Tillage and Nitrogen Influence Weed Population Dynamics in Barley (Hordeum vulgare)

1997 ◽  
Vol 11 (3) ◽  
pp. 502-509 ◽  
Author(s):  
John T. O'Donovan ◽  
David W. McAndrew ◽  
A. Gordon Thomas
Keyword(s):  
Population Dynamics ◽  
Field Experiments ◽  
Soil Surface ◽  
Conventional Tillage ◽  
Zero Tillage ◽  
Tillage Systems ◽  
Green Foxtail ◽  
Field Pennycress ◽  
Soil Seedbank ◽  
Four Levels

Field experiments were initiated at Alliance and Hairy Hill, Alberta, in 1989 to investigate the effects of conventional tillage, zero tillage, and four levels of nitrogen fertilizer on continuous barley production. In both tillage systems, the nitrogen was banded 6 to 8 cm deep between alternate barley rows. Herbicides were used for weed control each year. The influence of tillage and nitrogen on weed seed population dynamics was determined in 1991 and 1992. In the zero-tillage system, a large proportion of the weed seeds were present either at the soil surface or at the 5- to 10-cm depth. Green foxtail, the dominant species at Alliance, was also present at Hairy Hill where field pennycress was dominant. Green foxtail was consistently associated with low (residual) nitrogen and, in most cases, with conventional tillage. At both locations, green foxtail populations tended to decrease to very low levels as nitrogen rate increased, especially in zero tillage. At Hairy Hill, field pennycress populations in the soil seedbank were higher in zero tillage compared with conventional tillage, but plants that emerged from the soil seedbank in the field in spring were lower in zero tillage. Field pennycress populations were highest under low nitrogen. The results indicate that banding nitrogen has the potential to be an effective tool for green foxtail and field pennycress management in conventional- and zero-tillage systems, resulting in less dependence on herbicides for their control.

Root penetration profiles of wheat and barley as affected by soil penetration resistance in field conditions

1994 ◽  
Vol 74 (2) ◽  
pp. 193-200 ◽  
Author(s):  
Daniel L. Martino ◽  
Carl F. Shaykewich
Keyword(s):  
Soil Surface ◽  
Mechanical Impedance ◽  
Penetration Resistance ◽  
Conventional Tillage ◽  
Loamy Sand ◽  
Root Penetration ◽  
Silty Clay ◽  
Zero Tillage ◽  
Tillage Systems ◽  
Penetrometer Resistance

A study was conducted on three Manitoba soils (Marquette heavy clay, Fortier silty clay loam, and Souris loamy sand) with the objectives of: (a) assessing the effects of contrasting tillage systems on various soil physical properties; and (b) relating root penetration of cereals to these properties. The zero tillage (ZT) and conventional tillage (CT) treatments had been established between 3 (Marquette and Souris) and 10 (Fortier) years prior to the initiation of the study. Penetrometer resistance (PR), bulk density (BD) and pore size distribution (PSD) were measured at various depths and times during two growing seasons. The effects of tillage systems on soil properties were generally small, particularly in the poorly structured Souris loamy sand. PR in the top 10 cm of soil tended to be higher under ZT than under CT. PR varied markedly with time and was closely related to changes in soil water content. The proportion of macropores (> 100 μm in diameter) near the soil surface tended to be higher under ZT than under CT. There was no evidence of any detrimental effect of poor aeration on the final root penetration profiles of wheat. The proportion of roots penetrating the soil was inversely related to PR. Soil strength critical for root penetration was determined to be 2 MPa and was independent of soil type. In most situations, however, roots were able to grow into soil with mechanical impedance greater than 2 MPa, possibly by making use of biochannels and spatial and temporal heterogeneity in the soil structure. Key words: Wheat, barley, zero tillage, conventional tillage, root penetration, penetration resistance

Population Dynamics and Control of Annual Weeds in Corn (Zea mays) as Influenced by Tillage Systems

Weed Science ◽  
1992 ◽  
Vol 40 (2) ◽  
pp. 241-248 ◽  
Author(s):  
Douglas D. Buhler
Keyword(s):  
Population Dynamics ◽  
Conventional Tillage ◽  
No Tillage ◽  
Tillage Systems ◽  
Redroot Pigweed ◽  
Green Foxtail ◽  
Dynamics And Control ◽  
Chisel Plow ◽  
And Control ◽  
Ridge Tillage

Field research was conducted at Hancock, WI, from 1985 through 1987 to evaluate effects of conventional tillage, chisel plow, ridge tillage, and no-tillage systems on population dynamics and control of annual weed species in corn grown continuously on a loamy sand soil without irrigation. In all years of the study, green foxtail densities were greater in chisel plow and no-tillage than in the conventional tillage system, while ridge tillage had densities lower than all other tillage systems. Common lambsquarters density in the chisel plow system reached nearly 500 plants m−2compared to less than 75 plants m−2in the other tillage systems when averaged over years. Average redroot pigweed densities in the no-tillage and chisel plow systems were 307 and 245 plants m−2compared to less than 25 plants m−2in the conventional and ridge tillage systems. Horseweed was observed only in no-tillage and ridge tillage plots. Green foxtail and redroot pigweed were more difficult to control in chisel plow and no-tillage than in the conventional and ridge tillage systems with several herbicide treatments. Corn yields were not affected by tillage systems under weed-free conditions. Corn yield differences among tillage systems when the same herbicide treatment was applied appeared to be due to differences in weed control.

Glyphosate or sethoxydim for quackgrass (Elytrigia repens) control in two tillage regimes

Weed Science ◽  
1997 ◽  
Vol 45 (6) ◽  
pp. 812-823 ◽  
Author(s):  
K. Neil Harker ◽  
William H. Vanden Born
Keyword(s):  
Field Experiments ◽  
Conventional Tillage ◽  
Zero Tillage ◽  
Split Application ◽  
Short Term ◽  
Tillage Systems ◽  
Elytrigia Repens ◽  
Rhizome Biomass ◽  
Rhizome Buds ◽  
Better Than

Field experiments were conducted at Lacombe and Ellerslie, Alberta, Canada, to study the interaction of tillage with glyphosate and sethoxydim on quackgrass shoot and rhizome biomass, rhizome bud viability, and crop yield. Glyphosate was most effective in the conventional tillage regime, whereas sethoxydim was effective only in conventional tillage. Tillage reduced viable rhizome buds more than shoot or rhizome biomass. The large tillage effect on quackgrass control with either herbicide would likely be diminished in zero tillage systems that employ preseeding burn-off or preharvest application of glyphosate. Under zero and conventional tillage, glyphosate at 220 g ha−1often was as effective as glyphosate at 880 g ha−1.A split application of glyphosate at 220 g ha−1in the fall and spring was as effective as a single 880 g ha−1treatment in conventional tillage, and sometimes more effective than 880 g ha−1in zero tillage. Glyphosate followed by sethoxydim was usually no better than glyphosate alone. Short-term split applications of sethoxydim offered no consistent advantage over single applications.

KIH-485 and S-metolachlor Efficacy Comparisons in Conventional and No-Tillage Corn

2006 ◽  
Vol 20 (3) ◽  
pp. 622-626 ◽  
Author(s):  
Patrick W. Geier ◽  
Phillip W. Stahlman ◽  
John C. Frihauf
Keyword(s):  
Weed Control ◽  
Field Experiments ◽  
Conventional Tillage ◽  
Palmer Amaranth ◽  
Effective Control ◽  
No Tillage ◽  
Green Foxtail

Field experiments were conducted during 2003 and 2004 to compare the effectiveness of KIH-485 and S-metolachlor for PRE weed control in no-tillage and conventional-tillage corn. Longspine sandbur control increased as KIH-485 or S-metolachlor rates increased in conventional-tillage corn, but control did not exceed 75% when averaged over experiments. Both herbicides controlled at least 87% of green foxtail with the exception of no-tillage corn in 2004, when KIH-485 was more effective than S-metolachlor at lower rates. Palmer amaranth control ranged from 85 to 100% in 2003 and 80 to 100% in 2004, with the exception of only 57 to 76% control at the lowest two S-metolachlor rates in 2004. Puncturevine control exceeded 94% with all treatments in 2003. In 2004, KIH-485 controlled 86 to 96% of the puncturevine, whereas S-metolachlor controlled only 70 to 81%. Mixtures of atrazine with KIH-485 or S-metolachlor generally provided the most effective control of broadleaf weeds studied.

Soil microbial biomass and diversity respond to tillage and sulphur fertilizers

2001 ◽  
Vol 81 (5) ◽  
pp. 577-589 ◽  
Author(s):  
N. Z. Lupwayi ◽  
M. A. Monreal ◽  
G. W. Clayton ◽  
C. A. Grant ◽  
A. M. Johnston ◽  
...  
Keyword(s):  
Microbial Biomass ◽  
Microbial Diversity ◽  
Soil Microorganisms ◽  
Soil Microbial Biomass ◽  
Conventional Tillage ◽  
Bulk Soil ◽  
Zero Tillage ◽  
Negative Effects ◽  
Tillage Systems ◽  
Soil Microbial

There is little information on the effects of S management strategies on soil microorganisms under zero tillage systems o n the North American Prairies. Experiments were conducted to examine the effects of tillage and source and placement of S on soil microbial biomass (substrate induced respiration) and functional diversity (substrate utilization patterns) in a canola-wheat rotation under conventional and zero tillage systems at three sites in Gray Luvisolic and Black Chernozemic soils. Conventional tillage significantly reduced microbial biomass and diversity on an acidic and C-poor Luvisolic soil, but it had mostly no significant effects on the near-neutral, C-rich Luvisolic and Chernozemic soils, which underlines the importance of soil C in maintaining a healthy soil. Sulphur had no significant effects on soil microbial biomass, and its effects on microbial diversity were more frequent on the near-neutral Luvisol, which was more S-deficient, than on the acidic Luvisol or the Chernozem. Significant S effects on microbial diversity were observed both in the bulk soil (negative effects, compared with the control) and rhizosphere (positive effects) of the acidic Luvisol, but all significant effects (positive) were observed in root rhizospheres in the other soils. Sulphur by tillage interactions on acidic Luvisolic soil indicated that the negative effects of S in bulk soil occurred mostly under zero tillage, presumably because the fertilizer is concentrated in a smaller volume of soil than under conventional tillage. Sulphate S effects, either negative or positive, on microbial diversity were usually greater than elemental S effects. Therefore, S application can have direct, deleterious effects on soil microorganisms or indirect, beneficial effects through crop growth, the latter presumably due to increased root exudation in the rhizosphere of healthy crops. Key Words: Biolog, conservation tillage, microbial biodiversity, rhizosphere, soil biological quality, S fertilizer type and placement

Effect of Three Tillage Systems on the Persistence of Atrazine

Weed Science ◽  
1983 ◽  
Vol 31 (3) ◽  
pp. 423-426 ◽  
Author(s):  
Thomas T. Bauman ◽  
Merrill A. Ross
Keyword(s):  
Zea Mays ◽  
Soil Surface ◽  
Conventional Tillage ◽  
Biologically Active ◽  
Tillage Systems

Field sudies on the persistence of atrazine [2-chloro-4-(ethylamino)-6-(isopropylamino)-s-triazine] showed less persistence under coulter than chisel or conventional plow tillage in the year of application. The residue on the coulter system from the previous corn (Zea maysL.) crop initially prevented as much as 30% of the atrazine from reaching the soil surface. After five annual applications, the atrazine residue was generally higher in the coulter than the chisel or conventional tillage systems, but below levels considered to be biologically active.

Water and bromide movement in a Vertosol under four fallow management systems

Soil Research ◽  
1999 ◽  
Vol 37 (1) ◽  
pp. 75 ◽  
Author(s):  
J. E. Turpin ◽  
J. P. Thompson ◽  
B. J. Bridge ◽  
D. Orange
Keyword(s):  
Water Movement ◽  
Conventional Tillage ◽  
Management Systems ◽  
Zero Tillage ◽  
Tillage Systems ◽  
Fallow Management ◽  
Stubble Retention ◽  
Tracer Solution ◽  
Stubble Burning

Recent work on the Hermitage long-term fallow management found increased rates of anion movement under zero tillage systems compared with conventional tillage. Four separate experiments have been used to determine relative rates of water movement through different fallow management treatments on the Hermitage long-term fallow management trial and the causes of any differences. Photography of the aggregation patterns at the depth of tillage (approx. 15 cm) showed that conventional tillage combined with stubble burning has led to the formation of large massive peds up to 20 cm across below the tillage layer, whereas zero-tillage with stubble retention has maintained much smaller aggregates in this zone. Measurements of hydraulic conductivity at 15 cm under both dry and moist conditions indicated that, when the soil is dry and cracked, all tillage treatments have similar conductivities, but when the soil swells and cracks close, zero tillage–stubble retention maintains a greater volume of large pores and thereby greater conductivity. This effect was further demonstrated when a bromide tracer solution was applied to a relatively wet soil by ring infiltrometer, where only 15% of the solution moved below 15 cm in conventional tillage–stubble burning compared with 26% and 38% in zero tillage{stubble retention. In the final experiment, which followed the movement of surface applied bromide over a 6-month fallow, there were no significant differences in rates of leaching between management treatments.

Effect of Tillage Systems on the Efficacy and Phytotoxicity of Imazaquin and Imazethapyr in Soybean (Glycine max)

Weed Science ◽  
1989 ◽  
Vol 37 (2) ◽  
pp. 233-238 ◽  
Author(s):  
J. Anthony Mills ◽  
William W. Witt
Keyword(s):  
Glycine Max ◽  
Weed Control ◽  
Field Experiments ◽  
Conventional Tillage ◽  
No Tillage ◽  
Tillage Systems ◽  
Adequate Control ◽  
No Till ◽  
Herbicide Treatment ◽  
Giant Foxtail

Field experiments were conducted to evaluate the interactions of tillage systems with imazaquin and imazethapyr on weed control and soybean injury and yield. Control of jimsonweed, common cocklebur, ivyleaf morningglory, velvetleaf, and giant foxtail from imazaquin and imazethapyr in conventional tillage was generally equal to or greater than control in no-tillage. However, under limited rainfall, weed control in no-tillage was generally equal to or greater than control in conventional tillage. Reductions in soybean heights due to herbicide treatment were evident in both tillage systems in 1985 and 1986 but not in. Soybean yields were reduced in 1985 from imazaquin at 140, 210, and 250 g/ha and imazethapyr at 105 and 140 g/ha. Yields were not reduced in 1986 and. Imazaquin and imazethapyr appear to provide adequate control of jimsonweed, common cocklebur, ivyleaf morningglory, velvetleaf, and giant foxtail in conventional and no-till systems.

Weed seedbank response to crop rotation and tillage in semiarid agroecosystems

Weed Science ◽  
1999 ◽  
Vol 47 (1) ◽  
pp. 67-73 ◽  
Author(s):  
J. Dorado ◽  
J. P. Del Monte ◽  
C. López-Fando
Keyword(s):  
Weed Control ◽  
Field Experiments ◽  
Conventional Tillage ◽  
Crop Rotations ◽  
Soil Conditions ◽  
No Tillage ◽  
Tillage Systems ◽  
Mouse Ear ◽  
Tillage System ◽  
Number Of Seeds

In a semiarid Mediterranean site in central Spain, field experiments were conducted on a Calcic Haploxeralf (noncalcic brown soil), which had been managed with three crop rotations and two tillage systems (no-tillage and conventional tillage) since 1987. The crop rotations consisted of barley→vetch, barley→sunflower, and a barley monoculture. The study took place in two growing seasons (1992–1994) to assess the effects of management practices on the weed seedbank. During this period, spring weed control was not carried out in winter crops. In the no-tillage system, there was a significant increase in the number of seeds of different weed species: anacyclus, common purslane, corn poppy, knotted hedge-parsley, mouse-ear cress, spring whitlowgrass, tumble pigweed, venus-comb, andVeronica triphyllos.Conversely, the presence of prostrate knotweed and wild radish was highest in plots under conventional tillage. These results suggest large differences in the weed seedbank as a consequence of different soil conditions among tillage systems, but also the necessity of spring weed control when a no-tillage system is used. With regard to crop rotations, the number of seeds of knotted hedge-parsley, mouse-ear cress, and spring whitlowgrass was greater in the plots under the barley→vetch rotation. Common lambsquarters dominated in the plots under the barley→sunflower rotation, whereas venus-comb was the most frequent weed in the barley monoculture. Larger and more diverse weed populations developed in the barley→vetch rotation rather than in the barley→sunflower rotation or the barley monoculture.

Factors affecting the operation of the weed-sensing Detectspray system

Weed Science ◽  
1998 ◽  
Vol 46 (1) ◽  
pp. 127-131 ◽  
Author(s):  
Robert E. Blackshaw ◽  
Louis J. Molnar ◽  
Duane F. Chevalier ◽  
C. Wayne Lindwall
Keyword(s):  
Near Infrared ◽  
Field Experiments ◽  
Crop Residues ◽  
Soil Surface ◽  
Physical Factors ◽  
Weed Detection ◽  
Factors Affecting ◽  
Green Foxtail ◽  
Infrared Wavelengths ◽  
Herbicide Use

Field experiments were conducted for 3 yr to determine the effect of various biological and physical factors on the operation of the weed-sensing Detectspray system. Plant detection is achieved by sensors measuring differential reflectance of red and near-infrared wavelengths of light from green plants, crop residues, and soil. Weed detection was greatly reduced 70 to 80 min after sunrise and before sunset when operated at lat 50°N because of reduced solar irradiance. Tall, dense-standing crop stubble limited detection of small weeds at the soil surface. Weed detection varied with plant species. Canola with three to four leaves consistently was detected, but wheat or green foxtail usually required five to six leaves to be detected. Small weeds were detected if present at densities greater than 70 plants m−2. Growers and commercial applicators need to be aware of the limitations of the Detectspray system to use it effectively to control weeds with concurrent reductions in herbicide use.

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