Changes in farming practices impact on spore release patterns of the blackleg pathogen, Leptosphaeria maculans

2018 ◽  
Vol 69 (1) ◽  
pp. 1 ◽  
Author(s):  
J. McCredden ◽  
R. B. Cowley ◽  
S. J. Marcroft ◽  
A. P. Van de Wouw
Keyword(s):  
Cultural Practices ◽  
Cropping Systems ◽  
Leptosphaeria Maculans ◽  
Farming Practices ◽  
Blackleg Disease ◽  
Stubble Retention ◽  
No Till ◽  
Spore Release ◽  
Significant Yield ◽  
The Impact

Blackleg disease is caused by the stubble-borne pathogen Leptosphaeria maculans and results in significant yield losses in canola (Brassica napus) worldwide. Control of this disease includes breeding for resistance, fungicides and cultural practices including stubble management. In recent years, cropping systems have changed with the introduction of no-till farming and inter-row sowing, and it is unknown what impact these changes have had on stubble retention. The aim of this study is to investigate the impact of inter-row sowing on stubble retention and spore release. The use of inter-row sowing resulted in 25–48% of stubble remaining standing (vertical) in fields after 1 year. Furthermore, spore release was significantly (P < 0.05) delayed in stubble that remained vertical in the field compared with stubble lying down, with total spore release from vertical stubble 66% less than from horizontal stubble. The impact these changes have on the epidemiology of blackleg disease remains unknown.

Effect of long-term stubble management on yield and nitrogen-uptake efficiency of wheat topdressed with urea in north-eastern Victoria

2001 ◽  
Vol 41 (8) ◽  
pp. 1167 ◽  
Author(s):  
Philip J. Newton
Keyword(s):  
Nitrogen Uptake ◽  
Cropping Systems ◽  
Grain Legume ◽  
Wheat Crop ◽  
Stubble Retention ◽  
Eastern Australia ◽  
Nitrogen Inputs ◽  
The Impact ◽  
Stubble Burning

Use of urea fertiliser for cereal cropping in south eastern Australia has increased rapidly in recent years to arrest a general decline in grain protein and to increase yields. In conservation cropping systems, crop stubbles provide a source of carbon, which has the potential to retain a portion of the fertiliser nitrogen in the soil. The impact of fertiliser nitrogen was compared under 4 stubble management regimes for efficiency of nitrogen uptake by a wheat crop in a long-term cereal–grain legume rotation. The experiment was established on a duplex red-brown earth in 1985 to compare stubble retention (standing, shredded, incorporated) with stubble burning. In 1995, wheat following a failed lupin crop was topdressed with urea fertiliser at 50 kg nitrogen per hectare to split plots of each stubble treatment at the third-leaf stage of growth. The urea significantly increased nitrogen uptake by wheat grown on burnt stubbles and increased grain yield by 1 t/ha. Nitrogen applied to wheat grown on stubbles retained above-ground increased yield by 0.5 t/ha, whereas there was no significant yield increase from nitrogen when stubble was incorporated due to less transfer of dry matter to grain. Efficiency of urea-nitrogen uptake in grain was reduced under stubble retention. The total grain nitrogen uptake in response to stubble burning increased by 17.6 kg/ha, which was equivalent to a conversion efficiency of 35%, compared with only 26, 24 and 16% of the applied 50 kg nitrogen per hectare for stubble standing, shredding and incorporation treatments, respectively. Soil organic carbon and total nitrogen levels were 1 and 0.1%, respectively, irrespective of stubble treatment. Added urea increased microbial decomposition of cellulose in calico cloth buried beneath stubbles retained above-ground by 30%, compared with stubble incorporated or burnt treatments. These results suggest that where low levels of available nitrogen exist in cropping systems that use stubble retention, higher nitrogen inputs may be needed, due to less efficient uptake of nitrogen from urea fertiliser.

scholarly journals Biology and Management of Vulpia myuros—An Emerging Weed Problem in No-Till Cropping Systems in Europe

Plants ◽  
2020 ◽  
Vol 9 (6) ◽  
pp. 715
Author(s):  
Muhammad Javaid Akhter ◽  
Peter Kryger Jensen ◽  
Solvejg Kopp Mathiassen ◽  
Bo Melander ◽  
Per Kudsk
Keyword(s):  
Cropping Systems ◽  
Management Strategies ◽  
Cultural Control ◽  
Integrated Weed Management ◽  
No Till ◽  
Arable Farming ◽  
Wide Range ◽  
European Farming ◽  
The Impact ◽  
Grass Weed

Recently, Vulpia myuros has become a problematic grass weed species in parts of Europe. It is most common in no-till cropping systems. The inherent tolerance to several selective grass weed herbicides is of serious concern to the successful management of V. myuros in arable farming. Here, we reviewed the available knowledge about the biology of V. myuros to identify knowledge gaps and assess management efforts to identify best practices for control. V. myuros is a winter-annual species producing seeds with a short dormancy that can germinate at a wide range of conditions. Seed longevity in the soil is short. Little information is available on the influence of V. myuros on crop yield but some results suggest that yield losses can be significant. The findings provide a better understanding of the weedy characteristics of V. myuros and highlight that management strategies in Europe need to be diversified and integrate preventive and cultural control methods. Finally, we identify some of the management tools that should be considered to minimize the impact of V. myuros on European farming and future needs for research to develop sustainable integrated weed management strategies.

scholarly journals Weed communities and wheat yield are modified by cropping systems and climate conditions

2020 ◽  
Author(s):  
Tim Seipel ◽  
Suzanne L. Ishaq ◽  
Fabian D. Menalled
Keyword(s):  
Cropping Systems ◽  
Wheat Yield ◽  
Cropping System ◽  
Conventional System ◽  
Organic System ◽  
Weed Biomass ◽  
Climate Conditions ◽  
No Till ◽  
Weed Communities ◽  
The Impact

SummaryUnderstanding the impact of biological and environmental stresses on crop performance is essential to secure the long-term sustainability of agricultural production. How cropping systems modify weed communities and wheat yield in response to predicted climate conditions is unknown. We tested the effect of warmer, and warmer and drier conditions on weed biomass, weed community characteristics, and winter wheat yields in three contrasting cropping systems: a no-till chemically managed system, a tilled organic system, and an organic system that used grazing to reduce tillage. Weed communities in the organic systems were more diverse and more variable than the no-till conventional system, though the grazed organic and no-till conventional systems had more similar relative species abundance. Cropping system affected weed biomass and weed species composition recorded in 0.75 m2 split-plots, with the most biomass recorded in grazed organic system (38 g ±23.4 SE) compared to the tilled-organic (17 g ±10.3 SE) and no-till chemically managed systems (<1 g ±0.02). Climate conditions had relatively minor impacts on weed communities compared with cropping systems. Wheat yield was highest in the no-till conventional system but declined in response to warmer and drier conditions despite its low weed biomass. Yield was lower in the tilled organic and grazed organic cropping system but declines in warmer and drier conditions were more variable among years. In the Northern Great Plains, predicted climate scenarios have the potential to alter weed communities and reduce wheat yield, and designing resilient cropping systems is essential to mitigate these negative impacts.

scholarly journals Strategic tillage of a long-term, no-till soil has little impact on soil characteristics or crop growth over five years

2020 ◽  
Vol 71 (12) ◽  
pp. 945
Author(s):  
John Kirkegaard ◽  
Clive Kirkby ◽  
Albert Oates ◽  
Vince van der Rijt ◽  
Graeme Poile ◽  
...  
Keyword(s):  
Fine Fraction ◽  
Crop Growth ◽  
Total Carbon ◽  
Growth And Yield ◽  
Soil Conditions ◽  
Stubble Retention ◽  
No Till ◽  
C Stocks ◽  
The Impact

Strategic tillage describes the occasional use of tillage in an otherwise no-till system. The practice can provide a pragmatic solution to emerging agronomic issues in no-till systems but raises concerns about prolonged or irreversible soil damage. We investigated the impact of a single tillage event at a long-term no-till experiment under treatments with retained or annually autumn-burned crop residues. One half of each residue-treatment plot received a single pass of a rotary hoe (ST) 4 weeks before sowing in 2011, the first year of the experiment; the other half of each plot remained unchanged (NT). Soil physical, chemical and biological fertility in the surface layers (0–20 cm), as well as crop growth and yield were monitored for 5 years (2011–15). Following the ST treatment, soil bulk density and strength were initially reduced to the depth of cultivation (~15 cm) irrespective of residue treatment. Water-stable macroaggregates in the surface 0–5 cm were also reduced but recovered to pre-tillage levels within 1–2 years after ST treatment. Soil pH, total carbon (C), total nitrogen (N), and fine-fraction C and N were all initially stratified in the surface layer (0–5 cm) of the NT treatment but were redistributed more evenly throughout the 0–10 cm layer of the ST treatment and remained so throughout the 5-year period. With ST, there was an initial loss in total C stocks in the 0–10 cm layer of 2.2 t/ha, which recovered within 2 years; however, total C stocks remained lower in plots with stubble retained than with stubble burnt after 5 years. Soil Colwell P levels were not stratified and not influenced by tillage treatment, presumably because of the annual additions in the starter fertiliser at sowing. ST had no impact on crop establishment or grain yield in any year but increased the early biomass of wheat at Z30 compared with NT in the first 2 years. Annual stubble retention reduced the early growth of crops in all years, and yield of wheat in the first 3 years, consistent with long-term effects of retained stubble at the site, but there was no interaction between stubble retention and tillage treatments on soil conditions or crop growth. Crop yields of long-term, annually cultivated treatments were also similar to those of ST and NT treatments during the 5 years of the experiment. Overall, the minor short-term negative impacts on soil physical conditions, the persistent and arguably beneficial effects on soil chemistry and biology, and absence of impacts on crop production suggest that strategic tillage can be a valuable agronomic tool in sustainable production in this region.

scholarly journals Validating the Strategic Deployment of Blackleg Resistance Gene Groups in Commercial Canola Fields on the Canadian Prairies

2021 ◽  
Vol 12 ◽  
Author(s):  
Justine Cornelsen ◽  
Zhongwei Zou ◽  
Shuanglong Huang ◽  
Paula Parks ◽  
Ralph Lange ◽  
...  
Keyword(s):  
Key Management ◽  
Management Practices ◽  
Disease Incidence ◽  
Genetic Resistance ◽  
Leptosphaeria Maculans ◽  
R Genes ◽  
Blackleg Disease ◽  
Canadian Prairies ◽  
Blackleg Resistance ◽  
The Impact

Blackleg, caused by the fungal pathogen Leptosphaeria maculans, is a serious threat to canola (Brassica napus L.) production in western Canada. Crop scouting and extended crop rotation, along with the use of effective genetic resistance, have been key management practices available to mitigate the impact of the disease. In recent years, new pathogen races have reduced the effectiveness of some of the resistant cultivars deployed. Strategic deployment and rotation of major resistance (R) genes in cultivars have been used in France and Australia to help increase the longevity of blackleg resistance. Canada also introduced a grouping system in 2017 to identify blackleg R genes in canola cultivars. The main objective of this study was to examine and validate the concept of R gene deployment through monitoring the avirulence (Avr) profile of L. maculans population and disease levels in commercial canola fields within the Canadian prairies. Blackleg disease incidence and severity was collected from 146 cultivars from 53 sites across Manitoba, Saskatchewan, and Alberta in 2018 and 2019, and the results varied significantly between gene groups, which is likely influenced by the pathogen population. Isolates collected from spring and fall stubble residues were examined for the presence of Avr alleles AvrLm1, AvrLm2, AvrLm3, AvrLm4, AvrLm5, AvrLm6, AvrLm7, AvrLm9, AvrLm10, AvrLm11, AvrLepR1, AvrLepR2, AvrLep3, and AvrLmS using a set of differential host genotypes carrying known resistance genes or PCR-based markers. The Simpson’s evenness index was very low, due to two dominant L. maculans races (AvrLm2-4-5-6-7-10-11 and AvrLm2-5-6-7-10-11) representing 49% of the population, but diversity of the population was high from the 35 L. maculans races isolated in Manitoba. AvrLm6 and AvrLm11 were found in all 254 L. maculans isolates collected in Manitoba. Knowledge of the blackleg disease levels in relation to the R genes deployed, along with the L. maculans Avr profile, helps to measure the effectiveness of genetic resistance.

Blackleg disease of canola in Australia

2016 ◽  
Vol 67 (4) ◽  
pp. 273 ◽  
Author(s):  
A. P. Van De Wouw ◽  
S. J. Marcroft ◽  
B. J. Howlett
Keyword(s):  
Disease Resistance ◽  
Disease Control ◽  
Leptosphaeria Maculans ◽  
Control Measures ◽  
Blackleg Disease ◽  
Disease Mechanisms ◽  
Fungal Populations ◽  
Fungal Genes ◽  
The Impact ◽  
Important Disease

Blackleg disease caused by the fungus Leptosphaeria maculans is the most important disease of canola worldwide. The impact of this disease on the development of the Australian canola industry, particularly over the last 20 years, is discussed. Deployment of a range of disease control measures has resulted in a thriving canola industry with production now approaching 4 million tonnes annually. Discoveries about disease mechanisms and key plant and fungal genes are described. Analysis of the L. maculans genome sequence has enabled an understanding of how fungal populations can evolve rapidly to overcome disease resistance bred into canola cultivars.

scholarly journals Understanding Sclerotinia Risks Associated with Growing Peanuts in the South Burnett Area

Proceedings ◽  
2020 ◽  
Vol 36 (1) ◽  
pp. 150
Author(s):  
Claire-Marie Pepper
Keyword(s):  
Assessment Tool ◽  
Cropping Systems ◽  
Management Strategies ◽  
South Australia ◽  
Weather Data ◽  
Future Research ◽  
The South ◽  
Sclerotinia Blight ◽  
Significant Yield ◽  
The Impact

Sclerotinia Blight, caused by ascomycete fungal pathogen S. minor (Jagger), is a serious soil-borne disease of peanut crops within the South Burnett area in Queensland, Australia. The pathogen can infect root, stem and foliage tissues, forming characteristic fluffy white mycelial growth on stems leading to tissue wilting and necrosis. The disease can cause significant yield reductions and, in some cases, complete crop losses in peanut production. Outbreaks occur in cooler weather (under 18 °C) with high humidity levels (above 95%) as the higher humidity levels promote germination of sclerotia (Smith 2003, Maas, Dashiell et al. 2006). Therefore, knowledge of inoculum levels prior to sowing could enhance cropping systems through enhanced capacity to predict outbreaks. The South Australia Research and Development Institute (SARDI) offers a new soil test for Sclerotinia sp., called PreDictaB, available for farmers to asses inoculum levels pre-planting as a crop risk assessment tool. This project validated the accuracy of the PreDictaB test for Sclerotinia inoculum levels in the South Burnett soils, while gathering paddock and weather data to identify key characteristics linked to high risk of Sclerotinia Blight incidence to be transposed in a pre-season risk matrix model. Results demonstrated a close positive relationship between the level of Sclerotinia in the soil pre-planting and the paddock disease severity observed at harvest. The significance of the results for future research into potential management strategies is discussed. This new test has the potential to reduce the impact and presence of Sclerotinia in the field within the South Burnett region.

Nitrate Leaching to a Shallow Mid-Atlantic Coastal Plain Aquifer as Influenced by Conventional No-Till and Low-Input Sustainable Grain Production Systems

1993 ◽  
Vol 28 (3-5) ◽  
pp. 691-700 ◽  
Author(s):  
J. P. Craig ◽  
R. R. Weil
Keyword(s):  
Management Practices ◽  
Production Systems ◽  
Cropping Systems ◽  
Cropping System ◽  
Atlantic Coastal Plain ◽  
Grain Production ◽  
Nitrogen And Phosphorus ◽  
Mineral N ◽  
Low Input ◽  
No Till

In December, 1987, the states in the Chesapeake Bay region, along with the federal government, signed an agreement which called for a 40% reduction in nitrogen and phosphorus loadings to the Bay by the year 2000. To accomplish this goal, major reductions in nutrient loadings associated with agricultural management practices were deemed necessary. The objective of this study was to determine if reducing fertilizer inputs to the NT system would result in a reduction in nitrogen contamination of groundwater. In this study, groundwater, soil, and percolate samples were collected from two cropping systems. The first system was a conventional no-till (NT) grain production system with a two-year rotation of corn/winter wheat/double crop soybean. The second system, denoted low-input sustainable agriculture (LISA), produced the same crops using a winter legume and relay-cropped soybeans into standing wheat to reduce nitrogen and herbicide inputs. Nitrate-nitrogen concentrations in groundwater were significantly lower under the LISA system. Over 80% of the NT groundwater samples had NO3-N concentrations greater than 10 mgl-1, compared to only 4% for the LISA cropping system. Significantly lower soil mineral N to a depth of 180 cm was also observed. The NT soil had nearly twice as much mineral N present in the 90-180 cm portion than the LISA cropping system.

Competitive attributes ofA. sativa, T. aestivum, andH. vulgareare conserved in no-till cropping systems

Weed Science ◽  
1999 ◽  
Vol 47 (6) ◽  
pp. 712-719 ◽  
Author(s):  
Anne Légère ◽  
Yuguang Bai
Keyword(s):  
Hordeum Vulgare ◽  
Avena Sativa ◽  
Growth Parameters ◽  
Cropping Systems ◽  
Seedling Emergence ◽  
Biomass Accumulation ◽  
Tillage Systems ◽  
Area Index ◽  
No Till ◽  
Lower Test

The robustness of competitive attributes of cereals such as rapid and uniform seedling emergence, tillering, early biomass accumulation and canopy closure, and height advantage over weeds have not yet been tested under environmental conditions typical of no-till (NT) cropping systems. Our objective was to evaluate the effects or NT practices on growth and productivity ofAvena sativa, Triticum aestivum, Hordeum vulgare, and associated weeds. The experiment was conducted on a Kamouraska clay at La Pocatière, QC, in 1994, 1995, and 1996.Avena sativa, T. aestivum, andH. vulgarewere grown under tilled and NT practices. Cereal growth parameters were measured six (1994) or seven (1995) times between planting and the 11th week after planting but only once in 1996. Grain yields and yield components were determined at crop maturity.Avena sativaandH. vulgarepopulations were little affected by tillage, whereasT. aestivumpopulations were reduced by 16 to 20% in NT systems. Growth in height in NT systems was either similar or greater than in tilled systems in all three cereals. Cereal leaf area index (LAI) and biomass accumulation was also comparable between tillage systems, except forT. aestivumLAI in 1994, which was greater in tilled plots on two sampling dates. Response of annual dicots to tillage was inconsistent in all crops. Annual monocots dominated in some but not all NT systems. Perennial dicots dominated in NT systems, whereas perennial monocots were more abundant in tilled systems in all three cereals.Avena sativaandT. aestivumyields in NT plots were comparable or greater than in tilled plots, in spite of having either lower test weights (A. sativa) or lower 1,000-grain weights (T. aestivum). NTT. aestivumproductivity was maintained in spite of reduced plant establishment.Hordeum vulgareyields were also similar across tillage systems, except in 1995, when yields in tilled plots were greater than in NT plots. The height advantage observed for NTH. vulgaredid not result in improved yields. All three cereals, and particularlyA. sativa, appeared well suited to NT systems, despite the pressure provided by different weed groups, compared to tilled systems. However, results suggest that NT production of cereals could benefit from improved attention to perennial dicot control and crop seedling establishment, particularly forT. aestivum.

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