Influence of chaff and chaff lines on weed seed survival and seedling emergence in Australian cropping systems

Abstract Chaff lining and chaff tramlining are harvest weed seed control (HWSC) systems that involve the concentration of weed seed containing chaff material into narrow (20 to 30 cm) rows between or on the harvester wheel tracks during harvest. These lines of chaff are left intact in the fields through subsequent cropping seasons in the assumption that the chaff environment is unfavourable for weed seed survival. The chaff row environment effect on weed seed survival was examined in field studies, while chaff response studies determined the influence of increasing amounts of chaff on weed seedling emergence. The objectives of these studies were to determine 1) the influence of chaff lines on the summer-autumn seed survival of selected weed species; and 2) the influence of chaff type and amount on rigid ryegrass seedling emergence. There was frequently no difference (P>0.05) in survival of seed of four weed species (rigid ryegrass, wild oat, annual sowthistle and turnip weed) when these seed were placed beneath or beside chaff lines. There was one instance where wild oat seed survival was increased (P<0.05) when seed were placed beneath compared to beside a chaff line. The pot studies determined that increasing amounts of chaff consistently resulted in decreasing numbers of rigid ryegrass seedlings emerging through chaff material. The suppression of emergence broadly followed a linear relationship where there was approximately a 2.0% reduction in emergence with every 1.0 t ha-1 increase in chaff material. This relationship was consistent across wheat, barley, canola and lupin chaff types, indicating that the physical presence of the chaff was more important than chaff type. These studies indicated that chaff lines may not affect the over summer-autumn survival of the contained weed seeds but the subsequent emergence of weed seedlings will be restricted by high amounts of chaff (>40 t ha-1).

Download Full-text

Influence of chaff and chaff lines on weed seed survival and seedling emergence in Australian cropping systems – ERRATUM

Weed Technology ◽

10.1017/wet.2021.25 ◽

2021 ◽

pp. 1-1

Author(s):

Michael J. Walsh ◽

Annie E. Rayner ◽

Annie Ruttledge ◽

John C. Broster

Keyword(s):

Cropping Systems ◽

Seedling Emergence ◽

Weed Seed ◽

Seed Survival

Download Full-text

iHSD Mill Efficacy on the Seeds of Australian Cropping System Weeds

Weed Technology ◽

10.1017/wet.2017.95 ◽

2017 ◽

Vol 32 (2) ◽

pp. 103-108 ◽

Cited By ~ 6

Author(s):

Michael J. Walsh ◽

John C. Broster ◽

Stephen B. Powles

Keyword(s):

Moisture Content ◽

Crop Production ◽

Production Systems ◽

Cropping Systems ◽

Cropping System ◽

High Efficacy ◽

Weed Seed ◽

Rigid Ryegrass ◽

Mill Speed ◽

Wheat Chaff

AbstractIn Australia, widespread evolution of multi-resistant weed populations has driven the development and adoption of harvest weed seed control (HWSC). However, due to incompatibility of commonly used HWSC systems with highly productive conservation cropping systems, better HWSC systems are in demand. This study aimed to evaluate the efficacy of the integrated Harrington Seed Destructor (iHSD) mill on the seeds of Australia’s major crop weeds during wheat chaff processing. Also examined were the impacts of chaff type and moisture content on weed seed destruction efficacy. Initially, the iHSD mill speed of 3,000 rpm was identified as the most effective at destroying rigid ryegrass seeds present in wheat chaff. Subsequent testing determined that the iHSD mill was highly effective (>95% seed kill) on all Australian crop weeds examined. Rigid ryegrass seed kill was found to be highest for lupin chaff and lowest in barley, with wheat and canola chaff intermediate. Similarly, wheat chaff moisture reduced rigid ryegrass seed kill when moisture level exceeded 12%. The broad potential of the iHSD mill was evident, in that the reductions in efficacy due to wide-ranging differences in chaff type and moisture content were relatively small (≤10%). The results from these studies confirm the high efficacy and widespread suitability of the iHSD for use in Australian crop production systems. Additionally, as this system allows the conservation of all harvest residues, it is the best HWSC technique for conservation cropping systems.

Download Full-text

Seed germination ecology of Conyza stricta Willd. and implications for management

PLoS ONE ◽

10.1371/journal.pone.0244059 ◽

2020 ◽

Vol 15 (12) ◽

pp. e0244059

Author(s):

Safdar Ali ◽

Fakhar Din Khan ◽

Rehmat Ullah ◽

Rahmat Ullah Shah ◽

Saud Alamri ◽

...

Keyword(s):

Seed Germination ◽

Osmotic Potential ◽

Cropping Systems ◽

Seedling Emergence ◽

Management Strategies ◽

Conservation Agriculture ◽

Weed Species ◽

Seed Burial ◽

Germination Ecology ◽

Tillage Practices

Numerous cropping systems of the world are experiencing the emergence of new weed species in response to conservation agriculture. Conyza stricta Willd. is being a newly emerging weed of barley-based cropping systems in response to conservational tillage practices. Seed germination ecology of four populations (irrigated, rainfed, abandoned and ruderal habitats) was studied in laboratory and greenhouse experiments. The presence/absence of seed dormancy was inferred first, which indicated seeds were non-dormant. Seed germination was then recorded under various photoperiods, constant and alternating day/night temperatures, and pH, salinity and osmotic potential levels. Seedling emergence was observed from various seed burial depths. Seeds of all populations proved photoblastic and required 12-hour light/dark period for germination. Seeds of all populations germinated under 5–30°C constant temperature; however, peak germination was recorded under 17.22–18.11°C. Nonetheless, the highest germination was noted under 20/15°C alternating day/night temperature. Ruderal and irrigated populations better tolerated salinity and germinated under 0–500 mM salinity. Similarly, rainfed population proved more tolerant to osmotic potential than other populations. Seeds of all populations required neutral pH for the highest germination, whereas decline was noted in germination under basic and alkaline pH. Seedling emergence was retarded for seeds buried >2 cm depth and no emergence was recorded from >4 cm depth. These results add valuable information towards our understanding of seed germination ecology of C. stricta. Seed germination ability of different populations under diverse environmental conditions suspects that the species can present severe challenges in future if not managed. Deep seed burial along with effective management of the emerging seedlings seems a pragmatic option to manage the species in cultivated fields. However, immediate management strategies are needed for rest of the habitats.

Download Full-text

Factors Affecting Weed Seed Devitalization with the Harrington Seed Destructor

Weed Science ◽

10.1017/wsc.2017.23 ◽

2017 ◽

Vol 65 (5) ◽

pp. 650-658 ◽

Cited By ~ 8

Author(s):

Breanne D. Tidemann ◽

Linda M. Hall ◽

K. Neil Harker ◽

Hugh J. Beckie

Keyword(s):

Seed Size ◽

Cropping Systems ◽

Weed Seed ◽

Weed Species ◽

Factors Affecting ◽

Weed Seeds ◽

High Control ◽

Relationship Of ◽

The Impact ◽

Levels Of Control

The Harrington Seed Destructor (HSD), a novel weed control technology, has been highly effective in Australian cropping systems. To investigate its applicability to conditions in western Canada, stationary threshing was conducted to determine the impact of weed species, seed size, seed number, chaff load, and chaff type on efficacy of seed destruction. Control varied depending on species, with a range of 97.7% to 99.8%. Sieve-sized volunteer canola seed had a linear relationship of increasing control with increasing 1,000-seed weight. However, with greater than 98% control across all tested seed weights, it is unlikely that seed size alone will significantly influence control. Consistently high levels of control were observed at all tested seed densities (10 seeds to 1 million seeds). The response of weed seed control to chaff load was quadratic, but a narrow range of consistently high control (>97%) was again observed. Chaff type had a significant effect on weed seed control (98% to 98.6%); however, seed control values in canola chaff were likely confounded by a background presence of volunteer canola. Overall, the five parameters studied statistically influence control of weed seeds with the HSD. However, small differences between treatments are unlikely to affect the biological impact of the machine, which provides high levels of control for those weed seeds that can be introduced into the harvester.

Download Full-text

Evaluating Seed Shatter of Economically Important Weed Species

Weed Science ◽

10.1614/ws-d-16-00081.1 ◽

2016 ◽

Vol 64 (4) ◽

pp. 673-682 ◽

Cited By ~ 11

Author(s):

Nikki R. Burton ◽

Hugh J. Beckie ◽

Christian J. Willenborg ◽

Steven J. Shirtliffe ◽

Jeff J. Schoenau ◽

...

Keyword(s):

Weed Management ◽

Field Experiments ◽

Management Strategies ◽

Wild Oat ◽

Population Abundance ◽

Weed Seed ◽

Weed Species ◽

Wild Mustard ◽

Green Foxtail ◽

Crop Maturity

The increasing occurrence of herbicide resistance, along with no new herbicide modes of action developed in over 30 yr, have increased the need for nonherbicidal weed management strategies and tactics. Harvest weed seed control (HWSC) practices have been successfully adopted in Australia to manage problematic weeds. For HWSC to be effective, a high proportion of weed seeds must be retained on the plant at crop maturity. This 2-yr (2014, 2015) study evaluated seed shatter of wild oat, green foxtail, wild mustard, and cleavers in both an early (field pea) and late (spring wheat) maturity crop in field experiments at Scott, Saskatchewan. Seed shatter was assessed using shatter trays collected once a week during crop ripening stage, as well as at two crop maturation or harvest stages (swathing, direct-combining). Seed shatter differed among weed species, but was similar between crops at maturity: ca. 30% for wild oat, 5% for cleavers, < 2% for wild mustard, and < 1% for green foxtail. Overall, seed shatter of wild oat occurred sooner and at greater levels during the growing season compared with the other weed species. Viability of both shattered and plant-retained seeds was relatively high for all species. The small amount of seed shatter of cleavers, wild mustard, and green foxtail suggests that these species may be suitable candidates for HWSC. Due to the amount and timing of wild oat seed shatter, HWSC may not reduce population abundance of this grassy weed.

Download Full-text

Effect of roller-crimper technology on weed management in organic zucchini production in a Mediterranean climate zone

Renewable Agriculture and Food Systems ◽

10.1017/s1742170515000046 ◽

2015 ◽

Vol 31 (2) ◽

pp. 111-121 ◽

Cited By ~ 11

Author(s):

Corrado Ciaccia ◽

Stefano Canali ◽

Gabriele Campanelli ◽

Elena Testani ◽

Francesco Montemurro ◽

...

Keyword(s):

Weed Control ◽

Cover Crops ◽

Weed Management ◽

Cover Crop ◽

Cropping Systems ◽

Central Italy ◽

Competitive Balance ◽

Weed Species ◽

Wide Range ◽

Cropping Seasons

AbstractIntegrating cover crops into vegetable cropping systems can provide a wide range of ecological services, of which weed management is a key component. Cover crop effects on weed control, however, are dependent on termination methods and weed species present in specific cropping seasons. A 2-year weed management experiment with two cultivars of organic zucchini (Cucurbita pepo L.) in central Italy was carried out to compare the effect of a barley (Hordeum distichum L.) cover crop terminated with a modified roller-crimper (RC) to incorporated barley as green manure (GM) and a tilled control left fallow (FA) in the off-season. The effects of cover-crop management on crop competitiveness, yields and weed populations were evaluated by direct measurement, visual estimation and competition index methods. Results showed a significant reduction in weed biomass (>80%) and weed abundance with the RC compared to the GM and FA treatments. Moreover, the RC barley mulch maintained weed control in zucchini plots even under high weed pressure, as determined by the agronomic tolerance to competition (ATC) value of 67% in the RC treatment compared to 40 and 34% in the FA and GM treatments, respectively, averaged over both years of the experiment. The competitive balance (Cb), which quantified the ability of the zucchini crop to compete with weed populations, was also greater (+0.37) in the RC treatment compared to FA (−0.87) and GM (−0.69) treatments over the same period. Zucchini crop biomass was greatest in the RC treatment in 2011. Zucchini fruit yields varied from an average over both years of 1.4 Mg ha−1 in the RC treatment to 0.7 Mg ha−1 in the GM treatment, but yields in the FA treatment, 1.2 Mg ha−1, did not differ from the RC treatment. No differences in yield between ‘Dietary’ and ‘Every’ zucchini, or any significant interactions between cultivar and cover management related to fruit biomass, were observed. Our findings suggested the viability of the modified RC in creating a barley cover-crop mulch to effectively manage weeds and enhance yields in transplanted zucchini.

Download Full-text

Effect of Crop Residues on Weed Emergence

Agronomy ◽

10.3390/agronomy11010163 ◽

2021 ◽

Vol 11 (1) ◽

pp. 163

Author(s):

Nebojša Nikolić ◽

Donato Loddo ◽

Roberta Masin

Keyword(s):

Weed Management ◽

Crop Residues ◽

Cropping Systems ◽

Chenopodium Album ◽

Seedling Emergence ◽

Amaranthus Retroflexus ◽

Weed Species ◽

Field Quantity ◽

Crop Fields ◽

No Till

Weed behaviour in crop fields has been extensively studied; nevertheless, limited knowledge is available for particular cropping systems, such as no-till systems. Improving weed management under no-till conditions requires an understanding of the interaction between crop residues and the seedling emergence process. This study aimed to evaluate the influence of maize and wheat residues, applied in three different quantities (1, the field quantity, 0.5, and 1.5-fold amounts of the field quantity), on the emergence of eight weed species: Abutilon theophrasti, Amaranthus retroflexus, Chenopodium album, Digitaria sanguinalis, Echinochloa crus-galli, Setaria pumila, Sonchus oleraceus, and Sorghum halepense. The experiment was conducted over two consecutive years. The results showed that the quantities 1 and 1.5 could suppress seedling emergence by 20 and 44%, respectively, while the quantity 0.5 seems to promote emergence by 22% compared with the control without residues. Weed species showed different responses to crop residues, from C. album showing 56% less emergence to S. halepense showing a 44% higher emergence than the control without residues. Different meteorological conditions in the two-year experiment also exhibited a significant influence on weed species emergence.

Download Full-text

Harvest Weed Seed Control Systems are Similarly Effective on Rigid Ryegrass

Weed Technology ◽

10.1017/wet.2017.6 ◽

2017 ◽

Vol 31 (2) ◽

pp. 178-183 ◽

Cited By ~ 13

Author(s):

Michael J. Walsh ◽

Charlotte Aves ◽

Stephen B. Powles

Keyword(s):

Control Systems ◽

Seed Production ◽

Cropping Systems ◽

Vital Role ◽

Wild Radish ◽

Weed Seed ◽

Wild Oats ◽

Rigid Ryegrass ◽

Annual Weeds ◽

Crop Maturity

Harvest weed seed control (HWSC) systems have been developed to exploit the high proportions of seed retained at maturity by the annual weeds rigid ryegrass, wild radish, bromegrass, and wild oats. To evaluate the efficacy of HWSC systems on rigid ryegrass populations, three systems, the Harrington Seed Destructor (HSD), chaff carts, and narrow-windrow burning were compared at 24 sites across the western and southern wheat production regions of Australia. HWSC treatments were established at harvest (Nov. – Dec.) in wheat crops with low to moderate rigid ryegrass densities (1 to 26 plants m−2). Rigid ryegrass counts at the commencement of the next growing season (Apr. – May) determined that HWSC treatments were similarly effective in reducing emergence. Chaff carts, narrow-windrow burning, or HSD systems act similarly on rigid ryegrass seed collected during harvest to deliver substantial reductions in subsequent rigid ryegrass populations by restricting seedbank inputs. On average, population densities were reduced by 60%, but there was considerable variation between sites (37 to 90%) as influenced by seed production and the residual seedbank. Given the observed high rigid ryegrass seed production levels at crop maturity it is clear that HWSC has a vital role in preventing seedbank inputs in Australian conservation cropping systems.

Download Full-text

Burial Environment Drives Seed Mortality of Kochia (Bassia scoparia), Wild Oat (Avena fatua), and Volunteer Canola (Brassica napus) Irrespective of Crop Species

Plants ◽

10.3390/plants10091961 ◽

2021 ◽

Vol 10 (9) ◽

pp. 1961

Author(s):

Charles M. Geddes

Keyword(s):

Brassica Napus ◽

Avena Fatua ◽

Wild Oat ◽

Population Demography ◽

Weed Seed ◽

Brassica Napus L ◽

Crop Species ◽

Seed Survival ◽

Weed Population ◽

Seed Mortality

Models of weed population demography are critical to understanding the long-term viability of management strategies. The driving factors of weed seedbank persistence are often underrepresented in demographic models due to the cumbersome nature of seedbank research. Simplification of weed seedbank dynamics may induce substantial error in model simulations. A soil bioassay was conducted to determine whether growth of different crop species, including wheat (Triticum aestivum L.), canola (Brassica napus L.), and field pea (Pisum sativum L.), differentially impact seed mortality of kochia [Bassia scoparia (L.) A.J. Scott], wild oat (Avena fatua L.), and volunteer canola in seven burial environments in western Canada. Weed seed survival after the 7 week burial period varied widely among burial environments (from 8% to 88% when averaged among weed and crop species), whereas growth of the different crop species had negligible impact on seedbank persistence. Among environments, wild oat seed survived the greatest (79%), followed by kochia (20%), and volunteer canola (6%). Weed seed survival was associated with soil physical properties (texture) and seed microsite characteristics (temperature), but not crop species or soil chemical properties. Overall, these data support the need for greater integration of soil and environmental parameters into models of weed population demography.

Download Full-text

Economics of Pronamide and Pendimethalin Use in Weed Management during Artichoke Stand Establishment

HortScience ◽

10.21273/hortsci.36.4.650 ◽

2001 ◽

Vol 36 (4) ◽

pp. 650-653 ◽

Cited By ~ 4

Author(s):

Milton J. Haar ◽

Steven A. Fennimore ◽

Cheryl L. Lambert

Keyword(s):

Weed Management ◽

Financial Analysis ◽

Field Studies ◽

Avena Fatua ◽

Wild Oat ◽

Weed Species ◽

Cynara Scolymus ◽

A Site ◽

Heavy Infestation ◽

Better Than

Field studies were conducted to determine the potential economic impact of the loss of pronamide herbicide to artichoke (Cynara scolymus L.) growers, and to evaluate pendimethalin as an alternative herbicide during establishment of artichoke. Two rates of pronamide and one rate of pendimethalin were applied to perennial and annual artichokes. With the exception of wild oat (Avena fatua L.), pendimethalin controlled weeds as well as or better than pronamide. Financial analysis of treatment effects was based on weed management expenses and value of yield. The financial effect of using pronamide in perennial artichoke ranged from a loss of $247 to a gain of $326 per ha, whereas its use in annual artichoke increased revenue $542 to $5499 per ha. The effects on revenue of using pendimethalin varied with weed species composition and density. For three sites, revenue increased from $267 to $5056 per ha, while a loss of $1034 per ha occurred at a site with a heavy infestation of wild oat. We conclude that pendimethalin has potential as a pronamide replacement, or as a complement to pronamide. Chemical names used: 3,5-dichloro (N-1,1-dimethyl-2-propynyl)benzamide (pronamide); N-(1-ethylpropyl)-3,4-dimethyl-2,6-dinitrobenzenamine (pendimethalin).

Download Full-text