Integrative Approaches for Weed Management in Organic Citrus Orchards

Lack of effective weed control may hamper organic citrus establishment. Cover crop/weed biomass (CCW) indices were used to assess the effectiveness of annual and perennial cover crops (CC) in reducing weed growth. The CCW values for perennial peanut (PP) were 0.06, 0.14, 0.4, and 0.5 during 2002, 2003, 2004, and 2005, respectively (very poor to poor weed control). Initial PP growth was slow and repeated mowing was required, but, over time, PP became more effective in controlling weeds. Weed biomass with sunn hemp was 0.3 Mg/ha in 2002 (CCW = 25, outstanding weed control) compared to 1.4 Mg/ha with use of cowpea (CCW = 1) in 2004. In 2004, the dry weights (Mg/ha) for different summer CC were: hairy indigo = 7.6, pigeon pea = 7.6, sunn hemp = 5.3, cowpea = 5.1, alyce clover = 2.9, velvet bean = 1.3, and lablab bean = 0.8. Corresponding 2005 values were: 9.5, 3.7, 12.6, 1.0, 1.9, and 1.4. Respective CCWI values were: 7, 4, 2, 16, 28, 0.6, and 0.3 (2004) vs. 17, 2, 64, 80, 0.5, 2, and 14. In 2004, winter CC production (Mg/ha) was radish (R) = 3.2, crimson clover (CR) = 1.7, oats (O) + lupine = 1.6, and rye (WR)/vetch (V) mix = 1.1. Results for 2005 were: CR + R + WR = 8.0, WR = 6.0; CR + WR = 5.3, CR = 5.0, CR + O + WR = 5.0, R = 4.3, and O = 3.6 Mg/ha. Corresponding values for CCW-indices were 15, 2, 1, and 3 (2004) and 100, 25, 76, 35, 62, 11, and 16 (2005). Although OMRI-approved herbicides showed up to 84% weed injury for selected species, none of these products provided long-term weed control. Combination of repeated tillage, use of compact/reseeding CC mixes in tree rows, more vigorous annual CC and/or perennial PP in row middle and repeated use of organic herbicides near sprinklers and tree trunks are thus required to ensure effective weed suppression in organic citrus.

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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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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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Potential of Rye (Secale cereale) for Weed Management in Transplant Tomatoes (Lycopersicon esculentum)

Weed Science ◽

10.1017/s0043174500094406 ◽

1996 ◽

Vol 44 (3) ◽

pp. 596-602 ◽

Cited By ~ 19

Author(s):

Reid J. Smeda ◽

Stephen C. Weller

Keyword(s):

Weed Control ◽

Cover Crops ◽

Weed Management ◽

Production Systems ◽

Weed Suppression ◽

Management Technique ◽

Bare Ground ◽

Tomato Production ◽

Tomato Yield ◽

Weed Growth

Weed control in tomato production systems is difficult because few are registered. The use of rye for weed control and its influence on transplant tomato yields was investigated during 1986 and 1987 at two locations in IN to determine if cover crops can provide an alternative weed management technique. ‘Wheeler’ rye was sown in the fall of 1985 and 1986, and mowed or desiccated with glyphosate at various times before planting ‘IND 812'tomatoes. At the time of glyphosate application, rye residues reduced the growth of overwintering weeds by 93% or more compared to bare ground (no cover crop) areas. The time of desiccating rye prior to planting tomatoes affected the extent of weed suppression by rye residues. In 1986, rye treated 4 wk before planting (WBP) tomatoes provided up to 89% suppression of weed growth at 2 wk after planting (WAP) tomatoes, but no measurable weed suppression 5 WAP tomatoes. Rye treated 2 WBP tomatoes provided up to 97% weed suppression up to 5 WAP tomatoes. In 1987, weed suppression varied between locations and differed from 1986. At Lafayette, rye treated 2 and 1 WBP tomatoes provided greater than 81% suppression of weed growth up to 8 WAP tomatoes. Rye mowed and the residues placed into a plot at a known density also reduced weed growth (60%) 8 WAP tomatoes. At Vincennes, however, rye treated 2 and 1 WBP in 1987 did not reduce weed growth later than 4 WAP tomatoes compared to the unweeded, bare ground treatment. The mowed rye residues at Vincennes suppressed weed growth (96%) up to 8 WAP tomatoes. Tomato yield was correlated to weed suppression. In 1986, tomato yield in the rye treated 2 WBP tomatoes was comparable to yield in the bare ground, weeded controls. However, tomato yield in rye plots treated 4 WBP tomatoes was similar to yield in the bare ground, unweeded control. In 1987, tomato yields in all rye plots (mowed, treated 2 and 1 WBP tomatoes) were similar to tomato yields in the bare ground, weeded control at Lafayette. At Vincennes, only the mowed rye treatment yielded comparably to the bare ground, weeded control. In general, rye plots that were weeded yielded similar to or up to 28% more than a bare ground, weeded control. Tomato yields were not reduced by rye residues. Tomato yields in rye residues that provided effective suppression of weed growth (greater than 80%) for a minimum of 4 to 5 WAP tomatoes were comparable to bare ground, weeded controls.

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Influence of Cover Crop and Herbicide Treatment on Weed Control and Yield in No-Till Sweet Corn (Zea maysL.) and Pumpkin (Cucurbita maximaDuch.)

Weed Technology ◽

10.1017/s0890037x00040069 ◽

1996 ◽

Vol 10 (2) ◽

pp. 341-346 ◽

Cited By ~ 20

Author(s):

Bethany A. Galloway ◽

Leslie A. Weston

Keyword(s):

Weed Control ◽

Cover Crops ◽

Cover Crop ◽

Sweet Corn ◽

Total Yield ◽

Weed Suppression ◽

Herbicide Application ◽

Weed Biomass ◽

Crimson Clover ◽

Herbicide Treatment

Sweet corn and pumpkin were planted no-tillage (NT) into cover crop residue treatments of vetch, rye, crimson clover, and ladino clover controlled with glyphosate, and a bare ground conventional tillage (CT) control. Objectives included evaluation of crop growth, yield, and weed suppression in NT versus CT treatments. Herbicide application was also investigated, with a plus and minus herbicide treatment (alachlor plus cyanazine for sweet corn, or ethalfluralin for pumpkin) as the main factor in the factorial experiment, and cover crops the subfactors. Weed control 4 wk after planting was dependent upon cover crop. The fewest weed numbers and least biomass were found in the ladino clover plots, but clover regrowth and subsequent competition with the cash crop were severe. Herbicides also affected weed biomass at 4 wk after vegetable planting, with least biomass in herbicide-treated plots. Neither cover crop nor herbicide treatment significantly affected weed weight by 8 wk after planting or pumpkin fruit weight at harvest. Pumpkin yield was not influenced by herbicide application. The vetch cover, although harboring greatest weed biomass, produced the greatest total yield (ear weight) in sweet corn. When averaged over cover crop, sweet corn yields were higher in herbicide-treated plots than in untreated ones. Both sweet corn and pumpkin maturity were generally delayed in the absence of herbicide treatments or in the presence of cover crop residues, especially clover and rye residues.

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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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REPRODUCTION OF Pratylenchus zeae AND P. brachyurus IN COVER CROPS

Revista Caatinga ◽

10.1590/1983-21252019v32n201rc ◽

2019 ◽

Vol 32 (2) ◽

pp. 295-301

Author(s):

SIMONE DE MELO SANTANA-GOMES ◽

CLAUDIA REGINA DIAS-ARIEIRA ◽

JÚLIO CÉSAR ANTUNES FERREIRA ◽

RAIANE PEREIRA SCHWENGBER ◽

SEPHORA SERRANO BALDISERA

Keyword(s):

Cover Crops ◽

Cajanus Cajan ◽

Host Plants ◽

Pigeon Pea ◽

Velvet Bean ◽

Final Population ◽

Sunn Hemp ◽

Rf Values ◽

Antagonistic Plants ◽

Pratylenchus Zeae

ABSTRACT This study aimed to evaluate the reproduction of Pratylenchus zeae and P. brachyurus in leguminous plants used as cover crops. Seedlings of sunn hemp (Crotalaria juncea and C. spectabilis), pigeon pea cultivar IPR 43 (Cajanus cajan), dwarf velvet bean (Mucuna deeringiana), black velvet bean (Stizolobium aterrimum), and jack bean (Canavalia ensiformis) were inoculated with each nematode separately. Maize cultivar IPR 114 and soybean cultivar Pintado were used as controls to measure the viability of the inoculation of P. zeae and P. brachyurus. After 90 days of inoculation, the plants were collected and nematode g-1 root, final population, and reproduction factors (RF) were evaluated. The experiment was carried out at two different times of the year. The nematode’s RF on cover crops from treatments with the two Crotalaria species, dwarf pigeon pea, and black velvet bean were lower than one (bad host plants) in both experiments for P. zeae. For P. brachyurus, the lowest RFs were obtained for C. juncea, C. spectabilis, and pigeon pea, while the other plants presented RF values close to or higher than one in at least one of the experiments. Therefore, C. spectabilis, C. juncea, and C. cajan cultivar IPR 43 are antagonistic plants that represent useful options for rotation or succession systems that aim to control P. zeae and P. brachyurus.

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Cover Crop Effectiveness Varies in Cover Crop-Based Rotational Tillage Organic Soybean Systems Depending on Species and Environment

Agronomy ◽

10.3390/agronomy9060319 ◽

2019 ◽

Vol 9 (6) ◽

pp. 319 ◽

Cited By ~ 2

Author(s):

Laura Vincent-Caboud ◽

Léa Vereecke ◽

Erin Silva ◽

Joséphine Peigné

Keyword(s):

Cover Crops ◽

Weed Management ◽

Cover Crop ◽

Crop Yields ◽

Weed Suppression ◽

Future Research ◽

Weed Biomass ◽

Cereal Rye ◽

Cereal Grain ◽

Crop Biomass

Organic farming relies heavily on tillage for weed management, however, intensive soil disturbance can have detrimental impacts on soil quality. Cover crop-based rotational tillage (CCBRT), a practice that reduces the need for tillage and cultivation through the creation of cover crop mulches, has emerged as an alternative weed management practice in organic cropping systems. In this study, CCBRT systems using cereal rye and triticale grain species are evaluated with organic soybean directly seeded into a rolled cover crop. Cover crop biomass, weed biomass, and soybean yields were evaluated to assess the effects of cereal rye and winter triticale cover crops on weed suppression and yields. From 2016 to 2018, trials were conducted at six locations in Wisconsin, USA, and Southern France. While cover crop biomass did not differ among the cereal grain species tested, the use of cereal rye as the cover crop resulted in higher soybean yields (2.7 t ha−1 vs. 2.2 t ha−1) and greater weed suppression, both at soybean emergence (231 vs. 577 kg ha−1 of weed biomass) and just prior to soybean harvest (1178 vs. 1545 kg ha−1). On four out of six sites, cover crop biomass was lower than the reported optimal (<8000 kg ha−1) needed to suppress weeds throughout soybean season. Environmental conditions, in tandem with agronomic decisions (e.g., seeding dates, cultivar, planters, etc.), influenced the ability of the cover crop to suppress weeds regardless of the species used. In a changing climate, future research should focus on establishing flexible decision support tools based on multi-tactic cover crop management to ensure more consistent results with respect to cover crop growth, weed suppression, and crop yields.

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Cereal cover crops for weed suppression in a summer fallow-wheat cropping sequence

Canadian Journal of Plant Science ◽

10.4141/p99-099 ◽

2000 ◽

Vol 80 (2) ◽

pp. 441-449 ◽

Cited By ~ 19

Author(s):

J. R. Moyer ◽

R. E. Blackshaw ◽

E. G. Smith ◽

S. M. McGinn

Keyword(s):

Winter Wheat ◽

Weed Control ◽

Cover Crops ◽

Soil Conservation ◽

Cover Crop ◽

Wheat Yield ◽

Weed Suppression ◽

Wheat Crop ◽

Weed Growth ◽

Summer Fallow

Cropping systems in western Canada that include summer fallow can leave the soil exposed to erosion and require frequent weed control treatments. Cover crops have been used for soil conservation and to suppress weed growth. Experiments were conducted under rain-fed conditions at Lethbridge, Alberta to determine the effect of short-term fall rye (Secale cereale L.), winter wheat (Triticum aestivum L.) and annual rye cover crops in the fallow year on weed growth and subsequent wheat yield. Under favorable weather conditions fall rye was as effective as post-harvest plus early spring tillage or herbicides in spring weed control. Winter wheat and fall rye residues, after growth was terminated in June, reduced weed biomass in September by 50% compared to no cover crop in 1993 but had little effect on weeds in 1995. Fall-seeded cover crops reduced the density of dandelion (Taraxacum officinale Weber in Wiggers) and Canada thistle [Cirsium arvense (L.) Scop.] but increased the density of downy brome (Bromus tectorum L.), wild buckwheat (Polygonum convolvulus L.), and thyme-leaved spurge (Euphorbia serpyllifolia Pers.) in the following fall or spring. Wheat yields after fall rye and no cover crop were similar but yields after spring-seeded annual rye were less than after no cover crop. Spring-seeded annual rye did not adequately compete with weeds. Cover crops, unlike the no cover crop treatment, always left sufficient plant residue to protect the soil from erosion until the following wheat crop was seeded. Key words: Allelopathies, fall rye, nitrogen, soil conservation, soil moisture, weed control, spring rye, winter wheat

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Row Width Affects Weed Management in Type II Black Bean

Weed Technology ◽

10.1614/wt-d-12-00150.1 ◽

2013 ◽

Vol 27 (3) ◽

pp. 538-546 ◽

Cited By ~ 4

Author(s):

Ryan C. Holmes ◽

Christy L. Sprague

Keyword(s):

Weed Control ◽

Weed Management ◽

Control Strategies ◽

Field Studies ◽

Weed Suppression ◽

Type Ii ◽

Weed Biomass ◽

Black Bean ◽

Crop Injury ◽

Row Width

Field studies were conducted in 2010 and 2011 at two locations in Michigan to examine the effect of row width and herbicide combination on weed suppression and yield in the new Type II black bean variety ‘Zorro.' Black bean was planted in 38- and 76-cm rows. Six weed control strategies were examined:S-metolachlor + halosulfuron (PRE),S-metolachlor (PRE) followed by (fb) bentazon + fomesafen (POST), halosulfuron (PRE) fb clethodim (+ fomesafen at one site in one year) (POST), imazamox + bentazon (POST), a weed-free control, and a nontreated control. Weed control and crop injury were evaluated throughout the growing season. In addition, weeds were counted by species in late July, and weed biomass was harvested and weighed at the end of the season. Black bean yield was obtained by direct harvest. Narrow rows reduced weed populations in two of the four site–year combinations (referred to hereafter as site–years), reduced weed biomass in three of the four site–years, and often improved control of upright broadleaf weeds. All herbicide combinations generally reduced weed populations and biomass, but control of specific weeds was variable. Crop injury was generally slight and transient. Yield was greater in narrow rows in two of the four site–years. All herbicide combinations increased yield compared with the nontreated control and resulted in similar yields to one another. Yield and weed suppression was often maximized in narrow rows, while herbicide performance varied by year and weed spectrum.

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Effects of Management Type and Timing on Weed Suppression in Soybean No-Till Planted into Rolled-Crimped Cereal Rye

Weed Science ◽

10.1614/ws-d-12-00024.1 ◽

2012 ◽

Vol 60 (4) ◽

pp. 624-633 ◽

Cited By ~ 25

Author(s):

Eric A. Nord ◽

Matthew R. Ryan ◽

William S. Curran ◽

David A. Mortensen ◽

Steven B. Mirsky

Keyword(s):

Weed Control ◽

Community Composition ◽

Weed Management ◽

Cover Crop ◽

Weed Suppression ◽

Planting Dates ◽

Weed Biomass ◽

Cereal Rye ◽

No Till ◽

Weed Emergence

Knowledge of weed emergence periodicity can inform the timing and choice of weed management tactics. We tested the effects of weed management system (conventional [CNV] and herbicide-free [HF]), timing of rye sowing (two dates), timing of soybean planting (5 planting dates, 3 in each system), and supplemental control (with and without) on weed suppression and weed community composition in soybean no-till planted into a cereal rye cover crop. Cereal rye was terminated with a roller-crimper and herbicide (CNV) or with a roller-crimper alone (HF), and supplemental weed control was achieved with a postemergence glyphosate application (CNV) or with interrow high-residue cultivation (HF). Supplemental control with glyphosate in CNV was more effective than high-residue cultivation in HF. When soybean was planted on the same date, CNV resulted in less weed biomass and a more even community composition, whereas HF resulted in greater weed biomass, dominated by common ragweed. When we controlled for cereal rye biomass and compared the effects of cereal rye sowing and termination timing within each system, earlier management reduced weed biomass in HF, but tended to increase weed biomass in CNV. Our results suggest the ability to control emerged weeds prior to soybean planting is an important factor that influences the optimal cereal rye cover crop management timing for weed suppression.

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