Microsite Requirements for Establishment of Annual Rangeland Weeds

Weed Science ◽  
1972 ◽  
Vol 20 (4) ◽  
pp. 350-356 ◽  
Author(s):  
Raymond A. Evans ◽  
James A. Young
Keyword(s):  
Bromus Tectorum ◽  
Seedling Emergence ◽  
Soil Surface ◽  
Atmospheric Moisture ◽  
Downy Brome ◽  
Seed Burial ◽  
Soil Movement

Seedling emergence and growth of downy brome(Bromus tectorumL.), medusahead(Taeniatherum asperum(Sim.) Nevski), and tumble mustard(Sisymbrium altissimumL.) were favored by seed burial, pitting of the soil surface, and soil movement. These conditions maintained temperatures and soil and atmospheric moisture in the range required for establishment.

Influence of Soil Type and Depth of Planting on Downy Brome Seed

Weed Science ◽  
1971 ◽  
Vol 19 (1) ◽  
pp. 82-86 ◽  
Author(s):  
G. A. Wicks ◽  
O. C. Burnside ◽  
C. R. Fenster
Keyword(s):  
Triticum Aestivum ◽  
Winter Wheat ◽  
Soil Type ◽  
Bromus Tectorum ◽  
Seedling Emergence ◽  
Cropping System ◽  
Soil Surface ◽  
Downy Brome ◽  
Moldboard Plow

Downy brome (Bromus tectorumL.) seedling emergence was greatest from soil depths of 1 inch or less, but occasionally seedlings emerged from depths of 4 inches. Downy brome seed covered by soil germinated more rapidly than those seed on the soil surface. More downy brome seedlings emerged, and from greater depths, from coarse-textured soils than fine-textured soils when moisture was not limiting. Soil type did not influence longevity of downy brome seed buried in the soil. Most (98%) 8-month-old downy brome seed buried 8 inches in the soil germinated but did not emerge in 1 year; and none remained viable in the soil after 5 years. The moldboard plow was more effective in reducing downy brome populations than a sweep plow or one-way disk in a continuous winter wheat (Triticum aestivumL.) cropping system.

Effect of Herbicides on Germination and Growth of Four Grass Weeds

Weed Science ◽  
1984 ◽  
Vol 32 (4) ◽  
pp. 489-493 ◽  
Author(s):  
Frank L. Young ◽  
David R. Gealy ◽  
Larry A. Morrow
Keyword(s):  
Bromus Tectorum ◽  
Soil Surface ◽  
Dry Weight ◽  
Shoot Elongation ◽  
Downy Brome ◽  
Aegilops Cylindrica ◽  
Shoot Height ◽  
Shoot Dry Weight ◽  
Jointed Goatgrass ◽  
Germination And Growth

In the greenhouse, glyphosate [N-(phosphonomethyl)glycine] at 0.6 kg ae/ha applied directly to seeds alone or seeds on the soil surface reduced germination and shoot dry weight of common rye (Secale cerealeL. ♯3SECCE). Paraquat (1,1′-dimethyl-4,4′-bipyridinium ion) applied similarly at 0.6 kg ai/ha reduced germination and shoot dry weight of downy brome (Bromus tectorumL. ♯ BROTE) and wheat (Triticum aestivumL. ‘Daws' ♯ TRZAX). Metribuzin [4-amino-6-tert-butyl-3-(methylthio)-as-triazin-5 (4H)-one] at 0.6 kg ai/ha applied to seeds, soil, or seeds and soil had very little effect on germination, but significantly reduced shoot dry weight of common rye, downy brome, wheat, and jointed goatgrass (Aegilops cylindricaHost. ♯ AEGCY). Pronamide [3,5-dichloro(N-1,1-dimethyl-2-propynyl)benzamide] at 0.6 kg ai/ha, and propham (isopropyl carbanilate) at 3.4 kg ai/ha plus extender (p-chlorophenyl-N-methylcarbamate) at 0.4 kg ai/ha substantially reduced shoot height and dry weight of all species, regardless of application method, with pronamide completely inhibiting shoot elongation and dry-weight production in three of the four species.

Effects of Soil Texture and Seed Placement on Emergence of Four Subshrubs

Weed Science ◽  
1983 ◽  
Vol 31 (3) ◽  
pp. 380-384 ◽  
Author(s):  
H. S. Mayeux
Keyword(s):  
Seed Bank ◽  
Soil Texture ◽  
Seedling Emergence ◽  
Soil Surface ◽  
Seed Burial ◽  
Seed Placement ◽  
Buried Seed ◽  
Rate Of Emergence ◽  
Gutierrezia Sarothrae

Seedling emergence of broom snakeweed [Gutierrezia sarothrae(Pursh) Britt. & Rusby], threadleaf snakeweed [G. microcephala(DC.) Gray], common goldenweed [Isocoma coronopifolia(Gray) Greene], and false broomweed (Ericameria austrotexanaM.C. Johnston) was studied in the glasshouse. Germination of these species is known to be light-stimulated. Seed of all four subshrubs germinated readily if placed on the surface or partially pressed into the soil. Emergence was reduced by covering seed with soil to a depth of less than 1 mm. Few seedlings emerged from a depth of 1 cm, and none emerged from a depth of 2 cm. Rate of emergence also decreased with increasing depth of placement. Soil texture had little effect on emergence. Rapid germination on the soil surface is consistent with other aspects of the regenerative strategy of common goldenweed and false broomweed, which do not depend upon a buried seed bank for regeneration. Seed burial probably provides a form of enforced dormancy in the small, long-lived seeds of the two snakeweed species.

Downy Brome (Bromus tectorum) Emergence Variability in a Semiarid Region

1996 ◽  
Vol 10 (4) ◽  
pp. 750-753 ◽  
Author(s):  
R. L. Anderson
Keyword(s):  
Winter Wheat ◽  
Great Plains ◽  
Wind Erosion ◽  
Bromus Tectorum ◽  
Control Strategies ◽  
Seedling Emergence ◽  
Plant Diseases ◽  
Semiarid Region ◽  
Downy Brome ◽  
Wheat Stubble

This study characterized seedling emergence of downy brome from August to early December over a 6-yr period. Seedlings were counted weekly in quadrats established in winter wheat stubble at Akron, CO. Seedling emergence varied among years, which was caused by erratic seasonal precipitation. Producers delay planting of winter wheat to reduce downy brome density in the crop, but in only 1 yr out of 6 would producers have benefited from this control strategy. Furthermore, delayed planting has negative crop consequences: less grain yield and more susceptibility to plant diseases and wind erosion because of less fall plant growth. Because fall precipitation is erratic in the semiarid Great Plains, other control strategies, such as nitrogen placement and increased seeding rates of winter wheat, would be more effective for downy brome management, yet not detrimental to winter wheat production.

A technique to estimate the pre-fire depth of burial of Grevillea seeds by using seedlings after fire

2005 ◽  
Vol 53 (5) ◽  
pp. 401 ◽  
Author(s):  
Tony D. Auld ◽  
Andrew J. Denham
Keyword(s):  
Seedling Emergence ◽  
Seed Mass ◽  
Soil Surface ◽  
Small Scale ◽  
Residual Soil ◽  
Seed Burial ◽  
Soil Seed Banks ◽  
Below Ground ◽  
The Mean ◽  
Depth Of Burial

In a glasshouse experiment, we used the shrub Grevillea speciosa to examine the reliability of estimating the depth of seed burial based on the distance from the soil surface to the junction of the swollen hypocotyl with the radicle. We then examined the applicability of the technique in the field by using post-fire seedling emergence. We found that the mean length of the swollen hypocotyl in seedlings was a good predictor of the depth of seed burial (R2 = 0.97). Most variation occurred for seeds buried near the surface at 2-cm depth, where the swollen hypocotyl overestimated the depth of seed burial by about 1 cm. There was a decline in the ability of seeds to successfully emerge from soil depths below 2 cm, with seedlings of G. speciosa able to emerge from soil depths up to 8 cm in the glasshouse. This corresponds with the estimated maximum emergence depth based on seed mass. In the field, seedlings were estimated to have emerged from depths of 1–7 cm after an intense wildfire. There was an approximately normal distribution of seedling emergence depths; however, the mode of this distribution varied among locations. The technique gave comparable results to a similar technique developed for Acacia spp., allowing consideration of a greater range of species and post-fire locations. Use of the technique has the potential to provide insights into the impacts of fires below ground, including the nature of post-fire germination, residual soil seed banks, the depth-related action of fire-induced germination cues and small-scale spatial variation.

Weed Control in a Winter Wheat-Fallow Rotation

Weed Science ◽  
1968 ◽  
Vol 16 (2) ◽  
pp. 255-258 ◽  
Author(s):  
O. C. Burnside ◽  
C. R. Fenster ◽  
C. E. Domingo
Keyword(s):  
Winter Wheat ◽  
Weed Control ◽  
Bromus Tectorum ◽  
Soil Surface ◽  
Water Erosion ◽  
Plant Residues ◽  
Downy Brome ◽  
Feasible Method ◽  
Wind And Water Erosion ◽  
Moldboard Plow

Weed control during the fallow year and yields of subsequent winter wheat (Triticum aestivumL.) were lower on unsprayed plots than on plots treated with 2-chloro-4-ethylamino-6-isopropylamino-s-triazine (atrazine) at 2 lb/A or 3-amino-l,2,4-triazole (amitrole) at 1/2lb/A plus 3-(p-chlorophenyl)-l,l-dimethylurea (monuron) at 1 lb/A. The moldboard plow gave the most effective weed control in the winter wheat-fallow rotation followed by the oneway and the sweep plow. Sweep plow tillage left the greatest amount of plant residues on the soil surface to prevent wind and water erosion, but it did not consistently destroy shallow-rooted downy brome (Bromus tectorumL.) plants. Average downy brome stands in winter wheat on fallow plots tilled with the sweep plow, oneway, and moldboard plow were 331, 114, and 16 plants per 54 sq ft, respectively. Winter wheat yields averaged for the sweep plow, oneway, and moldboard plow treatments were 17, 18, and 20 bu/A, respectively. The most feasible method of controlling weeds in a winter wheat-fallow rotation, found in this study, was oneway tillage in combination with the lower herbicide rates.

Influence of Soil Moisture, Temperature, and Compaction on the Germination and Emergence of Downy Brome (Bromus tectorum)

Weed Science ◽  
1979 ◽  
Vol 27 (6) ◽  
pp. 625-630 ◽  
Author(s):  
D. C. Thill ◽  
R. D. Schirman ◽  
A. P. Appleby
Keyword(s):  
Soil Moisture ◽  
Soil Compaction ◽  
Bromus Tectorum ◽  
Seedling Emergence ◽  
Moisture Stress ◽  
Soil Matric Potential ◽  
Downy Brome ◽  
Matric Potential ◽  
Soil Moisture Stress ◽  
Rate Of Emergence

The influence of soil moisture stress, temperature, and bulk density on the germination and seedling emergence of downy brome (Bromus tectorumL.) was investigated in the laboratory. Reductions in soil matric potential from -2 to -16 bars markedly reduced the percentage and rate of emergence. Seedling emergence was better at constant than at alternating temperatures. At high matric potentials, the rate of emergence was accelerated by warmer soil temperature (20 C), while at very low matric potentials, the percentage and rate of seedling emergence were least restricted at cooler temperatures (10 and 15 C). Soil matric potential did not influence the percentage or rate of emergence of seedlings grown from seed lots harvested during climatologically diverse years. Seedling emergence but not germination was inhibited by increased levels of soil compaction. Soil compaction times moisture interaction were not observed, as measured by final seedling emergence.

Germination of Fresh Horse Purslane (Trianthema portulacastrum) Seeds in Response to Different Environmental Factors

Weed Science ◽  
2011 ◽  
Vol 59 (4) ◽  
pp. 495-499 ◽  
Author(s):  
Jihyun Lee ◽  
Bhagirath S. Chauhan ◽  
David E. Johnson
Keyword(s):  
Seed Germination ◽  
Environmental Factors ◽  
Seedling Emergence ◽  
Soil Surface ◽  
The Philippines ◽  
Integrated Weed Management ◽  
Burial Depth ◽  
Seed Burial ◽  
Soil Burial ◽  
Two Populations

Horse purslane, a C4 species, is a branched, prostrate, and annual weed of upland field crops throughout the tropics. Experiments were conducted to determine the influence of various environmental factors on seed germination and seedling emergence of two populations of horse purslane. Seeds were collected from rice fields of the International Rice Research Institute (the IR population) and from sorghum fields of the University of the Philippines (the UP population); the two sites were 5 km apart in Los Baños, Philippines. Germination response of both populations was greater at 30/20 C and35/25 C day/night temperatures than they were at 25/15 C alternating day/night temperatures. Germination of both populations was greater in the light/dark regime than in darkness. In dark, depending on the temperature, seed germination of the UP population ranged from 37 to 62%, whereas seed germination of the IR population was < 20%. Exposure to 5 min at 117 and 119 C for the IR and UP populations, respectively, reduced germination to 50% of maximum germination. Osmotic potential of −0.26 MPa inhibited germination to 50% of the maximum for the UP population, whereas the corresponding value for the IR population was −0.37 MPa. Seeds placed on or near the soil surface had maximum emergence, and emergence declined with increase in seed burial depth. Seedling emergence of the UP and IR populations was 74% and 13%, respectively, for seeds placed on the soil surface. For both populations, no seedlings emerged from a soil burial depth of 6 cm or more. Germination and emergence responses to light and seed burial depth differed between the two populations of horse purslane. Residues on the soil surface of up to 6 Mg ha−1 did not influence seedling emergence of either populations. Knowledge gained in this study could contribute to developing components of integrated weed management strategies for horse purslane.

Weedy rice (Oryza sativa) II. Response of Weedy Rice to Seed Burial and Flooding Depth

Weed Science ◽  
2012 ◽  
Vol 60 (3) ◽  
pp. 385-388 ◽  
Author(s):  
Bhagirath Singh Chauhan
Keyword(s):  
Seedling Emergence ◽  
Soil Surface ◽  
Production Costs ◽  
The Other ◽  
Weedy Rice ◽  
Burial Depth ◽  
Rice Accession ◽  
Seed Burial ◽  
Seedling Biomass ◽  
Flooding Depth

Weedy rice is a serious problem of cultivated rice in most of the rice-growing areas in Asia, causing increased production costs and yield losses in rice. A study was conducted to determine the response of weedy rice accessions from India (IWR), Malaysia (MWR), Thailand (TWR), and Vietnam (VWR) to seed burial and flooding depths. The greatest emergence for each weedy rice accession (97% for IWR, 82% for MWR, 97% for TWR, and 94% for VWR) was observed in seeds placed on the soil surface. Seedling emergence decreased with increase in burial depth. For the IWR accession, 0.5% of the seedlings emerged from 8-cm depth, whereas for the other three weedy rice accessions, no seedlings emerged from this depth. When seeds were sown on the soil surface, flooding depth ranging from 0 to 8 cm had no or very little effect on seedling emergence of different weedy rice accessions. On the other hand, flooding decreased seedling emergence in all weedy rice accessions when seeds were sown at 1 cm deep into the soil. Compared with seedling emergence, flooding had a more pronounced effect on seedling biomass for all weedy rice accessions. A flooding depth of 2 cm reduced seedling biomass by an amount greater than 85% of each weedy rice accession. The results of this study suggest that emergence and growth of weedy rice could be suppressed by deep tillage that buries seeds below their maximum depth of emergence (i.e., > 8 cm for the accessions studied) and by flooding fields as early as possible. The information gained from this study may help design cultural management strategies for weedy rice in Asia.

Plant Litter and Establishment of Alien Annual Weed Species in Rangeland Communities

Weed Science ◽  
1970 ◽  
Vol 18 (6) ◽  
pp. 697-703 ◽  
Author(s):  
Raymond A. Evans ◽  
James A. Young
Keyword(s):  
Bromus Tectorum ◽  
Soil Surface ◽  
Plant Litter ◽  
Downy Brome ◽  
Annual Species ◽  
Weed Species ◽  
Litter Cover

Plant litter that covers the soil surface acts as a layer of insulation moderating temperature and moisture, and creating favorable microsites for germination and the establishment of annual weed species in rangeland communities. Litter cover is an important factor in succession among annual species which culminates in dominance by downy brome (Bromus tectorumL.) and medusahead (Taeniatherum asperum(Sim.) Nevski) in these communities.

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