Behavior of Weed Seed in Soil Clods

Weed Science ◽  
1986 ◽  
Vol 34 (6) ◽  
pp. 889-895 ◽  
Author(s):  
Rinse Terpstra

Clods of three sizes (1.5-, 3.3-, and 5.3-cm diameter) and two hardnesses [soft (0.3 MPa) and hard (2.2 MPa)] were made by incorporating seed from one of the five following weed species: corn poppy (Papaver rhoeasL. # PAPRH), shepherdspurse [Capsella bursa-pastoris(L.) Medic. # CAPBP], smooth crabgrassDigitaria ischaemum(Schreb.) Muehlenb. # DIGIS], common lambsquarters (Chenopodium albumL. # CHEAL), and Canada thistle [Cirsium arvense(L.) Scop. # CIRAR], listed by increasing seed size. Under conditions of this experiment, higher germination occurred with larger seed. The higher germination was connected with fewer dormant seed remaining in the clods. Germination significantly decreased (13%) in the larger soft and hard clods with the smaller seed sizes (less germination associated with more dormant seed remaining in the clod). Germination of the two larger seed decreased (23%) only in the larger soft clods but was less significant with both small seed. Non-emerged seedlings increased with larger clods and was most significant with the three large seed in the hard clods and absent with the three large seed in the soft ones. On the average, 70% of the germinated seed emerged. Differences in germination as well as in nonemerged seedlings caused decreased emergence on larger clods. Clod influence in germination and emergence was explained by the volumes of the clod layers involved, and in some comparable aspects corresponded with volumes (depths) of soil layers.

Author(s):  
J.S. Rowarth ◽  
A.A. Johnson ◽  
P.T.P. Clifford ◽  
M.P. Rolston

Weed seeds are the major reason for white clover (Trifolium repens) seedlots being downgraded or rejected from certification. The occurrence of weed species in 537 white clover seedlots tested at the Official Seed Testing Station, Palmerston North, was analysed. The most commonly occurring species were field madder (Sherardia arvensis), chickweed (Stellaria media), fathen (Chenopodium album), sheep's sorrel (Rumex acetosella) and scarlet pimpernel (Anagaflis arvensis). The percentage occurrence of four specified undesirable weeds including Californian thistle (Cirsium arvense) and dodder (Cuscuta epithymum) are reported, and the implications of seed contamination are discussed. Keywords: white clover, contamination, weed seeds


2016 ◽  
Vol 27 (1) ◽  
pp. 9-19
Author(s):  
MJ Khatun ◽  
M Begum ◽  
MM Hossain

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


Weed Science ◽  
2013 ◽  
Vol 61 (2) ◽  
pp. 277-282 ◽  
Author(s):  
Mette Goul Thomsen ◽  
Lars-Olav Brandsæter ◽  
Haldor Fykse

In the present field study, the capability of Canada thistle to develop shoots from intact roots and root fragments at different soil depths was studied. The experiments were performed on four sites with high-density Canada thistle, with three or four replications per treatment. At each site, the soil in the plots was removed layer by layer (to 30 or 40 cm, depending on the site), within a 1 by 1-m quadrat, and spread out on a plastic sheet. All roots and other plant parts were removed, and the soil was either replaced without any root material (two sites), or the roots of the thistles were cut into 10-cm-long fragments and replaced into the source holes (two sites). The measured variables were shoot number and biomass. The number of shoots of Canada thistle decreased with increasing depth (P < 0.001) and increased with time. Additionally, the two factors interacted (P < 0.001) such that shoot development was slower from greater depths. Roots from ≤ 20 cm depth produced higher biomasses than did roots from below 20 cm depth. Replacement of root fragments did not affect the amount of biomass produced. It was concluded that the intact root system contributed considerably more to the total biomass produced by Canada thistle than did the root fragments in the upper soil layers.


Weed Science ◽  
2019 ◽  
Vol 67 (05) ◽  
pp. 485-496
Author(s):  
Andrea Smith ◽  
Nader Soltani ◽  
Allan C. Kaastra ◽  
David C. Hooker ◽  
Darren E. Robinson ◽  
...  

AbstractHerbicide-resistant weeds are a growing concern globally; in response, new herbicide resistance traits are being inserted into crops. Isoxaflutole-resistant soybean [Glycine max (L.) Merr.] will provide a new mode of action for use in this crop. Ten experiments were conducted over a 2-yr period (2017, 2018) to determine herbicide interactions between isoxaflutole and metribuzin on soybean injury, weed control efficacy, and soybean yield on a range of soil types. Soybean leaf-bleaching injury caused by isoxaflutole was most severe at sites with higher levels of rainfall after application. Control of weed species with isoxaflutole (52.5, 79, and 105 g ai ha−1) and metribuzin (210, 315, and 420 g ai ha−1) differed by site based on amount of rainfall after application. At sites where there was sufficient rainfall for herbicide activation, isoxaflutole at all rates controlled common lambsquarters (Chenopodium album L.), Amaranthus spp., common ragweed (Ambrosia artemisiifolia L.), and velvetleaf (Abutilon theophrasti Medik.) &gt;90%; metribuzin at all rates controlled Amaranthus spp. and witchgrass (Panicum capillare L.) &gt;80%. Control of every weed species evaluated was reduced when there was limited rainfall after herbicide application. The co-application of isoxaflutole + metribuzin resulted in additive or synergistic interactions for the control of C. album, Amaranthus spp., A. artemisiifolia, A. theophrasti, Setaria spp., barnyardgrass [Echinochloa crus-galli (L.) P. Beauv], and P. capillare. Isoxaflutole and metribuzin can be an effective management strategy for common annual broadleaf and grass weeds in Ontario if timely rainfall events occur after herbicide application.


Weed Science ◽  
1979 ◽  
Vol 27 (1) ◽  
pp. 7-10 ◽  
Author(s):  
R. B. Taylorson

AbstractGermination of seeds of 10 grass and 33 broadleaved weed species was examined for response to ethylene. Germination was promoted in nine species, inhibited in two, and not affected in the remainder. Of the species promoted, common purslane (Portulaca oleraceaL.), common lambsquarters (Chenopodium albumL.), and several Amaranths, including redroot pigweed (Amaranthus retroflexusL.), were affected most. Transformation of phytochrome to the active form (Pfr) gave interactions that ranged from none to syntergistic with the applied ethylene. In subsequent tests seeds of purslane, redroot pigweed, and giant foxtail (Setaria faberiHerrm.), a species not responsive to ethylene, were examined for germination response to 14 low molecular weight hydrocarbon gases other than ethylene. Some stimulation by the olefins propylene and propadiene was found for purslane and pigweed. Propionaldehyde and butyraldehyde were slightly stimulatory to purslane only.


2015 ◽  
Vol 95 (6) ◽  
pp. 1199-1204 ◽  
Author(s):  
Kimberly D. Belfry ◽  
Kristen E. McNaughton ◽  
Peter H. Sikkema

Belfry, K. D., McNaughton, K. E. and Sikkema, P. H. 2015. Weed control in soybean using pyroxasulfone and sulfentrazone. Can. J. Plant Sci. 95: 1199–1204. Pyroxasulfone and sulfentrazone are new herbicides currently being evaluated for weed control in soybean [Glycine max (L.) Merr.] in Ontario, Canada. Seven experiments were conducted over a 3-yr period (2011 to 2013) at Ridgetown and Exeter, Ontario, to evaluate weed management using pyroxasulfone, sulfentrazone and their tank-mixes relative to the industry standard, imazethapyr plus metribuzin. Tank-mixing pyroxasulfone and sulfentrazone provided up to 97, 46, 60, 100 and 71% control of common lambsquarters (Chenopodium album L.), common ragweed (Ambrosia artemisiifolia L.), green foxtail [Setaria viridis (L.) Beauv.], Powell amaranth [Amaranthus powellii (S.) Wats.] and velvetleaf (Abutilon theophrasti Medic.), respectively, at 2 wk after treatment. Control with pyroxasulfone and sulfentrazone was improved when tank-mixed, relative to application of each herbicide separately. Although control was variable across weed species, no difference in control was identified between pyroxasulfone plus sulfentrazone and imazethapyr plus metribuzin. Soybean yield was up to 2.7, 2.4 and 2.9 t ha−1 for pyroxasulfone, sulfentrazone and pyroxasulfone plus sulfentrazone application, yet imazethapyr plus metribuzin provided the highest yield (3.3 t ha−1). This research demonstrates that pyroxasulfone plus sulfentrazone may be used as a valuable weed control option in soybean; however, weed community composition may limit herbicidal utility.


Weed Science ◽  
1970 ◽  
Vol 18 (2) ◽  
pp. 206-214 ◽  
Author(s):  
R. P. Upchurch ◽  
F. L. Selman ◽  
H. L. Webster

Relatively pure stands of eight weed species were maintained under field conditions on a Goldsboro loamy sand at Lewiston, North Carolina, for all or part of a 6-year period. Herbicides evaluated as preemergence surface treatments for these species were 2-sec-butyl-4,6-dinitrophenol (dinoseb), isopropyl m-chlorocarbanilate (chloropropham), 3-(3,4-dichlorophenyl)-1,1-dimethyl-urea (diuron), 2-chloro-4,6-bis(ethylamino)-s-triazine (simazine), and 3-amino-2,5-dichlorobenzoic acid (amiben). S-ethyl dipropylthiocarbamate (EPTC) and a,a,a-trifluro-2,6-dinitro-N,N-dipropyl-p-toluidine (trifluralin) were evaluated as preemergence incorporated treatments. The first four herbicides were evaluated in 1961, 1964, and 1966 while the last three were evaluated in 1962, 1963, and 1965. A series of rates was used for each chemical with three replications. With the exception of diuron which failed to control goosegrass (Eleusine indica (L.) Gaertn.), all of the herbicides provided at least a moderate degree of control of goosegrass, smooth crabgrass (Digitaria ischaemum (Schreb.) Muhl.), and redroot pigweed (Amaranthus retroflexus L.) at the respective typical field use rates. In general, trifluralin and amiben gave the best grass control and dinoseb the poorest. None of the herbicides effectively controlled common cocklebur (Xanthium pensylvanicum Wallr.) or ivyleaf morningglory (Ipomoea hederacea (L.) Jacq.). Trifluralin and EPTC did not control Pennsylvania smartweed (Polygonum pensylvanicum L.), common ragweed (Ambrosia artemisiifolia L.), and common lambsquarters (Chenopodium album L.). Chloropropham was ineffective on common ragweed. Simazine, chloropropham, and amiben controlled Pennsylvania smartweed while diuron, simazine, dinoseb, and amiben were especially effective on common lambsquarters. Distinctive patterns of nematode infestations were observed as a function of weed species.


Weed Science ◽  
1997 ◽  
Vol 45 (1) ◽  
pp. 54-60 ◽  
Author(s):  
Dawit Mulugeta ◽  
David E. Stoltenberg

Field experiments were conducted in 1992 and 1993 to characterize the weed seed bank, to determine the influence of moldboard plowing and secondary soil disturbance on the emergence pattern of weeds, and to measure weed seed bank depletion by emergence in a long-term moldboard plow corn cropping system. Viable seeds of common lambsquarters, redroot pigweed, and each of 10 other species accounted for about 85, about 9, and less than 1%, respectively, of the total weed species in the seed bank. A negative binomial distribution described the spatial distribution of viable seeds of 10 species, but not of common lambsquarters or of redroot pigweed. Decreased density of seeds among species was associated with increased aggregation. Secondary soil disturbance increased the rate and magnitude of common lambs quarters emergence in 1992 but did not influence emergence in 1993. Secondary soil disturbance did not influence the magnitude and rate of emergence of redroot pigweed or velvetleaf. Whereas cumulative growing degree days from April through July were similar between years, the amount of rainfall was about 50% less in 1992 than in 1993. Secondary soil disturbance may have increased common lambsquarters emergence by increasing the availability of soil moisture and improving conditions for seed germination during the dry year. Even though seed bank depletion by seedling emergence was relatively low for all species, secondary soil disturbance in creased seed bank depletion of common lambsquarters and redroot pigweed about 7- and 3-fold, respectively, in 1992. Seasonal variation in the amount of rainfall may have influenced the effect of soil disturbance on emergence and seed bank depletion of common lambsquarters, which is the most abundant species in the weed community.


1999 ◽  
Vol 13 (3) ◽  
pp. 542-547 ◽  
Author(s):  
Brent E. Tharp ◽  
Oliver Schabenberger ◽  
James J. Kells

The recent introduction of glufosinate-resistant and glyphosate-resistant crops provides growers with new options for weed management. Information is needed to compare the effectiveness of glufosinate and glyphosate on annual weeds. Greenhouse trials were conducted to determine the response of barnyardgrass (Echinochloa crus-galli), common lambsquarters (Chenopodium album), common ragweed (Ambrosia artemisiifolia), fall panicum (Panicum dichotomiflorum), giant foxtail (Setaria faberi), large crabgrass (Digitaria sanguinalis), and velvetleaf (Abutilon theophrasti) to glufosinate and glyphosate. The response of velvetleaf and common lambsquarters was investigated at multiple stages of growth. Glufosinate and glyphosate were applied to each weed species at logarithmically incremented rates. The glufosinate and glyphosate rates that provided a 50% reduction in aboveground weed biomass, commonly referred to as GR50values, were compared using nonlinear regression techniques. Barnyardgrass, common ragweed, fall panicum, giant foxtail, and large crabgrass responded similarly to glufosinate and glyphosate. Common lambsquarters 4 to 8 cm in height was more sensitive to glufosinate than glyphosate. In contrast, 15- to 20-cm tall-velvetleaf was more sensitive to glyphosate than glufosinate.


2020 ◽  
Vol 13 (1) ◽  
pp. 14-22 ◽  
Author(s):  
Eric Oseland ◽  
Mandy Bish ◽  
Christine Spinka ◽  
Kevin Bradley

AbstractIn 2016 and 2017, 98 separate commercially available bird feed mixes were examined for the presence of weed seed. All weed seed contaminants were counted and identified by species. Amaranthus species were present in 94 of the 98 bags of bird feed. Amaranthus species present in bird feed mixes included waterhemp [Amaranthus tuberculatus (Moq.) Sauer], redroot pigweed (Amaranthus retroflexus L.), Palmer amaranth (Amaranthus palmeri S. Watson), smooth pigweed (Amaranthus hybridus L.), and tumble pigweed (Amaranthus albus L.). Amaranthus palmeri was present in 27 of the 98 mixes. Seed of common ragweed (Ambrosia artemisiifolia L.), kochia [Bassia scoparia (L.) A.J. Scott], grain sorghum [Sorghum bicolor (L.) Moench], wild buckwheat (Fallopia convolvulus L., syn: Polygonum convolvulus), common lambsquarters (Chenopodium album L.), large crabgrass [Digitaria sanguinalis (L.) Scop.], and Setaria species were also present in bird feed mixes. A greenhouse assay to determine Amaranthus species seed germinability and resistance to glyphosate revealed that approximately 19% of Amaranthus seed in bird feed mixes are readily germinable, and five mixes contained A. tuberculatus and A. palmeri seed that were resistant to glyphosate. Results from linear regression and t-test analysis indicate that when proso millet (Panicum miliaceum L.), grain sorghum, and corn (Zea mays L.) were present in feed mixes, Amaranthus seed contamination was increased. The presence of proso millet and grain sorghum also increased contamination of grass weed species, while sunflower (Helianthus annuus L.) increased A. artemisiifolia contamination and safflower (Carthamus tinctorius L.) increased contamination of Bassia scoparia.


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