including some novel pasture species. We investigated the effect of applying soil P, ranging from 0 to 384 μg P/g dry soil, on plant N status and nodulation in a glasshouse. Without exogenous P supply, shoot N concentration and N : P ratio were higher than at 6 μg P/g soil. Shoot N concentration and N : P ratio then changed little with further increase in P supply. There was a close positive correlation between the number of nodules and shoot P concentration in 7 of the 11 species. Total nodule dry weight and the percentage of plant dry weight that consisted of nodules increased when P supply increased from 6 to 48 μg P/g. Without exogenous P addition, N : P ratios partitioned into a two-group distribution, with species having a N : P ratio of either or g/g. We suggest that plants with a high N : P ratio may take up N from the soil constitutively, while those with a low N : P ratio may regulate their N uptake in relation to internal P concentration. The flexibility of the novel pasture legumes in this study to adjust their leaf N concentrations under different levels of soil P supplements other published evidence of good growth and high P uptake and P-use efficiency under low soil P supply and suggests their potential as pasture plants in low-P soils in Australian Mediterranean agro-ecosystems warrants further attention.
Publisher: Elsevier BV
Date: 2020
Publisher: Oxford University Press (OUP)
Date: 05-05-2021
DOI: 10.1111/JAM.15108
Publisher: Cold Spring Harbor Laboratory
Date: 07-01-2021
DOI: 10.1101/2021.01.04.425314
Abstract: We introduce the AusTraits database - a compilation of measurements of plant traits for taxa in the Australian flora (hereafter AusTraits). AusTraits synthesises data on 375 traits across 29230 taxa from field c aigns, published literature, taxonomic monographs, and in idual taxa descriptions. Traits vary in scope from physiological measures of performance (e.g. photosynthetic gas exchange, water-use efficiency) to morphological parameters (e.g. leaf area, seed mass, plant height) which link to aspects of ecological variation. AusTraits contains curated and harmonised in idual-, species- and genus-level observations coupled to, where available, contextual information on site properties. This data descriptor provides information on version 2.1.0 of AusTraits which contains data for 937243 trait-by-taxa combinations. We envision AusTraits as an ongoing collaborative initiative for easily archiving and sharing trait data to increase our collective understanding of the Australian flora.
Publisher: Elsevier BV
Date: 06-2019
Publisher: CSIRO Publishing
Date: 2006
DOI: 10.1071/FP06176
Abstract: Many Australian plant species have specific root adaptations for growth in phosphorus-impoverished soils, and are often sensitive to high external P concentrations. The growth responses of native Australian legumes in agricultural soils with elevated P availability in the surface horizons are unknown. The aim of these experiments was to test the hypothesis that increased P concentration in surface soil would reduce root proliferation at depth in native legumes. The effect of P placement on root distribution was assessed for two Australian legumes, Kennedia prorepens F. Muell. and Lotus australis Andrews, and the exotic Medicago sativa L. Three treatments were established in a low-P loam soil: amendment of 0.15 g mono-calcium phosphate in either (i) the top 50 mm (120 µg P g–1) or (ii) the top 500 mm (12 µg P g–1) of soil, and an unamended control. In the unamended soil M. sativa was shallow rooted, with 58% of the root length of in the top 50 mm. K. prorepens and L. australis had a more even distribution down the pot length, with only 4 and 22% of their roots in the 0–50 mm pot section, respectively. When exposed to amendment of P in the top 50 mm, root length in the top 50 mm increased 4-fold for K. prorepens and 10-fold for M. sativa, although the pattern of root distribution did not change for M. sativa. L. australis was relatively unresponsive to P additions and had an even distribution of roots down the pot. Shoot P concentrations differed according to species but not treatment (K. prorepens 2.1 mg g–1, L. australis 2.4 mg g–1, M. sativa 3.2 mg g–1). Total shoot P content was higher for K. prorepens than for the other species in all treatments. In a second experiment, mono-ester phosphatases were analysed from 1-mm slices of soil collected directly adjacent to the rhizosphere. All species exuded phosphatases into the rhizosphere, but addition of P to soil reduced phosphatase activity only for K. prorepens. Overall, high P concentration in the surface soil altered root distribution, but did not reduce root proliferation at depth. Furthermore, the Australian herbaceous perennial legumes had root distributions that enhanced P acquisition from low-P soils.
Publisher: Scientific Societies
Date: 08-2020
DOI: 10.1094/MPMI-03-20-0076-A
Abstract: Trichoderma species are widely used to control fungal and nematode diseases of crops. To date, only one complete Trichoderma genome has been sequenced, T. reesei QM6a, a model fungus for industrial enzyme production, while the species or strains used for biological control of plant diseases are only available as draft genomes. Previously, we demonstrated that two Trichoderma strains (T. afroharzianum and T. cyanodichotomus) provide effective control of nematode and fungal plant pathogens. Based on deep sequencing using Illumina and Pacbio platforms, we have assembled high-quality genomes of the above two strains, with contig N 50 reaching 4.2 and 1.7 Mbp, respectively, which is greater than those of published draft genomes. The genome data will provide a resource to assist research on the biological control mechanisms of Trichoderma spp.
Publisher: Informa UK Limited
Date: 07-02-2018
Publisher: Springer Science and Business Media LLC
Date: 09-08-2012
Publisher: Springer Science and Business Media LLC
Date: 29-11-2019
Publisher: Elsevier BV
Date: 03-2022
Publisher: Elsevier BV
Date: 09-2018
Publisher: Elsevier BV
Date: 07-2018
Publisher: Springer Science and Business Media LLC
Date: 05-07-2017
Start Date: 11-2021
End Date: 11-2025
Amount: $642,434.00
Funder: Australian Research Council
View Funded ActivityStart Date: 06-2016
End Date: 12-2021
Amount: $3,972,614.00
Funder: Australian Research Council
View Funded Activity