Effect of tillage andZea maysonChenopodium albumseedling emergence and density

Weed Science ◽  
1999 ◽  
Vol 47 (5) ◽  
pp. 551-556 ◽  
Author(s):  
Erivelton S. Roman ◽  
Stephen D. Murphy ◽  
Clarence J. Swanton

We studied the effect of tillage systems (no-till, chisel, and moldboard plow) and the presence or absence ofZea maysL. (corn) on soil temperature, moisture, and, subsequently, the emergence phenology and density ofChenopodium albumL. (common lambsquarters) at two sites (Elora and Woodstock) from 1993 to 1995. The tillage system affected the phenology ofC. albumseedling emergence only in 1995. In that year, more days were required to reach 80% cumulative seedling emergence in no-till than in the chisel or moldboard plow treatments. The delay in obtaining 80% cumulative emergence was attributed to a dry period from days 159 to 177 at Elora and from days 155 and 176 at Woodstock. The presence or absence of Z.maysdid not affect soil temperatures, soil moisture, orC. albumseedling emergence phenologies.Chenopodium albumseedling density was influenced by tillage and environmental conditions. Large variations in seedling density were attributed to environmental conditions. The presence or absence ofZ. maysdid not affectC. albumseedling density.

Weed Science ◽  
1997 ◽  
Vol 45 (1) ◽  
pp. 120-126 ◽  
Author(s):  
Joseph O. E. Oryokot ◽  
Stephen D. Murphy ◽  
Clarence J. Swanton

We studied the effect of no-till, chisel, and moldboard plow and the presence or absence of corn on soil temperature, moisture and, subsequently, the emergence phenology and density of pigweed seedlings at 2 sites from 1993 to 1995 inclusively. Tillage significantly affected the phenology of pigweed seedling emergence only during a June drought at one site in 1994. Soil temperature and moisture, measured at 2.5-cm depths, also were unaffected by tillage. Weed phenology is usually earlier in no-till because more seeds are located closer to the surface (< 5 cm deep) in no-till, thereby reducing the delay in penetrating through the soil, and because soil temperatures and moisture are nearer the germination and emergence optima. However, pigweed seedlings are already physiologically restricted to germination depths of less than 2.5 cm regardless of tillage; therefore, this prior constraint eliminated any potential differences in emergence phenologies caused by tillage. The presence or absence of corn also did not affect soil temperatures, soil moisture, or pigweed seedling emergence phenologies. Pigweed seedling density was significantly higher in no-till; this may have been caused by increased numbers of seeds near the soil surface in no-till. The presence or absence of corn did not affect pigweed seedling density; the lack of a significant effect probably reflects high variances in density. Although necessary for most weed species, tillage may be a less important factor to consider in predicting pigweed population dynamics and subsequent management recommendations.


Weed Science ◽  
1996 ◽  
Vol 44 (2) ◽  
pp. 298-308 ◽  
Author(s):  
John CardiNa ◽  
Denise H. Sparrow ◽  
Edward L. McCoy

Predictions of weed seedling populations from seedbank data should characterize the spatial distribution as well as the composition and abundance of weeds. The spatial distribution of seedbank and seedling populations of common lambsquarters and annual grasses (giant foxtail, large crabgrass, and fall panicum) were described in moldboard plow and no-tillage soybean fields from 1990 to 1993. Spearman rank correlations between seedbank and seedling densities were significant for common lambsquarters in both tillages and all years, but for annual grasses correlations were significant only in no-tillage. Semivariograms showed spatial autocorrelation in seedbank and seedling populations of common lambsquarters in all years in no-till, but less often in the moldboard plow field. Annual grass seed and seedling populations were autocorrelated in the no-till field every year except 1993, and in the moldboard plow field in 1992 and 1993 only. Cross-semivariograms showed spatial continuity between seedbank and seedling population densities in 3 of 4 yr in no-till for common lambsquarters, and in all years of no-till and 1 yr of moldboard plow for annual grasses. Grey-scale field maps of common lambsquarters seedbanks corresponded visually to maps of seedling populations and could have been used to target control efforts, but visual correspondence between annual grass seedbank and seedling maps was poor. Seedbank and seedling mapping may be useful for site-specific management, but additional information is needed to understand the variation in the relationships between these two populations over time and space.


Weed Science ◽  
1999 ◽  
Vol 47 (2) ◽  
pp. 149-155 ◽  
Author(s):  
Erivelton S. Roman ◽  
A. Gordon Thomas ◽  
Stephen D. Murphy ◽  
Clarence J. Swanton

The ability to predict time of weed seedling emergence relative to the crop is an important component of a mechanistic model describing weed and crop competition. In this paper, we hypothesized that the process of germination could be described by the interaction of temperature and water potential and that the rate of seedling shoot and radicle elongation vary as a function of temperature. To test these hypotheses, incubator studies were conducted using seeds and seedlings of common lambsquarters. Probit analysis was used to account for variation in cardinal temperatures and base water potentials and to develop parameters for a new mathematical model that describes seed germination and shoot and radicle elongation in terms of hydrothermal time and temperature, respectively. This hydrothermal time model describes the phenology of seed germination using a single curve, generated from the relationship of temperature and water potential.


2002 ◽  
Vol 82 (4) ◽  
pp. 855-859 ◽  
Author(s):  
M. L. Leblanc ◽  
D. C. Cloutier ◽  
C. Hamel

A 2-year field study was conducted in corn to determine the influence of rainfall, irrigation and soil water content on common lambsquarters and barnyardgrass emergence. Rainfall or irrigation had no influence on the final weed density and little on the pattern of weed emergence because the soil water content was at or greater than field capacity during the main weed emergence period. Irrigation may hasten the first weed emergence by warming the soil when temperature is limiting for germination. In southwestern Quebec, temperature appears to be the most important factor regulating germination in the spring since soil moisture is normally at field capacity for a long period, in part because of the melting of snow. Key words: Irrigation, weed emergence, soil moisture


Weed Science ◽  
1988 ◽  
Vol 36 (2) ◽  
pp. 207-214 ◽  
Author(s):  
Douglas D. Buhler

Application time did not greatly influence control of velvetleaf (Abutilon theophrastiMedik. # ABUTH) or common lambsquarters (Chenopodium albumL. # CHEAL) in no-till corn (Zea maysL. ‘Pioneer 3747’) with fluorochloridone {3-chloro-4-(chloromethyl)-1-[3-(trifluoromethyl) phenyl]-2-pyrrolidinone}. Giant foxtail (Setaria faberiHerrm. # SETFA) control was reduced as much as 25% by 90 days after planting when fluorochloridone was applied early preplant rather than preemergence. Fluorochloridone at 0.8 kg/ha applied preplant or preemergence gave 83% or greater control of common lambsquarters and giant foxtail for the entire growing season. However, velvetleaf control with the same treatments was 61% or less. Fluorochloridone caused minimal corn injury. Greenhouse bioassay indicated that fluorochloridone may carry over and injure soybean[Glycine max(L.) Merr.] the year after application. Imbibition of fluorochloridone by seed of corn and giant foxtail did not reduce germination at concentrations up to 10-3M. Giant foxtail seedling fresh weight was reduced 80% following imbibition of 10-5M fluorochloridone. Corn seedling fresh weight was not reduced by imbibition of up to 10-4M fluorochloridone.


Weed Science ◽  
1993 ◽  
Vol 41 (2) ◽  
pp. 309-316 ◽  
Author(s):  
Stephen J. Harvey ◽  
Frank Forcella

Knowledge of timing and extent of weed emergence before and immediately after crop seedbed preparation is needed to decrease need for preplant herbicides and increase efficacy of postemergence weed control in crops with either mechanical or chemical methods. Such knowledge is important for weeds that infest most crops over a wide area. For these reasons a mechanistic seedling emergence model based solely on soil temperature was developed for common lambsquarters. The model was validated using four sets of field data collected in 1988, 1990, and 1991 near Morris, MN. Agreement of predicted and observed emergence values across all site-years was 0.95 and the coefficient of determination (R2) was 0.98 (P < 0.001). Agreement for individual site-years was 0.96, 1.08, 1.08, and 0.98 and associated R2values were 0.99, 0.99, 0.99, and 0.98 (P < 0.001 for each site-year), indicating close agreement between predicted and actual emergence values.


1989 ◽  
Vol 3 (1) ◽  
pp. 136-142 ◽  
Author(s):  
Edward S. Hagood

Field experiments were established to evaluate preemergence and postemergence herbicides for control of triazine-resistant smooth pigweed and common lambsquarters in no-till corn. When applied preemergence, alachlor in the microencapsulated formulation controlled smooth pigweed better than the emulsifiable concentrate formulation and better than either metolachlor or pendimethalin. These herbicides applied preemergence did not control common lambsquarters consistently. Pendimethalin controlled both triazine-resistant species when applied as a sequential treatment of a preemergence and an early postemergence application. Control of triazine-resistant smooth pigweed and common lambsquarters was excellent when dicamba was applied early postemergence in treatments containing alachlor, metolachlor, or pendimethalin applied preemergence and/or early postemergence. Thiameturon and CGA-131036 controlled triazine-resistant smooth pigweed with acceptable crop tolerance. Thiameturon also controlled common lambsquarters, but control was unacceptable with CGA-131036.


Weed Science ◽  
1997 ◽  
Vol 45 (2) ◽  
pp. 234-241 ◽  
Author(s):  
Dawit Mulugeta ◽  
David E. Stoltenberg

The influence of secondary soil disturbance on the emergence pattern and seed bank depletion of an annual weed community in a long-term, no-tillage corn cropping system was determined in 1992 and 1993. As a component of this research, the seed bank was characterized prior to implementation of soil disturbance treatments. The seed bank was initially composed of common lambsquarters, redroot pigweed, and giant foxtail, with approximately 55, 36, and 8% of the total viable seeds, respectively. The remaining 1% was comprised of five other species in 1992 and eight in 1993. The spatial distribution of viable seeds of each species, except common lambsquarters and redroot pigweed, was described by a negative binomial distribution. Three dispersion indices indicated that seeds of individual and total weed species were aggregated and that the level of aggregation of viable seeds of a species was associated with seed density; at lower seed densities, the level of aggregation was greater. Soil disturbance increased common lambsquarters emergence 6-fold in 1992 relative to nondisturbed soil, but did not influence emergence in 1993. Rainfall was about 50% less in 1993. In contrast, soil disturbance increased giant foxtail and redroot pigweed emergence approximately 6- and 3-fold in 1992 and 1993, respectively. Seedling emergence associated with soil disturbance, relative to nondisturbed soil, increased seed bank depletion of common lambsquarters 16-fold in 1992, and giant foxtail and redroot pigweed and average of 6- and 3-fold in 1992 and 1993, respectively. These results indicated that soil disturbance increased seedling emergence and seed bank depletion of the predominant species in the weed community of a long-term, no-tillage system, but that this response was dependent on rainfall for common lambsquarters.


Weed Science ◽  
1999 ◽  
Vol 47 (2) ◽  
pp. 156-160 ◽  
Author(s):  
Eric Spandl ◽  
Beverly R. Durgan ◽  
Frank Forcella

Emergence patterns of foxtail in spring wheat following soybean were evaluated for three seeding dates and three tillage regimes. Cumulative foxtail emergence, as a percentage of total plants emerged in the growing season, was generally not influenced by tillage regime throughout most of the emergence period, but when differences occurred, emergence was lower with no-till than with moldboard plow. Foxtail seedling densities were greater in no-till and chisel plow than in moldboard plow. Weed biomass and wheat yields were not affected by tillage regime. Delaying wheat seeding reduced foxtail percent emergence and emerged seedling density. Differences in emergence patterns of foxtail were attributable to thermal accumulation after seeding. Wheat yield was not influenced by seeding date in 2 of 3 yr.


2009 ◽  
Vol 23 (3) ◽  
pp. 398-403 ◽  
Author(s):  
Randy L. Anderson

This study measured weed interference in soybean and corn as affected by residue management tactics following a sequence of oat and winter wheat. Residue management tactics compared were conventional tillage, no-till, and no-till plus cover crops. Treatments were split into weed-free and weed-infested conditions; prominent weeds were green and yellow foxtail and common lambsquarters. Grain yield of soybean did not differ between weed-free and weed-infested conditions with no-till, whereas weeds reduced yield 25% in the tilled system. Corn responded inconsistently to treatments, with more than 40% yield loss due to weed interference in 1 yr with all treatments. Cover crops did not improve weed management compared with no-till in either crop. Seedling emergence of the weed community differed between tillage and no-till; density of weed seedlings was fivefold higher with tillage, whereas seedling emergence was delayed in no-till. The initial flush of seedlings occurred 2 to 3 wk later in no-till compared with the tilled system. Designing rotations to include cool-season crops in a no-till system may eliminate the need for herbicides in soybean to manage weeds.


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