Overwintering and spring emergence of Heliothis armigera (Hübner) (Lepi–doptera: Noctuidae) in the Namoi Valley, New South Wales

1979 ◽  
Vol 69 (1) ◽  
pp. 97-109 ◽  
Author(s):  
A. G. L Wilson ◽  
T. Lewis ◽  
R. B. Cunningham

AbstractThe overwintering of Heliothis armigera (Hb.) was studied in the Namoi Valley, north-western New South Wales, Australia. In field observations, over 80% of pupae formed during late April and May were found to be in diapause and did not resume development until September. Moth emergence from diapausing pupae occurred in a protracted period between September and November. Laboratory studies indicated the probability of two phases of diapause development, one completed under cool soil conditions of winter and a second requiring a temperature above about 17° C. The threshold of the second phase was higher than that for non-diapausing pupae and was not normally reached until late September. The times to diapause termination in populations of overwintering pupae were satisfactorily fitted to a geometric distribution, which was reflected in the protracted emergence period of moths in field cages. The limited availability of suitable host-plants for the overwintering generation and for emerging moths is discussed.

1962 ◽  
Vol 2 (6) ◽  
pp. 185 ◽  
Author(s):  
RR Storrier

In a red-brown earth soil from Wagga Wagga the fluctuations in the level of mineral nitrogen (ammonia plus nitrate-nitrogen) and its availability to wheat under growing period rainfalls of 6 inches and 16 inches were studied. Ammonia-nitrogen did not exceed 8 lb nitrogen per acre 6 inches but showed statistically significant short term fluctuations. Mineral nitrogen decreased steadily from the 4-5 leaf stage of plant growth, reaching minimum values in the ear-emergence period when a temporary nitrogen deficiency occurred. Following rainfalls of about one inch or more, conditions favoured biological activity and nitrogen was mineralized, absorbed by the crop and/or leached down the profile. In one season a release of mineral nitrogen about two weeks before flowering contributed an estimated 20-30 per cent of the total nitrogen uptake of the crop. Nitrogen uptake by the wheat crop ceased after flowering and subsequent changes in mineral nitrogen level reflect the net result of mineralization and demineralization processes, and nitrogen uptake by weeds, particularly skeleton weed. Absorption of nitrogen from the profile depended upon seasonal conditions, with the surface 18 inches suppling the greater part of the nitrogen absorbed by the crop. This indicates the need to sample regularly to at least a depth of 18 inches, particularly during the period from 4-5 leaf to flowering, when studying the relation between mineral nitrogen and crop growth. The data suggest that the response of wheat, as measured by grain yield and protein content, to the higher levels of mineral nitrogen in the improved soils of southern New South Wales is determined by soil moisture levels, particularly in the post-flowering period.


2020 ◽  
Vol 10 (12) ◽  
pp. 4254 ◽  
Author(s):  
Abhirup Dikshit ◽  
Biswajeet Pradhan ◽  
Abdullah M. Alamri

Droughts can cause significant damage to agriculture and water resources, leading to severe economic losses and loss of life. One of the most important aspect is to develop effective tools to forecast drought events that could be helpful in mitigation strategies. The understanding of droughts has become more challenging because of the effect of climate change, urbanization and water management; therefore, the present study aims to forecast droughts by determining an appropriate index and analyzing its changes, using climate variables. The work was conducted in three different phases, first being the determination of Standard Precipitation Evaporation Index (SPEI), using global climatic dataset of Climate Research Unit (CRU) from 1901–2018. The indices are calculated at different monthly intervals which could depict short-term or long-term changes, and the index value represents different drought classes, ranging from extremely dry to extremely wet. However, the present study was focused only on forecasting at short-term scales for New South Wales (NSW) region of Australia and was conducted at two different time scales, one month and three months. The second phase involved dividing the data into three sample sizes, training (1901–2010), testing (2011–2015) and validation (2016–2018). Finally, a machine learning approach, Random Forest (RF), was used to train and test the data, using various climatic variables, e.g., rainfall, potential evapotranspiration, cloud cover, vapor pressure and temperature (maximum, minimum and mean). The final phase was to analyze the performance of the model based on statistical metrics and drought classes. Regarding this, the performance of the testing period was conducted by using statistical metrics, Coefficient of Determination (R2) and Root-Mean-Square-Error (RMSE) method. The performance of the model showed a considerably higher value of R2 for both the time scales. However, statistical metrics analyzes the variation between the predicted and observed index values, and it does not consider the drought classes. Therefore, the variation in predicted and observed SPEI values were analyzed based on different drought classes, which were validated by using the Receiver Operating Characteristic (ROC)-based Area under the Curve (AUC) approach. The results reveal that the classification of drought classes during the validation period had an AUC of 0.82 for SPEI 1 case and 0.84 for SPEI 3 case. The study depicts that the Random Forest model can perform both regression and classification analysis for drought studies in NSW. The work also suggests that the performance of any model for drought forecasting should not be limited only through statistical metrics, but also by examining the variation in terms of drought characteristics.


2004 ◽  
Vol 52 (5) ◽  
pp. 629 ◽  
Author(s):  
Ian Cole ◽  
Ian D. Lunt ◽  
Terry Koen

Temperate grassy woodlands are endangered ecosystems in Australia, and many degraded remnants are in desperate need of understorey restoration. This experiment compared the effects of soil disturbance, weed control and mulch treatments on establishment of the original dominant grass, Themeda triandra Forssk., in a degraded white box (Eucalyptus albens Benth.) woodland at Cowra in central New South Wales (NSW). Awned Themeda seeds were surface-sown into replicated plots treated as follows: soil scalping, soil disturbance (by ripping), herbicide (simazine) application and retention of natural mulch. Scalping combined with soil disturbance best promoted Themeda establishment (47.8% after 40 days and 28% after 518 days), and also reduced broadleaf-herb densities. By contrast, scalping without soil disturbance had the worst effect on Themeda establishment (5.2% after 40 days and 4.5% after 518 days). Disturbance significantly enhanced Themeda establishment and decreased the density of annual grasses and the basal cover of non-Themeda species. By contrast, the retention of 500–800 kg of natural surface mulch had no apparent effect on Themeda establishment. Contrary to expectations, simazine reduced the density and basal cover of all species, including Themeda, which is normally resistant to this herbicide. All combinations of the mulched, disturbed and herbicide treatments (i.e. all treatments except scalping) gave similar results, ranging from 10.7 to 22.0 Themeda plants m–2 after 518 days. These results suggest that Themeda stands can be established in degraded box woodlands by using awned seed materials, with minimal seedbed preparation and simple sowing techniques. Further studies are required to determine whether established swards can resist weed invasion in the absence of ongoing weed management, and whether establishment success varies with soil conditions and landscape position.


Soil Research ◽  
2016 ◽  
Vol 54 (1) ◽  
pp. 49 ◽  
Author(s):  
Jonathan M. Gray ◽  
Thomas F. A. Bishop ◽  
Peter L. Smith

Digital soil models and maps have been developed for pre-European (pre-clearing) levels of soil organic carbon (SOC) over New South Wales, Australia. These provide a useful first estimate of natural, unaltered soil conditions before agricultural development, which are potentially important for many carbon-accounting schemes such as those prescribed by the Intergovernmental Panel on Climate Change, carbon-turnover models such as RothC, and soil-condition monitoring programs. The modelling approach adopted included multiple linear regression and Cubist piecewise linear decision trees. It used 1690 soil profiles from undisturbed or only lightly disturbed native vegetation sites across all of eastern Australia, together with a range of covariates representing key soil-forming factors. The digital soil maps of pre-clearing SOC (% and mass) over New South Wales provide a more sophisticated alternative to currently available, equivalent maps. Independent validation of the SOC mass predictions over the top 30 cm revealed a concordance correlation coefficient of 0.76, which was 13% higher than the currently used map. Total pre-clearing SOC stocks amount to 4.21 Gt in the top 30 cm, which compared with a current stock estimate of 3.68 Gt, suggesting a total SOC loss of ~0.53 Gt over the entire state. The extent of SOC decline in both absolute and relative terms was found to be highly dependent on the climate, parent material and land use regime, reaching a maximum decline of 44.3 t/ha or 50.0% relative loss in cooler (moist) conditions over mafic parent materials under regular cropping use. The models also provide valuable pedological insights into the factors controlling SOC levels under natural conditions.


2021 ◽  
Vol 12 ◽  
Author(s):  
Yumi Tomari Kashida ◽  
Carlos Garcia-Esperon ◽  
Thomas Lillicrap ◽  
Ferdinand Miteff ◽  
Pablo Garcia-Bermejo ◽  
...  

Introduction: A telestroke network in Northern New South Wales, Australia has been developed since 2017. We theorized that the telestroke network development would drive a progressive improvement in stroke care metrics over time.Aim: This study aimed to describe changes in acute stroke workflow metrics over time to determine whether they improved with network experience.Methods: We prospectively collected data of patients assessed by telestroke who received multimodal computed tomography (mCT) and were diagnosed with ischemic stroke or transient ischemic attack from January 2017 to July 2019. The period was divided into two phases (phase 1: January 2017 – October 2018 and phase 2: November 2018 – July 2019). We compared median door-to-call, door-to-image, and door-to-decision time between the two phases.Results: We included 433 patients (243 in phase 1 and 190 in phase 2). Each spoke site treated 1.5–5.2 patients per month. There were Door-to-call time (median 39 in phase 1, 35 min in phase 2, p = 0.18), and door-to-decision time (median 81.5 vs. 83 min, p = 0.31) were not improved significantly. Similarly, in the reperfusion therapy subgroup, door-to-call time (median 29 vs. 24.5 min, p = 0.12) and door-to-decision time (median 70.5 vs. 67.5 min, p = 0.75) remained substantially unchanged. Regression analysis showed no association between time in the network and door-to-decision time (coefficient 1.5, p = 0.32).Conclusion: In our telestroke network, acute stroke timing metrics did not improve over time. There is the need for targeted education and training focusing on both stroke reperfusion competencies and the technical aspects of telestroke in areas with limited workforce and high turnover.


1980 ◽  
Vol 70 (1) ◽  
pp. 113-131 ◽  
Author(s):  
K. G. Wardhaugh ◽  
P. M Room ◽  
L. R Greenup

AbstractFour years of light-trap and crop survey data from the Namoi Valley of New South Wales are presented for Heliothis armigera (Hb.) and H. punctigera Wllgr. These suggest there are four generations a year. The associated seasonal sequence of major host-plants supporting successive generations, appeared to be: H. armigera—wheat; pre-flowering cotton; flowering cotton and sorghum; sorghum, flowering cotton and sunflowers; and H. punctigera—lucerne, linseed and medics; pre-flowering cotton; flowering cotton, sunflowers and soyabeans; lucerne, linseed and medics; pre-flowering cotton. On host-plants common to both species, a change in dominance from H. punctigera to H. armigera occured as each summer progressed. Suggested causes are: seasonal changes in the availability of host-plants, favouring H. armigera over H. punctigera; insecticide resistance in H. armigera; and the competitive superiority of H. armigera. Large numbers of H. armigera in cotton appeared to be related to: warm springs, which favoured moth emergence during the period of wheat anthesis; the incomplete control of infestations within cotton itself, leading to the development of resident populations; and the influx of moths from other host-plants, especially sorghum, during the latter half of the season.


Soil Research ◽  
2004 ◽  
Vol 42 (8) ◽  
pp. 905 ◽  
Author(s):  
S. Graham ◽  
B. R. Wilson ◽  
N. Reid ◽  
H. Jones

Scattered paddock trees are widespread throughout rural Australia but their effect on soil conditions has received only limited research attention. This study investigated the influence of 3 Eucalyptus species on surface soil properties on different parent materials at both stocked and unstocked sites on the Northern Tablelands of New South Wales. Mineral soil samples to a depth of 5 cm were collected at intervals up to twice the canopy radius away from tree trunks and litter samples were collected at corresponding points. Mineral soils were analysed for pH (CaCl2), organic carbon (C), and extractable phosphorus (P) concentration, while for the litter samples, P, sulfur, cations, and ash alkalinity were determined. Stocking with sheep and cattle increased surface soil acidity and C and P concentrations at each location. However, soils under E. melliodora and E. viminalis showed higher pH and increased C and P concentrations close to the tree stem irrespective of grazing. Soils under E. caliginosa, while having similar patterns of C and P, showed variable acidity patterns with instances of lower pH close to the tree stem. Spatial patterns in soil acidity were associated with the ash alkalinity of litter, indicating litter as a source of alkalinity addition to the soil surface, although different patterns of soil pH could not be fully explained by litter ash alkalinity alone. The close correlation of litter Ca content with ash alkalinity suggests that this element might be a suitable indicator of the acid amelioration capacity of different tree species.


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