Crop spatial uniformity, yield and weed suppression

A field experiment was conducted in order to estimate the influence of different arrangement patterns of maize plants (Zea mays L.) in combination with low rates of herbicides on weed infestation and on production parameters of the crop. The maize was sown at 70-, 50-, and 35-cm row space with the same crop density. The weed biomass declined with smaller row spaces and was, on average, the lowest with the 35-cm row space; even though the arrangement patterns of the maize plants had no significant effect on the average values of the weed biomass. The interaction of the arrangement pattern and the herbicide rate significantly influenced weed biomass. Maize grain yield expressed the greatest variation under the effects of applied factors, but did not differ significantly between treatments with the full and the half rate of herbicides. The results indicate that it is possible to control weed infestation level if maize is grown with increased spatial uniformity and combined application of other practices such are herbicides. In such a way, maize plants are more competitive against weeds and even lower amounts of herbicides could be applied in order to achieve high yields.    

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Effects of missing-row sowing supplemented with row spacing and nitrogen on weed competition and growth and yield of wheat

Crop and Pasture Science ◽

10.1071/cp10203 ◽

2011 ◽

Vol 62 (1) ◽

pp. 48 ◽

Cited By ~ 14

Author(s):

T. K. Das ◽

N. T. Yaduraju

Keyword(s):

Weed Management ◽

Wheat Yield ◽

Weed Suppression ◽

Growth And Yield ◽

Weed Competition ◽

Row Spacing ◽

Weed Growth ◽

Spatial Uniformity ◽

Weed Infestation ◽

Ecological Weed Management

Crop husbandry practices, i.e. sowing method, row spacing, and nitrogen (N) fertilisation, influence weed competition in a crop and play a role in ecological weed management. Missing-row sowing is a novel method of sowing wheat, with one row left unsown after several rows of continuous sowing. It affects density and spatial uniformity of wheat, which may influence the wheat plants’ competitiveness and weed suppression. It may have interactions with row spacing and N, which may further improve crop–weed balance, but is rarely studied in India or elsewhere. We undertook this study to optimise the method of missing-row sowing of wheat in combination with row spacing and N application. The results revealed that leaving 20% of rows unsown significantly reduced weed populations and dry weights, and increased the competitiveness of wheat plants through greater leaf area, numbers of ear-bearing tillers, and uptake of N. Leaving 20% of rows unsown increased wheat yield by 10.9%, 17.3%, and 8.2%, respectively, during the first, second, and third year compared with conventional sowing (no missing rows). An 18.5-cm row spacing resulted in a more weed suppression than 22.5-cm row spacing, but the latter gave higher yield. Application of N at 120 kg/ha resulted in higher yield than N at 60 kg/ha, due to a significant reduction in weed growth. A practice that combines 20% of rows unsown, 22.5-cm row spacing, and 120 kg N/ha will yield more through better suppression of a moderate weed infestation.

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How Important are Crop Spatial Pattern and Density for Weed Suppression by Spring Wheat?

Weed Science ◽

10.1614/ws-d-11-00172.1 ◽

2012 ◽

Vol 60 (3) ◽

pp. 501-509 ◽

Cited By ~ 26

Author(s):

Jannie Maj Olsen ◽

Hans-Werner Griepentrog ◽

Jon Nielsen ◽

Jacob Weiner

Keyword(s):

Spatial Pattern ◽

Biomass Production ◽

Spring Wheat ◽

Field Experiments ◽

Weed Suppression ◽

Total Biomass ◽

Weed Biomass ◽

Spatial Uniformity ◽

Crop Density ◽

Crop Biomass

Previous research has shown that both the density and spatial pattern of wheat have an influence on crop growth and weed suppression, but it is not clear what degree of uniformity is necessary to achieve major improvements in weed suppression. Field experiments were performed over 3 yr to investigate the effects of crop density and different spatial distributions on weed suppression. The spatial pattern of spring wheat sown in five patterns and three densities in small weed-infested plots were analyzed with the use of digitized photographs of field plots to describe the locations of individual wheat plants asxandycoordinates. We used a simple quantitative measure, Morisita's index, to measure the degree of spatial uniformity. Increased crop density resulted in reduced weed biomass and increased crop biomass every year, but crop pattern had significant effects on weed and crop biomass in the first year only. Weather conditions during the second and third years were very dry, resulting in very low weed biomass production. We hypothesize that water deficiency increased the importance of belowground relative to aboveground competition by reducing biomass production, making competition more size symmetric, and reducing the effect of crop spatial pattern on weed growth. The results indicate that increased crop density in cereals can play an important role in increasing the crop's competitive advantage over weeds, and that spatial uniformity maximizes the effect of density when low resource levels or abiotic stress do not limit total biomass production.

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Effect of Sunflower Residues and Herbicide on Weed Suppression, Grain Yield and Economics of Transplanted Aman Rice

Bangladesh Agronomy Journal ◽

10.3329/baj.v23i1.50116 ◽

2020 ◽

Vol 23 (1) ◽

pp. 47-58

Author(s):

SS Tanu ◽

P Biswas ◽

S Ahmed ◽

SC Samanta

Keyword(s):

Grain Yield ◽

Dry Matter ◽

Block Design ◽

Weed Suppression ◽

Cost Ratio ◽

Gross Margin ◽

Weed Density ◽

Benefit Cost Ratio ◽

Hand Weeding ◽

Environmentally Sound

A field experiment was conducted at Agronomy Field Laboratory, Patuakhali Science and Technology University, Dumki, Patuakhali from July 2018 to November 2018 to evaluate the effect of sunflower residues and herbicides on the yield and economic performance of transplanted Aman rice. Weed control methods tested were T1 = weedy check (Unweeded control), T2 = Weed-free check by hand weeding twice, T3 = Pendimethalin, T4 = Pretilachlor, T5 = Butachlor, T6 = Pyrazosulfuron ethyl, T7 = Bensulfuron methyl + Acetachlor, T8 = Bispyriback sodium, T9 = 2,4-D amine, T10 = MCPA, T11 = Sunflower residues, T12 = Sunflower residues + 100% Pyrazosulfuron ethyl, T13 = Sunflower residues + 75% Pyrazosulfuron ethyl, T14 = Sunflower residues + 50% Pyrazosulfuron ethyl. The experiment was laid out in a randomized complete block design with fourteen treatments replicated thrice. Weedy check registered significantly the highest total weed density (354.67 m-2) and total weed dry matter (51.81 g-2) while weed-free treatment by hand weeding twice recorded significantly the lowest total weed density (6.67 m-2) and total weed dry matter 0.49 g-2) . Weedy check produced the highest weed index (34.24%) and hand weeding produced the lowest. Among different herbicides applied alone, butachlor had the lowest total weed density (15 m-2) and total weed dry matter (6.43 g-2) after hand weeding. Hand weeding recorded the highest grain yield (5.14 t ha-1) which was statistically similar to pendimethalin, pretilachlor, butachlor, bensulfuron methyl + acetachlor and sunflower residues + 100% pyrazosulfuron ethyl. Higher grain yield was attributed to a higher number of panicle m-2, number of filled grains panicle-1 and 1000-grain weight. The highest gross margin (22955 Tk. ha-1) and benefit-cost ratio (1.32) were obtained from butachlor. Integration of sunflower residues with pyrazosulfuron ethyl produced effective weed suppression and satisfactory yield comparable to butachlor. Although the integration is less profitable than butachlor the farmers can use this technology as a feasible and environmentally sound approach in transplanted Aman rice field. Bangladesh Agron. J. 2020, 23(1): 47-58

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Stable Characteristics of Cover Crops for Weed Suppression in Organic Farming Systems

Plant Production Science ◽

10.1626/pps.14.75 ◽

2011 ◽

Vol 14 (1) ◽

pp. 75-85 ◽

Cited By ~ 18

Author(s):

Hiroshi Uchino ◽

Kazuto Iwama ◽

Yutaka Jitsuyama ◽

Keiko Ichiyama ◽

Eri Sugiura ◽

...

Keyword(s):

Organic Farming ◽

Cover Crops ◽

Farming Systems ◽

Weed Suppression ◽

Organic Farming Systems

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Spring-planted cover crops for weed control in soybean

Renewable Agriculture and Food Systems ◽

10.1017/s1742170521000107 ◽

2021 ◽

pp. 1-8

Author(s):

Katja Koehler-Cole ◽

Christopher A. Proctor ◽

Roger W. Elmore ◽

David A. Wedin

Keyword(s):

Weed Control ◽

Biomass Production ◽

Cover Crops ◽

Weed Management ◽

Block Design ◽

Weed Suppression ◽

Crop Species ◽

Cold Temperatures ◽

Weed Biomass ◽

Small Grains

Abstract Replacing tillage with cover crops (CC) for weed management in corn (Zea mays L.)-soybean [Glycine max (L.) Merr.] systems with mechanical weed control has many soil health benefits but in the western Corn Belt, CC establishment after harvest is hampered by cold temperatures, limited labor and few compatible CC species. Spring-planted CC may be an alternative, but information is lacking on suitable CC species. Our objective was to evaluate four spring-planted CC with respect to biomass production and weed suppression, concurrent with CC growth and post-termination. Cover crop species tested were oat (Avena sativa L.), barley (Hordeum vulgare L.), brown mustard [Brassica juncea (L.) Czern.] and yellow mustard (Brassica hirta Moench). They were compared to no-CC treatments that were either tilled pre- and post-planting of soybean (no-CC tilled) or not tilled at all (no-CC weedy). CC were planted in late March to early April, terminated 52–59 days later using an undercutter, and soybean was planted within a week. The experiment had a randomized complete block design with four replications and was repeated for 3 years. Mustards and small grains produced similar amounts of biomass (1.54 Mg ha−1) but mustard biomass production was more consistent (0.85–2.72 Mg ha−1) than that of the small grains (0.35–3.81 Mg ha−1). Relative to the no-CC weedy treatment, mustards suppressed concurrent weed biomass in two out of 3 years, by 31–97%, and small grains suppressed concurrent weed biomass in only 1 year, by 98%. Six weeks after soybean planting, small grains suppressed weed biomass in one out of 3 years, by 79% relative to the no-CC weedy treatment, but mustards did not provide significant weed suppression. The no-CC tilled treatment suppressed weeds each year relative to the no-CC weedy treatment, on average 87%. The ineffective weed control by CC reduced soybean biomass by about 50% six weeks after planting. While spring-planted CC have the potential for pre-plant weed control, they do not provide adequate early season weed suppression for soybean.

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Weed Control with Reduced Rates of Chlorimuron Plus Metribuzin and Imazethapyr in No-Till Narrow-Row Soybean (Glycine max)

Weed Technology ◽

10.1017/s0890037x00042536 ◽

1998 ◽

Vol 12 (1) ◽

pp. 32-36 ◽

Cited By ~ 9

Author(s):

William G. Johnson ◽

Jeffrey S. Dilbeck ◽

Michael S. Defelice ◽

J. Andrew Kendig

Keyword(s):

Glycine Max ◽

Weed Control ◽

Field Studies ◽

Weed Suppression ◽

Crop Response ◽

Soybean Production ◽

No Till ◽

Giant Foxtail ◽

The Difference ◽

Narrow Row

Field studies were conducted at three locations in 1993 and 1994 to evaluate weed control and crop response to combinations of glyphosate, metolachlor, 0.5 X and 1 X label rates of chlorimuron plus metribuzin applied prior to planting (PP), and 0.5 X and 1 X label rates of imazethapyr applied early postemergence (EPOST) or postemergence (POST) in no-till narrow-row soybean production. Giant foxtail densities were reduced with sequential PP followed by (fb) EPOST or POST treatments. Large crabgrass was reduced equivalently with all herbicide combinations involving chlorimuron plus metribuzin PP fb imazethapyr. Common cocklebur control was variable but was usually greater with treatments that included imazethapyr. Ivyleaf morningglory densities were not reduced with any herbicide combinations. Sequential PP fb EPOST or POST treatments tended to provide slightly better weed suppression than PP-only treatments, but the difference was rarely significant. Soybean yields with treatments utilizing 0.5 X rates were usually equal to 1 X rates.

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