Reduced herbicide rates provide acceptable weed control regardless of corn planting strategy in Ontario field corn

2008 ◽  
Vol 88 (2) ◽  
pp. 373-378 ◽  
Author(s):  
Peter H Sikkema ◽  
Robert E Nurse ◽  
Tom Welacky ◽  
Allan S Hamill
Keyword(s):  
Weed Control ◽  
Plant Density ◽  
Dry Weight ◽  
Row Spacing ◽  
Corn Yield ◽  
Seeding Rate ◽  
Field Corn ◽  
Crop Density ◽  
Full Rate ◽  
Untreated Check

A study was conducted at three locations in central-southwestern Ontario from 1996 to 1998 to determine if corn (Zea mays L.) productivity and weed control can be maintained when row spacing is narrowed, crop density is increased and herbicide rate is reduced. Post-emergence herbicides [(rimsulfuron + nicosulfuron) plus (dicamba + atrazine)] at four rates (full label rate (1×), 75% full rate (0.75×), 50% full rate (0.5×) and an untreated check) were tested at three corn row-spacings (38, 50, and 75 cm) and two plant densities (75 000 and 90 000 plants ha-1). Herbicide application at the 0.5× rate versus an untreated check still allowed for increased corn yield (8.3 vs. 4.9 t ha-1) and decreased weed dry weight (9.4 vs. 240.4 g m-2), weed plant density (11.0 vs. 52.6 plants m-2) and weed seed density (239 vs. 14 241 seeds m-2). Corn LAI was not affected by decreasing herbicide rate. In this study, increasing corn plant density and decreasing corn row spacing were not factors in reducing herbicide inputs in corn cropping systems in central-southwestern Ontario. Herbicide rate could be reduced by up to 50% while maintaining corn grain yield, weed density, weed dry weight, and the number of weed seeds entering into the soil seed bank. Implementation of these reduced rates will help to increase the economic and environmental sustainability of the Canadian field corn industry. Key words: Agricultural systems, crop yield, seeding rate, sustainability, weed biomass

Row Spacing and Seeding Rate Effects on Eastern Black Nightshade (Solanum Ptycanthum) and Soybean

2007 ◽  
Vol 21 (1) ◽  
pp. 124-130 ◽  
Author(s):  
Adrienne M. Rich ◽  
Karen A. Renner
Keyword(s):  
Dry Weight ◽  
Field Studies ◽  
Production Costs ◽  
Row Spacing ◽  
Seeding Rate ◽  
Soybean Yield ◽  
Eastern Black Nightshade ◽  
Solanum Ptycanthum ◽  
Black Nightshade ◽  
Rate Effects

Reducing seeding rates in 19- or 76-cm row soybean below the optimum rate may reduce soybean competitiveness with weeds, and indirectly increase production costs to the grower. Field studies in 2001 and 2002 evaluated the effect of soybean seeding rate and row spacing on the emergence, growth, and competitiveness of eastern black nightshade (EBN) in soybean. EBN emergence ceased within 45 d after planting (DAP), and was similar across soybean seeding rates and row spacing. EBN control by glyphosate was not affected by soybean population or row spacing. Soybean planted in 19-cm rows was more competitive with EBN, regardless of seeding rate. Increasing the soybean seeding rate in 76-cm rows from 185,000 seeds/ha to 432,000 seeds/ha reduced EBN dry weight threefold at East Lansing and nearly twofold at Clarksville in 2002. There was no increase in EBN density or dry weight in 19-cm row soybean planted at 308,000 seeds/ha compared with 556,000 seeds/ha, whereas a seeding rate of 432,000 seeds/ha in 76-cm row soybean did not suppress EBN dry weight or increase soybean yield in the presence of EBN compared with a seeding rate of 308,000 seeds/ha.

Economic decision rules for postemergence herbicide control of barnyardgrass (Echinochloa crus-galli) in corn (Zea mays)

Weed Science ◽  
1997 ◽  
Vol 45 (4) ◽  
pp. 557-563 ◽  
Author(s):  
Aca Č. Bosnić ◽  
Clarence J. Swanton
Keyword(s):  
Weed Control ◽  
Economic Model ◽  
Control Function ◽  
Decision Rules ◽  
Dry Weight ◽  
Practical Significance ◽  
Corn Yield ◽  
Economic Decision ◽  
Weed Emergence ◽  
Herbicide Control

Economic decision rules for postemergence herbicide control of barnyardgrass in corn were developed. Damage and control functions that formed the basis of an economic model were estimated. Barnyardgrass density and time of emergence relative to the crop were fundamental to calculate the damage function. The control function described barnyardgrass dry weight response to variable doses of two herbicides. Both the biologist's and economist's weed control decision rules, derived from the economic model, were influenced by time of weed emergence relative to the crop, corn yield, and price. Inclusion of time of weed emergence relative to the crop improved our interpretative ability of derived decision rules. The biologist's threshold weed density was more sensitive to changes in parameter values than the economist's optimal herbicide dose strategy. Herbicide use with recommended label dose was greater than either the economically optimal or the biologically effective doses. Use of the biologically effective dose for postemergence weed control decisions was cost efficient and could be of practical significance to corn growers.

scholarly journals Crop density and seed production of tall fescue (Festuca arundinacea Schreber). 1. Yield and plant development

1999 ◽  
Vol 79 (4) ◽  
pp. 535-541 ◽  
Author(s):  
N. A. Fairey ◽  
L. P. Lefkovitch
Keyword(s):  
Population Density ◽  
Seed Production ◽  
Seed Yield ◽  
Tall Fescue ◽  
Festuca Arundinacea ◽  
Plant Density ◽  
Initial Density ◽  
Row Spacing ◽  
Initial Population ◽  
Crop Density

A field study was conducted with tall fescue (Festuca arundinacea Schreber) to determine the effect of the initial population density and spatial arrangement of plants on crop development and seed yield. Individual seedling plants were transplanted at seven densities (1.6, 3.1, 6.3, 12.5, 25, 50, and 100 plants m−2) and three row spacings (20, 40, and 80 cm), and characteristics of seed production were determined for 3 yr (1991–1993). Over the 3 yr, heading commenced at dates differing by 15 d and was delayed, as density increased, by 8, 6, and 2 d, respectively, in the first, second, and third production years. The time of seed maturity differed among years (21 July to 4 August) but was generally unaffected by density or row spacing. In the first production year, seed yield increased with density up to 25 plants m−2 for each row spacing, then remained constant to at least 50 plants m−2 with both 20- or 40-cm rows; it decreased slightly at 100 plants m−2 with 20 cm rows. In the second production year, seed yield was relatively independent of plant density except that it decreased when the initial density was less than 6 plants m−2 with a row spacing of 80 cm, and tended to be greatest with the 40-cm row spacing at 6–25 plants m−2. In the third production year, seed yield was much lower than in the previous 2 yr but the pattern of response to the density and row spacing treatments was similar to that in the second production year. The seed yield of tall fescue can be optimized for at least 3 consecutive years by establishing an initial density of 20–100 plants m−2 in rows spaced 20–60 cm apart. If the maximization of first-year seed yield is a priority, then the initial establishment should be at a density of 25–50 plants m−2 in rows spaced 20–40 cm apart. Key words: Tall fescue, Festuca arundinacea Schreber, population density, plant spacing, seed production

Effect of plant density and herbicide application on alfalfa seed and weed yields

1991 ◽  
Vol 71 (2) ◽  
pp. 481-489 ◽  
Author(s):  
J. R. Moyer ◽  
R. W. Richards ◽  
G. B. Schaalje
Keyword(s):  
Seed Yield ◽  
Plant Density ◽  
Joint Effect ◽  
Seeding Rate ◽  
Perennial Weed ◽  
Weed Growth ◽  
Alfalfa Seed ◽  
Untreated Check ◽  
Plant Densities ◽  
Seed Yields

Alfalfa was seeded in row spacings of 36, 72 and 108 cm and at broadcast seeding rates of 0.33, 1.0 and 3.0 kg ha−1 on irrigated land at Tilley (1983) and Lethbridge (1984), Alberta to determine the effect of plant density on weed growth and alfalfa seed yield. During the seed-producing years at each location, herbicide treatments were overlaid on seeding treatments in a split-block arrangement to assess the joint effect of herbicides and plant density on alfalfa seed yield. Hexazinone was the main herbicide used for weed control. Alfalfa seed and weeds were harvested for 5 yr following alfalfa establishment. Alfalfa seed yields tended to be maximum with 36-cm row spacings or the 3.0 kg ha−1 broadcast seeding rate, and were similar in row-seeded and broadcast-seeded alfalfa. Dry matter yields of weeds decreased as row spacings decreased or the broadcast seeding rate increased. Hexazinone controlled quackgrass, sow thistle, flixweed and kochia. In the experiment at Tilley with perennial weed infestations, mean alfalfa seed yields from 1984 to 1985 were 20% larger when herbicides were used than in the untreated check. Alfalfa plant densities slightly larger than currently recommended usually produced the largest seed yields and smallest weed infestations. Key words: Medicago sativa, quackgrass, kochia, sow thistle, flixweed, hexazinone

Response of Corn to Preemergence and Postemergence Applications of Saflufenacil

2009 ◽  
Vol 23 (3) ◽  
pp. 331-334 ◽  
Author(s):  
Nader Soltani ◽  
Christy Shropshire ◽  
Peter H. Sikkema
Keyword(s):  
Weed Control ◽  
Petroleum Hydrocarbons ◽  
Field Studies ◽  
Corn Yield ◽  
Yield Losses ◽  
Leaf Stage ◽  
Field Corn ◽  
Corn Field ◽  
Use Pattern

Saflufenacil (BAS 800H) is a new herbicide being developed by BASF for PRE broadleaf weed control in corn. Field studies were conducted at two Ontario locations in 2006 and 2007 to evaluate the tolerance of field corn to PRE and POST (spike and two- to three-leaf corn) applications of saflufenacil at 50, 100, and 200 g ai/ha with and without an adjuvant (surfactant blend + solvent [petroleum hydrocarbons]; 1% v/v). Saflufenacil applied PRE reduced corn height by as much as 12% with the highest rate of 200 g/ha; however, corn yield was not affected. When saflufenacil was applied without an adjuvant to corn at the spike stage, injury was as much as 12%, 7 d after treatment (DAT). However, corn height and yield were not affected. Saflufenacil applied POST to two- to three-leaf corn at 50 to 200 g/ha without an adjuvant resulted in as much as 25% injury and reduced corn height 31% but did not affect yield. Adding an adjuvant to POST applications of saflufenacil caused as much as 4 and 99% injury, reduced corn height 13 and 77%, and reduced corn yield 0 and 59% when applied to corn at the spike and at the two- to three-leaf stages, respectively. Based on these results, saflufenacil applied PRE can be safely used in corn at rates up to 200 g/ha. Saflufenacil applied to corn at the spike and two- to three-leaf stage at 50 or 100 g/ha without an adjuvant demonstrated acceptable corn tolerance and may allow for the use of saflufenacil beyond the proposed PRE use pattern. In contrast, applying saflufenacil POST with an adjuvant to spike and two- to three-leaf stage corn resulted in unacceptable injury and yield losses in field corn.

EFFECT OF ROW SPACING AND SEEDING RATES ON SUMMER RAPE IN SOUTHERN MANITOBA

1990 ◽  
Vol 70 (1) ◽  
pp. 127-137 ◽  
Author(s):  
M. J. MORRISON ◽  
P. B. E. McVETTY ◽  
R. SCARTH
Keyword(s):  
Brassica Napus ◽  
Seed Quality ◽  
Plant Density ◽  
Chlorophyll Concentration ◽  
Plant Distribution ◽  
Row Spacing ◽  
Seeding Rate ◽  
Brassica Napus L ◽  
Plant Densities ◽  
Lower Plant

To determine the effects of varying plant densities on summer rape (Brassica napus L.), the cultivar Westar was seeded in 15- and 30-cm row spacings at seeding rates of 1.5, 3.0, 6.0, and 12.0 kg ha−1. Plants seeded in 15-cm rows yielded more per area, produced more pods per plant and lodged less than those in 30-cm rows. Higher yields were associated with a more even plant distribution and a lower degree of intra-row competition. There were no significant protein, oil and chlorophyll concentration differences between the row spacing treatments. The highest yields (kg ha−1) were achieved with the 1.5 and 3.0 kg ha−1 seeding rates. Summer rape compensated for lower plant densities with the production of more branch racemes. As seeding rate increased, competitive mortality increased, resulting in greater etiolation at bolting, and greater lodging at harvest. Seed oil and protein concentrations were not affected by seeding rate. However, seed chlorophyll concentration decreased with increased seeding rate.Key words: Brassica napus, plant density, seed quality, rape (summer)

scholarly journals Non-Structural Carbohydrate Metabolism, Growth, and Productivity of Maize by Increasing Plant Density

Agronomy ◽  
2018 ◽  
Vol 8 (11) ◽  
pp. 243 ◽  
Author(s):  
Jairo Cazetta ◽  
Marcos Revoredo
Keyword(s):  
Sucrose Synthase ◽  
Plant Density ◽  
Specific Activity ◽  
Sucrose Concentration ◽  
Soluble Sugars ◽  
Dry Weight ◽  
Plant Production ◽  
Crop Density ◽  
Plant Densities ◽  
Narrow Row

Increasing plant density seems to improve the productivity of maize crops, and the understanding of how the metabolism of non-structural carbohydrates is affected in plants under high crop density is critical. Thus, with the objective of further clarifying this issue, maize plants were subjected to densities from 30,000 to 90,000 plants ha−1, and the plant growth, soluble sugars and starch contents, invertase and sucrose synthase activities, and plant production were evaluated. We found that the stalk is more sensitive to the increasing plant density than leaves and kernels. The dry weight of the stalk and leaves per single plant decreased more drastically from low to intermediate plant densities, while grain production was reduced linearly in all plant density ranges, leading to higher values of harvest index in intermediate plant densities. The sucrose concentration did not change in leaves, stalk, or kernels of plants subjected to increasing plant densities at the R4 stage. Also, the specific activity of soluble invertase, bound invertase, and sucrose synthase did not change in leaf, stalk, or kernels of plants subjected to increased plant density. The productivity was increased with the increase in plant density, using narrow row (0.45 m) spacing.

scholarly journals Effect of reduced spacing on relationship of physiological, morphological and productive traits of corn yield

2020 ◽  
pp. 1202-1208
Author(s):  
Luan de Oliveira Nascimento ◽  
Josimar Batista Ferreira ◽  
Gleisson de Oliveira Nascimento ◽  
Vanderley Borges dos Santos ◽  
Clemeson Silva de Souza ◽  
...  
Keyword(s):  
Grain Yield ◽  
Plant Density ◽  
Block Design ◽  
Net Photosynthesis ◽  
Row Spacing ◽  
Corn Yield ◽  
Maize Breeding ◽  
Corn Hybrids ◽  
Productive Traits ◽  
Relationship Of

Increasing corn grain production without devastating new forest areas is a viable alternative to controlling deforestation. However, increasing plant density in the area may alter plant morphophysiological and productive traits. The objective of this study was to characterize relationships between physiological, morphological and yield traits of corn plants, as well as the cause, effect and relationship of the traits on grain yield. The experiment was carried out in randomized complete block design with four replications. The corn hybrids (2B655PW, AG7088PRO3 and P4285YHR) were grown with row spacing of 40 cm, 60 cm, 80 cm, 95 cm. The evaluated traits physiological were: net photosynthesis (PN), stomatal conductance (Gs), intercellular concentration of CO2 (Ci), leaf transpiration (E), water use efficiency (WUE) and carboxylation efficiency (CE). The morphological were: plant height (PH) and ear insertion height (EIH), stem diameter (SD), and leaf area (LA) and the productive traits were the total number of ear per hectare (NE), number of grains per ear (NGE), grain mass per ear (GME), 100 grain weight (100GW) and grain yield (GY). The characteristics of maize hybrids cultivated in environment with reduced spacing (40cm, 60cm, 80cm, 95cm) of the 2016/2017 crop were investigated through the multicollinearity path analysis. The physiological, morphological and productive traits are considered sources of variation of cause and effect of corn yield in reduced spaced. This traits are essential for observations in maize breeding programs to obtain high yielding varieties in reduced spacing. In conclusion, the physiological (PN, CE, WUE, Ci, Gs), morphological (EIH, SD, LA) and productive (NE, GME) traits provide gains in maize grain yield via indirect selection when the crop is subjected to 40 cm row spacing.

Herbicide efficacy for control of annual ryegrass (Lolium rigidum Gaud.) is influenced more by wheat seeding rate than row spacing

2013 ◽  
Vol 64 (7) ◽  
pp. 708 ◽  
Author(s):  
Deirdre Lemerle ◽  
Peter Lockley ◽  
Eric Koetz ◽  
Simon Diffey
Keyword(s):  
Grain Yield ◽  
Weed Control ◽  
Herbicide Resistance ◽  
Water Conservation ◽  
Competitive Ability ◽  
Crop Yields ◽  
Row Spacing ◽  
Lolium Rigidum ◽  
Seeding Rate ◽  
The Impact

Conservation cropping systems with no-till and stubble retention improve soil condition and water conservation. However, tillage is replaced by herbicides for weed control in these systems, increasing the threat of herbicide resistance. In the medium to high rainfall zones of the southern wheatbelt of Australia and under irrigation, wider row spacing is used to enable seeding into heavy stubble loads and to avoid stubble burning. Some evidence suggests that wider rows lead to reduced crop competitive ability and crop yields, greater herbicide dependence, and increased spread of resistance. Our aim was to test the hypothesis that increasing seeding rate compensated for reduced competitive ability at wider row spacings, especially when herbicide performance was suboptimal. We examined the impact of two wheat row spacings (18 and 36 cm) and five seeding rates (resulting in a range of densities of ~80–700 plants/m2) on control of Lolium rigidum with five rates of post-emergence application of diclofop-methyl (Hoegrass®), ranging from label rate to lower rates, over two growing seasons. In the presence of L. rigidum, wheat grain yield was unaffected by row spacing but was significantly reduced at low seeding rates, especially at lower herbicide rates. Lolium rigidum was suppressed at higher crop densities but was also unaffected by row spacing. Grain yield was maximised when post-emergence herbicide was applied at 60–100% of the recommended dose at wheat densities >~300 plants/m2. Significant levels of the weed remained in the crop at anthesis in all treatments. Weed dry matter ranged from 525 g/m2 at low crop densities and with no herbicide to 150 g/m2 with the recommended rate of herbicide and high wheat densities. The implications of manipulating crop competitive ability to improve weed control are discussed, especially in conditions where herbicide performance is unreliable due to weeds developing herbicide resistance or adverse environmental conditions.

Integrating Irrigation, Tillage, and Herbicides for Weed Control in Dry Bean

2014 ◽  
Vol 28 (3) ◽  
pp. 479-485 ◽  
Author(s):  
Robert G. Wilson ◽  
Gustavo M. Sbatella
Keyword(s):  
Weed Control ◽  
Plant Density ◽  
Production Systems ◽  
Field Trials ◽  
No Tillage ◽  
Dry Bean ◽  
Soil Crusting ◽  
Crop Injury ◽  
Overhead Irrigation ◽  
Crop Density

Field trials were conducted from 2010 through 2012 to evaluate the integration of three factors: overhead irrigation after planting great northern dry bean; three methods of seedbed preparation: no-tillage, one or two diskings; and eight weed control treatments on dry bean development and weed control. The previous crop each year was corn. Overhead irrigation with 13 mm of water immediately after herbicide application and planting in early June did not improve or reduce herbicide efficacy but where herbicides were not utilized, irrigation increased weed emergence. Soil crusting increased in 2 of 3 yr when soil was disked at a 20-cm depth before planting. Crop injury from herbicides applied PRE increased when soil crusting occurred. No tillage before planting reduced crop injury from herbicides in 2010 and 2011 and weed density in 2012. Dry bean injury was minimal from herbicides applied PRE except for flumioxazin, which reduced crop density in 2011 and 2012. Imazamox plus bentazon applied POST caused early-season dry bean injury in 2 of 3 yr and resulted in a reduction in crop seed yield compared to dimethenamid-P or halosulfuron applied PRE. As producers move away from intensive tillage before planting to reduced tillage or no-tillage production systems, the results of this experiment show that dimethenamid-P, halosulfuron, pendimethalin, andS-metolachlor can be utilized PRE to provide acceptable weed control and crop selectivity. Although flumioxazin applied PRE reduced plant density, Great Northern dry bean yields were not affected by the loss of plant stand.

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