‘Haying-off' in wheat is predicted to increase under a future climate in south-eastern Australia

2012 ◽  
Vol 63 (7) ◽  
pp. 593 ◽  
Author(s):  
J. G. Nuttall ◽  
G. J. O'Leary ◽  
N. Khimashia ◽  
S. Asseng ◽  
G. Fitzgerald ◽  
...  
Keyword(s):  
Grain Filling ◽  
Future Climate ◽  
Maximum Temperature ◽  
Wheat Crop ◽  
Semiarid Regions ◽  
South Eastern ◽  
Eastern Australia ◽  
Biomass Ratio ◽  
The Impact ◽  
South Eastern Australia

Under a future climate for south-eastern Australia there is the likelihood that the net effect of elevated CO2, (eCO2) lower growing-season rainfall and high temperature will increase haying-off thus limit production of rain-fed wheat crops. We used a modelling approach to assess the impact of an expected future climate on wheat growth across four cropping regions in Victoria. A wheat model, APSIM-Nwheat, was performance tested against three datasets: (i) a field experiment at Wagga Wagga, NSW; (ii) the Australian Grains Free Air Carbon dioxide Enrichment (AGFACE) experiment at Horsham, Victoria; and (iii) a broad-acre wheat crop survey in western Victoria. For down-scaled climate predictions for 2050, average rainfall during October, which coincides with crop flowering, decreased by 32, 29, 26, and 18% for the semiarid regions of the northern Mallee, the southern Mallee, Wimmera, and higher rainfall zone, (HRZ) in the Western District, respectively. Mean annual minimum and maximum temperature over the four regions increased by 1.9 and 2.2°C, respectively. A pair-wise comparison of the yield/anthesis biomass ratio across climate scenarios, used for assessing haying-off response, revealed that there was a 39, 49 and 47% increase in frequency of haying-off for the northern Mallee, southern Mallee and Wimmera, respectively, when crops were sown near the historically optimal time (1 June). This translated to a reduction in yield from 1.6 to 1.4 t/ha (northern Mallee), 2.5 to 2.2 t/ha (southern Mallee) and 3.7 to 3.6 t/ha (Wimmera) under a future climate. Sowing earlier (1 May) reduced the impact of a future climate on haying-off where decreases in yield/anthesis biomass ratio were 24, 28 and 23% for the respective regions. Heavy textured soils exacerbated the impact of a future climate on haying-off within the Wimmera. Within the HRZ of the Western District crops were not water limited during grain filling, so no evidence of haying-off existed where average crop yields increased by 5% under a future climate (6.4–6.7 t/ha). The simulated effect of eCO2 alone (FACE conditions) increased average yields from 18 to 38% for the semiarid regions but not in the HRZ and there was no evidence of haying-off. For a future climate, sowing earlier limited the impact of hotter, drier conditions by reducing pre-anthesis plant growth, grain set and resource depletion and shifted the grain-filling phase earlier, which reduced the impact of future drier conditions in spring. Overall, earlier sowing in a Mediterranean-type environment appears to be an important management strategy for maintaining wheat production in semiarid cropping regions into the future, although this has to be balanced with other agronomic considerations such as frost risk and weed control.

The impact of fire regimes on populations of an endangered lizard in montane south-eastern Australia

2014 ◽  
Vol 40 (2) ◽  
pp. 170-177 ◽  
Author(s):  
Sarsha Gorissen ◽  
Jacqueline Mallinson ◽  
Matthew Greenlees ◽  
Richard Shine
Keyword(s):  
Fire Regimes ◽  
South Eastern ◽  
Eastern Australia ◽  
The Impact ◽  
South Eastern Australia

scholarly journals Applying seed germination studies in fire management for biodiversity conservation in south-eastern Australia

Web Ecology ◽  
2008 ◽  
Vol 8 (1) ◽  
pp. 47-54 ◽  
Author(s):  
T. D. Auld ◽  
M. K. J. Ooi
Keyword(s):  
Seed Germination ◽  
Seed Dormancy ◽  
Fire Regimes ◽  
Functional Trait ◽  
Strong Response ◽  
South Eastern ◽  
Germination Response ◽  
Eastern Australia ◽  
The Impact ◽  
South Eastern Australia

Abstract. We examine the patterns of germination response to fire in the fire-prone flora of the Sydney basin, south-eastern Australia, using examples from several decades of research. The flora shows a strong response to fire-related germination cues. Most species show an interaction between heat and smoke, a number respond only to heat, whilst a few are likely to respond only to smoke. Many recruit in the first 12 months after fire and show no obvious seasonal patterns of recruitment, whilst several species have a strong seasonal germination requirement, even in this essentially aseasonal rainfall region. Key challenges remaining include designing future seed germination studies within the context of informing the germination response surface to smoke and heat interactions, and incorporation of the impact of varying soil moisture on seed germination post-fire, including its affect on resetting of seed dormancy. An understanding of the resilience of species to frequent fire also requires further work, to identify species and functional types most at risk. This work must ideally be integrated within the framework of the management of fire regimes that will change under a changing climate. We suggest that the functional classification of plant types in relation to fire could be enhanced by a consideration of both the type of germination response to fire (type of cues required) and the timing of the response (seasonally driven in response to seed dormancy characteristics, or independent of season). We provide a simplified version of such an addition to functional trait classification in relation to fire.

Crop damage caused by residual acetolactate synthase herbicides in the soils of south-eastern Australia

2006 ◽  
Vol 46 (10) ◽  
pp. 1323 ◽  
Author(s):  
K. L. Hollaway ◽  
R. S. Kookana ◽  
D. M. Noy ◽  
J. G. Smith ◽  
N. Wilhelm
Keyword(s):  
Acetolactate Synthase ◽  
Clay Soils ◽  
Alkaline Soil ◽  
Alkaline Soils ◽  
Metsulfuron Methyl ◽  
Herbicide Residues ◽  
South Eastern ◽  
Eastern Australia ◽  
The Impact ◽  
South Eastern Australia

Grain growers in south-eastern Australia have reported unexpected crop failures with theoretically safe recropping periods for acetolactate synthase herbicides in alkaline soils. This experience has led to the concern that these herbicides may degrade very slowly in alkaline soils, and herbicide residues have at times been blamed for unexplained crop losses. To address this issue, we established 5 recropping trials across Victoria and South Australia with 5 acetolactate synthase herbicides (chlorsulfuron, triasulfuron, metsulfuron-methyl, imazethapyr, and flumetsulam). The herbicides were applied to separate plots in years 1, 2 or 3, and sensitive crop species were sown in year 4 to measure the impact of herbicide residues. We observed that the persistence of the sulfonylureas (chlorsulfuron, triasulfuron, metsulfuron-methyl) varied between herbicides, but all persisted longer in alkaline soils than in acid soils, and were, therefore, more likely to damage crops in alkaline soil. Imazethapyr persisted longer in clay soils than in sandy soils and was, therefore, more likely to damage crops in clay soils. All herbicides persisted longer when rainfall was below average. Canola was more sensitive to imazethapyr than either pea, lentil or medic, but was less sensitive to the sulfonylureas. In contrast, lentil and medic were the most sensitive to sulfonylureas. Despite some damage, we found that safe recropping periods could be predicted from the product labels in all but one situation. The sole exception was that metsulfuron-methyl reduced dry matter and yield of lentil and medic sown 10 months after application in a soil with pH 8.5. We hypothesise that the real cause of crop failure in many situations is not unusual herbicide persistence, but failure to take full account of soil type (pH and clay content including variation in the paddock) and rainfall when deciding to recrop after using acetolactate synthase herbicides.

scholarly journals Modelling and mapping soil organic carbon stocks under future climate change in south-eastern Australia

Geoderma ◽  
2022 ◽  
Vol 405 ◽  
pp. 115442
Author(s):  
Bin Wang ◽  
Jonathan M. Gray ◽  
Cathy M. Waters ◽  
Muhuddin Rajin Anwar ◽  
Susan E. Orgill ◽  
...  
Keyword(s):  
Climate Change ◽  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Carbon Stocks ◽  
Future Climate ◽  
Future Climate Change ◽  
South Eastern ◽  
Soil Organic Carbon Stocks ◽  
Eastern Australia ◽  
South Eastern Australia

scholarly journals Determining the impact of the Holocene highstand at the coastal-fluvial interface, Shoalhaven River, south-eastern Australia

2013 ◽  
pp. n/a-n/a ◽  
Author(s):  
Stephanie J. Kermode ◽  
Martin R. Gibling ◽  
Brian G. Jones ◽  
Tim J. Cohen ◽  
David M. Price ◽  
...  
Keyword(s):  
The Holocene ◽  
South Eastern ◽  
Eastern Australia ◽  
The Impact ◽  
South Eastern Australia

Cradle-to-farmgate greenhouse gas emissions for 2-year wheat monoculture and break crop–wheat sequences in south-eastern Australia

2016 ◽  
Vol 67 (8) ◽  
pp. 812 ◽  
Author(s):  
Philippa M. Brock ◽  
Sally Muir ◽  
David F. Herridge ◽  
Aaron Simmons
Keyword(s):  
Ghg Emissions ◽  
Wheat Crop ◽  
Gross Margin ◽  
Life Cycle Assessment Methodology ◽  
Soil C ◽  
South Eastern ◽  
Field Peas ◽  
Eastern Australia ◽  
Rainfed Wheat ◽  
The Impact

We used life cycle assessment methodology to determine the cradle-to-farmgate GHG emissions for rainfed wheat grown in monoculture or in sequence with the break crops canola (Brassica napus) and field peas (Pisum sativum), and for the break crops, in the south-eastern grains region of Australia. Total GHG emissions were 225 kg carbon dioxide equivalents (CO2-e)/t grain for a 3 t/ha wheat crop following wheat, compared with 199 and 172 kg CO2-e/t for wheat following canola and field peas, respectively. On an area basis, calculated emissions were 676, 677 and 586 kg CO2-e/ha for wheat following wheat, canola and field peas, respectively. Highest emissions were associated with the production and transport of fertilisers (23–28% of total GHG emissions) and their use in the field (16–23% of total GHG emissions). Production, transport and use of lime accounted for an additional 19–21% of total GHG emissions. The lower emissions for wheat after break crops were associated with higher yields, improved use of fertiliser nitrogen (N) and reduced fertiliser N inputs in the case of wheat after field peas. Emissions of GHG for the production and harvesting of canola were calculated at 841 kg CO2-e/ha, equivalent to 420 kg CO2-e/t grain. Those of field peas were 530 kg CO2-e/ha, equivalent to 294 kg CO2-e/t grain. When the gross margin returns for the crops were considered together with their GHG emissions, the field pea–wheat sequence had the highest value per unit emissions, at AU$787/t CO2-e, followed by wheat–wheat ($703/t CO2-e) and canola–wheat ($696/t CO2-e). Uncertainties associated with emissions factor values for fertiliser N, legume-fixed N and mineralised soil organic matter N are discussed, together with the potentially high C cost of legume N2 fixation and the impact of relatively small changes in soil C during grain cropping either to offset all or most pre- and on-farm GHG emissions or to add to them.

Altitudinal Variation in the Photosynthetic Characteristics of Snow Gum, Eucalyptus pauciflora Sieb. Ex Spreng. I. Seasonal Changes Under Field Conditions in the Snowy Mountains Area of South-Eastern Australia

1977 ◽  
Vol 25 (1) ◽  
pp. 1 ◽  
Author(s):  
RO Slayter ◽  
PA Morrow
Keyword(s):  
Seasonal Changes ◽  
Photosynthetic Apparatus ◽  
Photosynthetic Characteristics ◽  
Maximum Temperature ◽  
Seasonal Temperature ◽  
South Eastern ◽  
Eastern Australia ◽  
Significant Difference ◽  
South Eastern Australia

A field study of seasonal changes in the photosynthetic characteristics of three altitudinal populations of the snow gum (Eucalyptus pauciflora Sieb. ex. Spreng) was conducted at elevations of 915, 1215 and 1645 m in the Snowy Mountains area of south-eastern Australia. At optimal temperatures in midsummer, peak rates of photosynthesis under CO2-saturating conditions (Psub) reached levels of 125-135 ng cm-2 sec-1, and under ambient CO2 conditions (Pamb) reached levels of 45-55 ng cm-2 sec-1. Corresponding values of the intracellular resistance to CO2 transfer (ri) were 5-6 sec cm-1, and of the gas phase resistance to water-vapour transfer (r,) 1.2-2 sec cm-1. Measured at temperatures of 15, 20 and 25°C, the peak seasonal values of Pmax showed no significant difference between sites, but at 5° and 10° peak values were highest at the highest elevation (coldest site), and at 30° and 35° peak values were highest at the lowest elevation (warmest site). Generally similar patterns applied to Paamb. These features are consistent with the view that E. Pauciflora shows continuous variation in many physiological characteristics over its altitudinal range. At each site the temperature optimum for photosynthesis changed markedly during the season, and was closely correlated both with the long-term maximum air temperature and with the mean maximum temperature of the 10 days prior to the date of measurement. This appeared to reflect long-term adaptation of the photosynthetic apparatus of each population to the general temperature conditions at each site, combined with a short-term acclimation to the prevailing seasonal temperature regime.

Assessing the impact of drought and forestry on streamflows in south-eastern Australia using a physically based hydrological model

2015 ◽  
Vol 74 (7) ◽  
pp. 6047-6063 ◽  
Author(s):  
Stuart C. Brown ◽  
Vincent L. Versace ◽  
Rebecca E. Lester ◽  
M. Todd Walter
Keyword(s):  
Hydrological Model ◽  
South Eastern ◽  
Eastern Australia ◽  
Physically Based ◽  
The Impact ◽  
South Eastern Australia
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