Timing of Tillage as a Driver of Weed Communities

Tillage is a foundational management practice in many cropping systems. Although effective at reducing weed populations and preparing a crop seedbed, tillage and cultivation can also dramatically alter weed community composition. We examined the impact of soil tillage timing on weed community structure at four sites across the northeastern United States. Soil was tilled every 2 wk throughout the growing season (late April to late September 2013), and weed seedling density was quantified by species 6 wk after each tillage event. We used a randomized complete block design with four replicates for each tillage-timing treatment; a total of 196 plots were sampled. The timing of tillage was an important factor in shaping weed community composition and structure at all sites. We identified three main periods of tillage timing that resulted in similar communities. Across all sites, total weed density tended to be greatest and weed evenness tended to be lowest when soils were tilled early in the growing season. From the earliest to latest group of timings, total abundance decreased on average from 428±393 to 159±189 plants m−2, and evenness increased from 0.53±0.25 to 0.72±0.20. The effect of tillage timing on weed species richness varied by site. Our results show that tillage timing affects weed community structure, suggesting that farmers can manage weed communities and the potential for weed interference by adjusting the timing of their tillage and cropping practices.

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Glyphosate-Resistant Cropping Systems in Ontario: Multivariate and Nominal Trait-Based Weed Community Structure

Weed Science ◽

10.1614/ws-d-09-00089.1 ◽

2010 ◽

Vol 58 (3) ◽

pp. 278-288 ◽

Cited By ~ 14

Author(s):

Robert H. Gulden ◽

Peter H. Sikkema ◽

Allan S. Hamill ◽

François J. Tardif ◽

Clarence J. Swanton

Keyword(s):

Community Structure ◽

Field Experiments ◽

Seedling Recruitment ◽

Cropping Systems ◽

Short Interval ◽

Conventional Tillage ◽

Weed Species ◽

Weed Communities ◽

Late Initiation ◽

Continuous Application

Glyphosate-resistant (GR) cropping systems are popular and used extensively by producers. However, the long-term impacts of heavy reliance of this technology on weed community structure are not known. Five fully phased field experiments (two no-tillage and three conventional tillage) were established at four locations in southwestern Ontario where the effects of herbicide system (glyphosate or conventional) in corn and soybean and crop rotation (corn–soybean or corn–soybean–winter wheat) on midseason weed communities were examined. Multivariate analysis on data over the last 3 yr of the 6-yr experiment showed that weed communities were distinctly different among the treatments within each experiment. At several locations, midseason weed communities were more similar in corn and soybean treated with glyphosate compared to the same crops treated with conventional herbicides, reflecting the continuous application of the same selection pressure in both crops. Analysis of trait-densities revealed an increase in species with late initiation of seedling recruitment at the expense of weed species with medium time of initiation of seedling recruitment rather than early recruiting species. Increases in perennial species, species with a short interval between recruitment and anthesis, and wind-dispersed species were also observed. Trait-density–based analysis of the weed community was an effective method for reducing the complexity of divergent weed communities that enabled direct quantitative comparison of the herbicide-induced effects on these weed communities.

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The Effect of Different Soil Tillage Systems and Crop Residues on the Composition of Weed Communities

Agronomy ◽

10.3390/agronomy11071276 ◽

2021 ◽

Vol 11 (7) ◽

pp. 1276

Author(s):

Vaida Steponavičienė ◽

Aušra Marcinkevičienė ◽

Lina Marija Butkevičienė ◽

Lina Skinulienė ◽

Vaclovas Bogužas

Keyword(s):

Soil Ph ◽

Crop Residues ◽

Soil Tillage ◽

Reduced Tillage ◽

Plant Residues ◽

No Tillage ◽

Agricultural Crops ◽

Weed Species ◽

Tillage Systems ◽

Weed Communities

The composition of weed communities in agricultural crops is dependent on soil properties and the applied agronomic practices. The current study determined the effect of different tillage systems and crop residue on the soil weed community composition. The research programme encompassed 2013–2015 in a long-term field experiment located in the Experimental Station of Vytautas Magnus University in Lithuania. The soil type in the experimental field was qualified as Endocalcaric Stagnosol (Aric, Drainic, Ruptic, Amphisiltic). Weeds were categorised into communities according to soil pH, nitrogen and moisture indicators. The results of investigations were grouped using cluster analysis. Agricultural crops were dominated by different weed species depending on the soil pH and moisture. Weed species were relatively more frequent indicating nitrogen-rich and very nitrogen-rich soils. In the reduced tillage and no-tillage systems, an increase in the abundance of weed species indicating moderate acidity and low acidity, moderately wet and wet, nitrogen-rich and very nitrogen-rich soils was observed. The application of plant residues decreased the weed species abundance. In the reduced tillage and no-tillage systems, the quantitative distribution of weed was often uneven. By evaluating the association of weed communities with groups of different tillage systems with or without plant residues, their control can be optimised.

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Environmental factors including management practices as correlates of weed community composition in spring seeded crops

Canadian Journal of Botany ◽

10.1139/b92-240 ◽

1992 ◽

Vol 70 (10) ◽

pp. 1931-1939 ◽

Cited By ~ 58

Author(s):

M. R. T. Dale ◽

A. G. Thomas ◽

E. A. John

Keyword(s):

Community Composition ◽

Correspondence Analysis ◽

Canonical Correspondence Analysis ◽

Environmental Variables ◽

Management Practices ◽

Geographic Region ◽

Climatic Conditions ◽

Weed Species ◽

Weed Communities ◽

Seed Crops

The relationship between the weed communities and environmental variables such as soil, crop, and management was investigated in two provinces of Canada. The frequencies of weed species were recorded in cereal and oilseed fields in Saskatchewan (2244 fields over 4 years) and Manitoba (864 fields over 3 years), Canada. Information on some of the physical characteristics of the fields and on the management practices imposed on them was also collected, in part by questionnaire. The two kinds of data were ordinated together using canonical correspondence analysis to assess the relationships between the species and the environmental variables. In the Saskatchewan data, there was a clear and consistent separation of the species into groups along an axis correlated with soil zone and the associated climatic gradient. In the Manitoba data, the same groups of species did not separate as clearly or as consistently, although geographic region was a major determinant of the weed communities. The greater variability may be due to the fact that the gradient of soil types is much more restricted in Manitoba and not as closely correlated with climatic conditions. In both provinces, culture practices were less important as correlates of the weed community composition than soil type or, to a certain extent, the previous crop. Key words: canonical correspondence analysis, cereal crops, oil seed crops.

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The impact of stubble crop on spring barley weed infestation

Acta Agrobotanica ◽

10.5586/aa.1674 ◽

2016 ◽

Vol 69 (3) ◽

Author(s):

Eleonora Wrzesińska ◽

Anna Komorowska ◽

Grażyna Nurkiewicz

Keyword(s):

Cover Crop ◽

Spring Barley ◽

Block Design ◽

Control Treatment ◽

White Mustard ◽

Weed Species ◽

Fresh Matter ◽

Species Dominance ◽

Weed Infestation ◽

The Impact

The condition and degree of weed infestation were determined in a spring barely crop grown in a short-term monoculture after mulching the soil with plants grown as a stubble crop (the control treatment without cover crop – lacy phacelia, white mustard, sunflower). The field experiment was carried out in 2010–2013 on good rye soil complex using a split-block design in four replications. The obtained results (the mean from all years of the experiment) showed that the stubble crop, especially sunflower, reduced the diversity of weed species without causing at the same time changes in weed species dominance. In all the control treatments of the experiment, <em>Chenopodium album</em> and <em>Fallopia convolvulus</em> were the dominant species. The degree of spring barley weed infestation depended on the species grown in the cover crop. White mustard and lacy phacelia slightly increased the number of weeds but their fresh matter significantly increased. However, the sunflower cover crop significantly increased the number of weeds without any substantial differentiation of their fresh mass.

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Dry Matter Production, Nutrient Cycled and Removed, and Soil Fertility Changes in Yam-Based Cropping Systems with Herbaceous Legumes in the Guinea-Sudan Zone of Benin

Scientifica ◽

10.1155/2016/5212563 ◽

2016 ◽

Vol 2016 ◽

pp. 1-12

Author(s):

Raphiou Maliki ◽

Brice Sinsin ◽

Anne Floquet ◽

Denis Cornet ◽

Eric Malezieux ◽

...

Keyword(s):

Soil Fertility ◽

Dry Matter ◽

Cropping Systems ◽

Block Design ◽

Chemical Properties ◽

Mucuna Pruriens ◽

Total N ◽

Herbaceous Legumes ◽

Andropogon Gayanus ◽

The Impact

Traditional yam-based cropping systems (shifting cultivation, slash-and-burn, and short fallow) often result in deforestation and soil nutrient depletion. The objective of this study was to determine the impact of yam-based systems with herbaceous legumes on dry matter (DM) production (tubers, shoots), nutrients removed and recycled, and the soil fertility changes. We compared smallholders’ traditional systems (1-year fallow ofAndropogon gayanus-yam rotation, maize-yam rotation) with yam-based systems integrated herbaceous legumes (Aeschynomene histrix/maize intercropping-yam rotation,Mucuna pruriens/maize intercropping-yam rotation). The experiment was conducted during the 2002 and 2004 cropping seasons with 32 farmers, eight in each site. For each of them, a randomized complete block design with four treatments and four replicates was carried out using a partial nested model with five factors: Year, Replicate, Farmer, Site, and Treatment. Analysis of variance (ANOVA) using the general linear model (GLM) procedure was applied to the dry matter (DM) production (tubers, shoots), nutrient contribution to the systems, and soil properties at depths 0–10 and 10–20 cm. DM removed and recycled, total N, P, and K recycled or removed, and soil chemical properties (SOM, N, P, K, and pH water) were significantly improved on yam-based systems with legumes in comparison with traditional systems.

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Preservation of spatial and environmental gradients by death assemblages

Paleobiology ◽

10.1666/07081.1 ◽

2009 ◽

Vol 35 (1) ◽

pp. 119-145 ◽

Cited By ~ 37

Author(s):

Adam Tomašových ◽

Susan M. Kidwell

Keyword(s):

Community Structure ◽

Community Composition ◽

Environmental Gradients ◽

Compositional Variation ◽

Time Averaging ◽

Data Sets ◽

Square Root ◽

Spatial Gradients ◽

Death Assemblages ◽

The Impact

Although only a few studies have explicitly evaluated live-dead agreement of species and community responses to environmental and spatial gradients, paleoecological analyses implicitly assume that death assemblages capture these gradients accurately. We use nine data sets from modern, relatively undisturbed coastal study areas to evaluate how the response of living molluscan assemblages to environmental gradients (water depth and seafloor type; “environmental component” of a gradient) and geographic separation (“spatial component”) is captured by their death assemblages. We find that:1. Living assemblages vary in composition either in response to environmental gradients alone (consistent with a species-sorting model) or in response to a combination of environmental and spatial gradients (mass-effect model). None of the living assemblages support the neutral model (or the patch-dynamic model), in which variation in species abundance is related to the spatial configuration of stations alone. These findings also support assumptions that mollusk species consistently differ in responses to environmental gradients, and suggest that in the absence of postmortem bias, environmental gradients might be accurately captured by variation in species composition among death assemblages. Death assemblages do in fact respond uniquely to environmental gradients, and show a stronger response when abundances are square-root transformed to downplay the impact of numerically abundant species and increase the effect of rare species.2. Species' niche positions (position of maximum abundance) along bathymetric and sedimentary gradients in death assemblages show significantly positive rank correlations to species positions in living assemblages in seven of nine data sets (both square-root-transformed and presence-absence data).3. The proportion of compositional variation explained by environmental gradients in death assemblages is similar to that of counterpart living assemblages. Death assemblages thus show the same ability to capture environmental gradients as do living assemblages. In some instances compositional dissimilarities in death assemblages show higher rank correlation with spatial distances than with environmental gradients, but spatial structure in community composition is mainly driven by spatially structured environmental gradients.4. Death assemblages correctly identify the dominance of niche metacommunity models in mollusk communities, as revealed by counterpart living assemblages. This analysis of the environmental resolution of death assemblages thus supports fine-scale niche and paleoenvironmental analyses using molluscan fossil records. In spite of taphonomic processes and time-averaging effects that modify community composition, death assemblages largely capture the response of living communities to environmental gradients, partly because of redundancy in community structure that is inherently associated with multispecies assemblages. The molluscan data sets show some degree of redundancy as evidenced by the presence of at least two mutually exclusive subsets of species that replicate the community structure, and simple simulations show that between-sample relationships can be preserved and remain significant even when a large proportion of species is randomly removed from data sets.

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Weed Phytosociological and Floristic Survey in Agricultural Areas of Southwestern Goiás Region

Planta Daninha ◽

10.1590/s0100-83582016340100007 ◽

2016 ◽

Vol 34 (1) ◽

pp. 65-80 ◽

Cited By ~ 3

Author(s):

SANTOS W.F. ◽

PROCÓPIO S.O. ◽

SILVA A.G. ◽

FERNANDES M.F. ◽

BARROSO A.L.L.

Keyword(s):

Cropping Systems ◽

Floristic Composition ◽

Sampling Period ◽

Weed Species ◽

Floristic Survey ◽

Commelina Benghalensis ◽

Number Of Species ◽

West Region ◽

Weed Communities ◽

Agricultural Areas

The use of the Roundup Ready(r) technology and the cultivation of a second crop influence the floristic composition of weed communities in Brazilian Central-West region cropping systems. This study has aimed to diagnose the dominant weed species in southwestern Goiás in areas of genetically-modified and conventional soybeans, using phytosociological and floristic surveys. Weed sampling was obtained by collecting all the plants present within a 0.5 m hollow frame, randomly thrown 20 times in each of thirty-five agricultural areas in the 2012/2013 harvest. Field survey was carried out in three periods: before desiccation for soybean sowing, before postemergence herbicide in soybean first application and before postemergence herbicide application in late harvest. A total of 525 m2 was inventoried and 3,219 weeds were collected, which included 79 species, 58 genera and 28 families. Families Poaceae, Asteraceae, Euphorbiaceae, Fabaceae, Amaranthaceae, were the most representative in the survey. Species Cenchrus echinatus, Glycine max, Chamaesyce hirta, Commelina benghalensis, and Alternanthera tenella stood out in importance. The RR+millet soybean treatment had the highest number of species (44), while the conventional soybean + sorghum treatment had the lowest number of species (18). The highest number of species was recorded in first sampling period. Treatments conventional soybean + maize and conventional soybean + millet showed higher similarity (70%), while treatments RR soybean + millet and conventional soybean + sorghum showed the least (51%). Species of difficult control were recorded in all cultivation systems analyzed.

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ADUBAÇÃO NITROGENADA E USO DE REGULADOR DE CRESCIMENTO NA PRODUÇÃO DE TRIGO DE SEQUEIRO

Colloquium Agrariae ◽

10.5747/ca.2018.v14.n4.a243 ◽

2018 ◽

Vol 14 (4) ◽

pp. 01-09

Author(s):

Claudio Hideo Martins da Costa ◽

Jordana Rafaela Guimarães Vilela ◽

Ana Laura Silva de Sousa ◽

Rogério Borges de Oliveira Paz ◽

Bárbara Fátima Silva Moura

Keyword(s):

Nitrogen Fertilization ◽

Management Practice ◽

Cropping Systems ◽

Flag Leaf ◽

Block Design ◽

Climatic Conditions ◽

Randomized Block Design ◽

Increase In Productivity ◽

Nitrogen Rates ◽

Ear Number

Nitrogen fertilization is an important management practice in grasses and quite complex, due to the different factors that influence such as climatic conditions, cropping systems, rates and available sources. The objective of this work was to evaluate the different rates of side dressing nitrogen and the effect of the trinexapac-ethyl on wheat (Triticum aestivumL.).The experiment was a randomized block design in a 5x2 factorial scheme, with 4 replicates. The treatments were composed of five nitrogen rates applied in side dressing(0, 20, 40, 80 and 160 kg ha-1of N) and two rates ofetil-trinexapac (0 e 100 g ha-1do active ingredient)in the wheat crop.The following variables were evaluated: shoot dry matter, plant height, flag leaf height, ear insertion height, distance of source and drain, ear length, number of ears per square meter, number of spikelets per ear, fertility of spikelets, number of grains per ear, number of grains per spikelet, mass of one thousand grains, grain yield), hectoliter weight, and grain protein. The growth regulator changes the morphological components of wheat, but does not alter the productive components and yield of grains, not justifying their use under the conditions under which the study took place. Nitrogen fertilization does not alter the morphological components of wheat plants, but increases the number of ears per m2up to a rate of 52 kg ha-1of N, reflecting the increase in productivity up to the rate of 59 kg ha-1.

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Weed infestations in soybean grown in succession to cropping systems with sorghum and cover plants

Pesquisa Agropecuária Brasileira ◽

10.1590/s1678-3921.pab2020.v55.01640 ◽

2020 ◽

Vol 55 ◽

Author(s):

Joilson Sodré Filho ◽

Ricardo Carmona ◽

Robélio Leandro Marchão ◽

Arminda Moreira de Carvalho

Keyword(s):

Cover Crops ◽

Dry Matter ◽

Cropping Systems ◽

Block Design ◽

Weed Species ◽

Importance Value ◽

Randomized Complete Block Design ◽

Weed Diversity ◽

Weed Infestation ◽

Urochloa Brizantha

Abstract: The objective of this work was to evaluate the influence of sorghum and cover plant cropping systems before soybean cultivation on the occurrence of weeds during soybean growing in the Brazilian Cerrado. The experiment was carried out in a randomized complete block design, with four replicates. The treatments comprised six cropping systems before soybean: sorghum (Sorghum bicolor), palisade grass (Urochloa brizantha), and Congo grass (Urochloa ruziziensis) as cover plants, alone or intercropped, in addition to fallowing. Weeds were evaluated as to: density, dry matter mass, diversity, importance value, and similarity. The greatest similarity of weeds ocurred in single crops of sorghum, palisade grass, and Congo grass, in comparison with their intercroppings. Congo grass before soybean promoted a greater reduction in weed diversity overtime, when compared with palisade grass. The absence of cover crops before soybean cultivation increased weed infestation during the soybean cycle. The cropping systems with sorghum intercropped with cover crops before the soybean cultivation affect the diversity and the importance value of weed species.

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Factors Affecting Weed Seed Devitalization with the Harrington Seed Destructor

Weed Science ◽

10.1017/wsc.2017.23 ◽

2017 ◽

Vol 65 (5) ◽

pp. 650-658 ◽

Cited By ~ 8

Author(s):

Breanne D. Tidemann ◽

Linda M. Hall ◽

K. Neil Harker ◽

Hugh J. Beckie

Keyword(s):

Seed Size ◽

Cropping Systems ◽

Weed Seed ◽

Weed Species ◽

Factors Affecting ◽

Weed Seeds ◽

High Control ◽

Relationship Of ◽

The Impact ◽

Levels Of Control

The Harrington Seed Destructor (HSD), a novel weed control technology, has been highly effective in Australian cropping systems. To investigate its applicability to conditions in western Canada, stationary threshing was conducted to determine the impact of weed species, seed size, seed number, chaff load, and chaff type on efficacy of seed destruction. Control varied depending on species, with a range of 97.7% to 99.8%. Sieve-sized volunteer canola seed had a linear relationship of increasing control with increasing 1,000-seed weight. However, with greater than 98% control across all tested seed weights, it is unlikely that seed size alone will significantly influence control. Consistently high levels of control were observed at all tested seed densities (10 seeds to 1 million seeds). The response of weed seed control to chaff load was quadratic, but a narrow range of consistently high control (>97%) was again observed. Chaff type had a significant effect on weed seed control (98% to 98.6%); however, seed control values in canola chaff were likely confounded by a background presence of volunteer canola. Overall, the five parameters studied statistically influence control of weed seeds with the HSD. However, small differences between treatments are unlikely to affect the biological impact of the machine, which provides high levels of control for those weed seeds that can be introduced into the harvester.

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