Nitrogen fertilizer timing and application method affect weed growth and competition with spring wheat

Weed Science ◽  
2004 ◽  
Vol 52 (4) ◽  
pp. 614-622 ◽  
Author(s):  
Robert E. Blackshaw ◽  
Louis J. Molnar ◽  
H. Henry Janzen
Keyword(s):  
Ammonium Nitrate ◽  
Spring Wheat ◽  
Nitrogen Fertilizer ◽  
Weed Management ◽  
Wheat Yield ◽  
Integrated Weed Management ◽  
Nitrogen Application ◽  
Application Method ◽  
Weed Growth ◽  
Density And Biomass

Managing crop fertilization may be an important component of integrated weed management systems that protect crop yield and reduce weed populations over time. A field study was conducted to determine the effects of various timings and application methods of nitrogen (N) fertilizer on weed growth and spring wheat yield. Nitrogen fertilizer was applied the previous fall (October) or at planting (May) at a dose of 50 kg ha−1. Nitrogen application treatments consisted of granular ammonium nitrate applied broadcast on the soil surface, banded 10 cm deep between every crop row, banded 10 cm deep between every second crop row, or point-injected liquid ammonium nitrate placed between every second crop row at 20-cm intervals and 10 cm deep. Treatments were applied in 4 consecutive yr to determine annual and cumulative effects over years. Density and biomass of wild oat, green foxtail, wild mustard, and common lambsquarters were sometimes lower with spring- than with fall-applied N. Spring wheat yield was never lower and was higher in 50% of the cases, when N was spring rather than fall applied. Nitrogen application method generally had larger and more consistent effects than application timing on weed growth and wheat yield. Shoot N concentration and biomass of weeds were often lower with subsurface banded or point-injected N than with surface broadcast N, and concurrent increases in spring wheat yield usually occurred with these N placement treatments. Depending on the weed species, the weed seedbank at the conclusion of the 4-yr study was reduced by 25 to 63% with point-injected compared with broadcast N. Information gained in this study will contribute to the development of more integrated and cost-effective weed management programs in wheat.

Phosphorus Fertilizer Application Method Affects Weed Growth and Competition with Wheat

Weed Science ◽  
2009 ◽  
Vol 57 (3) ◽  
pp. 311-318 ◽  
Author(s):  
Robert E. Blackshaw ◽  
Louis J. Molnar
Keyword(s):  
Weed Management ◽  
Wheat Yield ◽  
Fertilizer Application ◽  
Management Systems ◽  
Integrated Weed Management ◽  
Weed Species ◽  
Application Method ◽  
Weed Growth ◽  
P Fertilizer ◽  
Application Methods

Strategic fertilizer management is an important component of integrated weed management systems. A field study was conducted to determine the effect of various application methods of phosphorus (P) fertilizer on weed growth and wheat yield. Weed species were chosen to represent species that varied in their growth responsiveness to P: redroot pigweed (medium), wild mustard (medium), wild oat (medium), green foxtail (high), redstem filaree (high), and round-leaved mallow (high). P fertilizer application methods were seed placed at a 5-cm depth, midrow banded at a 10-cm depth, surface broadcast immediately before seeding, and surface broadcast immediately after seeding of wheat. An unfertilized control was included. P treatments were applied to the same plot in four consecutive years to determine annual and cumulative effects over years. Shoot P concentration and biomass of weeds were often lower with seed-placed or subsurface-banded P fertilizer compared with either surface-broadcast application method. This result occurred more frequently with the highly P-responsive weeds and was more evident in the latter study years. P application method had little effect on weed-free wheat yield but often had a large effect on weed-infested wheat yield. Seed-placed or midrow-banded P compared with surface-broadcast P fertilizer often resulted in higher yields when wheat was in the presence of competitive weeds. Seedbank determinations at the conclusion of the study indicated that the seed density of five of six weed species was reduced with seed-placed or subsurface-banded P compared with surface-broadcast P. Information gained in this study will aid development of more effective weed management systems in wheat.

Combining agronomic practices and herbicides improves weed management in wheat–canola rotations within zero-tillage production systems

Weed Science ◽  
2005 ◽  
Vol 53 (4) ◽  
pp. 528-535 ◽  
Author(s):  
Robert E. Blackshaw ◽  
Hugh J. Beckie ◽  
Louis J. Molnar ◽  
Toby Entz ◽  
James R. Moyer
Keyword(s):  
Crop Yield ◽  
Spring Wheat ◽  
Weed Management ◽  
Crop Yields ◽  
Wheat Yield ◽  
Integrated Weed Management ◽  
Weed Biomass ◽  
Weed Growth ◽  
Spring Canola ◽  
Crop Seed

Development of more comprehensive and cost-effective integrated weed management systems is required to facilitate greater integrated weed management adoption by farmers. A field experiment was conducted at two locations to determine the combined effects of seed date (April or May), seed rate (recommended or 150% of recommended), fertilizer timing (applied in fall or spring), and in-crop herbicide dose (50% or 100% of recommended) on weed growth and crop yield. This factorial set of treatments was applied in four consecutive years within a spring wheat–spring canola–spring wheat–spring canola rotation in a zero-till production system. Both wheat and canola phases of the rotation were grown each year. Weed biomass was often lower with May than with April seeding because more weeds were controlled with preplant glyphosate. However, despite fewer weeds being present with May seeding, wheat yield was only greater in 1 of 7 site-years, and canola yield was never greater with May compared with April seeding. Higher crop seed rates had a consistently positive effect on reducing weed growth and the weed seedbank. Crop yield was sometimes greater, and never lower, with higher seed rates. Fertilizer timing did not have a large effect on crop yield, but applying N in the spring compared with fall was less favorable for weeds as indicated by lower weed biomass and a 20% decrease in the weed seedbank. In-crop herbicides applied at 50% compared with 100% doses often resulted in similar weed biomass and crop yield, especially when higher crop seed rates were used. Indeed, the weed seedbank at the conclusion of the 4-yr experiment was not greater with the 50% compared with 100% herbicide dose at one of two locations. This study demonstrates the combined merits of early seeding (April), higher crop seed rates, and spring-applied fertilizer in conjunction with timely but limited herbicide use to manage weeds and maintain high crop yields in rotations containing wheat and canola.

Suppressing weed growth after wheat harvest with underseeded red clover in organic farming

2015 ◽  
Vol 31 (3) ◽  
pp. 185-190 ◽  
Author(s):  
Randy L. Anderson
Keyword(s):  
Winter Wheat ◽  
Spring Wheat ◽  
Weed Management ◽  
Cover Crop ◽  
Block Design ◽  
Wheat Yield ◽  
Red Clover ◽  
Downy Brome ◽  
Alternative Tactics ◽  
Weed Growth

AbstractOrganic producers are seeking alternative tactics for weed control so that they can reduce their need for tillage. In this study, we examined cover crop strategies for suppressing weed growth after harvest of wheat. Three cover crop treatments, red clover (mammoth type), a mixture of oat and dry pea, and a control were compared. Treatments were established in both winter and spring wheat, resulting in six treatments arranged in a randomized complete block design. Red clover was underseeded in wheat by drilling in the spring, and the oat/pea mixture was planted in August. Oat was planted uniformly across all treatments in the following growing season. The red clover treatment effectively suppressed weeds, reducing post-harvest weed biomass, density of volunteer winter wheat, and seed production of downy brome by more than 99% compared with the control. Oat/pea was not effective for weed management, likely because of less fall growth and competition compared with red clover. Underseeding red clover did not affect winter wheat yield, but reduced spring wheat yield by 17%. Oat yield, however, was reduced by volunteer crop plants and downy brome infestations in all treatments. Underseeding clovers in winter wheat may effectively manage weeds and, if they winterkill, can replace the need for tillage to control weeds after wheat harvest.

Spring Wheat, Canola, and Sunflower Response to Persian Darnel (Lolium persicum) Interference

2004 ◽  
Vol 18 (3) ◽  
pp. 509-520 ◽  
Author(s):  
Johnathon D. Holman ◽  
Alvin J. Bussan ◽  
Bruce D. Maxwell ◽  
Perry R. Miller ◽  
James A. Mickelson
Keyword(s):  
Crop Yield ◽  
Spring Wheat ◽  
Weed Management ◽  
Management Practices ◽  
Yield Loss ◽  
Wheat Yield ◽  
Integrated Weed Management ◽  
Crop Density ◽  
The Impact ◽  
Number Of Branches

Integrated weed management practices, such as crop rotation and increased seeding rates, potentially improve weed management. Yet, few studies compare competitive interactions of weeds with different crops. This research quantified the impact of Persian darnel on spring wheat, canola, and sunflower yield across different seeding rates. Increasing crop density increased yield when Persian darnel affected crop yield early in physiological development. Crop yield loss was estimated to reach 83, 70, and 57% for spring wheat, canola, and sunflower, respectively, at high Persian darnel densities. Persian darnel reduced spring wheat yield by limiting the number of tillers per plant and seed per tiller; reduced canola yield by limiting the number of branches per plant, pods per branch, and seed per pod; and reduced sunflower yield by limiting the number of seed per plant. Persian darnel affected crop growth early in physiological development, indicating that interspecific interference occurred early in the growing season. Cultural and resource management aimed at reducing Persian darnel impact on resource availability and crop yield components will reduce Persian darnel impact on crop yield.

An Integrated Weed Management Approach to Managing Foxtail Barley (Hordeum jubatum) in Conservation Tillage Systems

1999 ◽  
Vol 13 (2) ◽  
pp. 347-353 ◽  
Author(s):  
Robert E. Blackshaw ◽  
Greg Semach ◽  
Xiangju Li ◽  
John T. O'Donovan ◽  
K. Neil Harker
Keyword(s):  
Crop Yield ◽  
Weed Management ◽  
Conservation Tillage ◽  
Wheat Yield ◽  
Integrated Weed Management ◽  
Management Approach ◽  
Row Spacing ◽  
Seeding Rate ◽  
Tillage Systems ◽  
Perennial Plants

A 4-yr field experiment was conducted to determine the merits of combining cultural and chemical controls to manage foxtail barley in reduced-tillage systems. Factors studied were crop row spacing, seeding rate, and application rate and timing of glyphosate within a spring wheat-flax cropping sequence. Glyphosate applied preseeding at 400 or 800 g/ha killed foxtail barley seedlings but only suppressed established perennial plants. Glyphosate applied postharvest at 800 g/ha killed 60 to 70% of established plants. Combinations of preseeding and postharvest glyphosate gave the greatest reductions in foxtail barley biomass and seed production and resulted in the greatest increases in crop yield. Including flax in the rotation allowed use of grass herbicides such as quizalofop or sethoxydim that effectively controlled foxtail barley seedlings and provided some suppression of perennial plants. An increase in wheat seeding rate from 75 to 115 kg/ha reduced foxtail barley growth and increased wheat yield in 3 of 4 yr. Increasing the flax seeding rate from 40 to 80 kg/ha or reducing wheat and flax row spacing from 30 to 20 cm provided little benefit in managing foxtail barley or increasing crop yield. A multiyear approach combining agronomic practices and timely use of herbicides should allow growers to effectively manage foxtail barley in annual cropping systems using conservation tillage.

An Environmental and Economic Perspective on Integrated Weed Management in Iran

2013 ◽  
Vol 27 (2) ◽  
pp. 352-361
Author(s):  
Mohammad Ghorbani ◽  
Surendra Kulshreshtha
Keyword(s):  
Weed Management ◽  
Crop Production ◽  
Wheat Yield ◽  
Multinomial Logit Model ◽  
Negative Influence ◽  
Integrated Weed Management ◽  
Number Of Factors ◽  
Wheat Cultivation ◽  
Irrigated Wheat ◽  
Herbicide Use

Inputs, including herbicides, used in crop production may create negative environmental impacts. One solution to minimize these adverse effects is the adoption of integrated weed management (IWM) with the intention of reducing herbicide use. This study, conducted in 2010, estimates the willingness of farmers to pay for the adoption of more effective weed management methods. Results suggest that the willingness to pay (WTP) for IWM is greater than the WTP for other weed management methods, including chemical weed management and chemical and mechanical weed management. This study also identified a number of factors that influence the adoption of IWM on wheat farms in Iran using a multinomial logit model. Total annual income, area under irrigated wheat, wheat yield loss due to weeds, perennial nature of the weeds, and having awareness of weed resistance to herbicides had a positive effect on the adoption of IWM practices. However, having rain-fed (dryland) wheat cultivation and a larger number of plots on the farm had a negative influence on the choice of IWM.

Tillage, fertiliser and glyphosate timing effects on foxtail barley (Hordeum jubatum) management in wheat

2000 ◽  
Vol 80 (3) ◽  
pp. 655-660 ◽  
Author(s):  
R. E. Blackshaw ◽  
G. Semach ◽  
X. Li ◽  
J. T. O'Donovan ◽  
K. N. Harker
Keyword(s):  
Weed Management ◽  
Production Systems ◽  
Conservation Tillage ◽  
Wheat Yield ◽  
Soil Surface ◽  
Integrated Weed Management ◽  
Canadian Prairies ◽  
Application Timing ◽  
Hordeum Jubatum ◽  
Timing Effects

Foxtail barley (Hordeum jubatum L.) is becoming a more severe weed problem as conservation tillage becomes widely adopted on the southern Canadian prairies. A 5-yr field study was conducted to determine the combined effects of tillage, N rate, N placement and application timing of glyphosate to manage foxtail barley in spring wheat. Wide-blade tillage conducted in fall and spring, compared to zero-till, reduced foxtail barley biomass and seed production in all yr and increased wheat yield in 4 of 5 yr. Foxtail barley was highly competitive with wheat for added N. N fertiliser placed mid-row in 10-cm-deep bands reduced foxtail barley growth in 2 of 5 yr and increased wheat yield in 3 of 5 yr compared with soil surface broadcast N. Wheat yield sometimes was similar when N was banded at 60 kg ha−1 or broadcast at 120 kg ha−1, indicating the large advantage of banding N in some situations. Glyphosate at 800 g ha−1 applied preharvest or postharvest gave similar levels of foxtail barley control in 2 of 3 yr. Results indicate that foxtail barley can be adequately managed in wheat production systems utilizing conservation tillage. Key words: Foxtail barley, Hordeum jubatum, glyphosate, integrated weed management, nitrogen placement, zero tillage

Nitrogen Fertility and Weed Management Critical for Continuous No-Till Wheat in the Pacific Northwest

2006 ◽  
Vol 20 (3) ◽  
pp. 658-669 ◽  
Author(s):  
Frank L. Young ◽  
Mark E. Thorne ◽  
Douglas L. Young
Keyword(s):  
Winter Wheat ◽  
Pacific Northwest ◽  
Crop Yield ◽  
Spring Wheat ◽  
Weed Management ◽  
Weed Density ◽  
N Level ◽  
No Till ◽  
The Pacific ◽  
Density And Biomass

No-till cropping is an option for growers needing to reduce soil erosion in the Palouse annual-cropped region of the Pacific Northwest, which is well suited for wheat production. A 6-yr field study was conducted to determine optimum levels of fertilizer and herbicide inputs in a no-till continuous wheat crop production system. Three levels of nitrogen (N) and two weed management levels (WML) were compared in a spring wheat (SW)–winter wheat (WW)–WW rotation through two rotation cycles. The high WML reduced weed densities about 50% compared with the low WML. In general, herbicide treatments were more effective on broadleaf weeds and may have facilitated a shift toward grass weeds. The high WML reduced grass weed biomass only at the reduced N levels, whereas the high WML reduced broadleaf weed density at all N levels. Variable environmental conditions affected wheat yield; however, yield tended to be highest where winter wheat immediately followed spring wheat. Nitrogen had little effect on weed density but increased crop yield about 13% with each increased N level. Crop yield was greater at the high versus low WML at each N level, even though weed density and biomass were reduced least between WMLs at the highest N level. The highest crop yield and net returns were obtained with the highest N and WML; however, none of the N and WML combinations were profitable.

scholarly journals Weed Control in Maize with Gliricidia Intercropping

2015 ◽  
Vol 33 (2) ◽  
pp. 249-258
Author(s):  
L.B. Tavella ◽  
P.S.L. Silva ◽  
A.L. Monteiro ◽  
V.R. Oliveira ◽  
P.L.O.F. Siqueira
Keyword(s):  
Grain Yield ◽  
Weed Control ◽  
Weed Management ◽  
Gliricidia Sepium ◽  
Good Alternative ◽  
Production Costs ◽  
Integrated Weed Management ◽  
Maize Production ◽  
Maize Hybrids ◽  
Weed Growth

One of the very important components in the organic maize production costs refers to spending on weed control. In this research were assessed the effects of maize hybrids (AG 1051 and BR 205) in an intercropping with Gliricidia (Gliricidia sepium) and mechanical hoeing on weed control. The treatments assessed were: A - maize monocropping + two hoeings (20 and 40 days after sowing); B - maize with one hoeing at 20 days + intercropping with gliricidia sowed after hoeing; C - maize sowing intercropped with gliricidia at the time of maize sowing + hoeing at 40 days; D - maize sowing intercropped with gliricidia at the time of maize sowing without hoeing; E - monocropping maize without hoeing. In the intercroppings, gliricidia was sowed in broadcast seeding with 30 viable seeds m-2. Maize hybrids did not differ in their effects on weed growth and grain yield. Treatments A, B and C have reduced weed growth, compared to treatments D and E. The highest grain yield was obtained with treatment A and the lowest with treatment E. It was concluded that intercropping maize and gliricidia is not a good alternative for an integrated weed management in maize crops in the conditions assessed.

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