Genetic Approach to the Development of Cover Crops for Weed Management

Enriching agroecosystems with non-crop vegetation is a popular strategy for conservation biocontrol. In vineyards, the effects of specific seeded or planted cover crops on natural enemies are well-studied, whereas conserving spontaneously developing weeds received less attention. We compared parasitoid communities between matched pairs of vineyard plots in northern Israel, differing in weed management practices: “herbicide”, repeated herbicide applications vs. “ground cover”, maintaining resident weeds and trimming them when needed. Using suction sampling, we assessed the parasitoids’ abundance, richness, and composition during three grape-growing seasons. Ground cover plots had greater parasitoid abundances and cumulative species richness than herbicide-treated plots, possibly because of their higher vegetation cover and richness. Dominant parasitoid species varied in their magnitude and direction of response to weed management. Their responses seem to combine tracking of host distributions with attraction to additional vegetation-provided resources. Parasitoid community composition was mildly yet significantly influenced by weed management, while season, year, and habitat (weeds vs. vine) had stronger effects. Vineyard weeds thus support local biocontrol agents and provide additional previously demonstrated benefits (e.g., soil conservation, lower agrochemical exposure) but might also attract some crop pests. When the benefits outweigh this risk, weed conservation seems a promising step towards more sustainable agricultural management.

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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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Labile carbon and other soil quality indicators in two tillage systems during transition to organic agriculture

Renewable Agriculture and Food Systems ◽

10.1017/s1742170511000147 ◽

2011 ◽

Vol 26 (4) ◽

pp. 342-353 ◽

Cited By ~ 21

Author(s):

David Bruce Lewis ◽

Jason P. Kaye ◽

Randa Jabbour ◽

Mary E. Barbercheck

Keyword(s):

Soil Quality ◽

Cover Crops ◽

Organic Agriculture ◽

Weed Management ◽

Cover Crop ◽

Transition Period ◽

Interactive Effects ◽

Labile Carbon ◽

Initial Field ◽

Soil Attributes

AbstractWeed management is one of the primary challenges for producers transitioning from conventional to organic agriculture. Tillage and the use of cover crops are two weed control tactics available to farmers transitioning to organic management, but little is known about their interactive effects on soil quality during the transition period. We investigated the response of soils to tillage and initial cover crop during the 3-year transition to organic in a cover crop–soybean (Glycine max)–maize (Zea mays) rotation in the Mid-Atlantic region of the USA. The tillage treatment contrasted full, inversion tillage with moldboard plowing (FT) versus reduced tillage with chisel plowing (RT). The cover crop treatment contrasted annual versus mostly perennial species during the first year of the rotation. The experiment was initiated twice (Start 1 and Start 2), in consecutive years in adjacent fields. By the end of the experiment, labile carbon, electrical conductivity, pH and soil moisture were all greater under RT than under FT in both starts. Soil organic matter and several other soil attributes were greater under RT than under FT in Start 1, but not in Start 2, perhaps owing to differences between starts in initial field conditions and realized weather. Soil attributes did not differ between the two cover crop treatments. Combining our soils results with agronomic and economic analyses on these plots suggests that using RT during the organic transition can increase soil quality without compromising yield and profitability.

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Influence of Weed Management Practices and Crop Rotation on Glyphosate-Resistant Horseweed (Conyza canadensis) Population Dynamics and Crop Yield-Years III and IV

Weed Science ◽

10.1614/ws-09-006.1 ◽

2009 ◽

Vol 57 (4) ◽

pp. 417-426 ◽

Cited By ~ 40

Author(s):

Vince M. Davis ◽

Kevin D. Gibson ◽

Thomas T. Bauman ◽

Stephen C. Weller ◽

William G. Johnson

Keyword(s):

Population Dynamics ◽

Crop Rotation ◽

Crop Yield ◽

Cover Crops ◽

Weed Management ◽

Management Practices ◽

Plant Density ◽

Crop Yields ◽

Management Systems ◽

No Till

Horseweed is an increasingly common and problematic weed in no-till soybean production in the eastern cornbelt due to the frequent occurrence of biotypes resistant to glyphosate. The objective of this study was to determine the influence of crop rotation, winter wheat cover crops (WWCC), residual non-glyphosate herbicides, and preplant application timing on the population dynamics of glyphosate-resistant (GR) horseweed and crop yield. A field study was conducted from 2003 to 2007 in a no-till field located at a site that contained a moderate infestation of GR horseweed (approximately 1 plant m−2). The experiment was a split-plot design with crop rotation (soybean–corn or soybean–soybean) as main plots and management systems as subplots. Management systems were evaluated by quantifying in-field horseweed plant density, seedbank density, and crop yield. Horseweed densities were collected at the time of postemergence applications, 1 mo after postemergence (MAP) applications, and at the time of crop harvest or 4 MAP. Viable seedbank densities were also evaluated from soil samples collected in the fall following seed rain. Soybean–corn crop rotation reduced in-field and seedbank horseweed densities vs. continuous soybean in the third and fourth yr of this experiment. Preplant herbicides applied in the spring were more effective at reducing horseweed plant densities than when applied in the previous fall. Spring-applied, residual herbicide systems were the most effective at reducing season-long in-field horseweed densities and protecting crop yields since the growth habit of horseweed in this region is primarily as a summer annual. Management systems also influenced the GR and glyphosate-susceptible (GS) biotype population structure after 4 yr of management. The most dramatic shift was from the initial GR : GS ratio of 3 : 1 to a ratio of 1 : 6 after 4 yr of residual preplant herbicide use followed by non-glyphosate postemergence herbicides.

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Integration of cover crops and fertilizer rates for weed management in celery

Weed Science ◽

10.1614/ws-05-078r.1 ◽

2006 ◽

Vol 54 (02) ◽

pp. 326-334 ◽

Cited By ~ 9

Author(s):

Kevin S. Charles ◽

Mathieu Ngouajio ◽

Darryl D. Warncke ◽

Kenneth L. Poff ◽

Mary K. Hausbeck

Keyword(s):

Soil Fertility ◽

Cover Crops ◽

Weed Management ◽

Weed Suppression ◽

Fertility Level ◽

Hairy Vetch ◽

Bare Ground ◽

Weed Biomass ◽

Cereal Rye ◽

Oilseed Radish

Field studies were carried out in Laingsburg, MI, from 2002 to 2004 on Houghton muck soil to assess the impacts of cover crops and soil fertility regimes on weed populations and celery yield. The cover crops were oilseed radish, cereal rye, hairy vetch, and a bare ground control. The fertility rates were full (180, 90, and 450 kg ha−1nitrogen [N], phosphorus pentoxide [P2O5], and potassium oxide [K2O], respectively), half (90, 45, and 225 kg ha−1N, P2O5, and K2O, respectively), and low (90 kg ha−1N). Each cover crop treatment was combined with the low or half rate of fertilizer. An additional treatment with bare ground plus the full rate of fertilizer was added as standard practice. Treatments were maintained in the same location for the duration of the study. Major weed species were common chickweed, prostrate pigweed, shepherd's-purse, common purslane, and yellow nutsedge. Each year, oilseed radish consistently produced the greatest biomass and provided over 98% early season weed biomass suppression. Hairy vetch and cereal rye provided about 70% weed suppression in early spring. Soil fertility level affected weed populations during the 2004 growing season. In 2004, weed biomass in treatments without cover crops or with vetch increased when greater amounts of fertilizer were applied. Within individual fertility levels, higher celery yields were recorded in the oilseed radish plots. For example, in the low fertility rate, celery yield was 34.8, 29.2, 23.9, and 24.4 ton ha−1in the oilseed radish, cereal rye, hairy vetch, and control plots, respectively in 2003. Overall, the results of this experiment indicate that when included in a system where hoeing and hand-weeding are the only weed control methods, cover crops can successfully improve weed management and celery yield on muck soils, allowing reduced fertilizer inputs.

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Strategies to terminate summer cover crops for weed management in no-tillage vegetable production in southeast Brazil

Weed Science ◽

10.1017/wsc.2021.58 ◽

2021 ◽

pp. 1-26

Author(s):

Roberto Botelho Ferraz Branco ◽

Fernando de Carvalho ◽

João Paulo de Oliveira ◽

Pedro Luis da Costa Alves

Keyword(s):

Pearl Millet ◽

Cover Crops ◽

Weed Management ◽

Cover Crop ◽

Weed Suppression ◽

No Tillage ◽

Weed Biomass ◽

Jack Bean ◽

Organic Mulch ◽

Sunn Hemp

Abstract Cover crop residue left on the soil surface as organic mulch in no-tillage crop production provides several environmental benefits, including weed suppression. Thus, many farmers who use cover crops attempt to reduce the use of agricultural inputs, especially herbicides. Therefore, our objectives were to study the potential of different cover crop species to suppress weeds and produce an in situ organic mulch, and evaluate the effect of the organic mulch with and without spraying glyphosate on weed suppression for vegetable (tomato (Solanum lycopersicum L. and broccoli (Brassica oleracea L. var. botrytis) growth and yield. Five cover crop treatments (sunn hemp (Crotalaria juncea L.), jack bean [Canavalia ensiformis (L.) DC.], pearl millet [Pennisetum glaucum (L.) R. Br.], grain sorghum [Sorghum bicolor (L.) Moench ssp. bicolor] and a no-cover crop (control)) were used in the main plots; and spraying or no spraying glyphosate on the flattened cover crop in the sub plots of split-plot experimental design. Organic mulch from pearl millet, sorghum and sunn hemp resulted in lower weed biomass during the early season of both tomato and broccoli than jack bean and no-cover crop (control). Spraying glyphosate after roller crimping reduced weed biomass by 103 g m−2 and 20 g m−2 by 45 and 60 days after transplanting (DAT) of tomato, respectively and resulted in a better tomato yield compared to non spraying. Glyphosate reduced weed biomass by 110 g m−2 in the early season of broccoli (30 DAT), but did not affect yield. Terminating high biomass cover crops with a roller crimper is a promising technique for weed management in vegetable crops, which has the potential to reduce or even eliminate the need for herbicide.

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Cover crops and weed management.

Non-chemical weed management: principles, concepts and technology ◽

10.1079/9781845932909.0049 ◽

2009 ◽

pp. 49-64 ◽

Cited By ~ 39

Author(s):

J. R. Teasdale ◽

L. O. Brandsæter ◽

A. Calegari ◽

F. Skora Neto

Keyword(s):

Cover Crops ◽

Weed Management

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Weeds, nitrogen and yield: measuring the effectiveness of an organic cover cropped vegetable no-till system

Renewable Agriculture and Food Systems ◽

10.1017/s1742170517000795 ◽

2018 ◽

Vol 34 (5) ◽

pp. 439-446 ◽

Cited By ~ 1

Author(s):

David Robb ◽

Geoff Zehnder ◽

Robin Kloot ◽

William Bridges ◽

Dara Park

Keyword(s):

Cover Crops ◽

Weed Management ◽

Field Experiments ◽

Soil Health ◽

Soil Disturbance ◽

Weed Suppression ◽

Vegetable Production ◽

Soil N ◽

No Till ◽

Mechanical Methods

AbstractOrganic vegetable growers rely heavily on mechanical methods such as tillage and other forms of labor-intensive soil cultivation for weed management despite the negative effects to soil health associated with intensive soil disturbance. The use of cover crops and no-till (NT) vegetable production represents an alternative approach to weed control that can enhance rather than degrade soil health; however, there are challenges inherent with this practice and previous results in vegetable production have been mixed. Field experiments were conducted over 2 yr at the Clemson Student Organic Farm to examine the effects of tillage [NT versus conventional tillage (CT)] on weed development and management in organic tomato and summer squash production under different nitrogen (N) fertility regimes, and to assess soil N dynamics in both systems. Squash yields were similar between tillage treatments in both years. NT tomato yields were 43% greater than CT yields in 2014, whereas CT tomato yields were 46% greater than NT yields in 2015. Squash and tomato yields per unit of management labor (time) were significantly greater in NT compared with CT treatments for both years. There were no statistical differences in squash and tomato yields between N fertilization treatments in either year. Pre- and post-season soil N results were mixed. Pre-season soil N levels were significantly higher in NT tomato plots in 2014 but similar between tillage treatments in tomato plots in 2015 and in squash plots both years. Post-season soil N levels in tomato plots were similar between tillage treatments both years. Post-season soil N levels were significantly higher in NT squash plots in 2014 and in CT squash plots in 2015. Roller-crimped NT mulches provided adequate early-season weed suppression in both years and saved considerable weed management and seedbed preparation labor. Overall, the results demonstrated that organic NT is a viable method for reduced tillage summer vegetable production in the southeastern Piedmont region.

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Growth suppression of sandspur grass by cover crops1

Pesquisa Agropecuária Tropical ◽

10.1590/1983-40632015v4534680 ◽

2015 ◽

Vol 45 (3) ◽

pp. 319-325 ◽

Cited By ~ 1

Author(s):

Rodrigo Fonseca da Silva ◽

Leandro Pereira Pacheco ◽

Leandro dos Santos Soares ◽

Wéverson Lima Fonseca ◽

João Batista da Silva Oliveira ◽

...

Keyword(s):

Leaf Area ◽

Cover Crops ◽

Weed Management ◽

Pennisetum Glaucum ◽

Control Treatment ◽

Integrated Weed Management ◽

Fagopyrum Tataricum ◽

Root Volume ◽

Crambe Abyssinica ◽

Dry Biomass

ABSTRACTSandspur grass has hindered the integrated weed management in the Brazilian crop systems. This study aimed at evaluating the efficiency of biomass levels of different cover crops on the soil surface to control the sandspur grass. A complete randomized blocks design with four replications, in a 6 x 5 + 1 factorial arrangement, was used. The first factor consisted of six cover crops (Pennisetum glaucum-ADR 7010 and ADR 300 cultivars, Crotalaria ochroleuca, Urochloa ruziziensis, Fagopyrum tataricum and Crambe abyssinica) and the second one consisted of five biomass levels of each species (2 t ha-1, 4 t ha-1, 8 t ha-1, 12 t ha-1 and 16 t ha-1), plus a control treatment without soil cover. The variables analyzed were the total number of emerged plants, germination speed index, leaf area, root volume and shoot and root dry biomass. U. ruziziensis excelled in the suppression of C. echinatus growth by reducing the number of emerged plants, emergence speed index, shoot and root dry biomass, root volume and leaf area.

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