&nbsp; Weed suppression and crop productivity by different arrangement patterns of maize

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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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 POPULATION DENSITY OF SWEET POTATO ON THE YIELD OF MAIZE-SWEET POTATO INTERCROP FOR WEEDS SUPPRESSION IN SOUTHERN GUINEA SAVANNAH NIGERIA

JOURNAL OF WEED SCIENCE RESEARCH ◽

10.28941/pjwsr.v26i2.853 ◽

2020 ◽

Vol 27 (2) ◽

pp. 215-230

Author(s):

Felix O Takim

Keyword(s):

Grain Yield ◽

Sweet Potato ◽

Block Design ◽

Crop Productivity ◽

Weed Suppression ◽

Cost Ratio ◽

Weed Species ◽

Planting Time ◽

Guinea Savanna ◽

Weed Infestation

ABSTRACT Maize–sweet potato intercropping often results in weed suppression and increased crop productivity. This study was designed to determine the appropriate planting time and optimal density of sweet potato in a maize-sweet potato intercropping system that will minimize weed infestation and improve yield of the component crops in a drought-prone southern Guinea savanna of Nigeria. The experiment was laid as a randomized complete block design with a split-plot arrangement and 3 replications in 2018 and 2019 growing seasons. The main plots were planting time (May, June and July) while the sub-plots consisted of 3 maize-sweet potato intercropping populations(maize at 53,333 plants/ha + 33,333 plants/ha of sweet potato, maize at 53,333 plants/ha + 66,666 plants/ha of sweet potato and maize at 53,333 plants/ha +99,999plants/ha of sweet potato), sole maize at 53,333 plants/ha and sole sweet potato at 33,333 plants/ha. The results revealed that, 7 weed species were the most prevalent and there was inconsistent effect of planting date on weed flushes while weed smothering efficiency of intercropping was between 31 to 49 % and 48 to 73% for weed density and weed biomass, respectively. Intercropping resulted in land equivalent ratios (LER) of 1.29 to 1.74 while the competitive ability of maize was increased with an increase in sweet potato density. Planting in the month of June had significantly higher tuber yield of 9.56 t/ha of sweet potato and maize grain yield of 3.28 t/ha while intercropping 33,333 plants/ha of sweet potato (1 vine of sweet potato planted at 0.40m apart on the ridge and 0.75m between ridges) and maize at 53,333 plants/ha (0.25m x 0.75m) gave an intercrop yield of 7.32 t/ha tubers and 3.46 t/ha grain yield with highest LER of 1.74, a net profit of ₦566,435.00 and benefit cost ratio of 1.44 was relatively similar to sole sweet potato. Therefore, the above intercropping pattern established in the month of June will minimize weed infestation and improve productivity of maize and sweet potato in the southern Guinea savanna of Nigeria.

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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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Differences in Weed Suppression between Two Modern and Two Old Wheat Cultivars at Different Sowing Densities

Agronomy ◽

10.3390/agronomy11020253 ◽

2021 ◽

Vol 11 (2) ◽

pp. 253

Author(s):

Yue Wu ◽

Nianxun Xi ◽

Jacob Weiner ◽

Da-Yong Zhang

Keyword(s):

Cropping Systems ◽

Wheat Yield ◽

Triticum Aestivum L ◽

High Density ◽

Weed Suppression ◽

Agricultural Systems ◽

Weed Growth ◽

Crop Density ◽

High Yields ◽

Better Than

Crop losses to weeds can be exacerbated in modern agricultural systems because modern crop cultivars have high population yields but low individual competitiveness. High density cropping systems offer the possibility of effectively suppressing weeds by increasing the initial size-asymmetric advantage of crops over the weeds. We tested this hypothesis in an outdoor mesocosm experiment with two old (Cultivar Heshangtou (HST) and Jinbaoyin (JBY)) and two modern (Xihan2 (XH2) and Xihan3 (XH3)) cultivars of spring wheat (Triticum aestivum L.), grown in a uniform pattern at four sowing densities under high weed pressure. Two annuals (Brassica napus and Linum usitatissimum) were used as model weeds sown at the same density in all treatments. Weed growth decreased and wheat yield increased with increasing crop density for all the cultivars, although yield levelled off at the highest densities. The old cultivars suppressed weeds better than the new cultivars at low density, reflecting the decline in individual competitiveness in modern cultivars. At high crop density, however, the modern XH3 suppressed the weeds as well as the old cultivars, supporting the hypothesis that traits that promote weed suppression are different at low vs. high density. Increasing crop density can be an effective way to suppress weed growth in many agricultural systems, and there is great potential for developing genotypes that can do this and produce high yields much better than the cultivars currently available.

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Potential Synergistic Effects of Cereal Rye Biomass and Soybean Planting Density on Weed Suppression

Weed Science ◽

10.1614/ws-d-10-00110.1 ◽

2011 ◽

Vol 59 (2) ◽

pp. 238-246 ◽

Cited By ~ 54

Author(s):

Matthew R. Ryan ◽

Steven B. Mirsky ◽

David A. Mortensen ◽

John R. Teasdale ◽

William S. Curran

Keyword(s):

Cover Crops ◽

Weed Management ◽

Management Practice ◽

Synergistic Effects ◽

Weed Suppression ◽

Planting Density ◽

Hyperbolic Model ◽

Weed Biomass ◽

Cereal Rye ◽

Crop Density

Increasing crop density is a cultural weed management practice that can compliment the use of cover crops for weed suppression. In this research, we created a range of cover crop biomass and soybean densities to assess their weed-suppressive ability alone and in combination. The experiment was conducted in 2008 and 2009 in Maryland and Pennsylvania using five levels of cereal rye residue, representing 0, 0.5, 1.0, 1.5, and 2.0 times the ambient level, and five soybean densities ranging from 0 to 74 seeds m−2. Weed biomass decreased with increasing rye residue and weeds were completely suppressed at levels above 1,500 g m−2. Weed biomass also decreased with increasing soybean density in 2 of 4 site–years. We evaluated weed suppression by fitting an exponential decay model of weed biomass as a function of rye biomass and a hyperbolic model of weed biomass as a function of soybean density at each of the five tactic levels. We multiplied these individual tactic models and included an interaction term to test for tactic interactions. In two of the four site-years, the combination of these tactics produced a synergistic interaction that resulted in greater weed suppression than would be predicted by the efficacy of each tactic alone. Our results indicate that increasing soybean planting rate can compensate for lower cereal rye biomass levels when these tactics are combined.

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Water Infiltration in Fall Broccoli

HortScience ◽

10.21273/hortsci.41.4.998b ◽

2006 ◽

Vol 41 (4) ◽

pp. 998B-998

Author(s):

Carlene A. Chase ◽

Odemari S. Mbuya ◽

Danielle D. Treadwell

Keyword(s):

Hydraulic Conductivity ◽

Cover Crops ◽

Organic Production ◽

Weed Suppression ◽

Water Infiltration ◽

Growth And Yield ◽

Weed Biomass ◽

Central Florida ◽

Live Oak ◽

Weed Infestation

The effect of living mulches (LM) on weed suppression, crop growth and yield, and soil hydraulic conductivity were evaluated in broccoli in North Central Florida at Citra and in North Florida at Live Oak, using organic production methods. `Florida 401' rye, `Wrens Abruzzi' rye, black oat, and annual ryegrass, were either mowed or left untreated and compared with weedy and weed-free controls. Cover crop biomass was highest with `Florida 401' at both locations, intermediate with black oat and `Wrens Abruzzi', and lowest with ryegrass. The greatest weed infestation occurred with the weedy control. In Citra, ryegrass decreased weed biomass by 21% compared with ≈45% by the other LM with no differences due to mowing. However, at Live Oak, mowed LM and the weedy control had similar amounts of weed biomass; whereas unmowed LM had 30% to 40% less weed biomass than the weedy control. At both locations, broccoli heights were greatest with the weed-free control, intermediate with the cover crops, and lowest with the weedy control. Total above-ground broccoli biomass and marketable weight of broccoli at Live Oak, and number of marketable heads at both locations, were unaffected by the LM. At Citra, total broccoli biomass with LM and the weedy control decreased in a similar manner, so that total broccoli biomass was highest with the weed-free control. Ryegrass and the weedy control suppressed marketable broccoli weight by 24%; however, greater decrease in marketable weight (39% to 43%) occurred with `Florida 401', `Wrens Abruzzi', and black oat. At both locations, mowing of LM had no effect on broccoli growth or yield. There was no difference in saturated hydraulic conductivity among treatments.

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Weed infestation of winter pea crops under the action of herbicides, plant growth regulators and microbial preparations

Collected Works of Uman National University of Horticulture ◽

10.31395/2415-8240-2020-97-1-171-180 ◽

2020 ◽

Vol 1 (97) ◽

pp. 171-180

Author(s):

V.P. Karpenko ◽

◽

Ya. O. Boyko ◽

R. M. Pritulyak

Keyword(s):

Plant Growth ◽

Growth Regulator ◽

Plant Growth Regulator ◽

Seed Treatment ◽

Direct Action ◽

Statistical Processing ◽

Combined Application ◽

Weed Infestation ◽

Microbial Preparation ◽

High Yields

Weed infestation of agricultural crops in Ukraine is growing and is becoming a big threat to stable and high yields. Therefore, today, it is impossible to do without the development of science-based measures to control the level of weed infestation in crops, adaptation of herbicides to ecological farming methods and energy-optimized cultivation technologies. The analysis of the results of studies of weediness of winter pea crops at different rates of application of MaxiMox herbicide (0.8; 0.9; 1.0 and 1.1 l/ha) separately and in tank mixtures with plant growth regulator Agriflex Amino at the rate of 1.0 kg/ha on the background of seed treatment before sowing with the microbial preparation Optimize Pulse at the rate of 3.28 l/t, and without treatment is given. Spraying of vegetating plants with herbicide and their tank mixture with a plant growth regulator was carried out in the phase of 3-4 developed runners (BBCH 13–14) of the crop. Weed infestation of winter pea crops was counted on the thirtieth day after plant treatment with preparations. Weeds were counted by the quantitative weight method per 1 m2 according to the method of S. A. Tribel. Statistical processing of the data was carried out according to the generally accepted methods. It has been established that with the combined application of different rates of MaxiMox herbicide with plant growth regulator Agriflex Amino on the background of seed treatment before sowing with the microbial preparation Optimize Pulse, the technical efficiency of weed control increases, both in terms of quantity and weight. The greatest number and weight of destroyed weeds was noted in variants with the introduction of MaxiMox herbicide at the rates of 0.8; 0.9; 1.0 and 1.1 l/ha in combination with plant growth regulator Agriflex Amino at the rate of 1.0 kg/ha on the background of seed treatment with the microbial preparation Optimize Pulse at the rate of 3.28 l/t, where the percentage of destroyed weeds averaged 91–99 % quantitatively and 94–100 % in mass. The increase in the effectiveness of the studied preparations obviously occurred due to the improvement of biometric indices of winter pea plants under the direct action of the plant growth regulator and microbial preparation, which eventually increased the competitiveness of the crop to weeds.

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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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Predicting the competitive effects of weed and crop density on weed biomass, weed seed production and crop yield in wheat

Weed Research ◽

10.1111/j.1365-3180.1995.tb01789.x ◽

2006 ◽

Vol 35 (4) ◽

pp. 265-278 ◽

Cited By ~ 56

Author(s):

B. J. WILSON ◽

K. J. WRIGHT ◽

P. BRAIN ◽

M. CLEMENTS ◽

E. STEPHENS

Keyword(s):

Seed Production ◽

Crop Yield ◽

Weed Seed ◽

Weed Biomass ◽

Competitive Effects ◽

Crop Density

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Can hemp hurd or paper mulch and biochar application improve weed management in matted-row strawberry production systems?

Renewable Agriculture and Food Systems ◽

10.1017/s1742170521000533 ◽

2021 ◽

pp. 1-11

Author(s):

Greta G. Gramig ◽

Samantha K. Hogstad ◽

Patrick M. Carr

Keyword(s):

Weed Management ◽

Production Systems ◽

Weed Suppression ◽

Plastic Mulch ◽

Yield Data ◽

Weed Biomass ◽

Soil Temperatures ◽

The Impact ◽

Hemp Hurd ◽

Amended Soil

Abstract During 2015 and 2016, studies were conducted at Absaraka and Dickinson, North Dakota to evaluate the impacts of hemp (applied at 1156 m3 ha−1) and commercial paper mulch, as well as soil-applied biochar (applied at 11.25 m3 ha−1), on weed suppression and strawberry growth during the establishment year, and on weed suppression and strawberry yield during the production year, in a matted row production (MRP) system. During 2015, biochar influenced dry weed biomass only within the hemp mulch, with slightly more weed biomass associated with biochar application compared to zero biochar (3.1 vs 0.4 g m−2), suggesting that biochar may have increased weed germination and/or emergence from beneath hemp mulch. Biochar application also slightly increased soil pH, from 6.9 in non-amended soil to 7.0 in amended soil. Strawberry runner number during 2015 was greater in association with hemp or paper mulch compared to zero mulch (4.5 and 4.9 vs 2.4 runners plant −1, respectively). This result mirrored a similar differential in per berry mass across sites (7.6 and 7.4 vs 6.2 g berry −1 for hemp mulch, paper mulch and zero mulch, respectively). These results may be related to hemp and paper mulch reducing maximum soil temperatures during summer 2015. During the establishment year, both hemp and paper mulch suppressed weeds well compared to zero mulch, although at Absaraka hemp mulch provided slightly better weed suppression than paper mulch. During the production year, both mulches continued to suppress weeds compared to zero mulch at Dickinson. However, at Absaraka, only hemp mulch provided weed suppression compared to zero mulch, possibly because of faster paper degradation caused by greater numbers of large precipitation events and greater relative humidity at Absaraka compared to Dickinson. Weeds were removed from plots during 2015 to allow separation of weed suppression from other possible mulch impacts; therefore, yield data do not reveal striking differences among mulch treatments. Because previous research has demonstrated the impact of weed management during the establishment of strawberries in a matted row system, we concluded that hemp mulch may provide more durable weed suppression compared to paper mulch, which would increase strawberry yield protection in an MRP system. Material cost may be an issue for implementing hemp mulch, as hemp hurd cost was 25 times paper mulch at the application rates used in this study. However, hemp mulch could still be a beneficial option, especially for organic strawberry growers desiring a renewable and environmentally sound replacement for plastic mulch who are able to find affordable local sources of this material.

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