Canada thistle (Cirsium arvense) management in canola (Brassica rapa) and barley (Hordem vulgare) rotations under zero tillage

2001 ◽  
Vol 81 (1) ◽  
pp. 183-190 ◽  
Author(s):  
J. T. O’Donovan ◽  
R. E. Blackshaw ◽  
K. N. Harker ◽  
D. W McAndrew ◽  
G. W. Clayton

The effect of in-crop herbicide rate, crop row spacing and seeding rate on Canada thistle [Cirsium arvense (L.) Scop.] management in two cycles of a canola (Brassica rapa L.)/barley (Hordeum vulgare L.) rotation was investigated under zero tillage at Vegreville, Alberta. The entire plot area received pre-harvest glyphosate from 1993 through 1995. In crop, either no herbicides were applied or clopyralid and dicamba/MCPA-K were applied at one-half or full recommended rates to canola and barley, respectively. In most cases, Canada thistle shoot density and dry weight were lower when the herbicides were used at either rate compared with no herbicide application. Pre-harvest glyphosate followed by either clopyralid or dicamba/MCPA-K in-crop reduced Canada thistle shoot densities from approximately 20 m–2 in 1993 to one or fewer m–2 in 1996. In-crop herbicides resulted in higher crop yields and revenues in 1993 and 1994, but not in 1996 when the Canada thistle infestation was relatively low. The effect of crop row spacing was inconsistent, and had little effect on Canada thistle shoot density or dry weight. In some cases, crop yield was higher at 20-cm than at 30-cm row spacing. Crop seeding rate had no effect on crop or Canada thistle variables. Key words: Cirsium arvense, zero tillage, pre-harvest glyphosate, clopyralid, dicamba/MCPA-K, crop row spacing, crop seeding rate.

1988 ◽  
Vol 2 (4) ◽  
pp. 445-455 ◽  
Author(s):  
Steven J. Carlson ◽  
William W. Donald

Effects of repeated late-fall applications of the isopropylamine salt of glyphosate at 1.7 kg ae/ha plus 0.5% (v/v) surfactant on adventitious root buds, thickened propagative roots (> 1.3 mm diam), and shoot density of Canada thistle were studied in continuous hard red spring wheat over a 4-yr period. Glyphosate suppressed Canada thistle shoot density more quickly and to a greater extent than thickened root fresh weight or root bud number. A single fall application of glyphosate drastically decreased Canada thistle shoot density for 1 yr after treatment. However, shoot density was the same as the untreated control by 2 yr after a single fall treatment. Two consecutive late-fall applications of glyphosate in 2 yr decreased Canada thistle shoot density 94% in the fall 1 yr after the last treatment. Glyphosate reduced Canada thistle thickened root fresh weight 70% in the first fall 1 yr after a single fall treatment. However, 2 yr after a single fall application of glyphosate, root fresh weight equalled the controls. Two consecutive fall applications of glyphosate reduced thickened root fresh weight 77% 1 yr after the second treatment.


2007 ◽  
Vol 21 (1) ◽  
pp. 124-130 ◽  
Author(s):  
Adrienne M. Rich ◽  
Karen A. Renner

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.


1995 ◽  
Vol 75 (3) ◽  
pp. 613-618 ◽  
Author(s):  
D. Pageau ◽  
G. F. Tremblay

A 4-yr study was conducted to evaluate the effect of two row spacings (10 and 20 cm) and five seeding rates of the cereal (100, 200, 300, 400 and 500 viable seeds m−2) on the interference between quackgrass [Elymus repens (L.) Nevski] and barley (Hordeum vulgare L. 'Cadette'). Narrow row spacings had no effect on the yield of barley in presence or absence of quackgrass. However, seeding rates influenced the productivity and development of barley when quackgrass was present. At a seeding rate of 100 seeds m−2, the yield reduction caused by the presence of quackgrass was 41%. When barley was seeded at 500 seeds m−2, the yield reduction was 19%. These yield reductions were mainly attributed to a decrease of spike density. In presence of quackgrass, the specific weight, number of kernels per spike, number of spikes per plant, 1000-kernel weight, harvest index and N concentration of grain were reduced. In contrast to a decrease of the row spacing, increasing seeding rate can be used to reduce interference between quackgrass and barley. Key words: Barley, quackgrass, interference, row spacing, seeding rate


Author(s):  
Ye.N. Rostova ◽  

Dense white mustard (Sinapis alba L.) can suppress weeds, however excessive density negatively influences crop yields. The search for the optimal parameters for applying mineral fertilizers and the consumption of seed material will increase the crop yield and will improve its competitive ability. This work aimed to identify the seeding rate and doses of nitrogen fertilization at which white mustard plants can actively suppress weeds without reducing the productivity of the crop. In the course of this research, we established that S. alba sown at a rate of 2, 2.5 and 3 million seeds per ha suppressed the growth and development of weeds as much as possible. On average, in 2017-2019, the dry weight of weeds in the aforementioned variants was the least and reached 57.9; 42.3 and 38.4 g/m2, respectively. Weed species composition and quantitative parameters of weed infestation depended on the weather conditions of the year. The application of nitrogen fertilizer did not affect significantly the weediness of S. alba crops. The optimal density white mustard plant formed at a seeding rate of 2 million units/ha and, on average, for three years of research, the seed yield in this variant was the highest (0.6 t/ha).


2013 ◽  
Vol 64 (7) ◽  
pp. 708 ◽  
Author(s):  
Deirdre Lemerle ◽  
Peter Lockley ◽  
Eric Koetz ◽  
Simon Diffey

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.


1998 ◽  
Vol 78 (1) ◽  
pp. 145-150 ◽  
Author(s):  
K. L. Bailey ◽  
Guy P. Lafond ◽  
Daryl Domitruk

Changes in tillage and other agronomic practices have shown benefits of increased grain yield for many crops, but these changes may alter the micro-environment resulting in changes to populations of disease-causing agents and other micro-organisms. This study examined the effects of row spacing (10, 20, 30 cm), seeding rate (54, 108, 161 kg ha−1 for barley; 67, 134, 202 kg ha−1 for spring wheat) and seed-placed phosphorus (0, 8, 16 kg ha−1) on root diseases in spring wheat and barley using a zero-tillage production system in four environments. Root rot severity was assessed by visual ratings and the causal agents were identified. Analyses of variance indicated significant differences in root rot severity and the incidence of some causal agents for the main treatment effects (i.e. row spacing, seeding rate, seed-placed phosphorus) and no significant interactions between locations, years, and cultural practices. Contrasts of treatment means showed that higher rates of seeding decreased root rot severity and the incidence of Fusarium in wheat but these effects were small (less than 6%). The higher rates of monoammonium phosphate fertilizer reduced root rot severity in barley by 7% and the incidence of Gaeumannomyces graminis var. tritici in wheat by greater than 40%. Wider row spacings showed a small reduction of 6% in root rot severity in wheat but mostly had no effect on root diseases. Wheat yields were negatively associated with root rot severity in three of four environments. Fertility, root rot severity, and seeding rate had the greatest impact on wheat yield. Root diseases did not affect barley yields. Therefore, the use of wider row spacings and higher seeding rates with zero tillage practices will not lead to adverse effects on root diseases in wheat and barley. Phosphorus fertilizer should be used to reduce losses resulting from take-all disease in wheat. Key words: Zero tillage, cultural practices, common root rot, take-all, cereals


1984 ◽  
Vol 64 (1) ◽  
pp. 215-217 ◽  
Author(s):  
P. A. O’SULLIVAN ◽  
V. C. KOSSATZ

Control of topgrowth of 10-cm-tall Canada thistle (Cirsium arvense L. Scop.) was excellent, and barley (Hordeum vulgare L. ’Gait’) yields were increased when 3,6-dichloropicolinic acid was applied at rates of 0.2 kg/ha and higher. No injury to barley cvs. Gait and Klondike was evident with herbicide rates of 0.1–0.9 kg/ha applied at the three-leaf, six-leaf and boot stages and yields were not adversely affected.Key words: Canada thistle, barley tolerance, 3,6-dichloropicolinic acid


1994 ◽  
Vol 74 (4) ◽  
pp. 703-711 ◽  
Author(s):  
G. P. Lafond

Adopting water-conserving tillage practices on the Canadian prairies will protect the soil against erosion while conserving soil water. The use of tall-standing stubble to conserve water creates a dilemma for producers because maximum yields can only be obtained with narrow rows, and tall stubble may limit the use of narrow row spacings. A 4-yr study on a thin Black clay soil investigated the effects of three row spacings (10, 20 and 30 cm), six seeding rates (34, 67, 100, 134, 168 and 202 kg ha−1 for wheat and 27, 54, 81, 108, 134 and 161 kg ha−1 for barley) and two rates of N (low and high) in hard red wheat (Triticum aestivum L.), durum (Triticum durum L.) and barley (Hordeum vulgare L.) using a continuous cropping, zero-till production system. The yields of cereals were maintained with 30-cm row spacing over a wide range of growing conditions under zero-till management. Durum had a 5.8% yield advantage and barley a 2.4% advantage for the 30-cm row spacing over the 10-cm row spacing. The number of plants established and the number of spikes produced decreased as row spacing increased for all crops. But wider row spacing resulted in more kernels produced per spike, which, in the case of barley and durum, more than compensated for the lower number of spikes. Increasing seeding rates significantly improved grain yield in all crops and years because more spikes were produced. Grain yield was related to the reciprocal of seeding rate. The few row spacing × seeding rate interactions observed in 2 of 12 cases suggest that seeding rates need not be adjusted for changes in row spacing. The results obtained have important implications for equipment design and the ability to more easily handle high-crop-residue situations. Key words: Yield components, seeding rate, row spacing, yield compensation


2008 ◽  
Vol 88 (2) ◽  
pp. 373-378 ◽  
Author(s):  
Peter H Sikkema ◽  
Robert E Nurse ◽  
Tom Welacky ◽  
Allan S Hamill

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


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