scholarly journals Effect of climate variability on event frequency of sorghum ergot in Australia

2003 ◽  
Vol 54 (6) ◽  
pp. 599 ◽  
Author(s):  
Enli Wang ◽  
Malcolm Ryley ◽  
Holger Meinke
Keyword(s):  
Climate Variability ◽  
Southern Oscillation ◽  
Climatic Conditions ◽  
Considerable Research ◽  
Significant Difference ◽  
Negative Effect ◽  
Claviceps Africana ◽  
Relative Risk Assessment ◽  
Resistant Genotypes

The significant effect of ergot, caused by Claviceps africana, on the Australian sorghum industry, has led to considerable research on the identification of resistant genotypes and on the climatic conditions that are conducive to ergot outbreaks. Here we show that the potential number of monthly ergot events differs strongly from year to year in accordance with ENSO (El Niño–Southern Oscillation)-related climate variability. The analysis is based on long-term weather records from 50 locations throughout the sorghum-growing areas of Australia and predicts the potential number of monthly ergot events based on phases of the Southern Oscillation Index (SOI). For a given location, we found a significant difference in the number of potential ergot events based on SOI phases in the preceding month, with a consistently positive SOI phase providing the greatest risk for the occurrence of ergot for most months and locations. This analysis provides a relative risk assessment for ergot outbreaks based on location and prevailing climatic conditions, thereby assisting in responsive decision-making to reduce the negative effect of sorghum ergot.

Effects of sorghum ergot on grain sorghum production: a preliminary climatic analysis

1997 ◽  
Vol 48 (8) ◽  
pp. 1241 ◽  
Author(s):  
Holger Meinke ◽  
Malcolm Ryley
Keyword(s):  
Southern Oscillation ◽  
Warning System ◽  
Grain Sorghum ◽  
Climatic Conditions ◽  
Hybrid Seed Production ◽  
Breeding Programs ◽  
South Wales ◽  
Claviceps Africana ◽  
Sorghum Production

Until 1996 the disease ‘sorghum ergot’ (Claviceps africana and Claviceps sorghi) was unknown in Australia. Following an outbreak near Gatton, the disease was found throughout most of the sorghum-producing areas in Queensland within 4 weeks. A climatic risk analysis was conducted to assess the likely timing and frequencies of further outbreaks of the disease across the main sorghum-producing regions of Australia. Based on the information available, likely conditions that could lead to a disease outbreak were formulated and a computer program developed to interrogate an existing database of long-term, daily weather records. Case studies were conducted for 10 key sorghum-producing locations, ranging from Narromine in central New South Wales to Mareeba in far North Queensland and Kununurra in Western Australia. For grain sorghum production, crops flowering in January and February are unlikely to be affected, regardless of location. However, in up to 30% of years, late-sown grain sorghum crops and crops flowering before January could be affected, depending on climatic conditions prior to and around anthesis. The frequency and timing of these events differed strongly temporally and spatially and appeared highest in high rainfall years and in regions with relatively cooler temperatures and more frequent autumn rains. Hybrid seed production (i.e. breeding programs) and forage sorghum production are likely to be more affected due to their inherently low pollen generation, again with strong regional variation. Further applications of the methodology, such as the development of an early warning system, based on phases of the Southern Oscillation Index, are discussed.

scholarly journals Climate variability in West Antarctica derived from annual accumulation-rate records from ITASE firn/ice cores

2004 ◽  
Vol 39 ◽  
pp. 585-594 ◽  
Author(s):  
Susan Kaspari ◽  
Paul A. Mayewski ◽  
Daniel A. Dixon ◽  
Vandy Blue Spikes ◽  
Sharon B. Sneed ◽  
...  
Keyword(s):  
Climate Variability ◽  
Moisture Transport ◽  
Southern Oscillation ◽  
Accumulation Rate ◽  
Drainage System ◽  
Ice Cores ◽  
Cyclonic Activity ◽  
West Antarctica ◽  
Sea Level Pressure

AbstractThirteen annually resolved accumulation-rate records covering the last ~200 years from the Pine Island–Thwaites and Ross drainage systems and the South Pole are used to examine climate variability over West Antarctica. Accumulation is controlled spatially by the topography of the ice sheet, and temporally by changes in moisture transport and cyclonic activity. A comparison of mean accumulation since 1970 at each site to the long-term mean indicates an increase in accumulation for sites located in the western sector of the Pine Island–Thwaites drainage system. Accumulation is negatively associated with the Southern Oscillation Index (SOI) for sites near the ice divide, and periods of sustained negative SOI (1940–42, 1991–95) correspond to above-mean accumulation at most sites. Correlations of the accumulation-rate records with sea-level pressure (SLP) and the SOI suggest that accumulation near the ice divide and in the Ross drainage system may be associated with the mid-latitudes. The post-1970 increase in accumulation coupled with strong SLP–accumulation-rate correlations near the coast suggests recent intensification of cyclonic activity in the Pine Island– Thwaites drainage system.

scholarly journals Deep Planting Has No Short- or Long-Term Effect on the Survival and Growth of White Spruce, Black Spruce, and Jack Pine

2011 ◽  
Vol 28 (3) ◽  
pp. 146-151 ◽  
Author(s):  
Alain Paquette ◽  
Jean-Pierre Girard ◽  
Denis Walsh
Keyword(s):  
Black Spruce ◽  
White Spruce ◽  
Jack Pine ◽  
Eastern Canada ◽  
Planting Depth ◽  
Early Results ◽  
Significant Difference ◽  
Negative Effect ◽  
Tukey Honestly Significant Difference

Abstract Although studies in the past have reported that the deeper planting of conifers has no effect on seedling performance, most planting guidelines in use today still recommend that seedlings be planted to the rootcollar. Past studies were mostly observational, used bareroot seedlings, and often reported early results from just one or two depths of planting treatments. Most of the results available regarding planting depth for boreal species are anecdotal, although they are planted by the hundreds of millions every year. The present study reports no short-term (1 year) or long-term (15 to 19 years) negative effect of planting depth on the survival and height and diameter growth of black spruce, white spruce, and jack pine seedlings over three large, replicated experiments in the boreal forest of eastern and northern Quebec (eastern Canada). Four different depth treatments were compared, from manual planting at the rootcollar to the deepest mechanical planting treatment at 10 cm or more, making this the largest, longest-lasting study of its kind. Although, as expected, important differences in growth were present between species, all three commonly planted conifers reacted similarly to the planting depth treatments (no effect). This result can in part be attributed to an almost perfect control of frost heaving in the deepest two treatments. Planting depth effects were assessed using analysis of variance, multiple Tukey honestly significant difference, and uncorrected pairwise one-tailed t-tests to increase the probability of detecting a negative effect. Absolute differences and effect sizes (generally small and often positive with greater depths) were also analyzed.

scholarly journals Effect of Cultivar, Controlled Atmosphere Storage, and Fruit Ripeness on the Long-term Storage of Highbush Blueberries

2008 ◽  
Vol 18 (2) ◽  
pp. 199-205 ◽  
Author(s):  
Jim Hancock ◽  
Pete Callow ◽  
Sedat Serçe ◽  
Eric Hanson ◽  
Randy Beaudry
Keyword(s):  
Ambient Air ◽  
Controlled Atmosphere ◽  
Storage Quality ◽  
Controlled Atmosphere Storage ◽  
Long Term Storage ◽  
Significant Difference ◽  
Highbush Blueberries ◽  
Atmosphere Storage ◽  
Resistant Genotypes

Controlled-atmosphere storage had little effect on the quality of fruit of eight cultivars held under 2 kPa oxygen (O2) and 8 kPa carbon dioxide (CO2) versus ambient air. ‘Elliott’ fruit harvested from bushes with only 30% ripe fruit had significantly better storage quality than fruit picked later; however, there was no significant difference in the storage life of fruit that was stored fully blue versus partially green. Fruit from the first harvest of four cultivars had superior storage quality to that of the second. In one comparison of the long-term storability of nine cultivars, ‘Bluegold’, ‘Brigitta’, and ‘Legacy’ performed the best, storing for 4 to 7 weeks. In another postharvest trial of 17 cultivars, ‘Brigitta’ stored the longest (8 weeks) followed by ‘Aurora’ and ‘Draper’ (7 weeks). The most resistant genotypes to Alternaria spp. were ‘Brigitta’, ‘Aurora’, ‘Elliott’, and ‘Draper’, whereas the most resistant genotypes to Colletotrichum spp. were ‘Elliott’, ‘Brigitta’, ‘Toro’, ‘Draper’, and ‘Bluejay’.

scholarly journals Climate variability and long-term expansion of peat lands in Arctic Norway during the late Pliocene (ODP Site 642, Norwegian Sea)

2015 ◽  
Vol 11 (6) ◽  
pp. 5755-5798 ◽  
Author(s):  
S. Panitz ◽  
U. Salzmann ◽  
B. Risebrobakken ◽  
S. De Schepper ◽  
M. J. Pound
Keyword(s):  
Climate Variability ◽  
Boreal Forest ◽  
Climatic Conditions ◽  
Forest Zone ◽  
Norwegian Sea ◽  
Late Pliocene ◽  
Oxygen Isotope Stage ◽  
Cool Temperate ◽  
Vegetation And Climate

Abstract. Little is known about the terrestrial response of high latitude Scandinavian vegetation to the warmer-than-present climate of the Late Pliocene (Piacenzian, 3.60–2.58 Ma). In order to assess Piacenzian terrestrial climate variability we present the first high resolution reconstruction of vegetation and climate change in northern Norway between 3.6–3.14 Ma. The reconstructions are derived from pollen assemblages in the marine sediments of ODP Hole 642B, Norwegian Sea (67° N). The palynological assemblages provide a unique record of latitudinal and altitudinal shifting of the forest boundaries, with vegetation alternating between cool temperate forest during warmer-than-present intervals, and boreal forest similar to today during cooler intervals. The northern boundary of the nemoral to boreonemoral forest zone was displaced at least 4–8° further north and warmest month temperatures were 6–14.5 °C higher than present during warm phases. Warm climatic conditions persisted during the earliest Piacenzian (ca. 3.6–3.47 Ma) with diverse cool temperate nemoral to boreonemoral forests growing in the lowlands of the Scandinavian mountains. A distinct cooling event at ca. 3.47 Ma resulted in a southward shift of vegetation boundaries, leading to the predominance of boreal forest and the development of open, low alpine environments. The cooling culminated around 3.3 Ma, coinciding with Marine Oxygen Isotope Stage (MIS) M2. Warmer climate conditions returned after ca. 3.29 Ma with higher climate variability indicated by the repeated expansion of forests and peat lands during warmer and cooler periods, respectively. Climate progressively cooled after 3.18 Ma, resembling climatic conditions during MIS M2. A high variability of Norwegian vegetation and climate changes during the Piacenzian is superimposed on a long-term cooling trend. This cooling was accompanied by an expansion of Sphagnum peat lands that potentially contributed to the decline in atmospheric CO2-concentrations at the end of the Piacenzian warm period and facilitated ice growth through positive vegetation-snow albedo feedbacks. Correlations with other Northern Hemisphere vegetation records suggest hemisphere-wide effects of climate cooling.

scholarly journals Recent climate variability around the Kerguelen Islands (Southern Ocean) seen through weather regimes

2021 ◽  
Author(s):  
Benjamin Pohl ◽  
Thomas Saucède ◽  
Vincent Favier ◽  
Julien Pergaud ◽  
Deborah Verfaillie ◽  
...  
Keyword(s):  
Climate Variability ◽  
Southern Ocean ◽  
Sea Water ◽  
Southern Oscillation ◽  
Surface Wind ◽  
Southern Annular Mode ◽  
Weather Regimes ◽  
Kerguelen Islands ◽  
Recent Climate

AbstractDaily weather regimes are defined around the Kerguelen Islands (Southern Ocean) based on daily 500 hPa geopotential height anomalies derived from the ERA5 ensemble reanalysis over the period 1979-2018. Ten regimes are retained as significant. Their occurrences are highly consistent across reanalysis ensemble members. Regimes show weak seasonality and non-significant long-term trends in their occurrences. Their sequences are usually short (1-3 days), with extreme persistence values above 10 days. Seasonal regime frequency is mostly driven by the phase of the Southern Annular Mode over Antarctica, mid-latitude dynamics over the Southern Ocean like the Pacific South American mode, and to a lesser extent, tropical variability, with significant but weaker relationships with El Niño Southern Oscillation. At the local scale over the Kerguelen Islands, regimes have a strong influence on measured atmospheric and oceanic variables, including minimum and maximum air temperature, mostly driven by horizontal advections, sea water temperature recorded 5 m below the surface, wind speed and sea level pressure. Relationships are weaker for precipitation amounts. Regimes also modify regional contrasts between observational sites in Kerguelen, highlighting strong exposure contrasts. The regimes allow improving our understanding of weather and climate variability and interactions in this region; they will be used in future work to assess past and projected long-term circulation changes in the southern mid-latitudes.

scholarly journals Climate variability and long-term expansion of peatlands in Arctic Norway during the late Pliocene (ODP Site 642, Norwegian Sea)

2016 ◽  
Vol 12 (4) ◽  
pp. 1043-1060 ◽  
Author(s):  
Sina Panitz ◽  
Ulrich Salzmann ◽  
Bjørg Risebrobakken ◽  
Stijn De Schepper ◽  
Matthew J. Pound
Keyword(s):  
Climate Variability ◽  
Boreal Forest ◽  
Climatic Conditions ◽  
Forest Zone ◽  
Climate Conditions ◽  
Norwegian Sea ◽  
Late Pliocene ◽  
Cool Temperate ◽  
Vegetation And Climate

Abstract. Little is known about the terrestrial response of high-latitude Scandinavian vegetation to the warmer-than-present climate of the late Pliocene (Piacenzian, 3.60–2.58 Ma). In order to assess Piacenzian terrestrial climate variability, we present the first high-resolution reconstruction of vegetation and climate change in northern Norway between 3.6 and 3.14 Ma. The reconstructions are derived from pollen assemblages in the marine sediments of ODP Hole 642B, Norwegian Sea (67° N). The palynological assemblages provide a unique record of latitudinal and altitudinal shifting of the forest boundaries, with vegetation alternating between cool temperate forest during warmer-than-present intervals and boreal forest similar to today during cooler intervals. The northern boundary of the nemoral to boreonemoral forest zone was displaced at least 4–8° further north, and warmest-month temperatures were 6–14.5 °C higher than at present during warm phases. Warm climatic conditions persisted during the earliest Piacenzian (ca. 3.6–3.47 Ma) with diverse cool temperate nemoral to boreonemoral forests growing in the lowlands of the Scandinavian mountains. A distinct cooling event at ca. 3.47 Ma resulted in a southward shift of vegetation zones, leading to the predominance of boreal forest and the development of open, low alpine environments. The cooling culminated around 3.3 Ma, coinciding with Marine Isotope Stage (MIS) M2. Warmer climate conditions returned after ca. 3.29 Ma, with higher climate variability indicated by the repeated expansion of forests and peatlands during warmer and cooler periods, respectively. Climate progressively cooled after 3.18 Ma, resembling climatic conditions during MIS M2. A high variability of Norwegian vegetation and climate changes during the Piacenzian is superimposed on a long-term cooling trend. This cooling was accompanied by an expansion of Sphagnum peatlands that potentially contributed to the decline in atmospheric CO2 concentrations at the end of the Piacenzian warm period and facilitated ice growth through positive vegetation–snow albedo feedbacks. Correlations with other Northern Hemisphere vegetation records suggest hemisphere-wide effects of climate cooling.

scholarly journals Seed dormancy removal treatments and germnaton characterstcs of Acer trautvetteri Medvedev seeds

2020 ◽  
Vol 144 (9-10) ◽  
pp. 473-473
Author(s):  
Hanife Erdogan Genç ◽  
Ali Ömer Üçler
Keyword(s):  
Seed Dormancy ◽  
Germination Percentage ◽  
Climatic Conditions ◽  
Black Sea Region ◽  
Seed Collection ◽  
Germination Characteristics ◽  
Significant Difference ◽  
Physiological Dormancy ◽  
Negative Effect ◽  
Collection Time

In this study, seed dormancy removal and germination characteristics of Acer trautvetteri Medvedev, is one of the major maple species of the eastern Black Sea region, were studied. To do that, the seeds were collected in 2008 three times with aproximately 15-days intervals. In order to remove dormancy, several germination treatments were applied. The treatments were (1) different seed collection time, (2) soaking in water, (3) cold-moist stratification and (4) GA3 (gibberellic acid) application. The treated seeds were germinated in growing chamber at 5 0C and in greenhouse conditions. This research indicated that seeds of Acer trautvetteri exhibit physiological dormancy and require stratification period to remove seed dormancy. The highest germination percentage in the growing chamber subjected to GA3 application after eight weeks of stratification treatment was 66 % for Acer trautvetteri seeds. The highest germination percentage in greenhouse was obtained with cold stratification after eight weeks (81 %). Although GA3 treatment had a positive effect on germination in growth chamber + 5 0C, GA3 treatment had a negative effect on germination in greenhouse conditions. Soaking in water of nonstratified seeds wasn’t any significant difference on seed germination. There was a positive correlation between seed collection time and germination (r=0.59). As a result, the third collection time (in october) should be preferred as seed collection time in Acer trautvetteri seeds, considering that it may vary according to the climatic conditions of the year.

The Influence of Perioperative Soft Tissue Complications on the Clinical Outcome in Surgically Treated Ankle Fractures

2001 ◽  
Vol 22 (8) ◽  
pp. 642-648 ◽  
Author(s):  
P. Höiness ◽  
L. Engebretsen ◽  
K. Strömsöe
Keyword(s):  
Soft Tissue ◽  
Functional Outcome ◽  
Ankle Fractures ◽  
Functional Score ◽  
Primary Surgery ◽  
Significant Difference ◽  
Negative Effect ◽  
Fracture Types ◽  
Dorsal Extension

The influence of perioperative soft tissue complications on the functional outcome after open reduction and internal fixation of closed ankle fractures was investigated. Eighty-eight consecutive patients were followed 3.7 years (SD ± 0.6) after the injury. Two major and 21 minor soft tissue complications were registered. Average dorsal extension was 29.9° (range four to 54, SD ± 9.5) of the fractured ankles and 37.2° (range eight to 60, SD ± 9.1) of the non-fractured ankles. The average subjective functional score was 84.6 (range 40 to 100, SD±14.9). A significant difference was found with respect to the subjective functional score (p = 0.048, Kruskal-Wallis test) but not with respect to dorsal extension (0.358, Kruskal-Wallis test) when comparing groups of minor, major and no soft tissue complications. This study suggests that major soft tissue complications have a negative effect on the long-term functional outcome after surgical repair of an ankle fracture. Minor soft tissue complications, primary skin problems, the timing of primary surgery and fracture types according to AO/ASIF have no or minor influence on the long-term functional result. This study confirms previous reports that the presence of osteoarthritis is frequently associated with a reduced functional outcome.

An Empirical Decomposition of Deep Groundwater Time Series and Possible Link to Climate Variability

2013 ◽  
Vol 16 (1) ◽  
pp. 87-103
Keyword(s):  
Time Series ◽  
Climate Variability ◽  
Polynomial Interpolation ◽  
Southern Oscillation ◽  
Global Climate ◽  
Deep Groundwater ◽  
Anthropogenic Effect ◽  
Cyclic Patterns ◽  
History Of

<p>Deep groundwater data reflects hydrological processes, climate change and variability, as well as any anthropogenic influence. Decomposition of deep groundwater signal examines the history of the groundwater region. Detrending is a vital step in decomposition of groundwater time series because it is expected to remove anthropogenic effects and long-term cyclic patterns. Eight detrending methods were applied to long-term groundwater records monitored in the Lower Chao Phraya basin in Thailand. Detrended residuals and subsequently periodograms of the residuals were computed by applying the Fourier series analysis. The result from this study indicates that the 5th order polynomial interpolation provides the trendlines that significantly relate to the groundwater withdrawal background. The detrended residual function is imbedded with two major cyclic patterns, which can be the result from global climate variability, e.g. Indian Ocean Dipole and the El Niño Southern Oscillation. The magnitude of deep groundwater dynamics as the result from the anthropogenic effect is much greater than that of the climate variability in this region. In addition, this study demonstrates that caution must be exercised when fitting groundwater time series with different detrending techniques can yield mistaken cyclic patterns and may infer to different climate variability phenomenon.</p>

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