The occurrence and control of yellow spot of wheat in north-eastern Australia

1979 ◽  
Vol 19 (98) ◽  
pp. 369 ◽  
Author(s):  
RG Rees ◽  
GJ Platz

Explanations were sought for the increased severity of yellow spot of wheat (Pyrenophora tritici-repentis) in the north-eastern wheat growing areas of Australia. A close association between the severity of yellow spot and stubble management practices was found in a field experiment. There was less disease in plots where stubble had been burned (0.83 lesions per leaf) or burned and cultivated (0.62) than in plots which were mechanically cultivated (2.43) or untreated (11.75). In another study severe yellow spot developed as early as in the second wheat crop in a rotation. Differences in susceptibility to the disease were found among 11 wheat cultivars and lines. Vigorous development of the pathogen occurred on cereal rye and triticale while the fungus was isolated from small lesions on barley and four common grasses. Avoidance of planting wheat into infected wheat stubble, either by crop rotation or removal of surface stubble by incorporation or burning, should provide effective control of the disease in most situations.


2007 ◽  
Vol 47 (1) ◽  
pp. 57 ◽  
Author(s):  
V. A. Osten ◽  
S. R. Walker ◽  
A. Storrie ◽  
M. Widderick ◽  
P. Moylan ◽  
...  

The main weeds and weed management practices undertaken in broad acre dryland cropping areas of north-eastern Australia have been identified. The information was collected in a comprehensive postal survey of both growers and agronomists from Dubbo in New South Wales (NSW) through to Clermont in central Queensland, where 237 surveys were returned. A very diverse weed flora of 105 weeds from 91 genera was identified for the three cropping zones within the region (central Queensland, southern Queensland and northern NSW). Twenty-three weeds were common to all cropping zones. The major common weeds were Sonchus oleraceus, Rapistrum rugosum, Echinochloa spp. and Urochloa panicoides. The main weeds were identified for both summer and winter fallows, and sorghum, wheat and chickpea crops for each of the zones, with some commonality as well as floral uniqueness recorded. More genera were recorded in the fallows than in crops, and those in summer fallows exceeded the number in winter. Across the region, weed management relied heavily on herbicides. In fallows, glyphosate and mixes with glyphosate were very common, although the importance of the glyphosate mix partner differed among the cropping zones. Use and importance of pre-emergence herbicides in-crop varied considerably among the zones. In wheat, more graminicides were used in northern NSW than in southern Queensland, and virtually none were used in central Queensland, reflecting the differences in winter grass weed flora across the region. Atrazine was the major herbicide used in sorghum, although metolachlor was also used predominantly in northern NSW. Fallow and inter-row cultivation were used more often in the southern areas of the region. Grazing of fallows was more prominent in northern NSW. High crop seeding rates were not commonly recorded indicating that growers are not using crop competition as a tool for weed management. Although many management practices were recorded overall, few growers were using integrated weed management, and herbicide resistance has been and continues to be an issue for the region.



1982 ◽  
Vol 30 (1) ◽  
pp. 49 ◽  
Author(s):  
FJ Odendaal ◽  
CM Bull

Ranidella signifera has a wide distribution in south-eastern Australia; R. riparia is endemic to the Flin- ders Ranges in South Australia. The ranges of the two species are largely allopatric, but they contact and overlap in a zone about 10 km wide, in the southern Flinders Ranges. The nature of the creeks changes across this zone. Immediately to the south and east, where only R. signifera is found, the creeks are slow-flowing and heavily vegetated, with mud or sand substrates. To the north and west the creeks are swift-flowing, and have rocky substrates and little vegetation; only R. riparia is found in these. In the sympatric overlap zone creeks are heterogeneous, with both habitat types represented. The close association between species and creek habitat is lost in populations not immediately adjacent to the overlap zone. This implies that each species can survive in both creek habitats but that R. riparia has a competitive advantage in swift, rocky creeks and R, signifera has an advantage in slow, vegetated creeks. This prevents either species from expanding its distribution beyond the narrow overlap area.



2006 ◽  
Vol 46 (1) ◽  
pp. 19 ◽  
Author(s):  
Y. P. Dang ◽  
R. C. Dalal ◽  
R. Routley ◽  
G. D. Schwenke ◽  
I. Daniells

In dryland agricultural systems of the subtropical, semi-arid region of north-eastern Australia, water is the most limiting resource. Crop productivity depends on the efficient use of rainfall and available water stored in the soil during fallow. Agronomic management practices including a period of fallow, stubble retention, and reduced tillage enhance reserves of soil water. However, access to stored water in these soils may be restricted by the presence of growth-limiting conditions in the rooting zone of the crop. These have been termed as subsoil constraints. Subsoil constraints may include compacted or gravel layers (physical), sodicity, salinity, acidity, nutrient deficiencies, presence of toxic elements (chemical) and low microbial activity (biological). Several of these constraints may occur together in some soils. Farmers have often not been able to obtain the potential yield determined by their prevailing climatic conditions in the marginal rainfall areas of the northern grains region. In the past, the adoption of soil management practices had been largely restricted to the top 100 mm soil layer. Exploitation of the subsoil as a source of water and nutrients has largely been overlooked. The key towards realising potential yields would be to gain better understanding of subsoils and their limitations, then develop options to manage them practically and economically. Due to the complex nature of the causal factors of these constraints, efforts are required for a combination of management approaches rather than individual options, with the aim to combat these constraints for sustainable crop production, managing natural resources and avoiding environmental damage.



Soil Research ◽  
1997 ◽  
Vol 35 (3) ◽  
pp. 553 ◽  
Author(s):  
Donald S. Ross ◽  
Richmond J. Bartlett

The charge fingerprint procedure was used to characterise the exchange properties of high- organic forest soils from the north-eastern USA. Twenty-six Oa or A horizon samples were obtained from active research sites to provide samples with a range in carbon from 15·1 to 49·4% and pH (in 1 mM CaCl2) from 2·8 to 4·2. Fingerprints were similar to those developed for other variably charged soils except that significant quantities of exchangeable H+ were found and no appreciable anion exchange capacity was measured. The magnitude of the ‘base’ cation capacity (CECB) varied linearly with pH, averaging >50% change per unit pH change. A good estimate of the CECB was obtained from the sum of cations removed by a single extraction with 1·0 М choline chloride (slope 1·03, r2 = 0·91). Variations in exchangeable Al3+ or H+ with pH were related to the quantity found in untreated samples, probably because of the close association between exchangeable and organically complexed forms. The total CEC was closely related to the sum of cations removed by 0·1 M BaCl2 (slope 1·05, r2 = 0·96). Although low ionic strength may be difficult to maintain in low pH samples, the fingerprint method appears to allow precise interpolation of the organic soils’ exchange capacity at field pH.



Soil Research ◽  
2020 ◽  
Vol 58 (4) ◽  
pp. 346
Author(s):  
K. L. Page ◽  
R. C. Dalal ◽  
S. H. Reeves ◽  
W. J. Wang ◽  
Somasundaram Jayaraman ◽  
...  

No-till (NT) farming has been widely adopted to assist in reducing erosion, lowering fuel costs, conserving soil moisture and improving soil physical, chemical and biological characteristics. Improvements in soil characteristics are often driven by the greater soil organic matter accumulation (as measured by soil organic carbon (SOC)) in NT compared to conventional tillage (CT) farming systems. However, to fully understand the effect of NT it is important to understand temporal changes in SOC by monitoring over an extended period. We investigated the long-term effect of NT and stubble retention (SR) on changes in SOC and total soil nitrogen (STN) using results from an experiment that has been running for 50 years in a semi-arid subtropical region of north-eastern Australia. In this experiment, the effects of tillage (CT vs NT), residue management (stubble burning (SB) vs SR), and nitrogen (N) fertiliser (0 and 90 kg-N ha–1) were measured in a balanced factorial experiment on a Vertisol (Ustic Pellusert). The use of NT, SR and N fertiliser generally improved SOC (by up to 12.8%) and STN stocks (by up to 31.7%) in the 0–0.1 m layer relative to CT, SB and no N fertiliser, with the greatest stocks observed where all three treatments were used in combination. However, declines in SOC (up to 20%) and STN (up to 25%) occurred in all treatments over the course of the experiment, indicating that changes in management practices were unable to prevent a loss of soil organic matter over time in this farming system. However, the NT and SR treatments did lose less SOC than CT and SB treatments, and SR also reduced STN loss. The δ13C analysis of samples collected in 2008 and 2015 highlighted that crop residues have significantly contributed to SOC stocks at the site and that their contribution is increasing over time.



1990 ◽  
Vol 3 (3) ◽  
pp. 293 ◽  
Author(s):  
AJK Millar

The marine benthic red algae of the Coffs Harbour region are described and illustrated in detail. The survey constitutes the first ever detailed descriptive and illustrative mainland regional monograph of any area along the entire eastern Australian seaboard. Collections made intertidally and to depths of 20 m have included 119 species in 74 genera, 26 families, and 8 orders of Rhodophyta, of which 54 (45%) were previously unrecorded from eastern Australia, 22 (18%) are new records for the whole of Australia (16 being new Southern Hemisphere records), 1 (Dictyothumnion) constitutes a new genus, and 16 (13%) are new species in the genera Gracilaria, Curdiea, Botryocladia, Dictyothamnion, Antithamnion, Ceramium, Callithumnion, Anotrichium, Nitophyllum, Phycodrys, Apoglossum, Dasya, Fernandosiphonia, and Herposiphonia. Also included are major Australian revisions of the genera Martensia and Nitophyllum, and six new combinations are proposed (Chondria infestans, Curdiea angustata, Dasya pilosa, Haraldiophyllum sinuosum, Myriogramme pulchellum, and Stenograrnme phyllophoroides). The Coffs Harbour flora, although related to the north-eastern and, to a lesser degree, southern Australian floras, has a number of species previously known only from much more remote localities, such as Japan (6 species), California (4 species), New Zealand (3 species), India (2 species), South America (2 species), the Galapagos Islands (1 species), China (1 species), South Africa (1 species), and the Mediterranean (1 species). Twelve of the 22 species newly recorded for Australia show a definite western Pacific distribution, a region with which the overall Coffs Harbour flora has strong affinities.



2021 ◽  
Vol 26 (4) ◽  
pp. 40-46
Author(s):  
MSHELIA RICHARD BALTHI

Greenhouse gas (GHG) emissions due to solid waste management (SWM) techniques being practiced in the North eastern region of Nigeria are unaccounted for as such these emissions cannot be monitored or controlled. This research estimated GHG emissions into the atmosphere from the current SWM technique practiced in the region, GHG emissions from two different waste management techniques – open burning and incineration was also simulated. The research found that incineration with electricity recovery is the most suitable SWM process therefore suggested that the authorities and other stakeholders in the region should give it serious consideration.



1984 ◽  
Vol 32 (1) ◽  
pp. 87 ◽  
Author(s):  
NC Duke ◽  
JS Bunt ◽  
WT Williams

The mangrove forests of north-eastern Australia are both species-rich and well developed but there is very little information available on their vegetative growth or flowering and fruiting behaviour. This account attempts to rectify this situation by presenting the results of at least 4 years of field studies and observations. Previous reports recorded no less than 35 mangrove species occumng along the north-eastern coast and observations of the flowering and fruiting status of all these species were made. The results are supported by some litter fall studies and overall they reflect the diversity of mangrove species by displaying a range of peak activity months. However, there are some common trends and most species flower mainly during the dry hot summer (September-December) prior to the rainy season when they drop their propaguies during the morniks of peak rainfall (around February). Detailed studies of litter fall were camed out in Missionary Bay, Hinchinbrook Island (18° 16̸2S.,146° 13̸2E.), and care was taken to record components of floral development and vegetative growth. The results for five species (Rhizophora apiculata, R. stylosa, R. × lamarckii, Bruguiera gymnorhiza and Ceriops tagal var. tagal) include estimates of mean leaf longevity and also suggest that the floral and vegetative cycles are coordinated.



2017 ◽  
Author(s):  
Priya Ranjan Kumar

Wheat crop in the North Eastern Plain Zone (IGP) of India, is the part of one of the largest agricultural production systems viz., rice-wheat rotation, occupying more than 11 million ha. The yield potential of wheat in the North Eastern Plains Zone of India is about 4.5 tons per hectare but generally, farmers realize a yield of only 2.2 tons per hectare. Seed replacement rate of wheat in different eastern states has also been quite low. A study was initiated at the Indian Agricultural Research Institute, Regional Station, Pusa (Samastipur) in 2014-15 to evaluate germination and seedling growth parameters of wheat grown from seeds of varying size. Experiments were conducted on quality evaluation of different seed grades of bread wheat available to the farmers for sowing to study the status of quality vis-à-vis size grading and what is its effect on germination and early dry matter gain with two objectives of this investigation. First, to assess the physical quality of wheat seed available to farmers in North Eastern Plains Zone (which is also known as lower Gangetic plains) in terms of seed size and seed grading and second, to determine the relationships between seed size on one hand and germination and seedling developmental and biomass traits on the other. This paper presents the results of an enquiry into the status vis-à-vis seed grading, of seed lots of wheat which are available to farmers for sowing with the aim of estimating the extent to which the quality of wheat seed can be improved by merely grading and to establish the relation between seed size and crop establishment. From the results of this study, it can be inferred that 67.97% of area in North eastern plains zone (NEPZ) of India is sown with seed either saved by farmers or obtained locally. Use of sub-standard seed may be counted prime among many factors responsible for low productivity of wheat in lower Gangetic plains. Only seeds from authentic sources were found to be properly graded. It was also observed that wheat seed supplied by registered companies are as good in terms of grading and germination as seeds supplied by government organizations including national and state seed corporations. Graded seeds not only have higher germination ability but also higher seedling vigour in terms of dry matter gain in seedlings during early vegetative growth phase.



2014 ◽  
Vol 62 (7) ◽  
pp. 609 ◽  
Author(s):  
J. F. Sampson ◽  
M. Byrne ◽  
H. C. Norman ◽  
E. Barrett-Lennard

Until recently, ‘Eyres Green’ was the only commercial cultivar of oldman saltbush available for forage planting and landscape rehabilitation. ‘Eyres Green’ is believed to be a clonal cultivar of the ecologically and economically important octoploid dioecious species Atriplex nummularia (Lindl.), but its actual identity is unknown. The genetic relationship of the ‘Eyres Green’ clonal cultivar to the two subspecies A. nummularia ssp. nummularia and A. nummularia ssp. spathulata (Aellen) was assessed using nuclear microsatellite markers, principal coordinate analysis and Bayesian clustering. ‘Eyres Green’ clustered with ssp. nummularia in all analyses, suggesting that the cultivar was derived from an individual of this subspecies, probably from the north-eastern part of the subspecies’ distribution in eastern Australia. Atriplex species are dioecous and substantially wind-pollinated. Plants of the ‘Eyres Green’ cultivar are female, so risk of genetic contamination from initial plantings is low, but could occur if plantings within pollination distance of natural populations set seed and establish male plants that subsequently become a source of pollen contamination.



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