Seed retention of ten common weed species at oat harvest reveals the potential for harvest weed seed control

AbstractDowny brome, feral rye, and jointed goatgrass are problematic winter annual grasses in central Great Plains winter wheat production. Integrated control strategies are needed to manage winter annual grasses and reduce selection pressure exerted on these weed populations by the limited herbicide options currently available. Harvest weed-seed control (HWSC) methods aim to remove or destroy weed seeds, thereby reducing seed-bank enrichment at crop harvest. An added advantage is the potential to reduce herbicide-resistant weed seeds that are more likely to be present at harvest, thereby providing a nonchemical resistance-management strategy. Our objective was to assess the potential for HWSC of winter annual grass weeds in winter wheat by measuring seed retention at harvest and destruction percentage in an impact mill. During 2015 and 2016, 40 wheat fields in eastern Colorado were sampled. Seed retention was quantified and compared per weed species by counting seed retained above the harvested fraction of the wheat upper canopy (15 cm and above), seed retained below 15 cm, and shattered seed on the soil surface at wheat harvest. A stand-mounted impact mill device was used to determine the percent seed destruction of grass weed species in processed wheat chaff. Averaged across both years, seed retention (±SE) was 75% ± 2.9%, 90% ± 1.7%, and 76% ± 4.3% for downy brome, feral rye, and jointed goatgrass, respectively. Seed retention was most variable for downy brome, because 59% of the samples had at least 75% seed retention, whereas the proportions for feral rye and jointed goatgrass samples with at least 75% seed retention were 93% and 70%, respectively. Weed seed destruction percentages were at least 98% for all three species. These results suggest HWSC could be implemented as an integrated strategy for winter annual grass management in central Great Plains winter wheat cropping systems.

Download Full-text

Seed Retention of Grass Weeds at Wheat Harvest in the Pacific Northwest

Weed Science ◽

10.1017/wsc.2020.91 ◽

2020 ◽

pp. 1-32

Author(s):

Carolina San Martín ◽

Mark E Thorne ◽

Jennifer A Gourlie ◽

Drew J Lyon ◽

Judit Barroso

Keyword(s):

Pacific Northwest ◽

Seed Production ◽

Secale Cereale ◽

Bromus Tectorum ◽

Wheat Crop ◽

Weed Seed ◽

Weed Species ◽

Seed Shattering ◽

Seed Retention ◽

The Pacific

Abstract Harvest weed seed control (HWSC) may control problematic weeds by decreasing contributions to the weed seed bank. However, HWSC practices will not be effective if plants have shed a great part of their seeds before harvest, or if a low proportion of seed production is retained at a height that enables collection during harvest. The seed shattering pattern of several weed species was evaluated over three growing seasons to determine their potential to be controlled with HWSC in the Pacific Northwest (PNW). The studied weed species were downy brome (Bromus tectorum L.), feral rye (Secale cereale L.), Italian ryegrass [Lolium perenne ssp. multiflorum (Lam.) Husnot,], and rattail fescue [Vulpia myuros (L.) C.C. Gmel.]. Seed retention at harvest, seed production, and plant height differed among species, locations, and years. Environmental conditions influenced seed shattering patterns, particularly the time plants started to shatter seeds and the rate of the shattering. Agronomic factors such as herbicide use, inter-row space, or crop height/vigor also seemed to affect shattering patterns and seed production, but more specific studies must be conducted to determine their individual effects. Bromus tectorum, L. perenne ssp. multiflorum, and V. myuros had an average seed retention at harvest of less than 50%. In addition, the low seed retention height of V. myuros makes this species a poor candidate for HWSC. Secale cereale had average seed retention at harvest greater than 50% and seed retention height was greater than 30 cm. The variability of seed retention in different species will make the efficacy of HWSC practices species and environment dependent in PNW winter wheat cropping systems. Harvesting the wheat crop as early as possible will be crucial to the success of HWSC.

Download Full-text

Seed Retention of Palmer amaranth (Amaranthus palmeri) and Barnyardgrass (Echinochloa crus-galli) in Soybean

Weed Technology ◽

10.1017/wet.2017.25 ◽

2017 ◽

Vol 31 (4) ◽

pp. 617-622 ◽

Cited By ~ 12

Author(s):

Lauren M. Schwartz-Lazaro ◽

Jeremy K. Green ◽

Jason K. Norsworthy

Keyword(s):

Weed Management ◽

Palmer Amaranth ◽

Amaranthus Palmeri ◽

Weed Seed ◽

Weed Species ◽

Seed Retention ◽

The Us ◽

Amaranth Seed ◽

Soil Seedbank ◽

Crop Harvest

Harvest weed seed control is an alternative non-chemical approach to weed management that targets escaped weed seeds at the time of crop harvest. Relatively little is known on how these methods will work on species in the US. Two of the most prominent weeds in soybean production in the midsouthern US are Palmer amaranth and barnyardgrass. Typically, when crop harvesting occurs the weed seed has already either shattered or is taken into the combine and may be redistributed in the soil seedbank. This causes further weed seed spread and may contribute to the addition of resistant seeds in the seedbank. There is little research on how much seed is retained on different weed species at or beyond harvest time. Thus, the objective of this study was to determine the percentage of total Palmer amaranth and barnyardgrass seed production that was retained on the plant during delayed soybean harvest. Retained seed over time was similar between 2015 and 2016, but was significantly different between years for only Palmer amaranth. Seed retention did not differ between years for either weed species. Palmer amaranth and barnyardgrass retained 98 and 41% of their seed at soybean maturity and 95 and 32% of their seed one month after soybean maturity, respectively. Thus, this research indicates that if there are escaped Palmer amaranth plants and soybean is harvested in a timely manner, most seed will enter the combine and offer potential for capture or destruction of these seeds using harvest weed seed control tactics. While there would be some benefit to using HWSC for barnyardgrass, the utility of this practice on mitigating herbicide resistance would be less pronounced than that of Palmer amaranth because of the reduced seed retention or early seed shatter.

Download Full-text

Seed shattering phenology at soybean harvest of economically important weeds in multiple regions of the United States. Part 1: broadleaf species

Weed Science ◽

10.1017/wsc.2020.80 ◽

2020 ◽

pp. 1-29

Author(s):

Lauren M. Schwartz-Lazaro ◽

Lovreet S. Shergill ◽

Jeffrey A. Evans ◽

Muthukumar V. Bagavathiannan ◽

Shawn C. Beam ◽

...

Keyword(s):

The United States ◽

Ambrosia Artemisiifolia ◽

Retention Rates ◽

Weed Species ◽

Physiological Maturity ◽

Seed Retention ◽

Northern Latitudes ◽

Multiple Regions ◽

Broadleaf Species ◽

Crop Maturity

Abstract Potential effectiveness of harvest weed seed control (HWSC) systems depends upon seed shatter of the target weed species at crop maturity, enabling its collection and processing at crop harvest. However, seed retention likely is influenced by agroecological and environmental factors. In 2016 and 2017, we assessed seed shatter phenology in thirteen economically important broadleaf weed species in soybean [Glycine max (L.) Merr.] from crop physiological maturity to four weeks after physiological maturity at multiple sites spread across fourteen states in the southern, northern, and mid-Atlantic U.S. Greater proportions of seeds were retained by weeds in southern latitudes and shatter rate increased at northern latitudes. Amaranthus species seed shatter was low (0 to 2%), whereas shatter varied widely in common ragweed (Ambrosia artemisiifolia L.) (2 to 90%) over the weeks following soybean physiological maturity. Overall, the broadleaf species studied shattered less than ten percent of their seeds by soybean harvest. Our results suggest that some of the broadleaf species with greater seed retention rates in the weeks following soybean physiological maturity may be good candidates for HWSC.

Download Full-text

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

Weed Technology ◽

10.1017/wet.2020.142 ◽

2020 ◽

pp. 1-22

Author(s):

Michael J. Walsh ◽

Annie E. Rayner ◽

Annie Rutledge ◽

John C. Broster

Keyword(s):

Cropping Systems ◽

Seedling Emergence ◽

Field Studies ◽

Wild Oat ◽

Weed Seed ◽

Weed Species ◽

Environment Effect ◽

Seed Survival ◽

Cropping Seasons ◽

Rigid Ryegrass

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 crop rotation, tillage, and management inputs on weed seed production

Weed Science ◽

10.1017/s0043174500091591 ◽

1999 ◽

Vol 47 (2) ◽

pp. 175-183 ◽

Cited By ~ 44

Author(s):

George O. Kegode ◽

Frank Forcella ◽

Sharon Clay

Keyword(s):

Seed Production ◽

Crop Rotation ◽

Crop Production ◽

Conservation Tillage ◽

Farming Systems ◽

Crop Rotations ◽

Weed Seed ◽

Weed Species ◽

Weed Seeds ◽

Ridge Tillage

Approaches to crop production that successfully reduce weed seed production can benefit farming systems by reducing management inputs and costs. A 5-yr rotation study was conducted in order to determine the effects that interactions between crop rotation, tillage, and amount of herbicide and fertilizer (management inputs) have on annual grass and broad-leaved weed seed production and fecundity. There were 10 crop rotation and tillage system combinations and three levels of management inputs (high, medium, and low). Green and yellow foxtail were the major weed species, and together they yielded between 76 and 93% of collected weed seeds. From 1990 to 1994, average grass weed seed productions were 7.3 by 103, 3.7 by 1036.1 by 103and 5.7 by 103seeds m−-2, whereas average broad-leaved weed seed productions were 0.4 by 103, 0.4 by 103, 1.4 by 103, and 0.4 by 103seeds m−-2in crop rotations using conventional tillage (moldboard plow), conservation tillage, no tillage, and ridge tillage, respectively. Crop rotations using conventional or ridge tillage consistently produced more grass and broad-leaved weed seeds, especially in low-input plots. There was little difference in weed seed production among input levels for crop rotations using conservation tillage. Comparing rotations that began and ended with a corn crop revealed that by increasing crop diversity within a rotation while simultaneously reducing the amount of tillage, significantly fewer grass and broad-leaved weed seeds were produced. Among the rotations, grass and broad-leaved weed fecundity were highly variable, but fecundity declined from 1990 to 1994 within each rotation, with a concomitant increase in grass and broad-leaved weed density over the same period. Crop rotation in combination with reduced tillage is an effective way of limiting grass and broad-leaved weed seed production, regardless of the level of management input applied.

Download Full-text

Combine Harvesting Affects Weed Seed Germination

Weed Technology ◽

10.1017/s0890037x00032346 ◽

1988 ◽

Vol 2 (4) ◽

pp. 499-504 ◽

Cited By ~ 9

Author(s):

Randall S. Currie ◽

Thomas F. Peeper

Keyword(s):

Seed Germination ◽

Winter Wheat ◽

Weed Seed ◽

Weed Species ◽

Hard Red Winter Wheat ◽

Small Plot ◽

Red Winter Wheat ◽

Grain Bins ◽

Better Than

Seed of three weed species collected from the grain bins of combines while standing hard red winter wheat was harvested germinated better than hand-harvested seed. Combine-harvested curly dock seed germinated from 4 to 24% more than hand-harvested seed. Curly dock seed harvested with a commercial-type combine germinated better than those harvested with a small-plot combine. Harvesting slimleaf lambsquarters and Venice mallow seed with a commercial-type combine also enhanced germination compared to hand-harvested seed.

Download Full-text

Relation between Soil Weed Seedbank and Weed Management Practises and Diversity in Farms in Kisii Central Sub County, Nyanza

Journal of Horticulture and Plant Research ◽

10.18052/www.scipress.com/jhpr.10.1 ◽

2020 ◽

Vol 10 ◽

pp. 1-14

Author(s):

Charles N. Nyamwamu ◽

Rebecca Karanja ◽

Peter Mwangi

Keyword(s):

Seed Bank ◽

Weed Management ◽

Management Practices ◽

Soil Seed Bank ◽

Shannon Index ◽

Weed Seed ◽

Weed Species ◽

Western Kenya ◽

Weed Diversity ◽

Hand Weeding

This study sought to determine the relation between soil weed seed bank and weed management practices and diversity in farms in Kisii Central Sub County, Western Kenya. Eight administrative sub-locations were randomly selected. Ten farms were selected at equal distance along transect laid across each sub-location. Weed soil seed bank was assessed from soil samples collected from each of the farms; a sub-sample was taken from a composite sample of ten soil cores of 5cm diameter and 15cm deep and placed in germination trays in a greenhouse. Weed diversity in soil weed seedbank was calculated using the Shannon index (H’). Twelve weed species from 12 genera of nine families were recorded. Diversity of the weed species in soil weed seed bank was (H'=1.48). Weed management practises significantly affected weed species soil weed seedbank reserves. Use of inefficient and ineffective hand-weeding techniques resulted in high weed species diversity and abundance.

Download Full-text

Seed shattering phenology at soybean harvest of economically important weeds in multiple regions of the United States. Part 2: grass species

Weed Science ◽

10.1017/wsc.2020.79 ◽

2020 ◽

pp. 1-19

Author(s):

Lauren M. Schwartz-Lazaro ◽

Lovreet S. Shergill ◽

Jeffery A. Evans ◽

Muthukumar V. Bagavathiannan ◽

Shawn C. Beam ◽

...

Keyword(s):

The United States ◽

Grass Species ◽

Annual Grass ◽

Weed Seed ◽

Weed Species ◽

Seed Shattering ◽

Physiological Maturity ◽

Rate Of Progression ◽

Multiple Regions ◽

Grass Weed

Abstract Seed shatter is an important weediness trait on which the efficacy of harvest weed seed control (HWSC) depends. The level of seed shatter in a species is likely influenced by agroecological and environmental factors. In 2016 and 2017, we assessed seed shatter of eight economically important grass weed species in soybean [Glycine max (L.) Merr.] from crop physiological maturity to four weeks after maturity at multiple sites spread across eleven states in the southern, northern, and mid-Atlantic U.S. From soybean maturity to four weeks after maturity, cumulative percent seed shatter was lowest in the southern U.S. regions and increased as the states moved further north. At soybean maturity, the percent of seed shatter ranged from 1 to 70%. That range had shifted to 5 to 100% (mean: 42%) by 25 days after soybean maturity. There were considerable differences in seed shatter onset and rate of progression between sites and years in some species that could impact their susceptibility to HWSC. Our results suggest that many summer annual grass species are likely not ideal candidates for HWSC, although HWSC could substantially reduce their seed output at during certain years.

Download Full-text

Effect of tillage method and weeding regime on soil weed seed bank status and yield performance of wheat

Progressive Agriculture ◽

10.3329/pa.v27i1.27528 ◽

2016 ◽

Vol 27 (1) ◽

pp. 9-19

Author(s):

MJ Khatun ◽

M Begum ◽

MM Hossain

Keyword(s):

Grain Yield ◽

Seed Bank ◽

Cynodon Dactylon ◽

Chenopodium Album ◽

Conventional Tillage ◽

Weed Seed ◽

Weed Species ◽

Sonchus Arvensis ◽

Tillage Method ◽

Tillage Methods

An experiment was conducted at the Agronomy Field Laboratory and net house of the Department of Agronomy, Bangladesh Agricultural University, Mymensingh from November 2012 to March 2014. Wheat (cv. BARI Gom-26) was sown with two tillage methods viz., (i) conventional tillage and (ii) stale seedbed technique and nine weeding regimes viz., (i) Unweeded (Control), (ii) Weed free, (iii) Hand weeding (HW) at 15 Days after sowing (DAS), (iv) HW at 15 and 45 DAS, (v) HW at 25 and 45 DAS (vi) HW at 25 DAS (vii) HW at 25 and 60 DAS (viii) 2,4-D amine at 15 DAS and (ix) 2,4-D amine at 15 DAS + HW at 60 DAS. The design was split-plot with three replications where tillage method was assigned to the main plots and weeding regime to the sub plots. Conventionally tilled plots were infested with 12 weed species of which the five most dominant weed species in descent order were Polygonum coccineum L, Chenopodium album L, Cynodon dactylon L., Sonchus arvensis L. and Cyperus rotundus L. In stale seedbed out of 15 weed species Digitaria sanguinalis L. and Hedyotis corymbosa (L.) Lamk. was dominant instead of Chenopodium album L. and Sonchus arvensis L. identified in conventional tillage. In soil weed seed bank study, 28 species were identified in conventional tillage and 30 in stale seedbed. Among them annuals were dominant over perennials and broadleaves over grasses and sedges. In conventional tillage, the five most dominant weed species in descent order were Chenopodium album L., Hedyotis corymbosa L., Sonchus arvensis L., Polygonum coccineum L. and Rotala ramosior L. while in stale seedbed, five dominant weeds were Polygonum coccineum L., Chenopodium album L., Cynodon dactylon L., Lindernia procumbens Krock. and L. hyssopifolia L. Except the number of spikelets spike-1, rest of all other yield attributes and yield of wheat were affected significantly by the tillage methods. Stale seedbed technique yielded the higher grain (3.54 t ha-1) and the conventional tillage yielded the lower (3.13 t ha-1). The effect of weeding regime was significant on wheat except plant height and 1000-grain weight. The highest grain yield (3.85 t ha-1) was recorded from weed free treatment followed by 2,4-D amine at 15 DAS and lowest (3.22 t ha-1) from control. Interaction between the treatments was also. The highest grain yield (4.09 t ha-1) was recorded from the stale seedbed technique kept weed free followed by 2,4-D amine at 15 DAS and lowest grain yield (3.04 t ha-1) recorded from the conventional tillage retained unweeded.Progressive Agriculture 27 (1): 9-19, 2016

Download Full-text