Role of Cover Crops and Planting Dates for Improved Weed Suppression and Nitrogen Recovery in No till Systems

AbstractCover crop mulches have been successful in reducing weed severity in organic soybeans. This study examined six rye cultivars (SRCs) used as cover crops to determine which were most adapted for use with a roller–crimper in the southeastern U.S. To be an effective mulch, a rye cultivar must produce high biomass and reach reproductive growth stage to facilitate mechanical termination via the roller–crimper prior to soybean planting. Rye cultivars were planted at three locations in North Carolina over the 2009 and 2010 growing seasons. Each rye cultivar was mechanically terminated via a roller–crimper implement. Rye cover crops were terminated on two dates and soybeans were immediately no-till planted into the mulch. In 2009, all rye cultivars produced greater than 9000 kg ha−1 rye biomass dry matter (DM) with the exception of Rymin at Plymouth (2009), but in 2010 only the early flowering cultivars produced in excess of 9000 kg ha−1 DM. There were no detectable soybean yield differences between the SRCs and the weed-free checks, and weed control was excellent across all SRCs at both Plymouth and Salisbury (2009). After an unseasonably cold and wet winter in 2010, the late flowering rye cultivars were not fully controlled by the early termination date due to delayed maturation (less than 65% control at 2 WAP) whereas the early flowering cultivars were fully controlled (100% control at 2 WAP). Rye biomass production was below 9000 kg ha−1 DM for the late flowering and dough development rye cultivars. The early-terminated rye plots had greater weed coverage across all SRCs than those from the late termination date (P < 0.01). However, weeds did not impact soybean yield for either of the termination dates. Soybean yield in 2010 was modeled with rye biomass and soybean population used as covariates, and for both termination dates, soybean yield was proportional to rye biomass production. Early flowering rye cultivars offer producers the widest range of termination opportunities that best coincide with their cash crop planting dates.

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Investigating tarps to facilitate organic no-till cabbage production with high-residue cover crops

Renewable Agriculture and Food Systems ◽

10.1017/s1742170518000509 ◽

2018 ◽

Vol 35 (3) ◽

pp. 227-233 ◽

Cited By ~ 1

Author(s):

Natalie P Lounsbury ◽

Nicholas D Warren ◽

Seamus D Wolfe ◽

Richard G Smith

Keyword(s):

Biological Activity ◽

Soil Temperature ◽

Biomass Production ◽

Nutrient Availability ◽

Cover Crops ◽

Cover Crop ◽

Weed Suppression ◽

Winter Rye ◽

No Till ◽

Crop Biomass

AbstractHigh-residue cover crops can facilitate organic no-till vegetable production when cover crop biomass production is sufficient to suppress weeds (>8000 kg ha−1), and cash crop growth is not limited by soil temperature, nutrient availability, or cover crop regrowth. In cool climates, however, both cover crop biomass production and soil temperature can be limiting for organic no-till. In addition, successful termination of cover crops can be a challenge, particularly when cover crops are grown as mixtures. We tested whether reusable plastic tarps, an increasingly popular tool for small-scale vegetable farmers, could be used to augment organic no-till cover crop termination and weed suppression. We no-till transplanted cabbage into a winter rye (Secale cereale L.)-hairy vetch (Vicia villosa Roth) cover crop mulch that was terminated with either a roller-crimper alone or a roller-crimper plus black or clear tarps. Tarps were applied for durations of 2, 4 and 5 weeks. Across tarp durations, black tarps increased the mean cabbage head weight by 58% compared with the no tarp treatment. This was likely due to a combination of improved weed suppression and nutrient availability. Although soil nutrients and biological activity were not directly measured, remaining cover crop mulch in the black tarp treatments was reduced by more than 1100 kg ha−1 when tarps were removed compared with clear and no tarp treatments. We interpret this as an indirect measurement of biological activity perhaps accelerated by lower daily soil temperature fluctuations and more constant volumetric water content under black tarps. The edges of both tarp types were held down, rather than buried, but moisture losses from the clear tarps were greater and this may have affected the efficacy of clear tarps. Plastic tarps effectively killed the vetch cover crop, whereas it readily regrew in the crimped but uncovered plots. However, emergence of large and smooth crabgrass (Digitaria spp.) appeared to be enhanced in the clear tarp treatment. Although this experiment was limited to a single site-year in New Hampshire, it shows that use of black tarps can overcome some of the obstacles to implementing cover crop-based no-till vegetable productions in northern climates.

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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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Evaluating Cover Crop Mulches for No-till Organic Production of Onions

HortScience ◽

10.21273/hortsci.45.1.61 ◽

2010 ◽

Vol 45 (1) ◽

pp. 61-70 ◽

Cited By ~ 11

Author(s):

Emily R. Vollmer ◽

Nancy Creamer ◽

Chris Reberg-Horton ◽

Greg Hoyt

Keyword(s):

Soybean Meal ◽

Cover Crops ◽

Cover Crop ◽

N Uptake ◽

Organic Production ◽

Weed Suppression ◽

Soil Mineral N ◽

Soil Mineral ◽

Mineral N ◽

No Till

Cover crops of foxtail millet ‘German Strain R’ [Setaria italica (L.) Beauv.] and cowpea ‘Iron & Clay’ [Vigna unguiculata (L.) Walp.] were grown as monocrops (MIL, COW) and mixtures and compared with a bare ground control (BG) for weed suppression and nitrogen (N) contribution when followed by organically managed no-till bulb onion (Allium cepa L.) production. Experiments in 2006–2007 and 2007–2008 were each conducted on first-year transitional land. Mixtures consisted of cowpea with high, middle, and low seeding rates of millet (MIX-70, MIX-50, MIX-30). During onion production, each cover crop treatment had three N rate subplots (0, 105, and 210 kg N/ha) of surface-applied soybean meal [Glycine max (L.) Merrill]. Cover crop treatments COW and BG had the greatest total marketable onion yield both years. Where supplemental baled millet was applied in 2006–2007, onion mortality was over 50% in MIL and MIX and was attributed to the thickness of the millet mulch. Nitrogen rates of 105 and 210 kg N/ha increased soil mineral N (NO3– and NH4+) on BG plots 2 weeks after surface application of soybean meal each year, but stopped having an effect on soil mineral N by February or March. Split applications of soybean meal could be an important improvement in N management to better meet increased demand for N uptake during bulb initiation and growth in the spring.

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Weed Control and Sweet Corn (Zea maysvar.rugosa) Response in a No-till System with Cover Crops

Weed Science ◽

10.1017/s0043174500094005 ◽

1996 ◽

Vol 44 (2) ◽

pp. 355-361 ◽

Cited By ~ 50

Author(s):

Nilda R. Burgos ◽

Ronald E. Talbert

Keyword(s):

Cover Crops ◽

Cover Crop ◽

Sweet Corn ◽

Weed Suppression ◽

Growth And Yield ◽

Hairy Vetch ◽

Yellow Nutsedge ◽

No Till ◽

Agricultural Experiment ◽

And Control

Studies were conducted at the Main Agricultural Experiment Station in Fayetteville and the Vegetable Substation in Kibler, Arkansas, in 1992 and 1993 on the same plots to evaluate weed suppression by winter cover crops alone or in combination with reduced herbicide rates in no-till sweet corn and to evaluate cover crop effects on growth and yield of sweet corn. Plots seeded to rye plus hairy vetch, rye, or wheat had at least 50% fewer early season weeds than hairy vetch alone or no cover crop. None of the cover crops reduced population of yellow nutsedge. Without herbicides, hairy vetch did not suppress weeds 8 wk after cover crop desiccation. Half rates of atrazine and metolachlor (1.1 + 1.1 kg ai ha−1) reduced total weed density more effectively in no cover crop than in hairy vetch. Half rates of atrazine and metolachlor controlled redroot pigweed, Palmer amaranth, and goosegrass regardless of cover crop. Full rates of atrazine and metolachlor (2.2 + 2.2 kg ai ha−1) were needed to control large crabgrass in hairy vetch. Control of yellow nutsedge in hairy vetch was marginal even with full herbicide rates. Yellow nutsedge population increased and control with herbicides declined the second year, particularly with half rates of atrazine and metolachlor. All cover crops except hairy vetch alone reduced emergence, height, and yield of sweet corn. Sweet corn yields from half rates of atrazine and metolachlor equalled the full rates regardless of cover crops.

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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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Integration of cover crops with postemergence herbicides in no-till corn and soybean

Weed Science ◽

10.1614/p2002-062 ◽

2003 ◽

Vol 51 (6) ◽

pp. 995-1001 ◽

Cited By ~ 16

Author(s):

Robert S. Gallagher ◽

John Cardina ◽

Mark Loux

Keyword(s):

Cover Crops ◽

Cover Crop ◽

Crop Productivity ◽

Weed Suppression ◽

Hairy Vetch ◽

Grain Yields ◽

No Till ◽

Full Rate ◽

Postemergence Herbicides ◽

Corn Grain

The integration of cover crops with selected postemergence herbicides was evaluated on the basis of weed control and grain yields in no-till soybean and corn. Soybean was planted into wheat residue, whereas corn was planted into hairy vetch residue. Full, half, and quarter rates and sequential herbicide applications were made. The wheat cover crop did not increase weed suppression but increased soybean grain yields. Half rates of thifensulfuron plus quizalofop-P as single or split applications were as effective as full rates in reducing weed weight in soybean. Soybean grain yields were similar in the half- and full-rate treatments in 1994, but yield was highest in the full-rate treatment in 1995. The hairy vetch cover crop did not increase weed suppression but lowered corn stands and grain yields in 1995 and enhanced corn grain yields in 1996. Full, half, and quarter rates (1996 only) of nicosulfuron plus primisulfuron were equally effective in reducing weed weight. Corn grain yields were similar at all herbicide rates in 1995 but were inversely related to herbicide rate in 1996. Split herbicide applications did not improve weed suppression over single applications of the same herbicide rate in either crop. Results indicate that cover crops can improve crop productivity and reduced rates of environmentally benign herbicides can minimize the herbicide requirements in no-till corn and soybean.

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Winter Wheat (Triticum aestivum L.) Tolerance to Mulch

Plants ◽

10.3390/plants10102047 ◽

2021 ◽

Vol 10 (10) ◽

pp. 2047

Author(s):

Matthew R. Ryan ◽

Sandra Wayman ◽

Christopher J. Pelzer ◽

Caitlin A. Peterson ◽

Uriel D. Menalled ◽

...

Keyword(s):

Triticum Aestivum ◽

Winter Wheat ◽

Grain Yield ◽

Cover Crops ◽

Seedling Emergence ◽

Triticum Aestivum L ◽

Weed Suppression ◽

Future Research ◽

Wheat Grain ◽

No Till

Mulch from cover crops can effectively suppress weeds in organic corn (Zea mays L.) and soybean (Glycine max L.) as part of cover crop-based rotational no-till systems, but little is known about the feasibility of using mulch to suppress weeds in organic winter small grain crops. A field experiment was conducted in central NY, USA, to quantify winter wheat (Triticum aestivum L.) seedling emergence, weed and crop biomass production, and wheat grain yield across a gradient of mulch biomass. Winter wheat seedling density showed an asymptotic relationship with mulch biomass, with no effect at low rates and a gradual decrease from moderate to high rates of mulch. Selective suppression of weed biomass but not wheat biomass was observed, and wheat grain yield was not reduced at the highest level of mulch (9000 kg ha−1). Results indicate that organic winter wheat can be no-till planted in systems that use mulch for weed suppression. Future research should explore wheat tolerance to mulch under different conditions, and the potential of no-till planting wheat directly into rolled-crimped cover crops.

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(14) Establishment of Buckwheat as a Summer Cover Crop after Early Vegetables

HortScience ◽

10.21273/hortsci.41.4.1063d ◽

2006 ◽

Vol 41 (4) ◽

pp. 1063D-1064

Author(s):

Thomas Björkman

Keyword(s):

Cover Crops ◽

Cover Crop ◽

Herbicide Tolerance ◽

Minimum Cost ◽

Soil Condition ◽

Weed Suppression ◽

Volunteer Management ◽

Weed Growth ◽

No Till ◽

Excellent Growth

Buckwheat has historically been used to suppress weeds and improve soil condition, but many of the tricks to success have been lost to history. Buckwheat is inexpensive and particularly effective in short windows between crops. We are documenting the techniques of existing experts and complementing that with research. We surveyed northeastern vegetable and strawberry growers to identify what information they need in order to feel confident that they could succeed with a buckwheat cover crop. Top questions include seed availability, types of weeds controlled, relation to other cover crops, volunteer management, and herbicide tolerance. One question tested experimentally was how to establish a full stand with minimum cost. We tested the minimum tillage requirement following pea harvest. No-till resulted in good emergence but slow growth, and dominance by weeds. Disk incorporating the pea residue resulted in excellent growth, which was not further enhanced by chisel plowing before disking. Buckwheat seedlings are intolerant of waterlogging, so deeper tillage may be important in wet years. Sowing buckwheat immediately after tillage resulted in emergence of 35%, leaving gaps large enough for weeds to grow. Waiting 1 week gave an 80% stand and complete weed suppression. Waiting 2 weeks also gave an 80% stand, but weed growth was advanced enough that weed suppression was incomplete. Therefore, a buckwheat cover crop following early vegetables requires light tillage to permit root growth, and up to a week of decomposition. If those provisions are made, complete weed suppression is obtainable.

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Weed Control by Spring Cover Crops and Imazethapyr in No-till Southern Pea (Vigna unguiculata)

Weed Technology ◽

10.1017/s0890037x00040987 ◽

1996 ◽

Vol 10 (4) ◽

pp. 893-899 ◽

Cited By ~ 16

Author(s):

Nilda R. Burgos ◽

Ronald E. Talbert

Keyword(s):

Weed Control ◽

Cover Crops ◽

Cover Crop ◽

Palmer Amaranth ◽

Weed Suppression ◽

Italian Ryegrass ◽

No Till ◽

Sorghum Sudangrass ◽

Reduced Rate ◽

Large Crabgrass

Studies were conducted at the Vegetable Substation in Kibler, AR, in 1992 and 1993, in the same plots, to evaluate weed suppression by spring-seeded cover crops and to determine the effects of cover crop and imazethapyr on no-till southern pea. A plot without cover, conventionally tilled before planting southern pea, served as control. Weed control treatments, applied as subplots in each cover crop, included a weedy check, handweeded check, and half and full rates of imazethapyr (0.035 and 0.07 kg/ha) followed by sethoxydim (0.22 kg/ha). Biomass of Palmer amaranth 6 WAR without herbicides, was less in Italian ryegrass and sorghum-sudangrass residues than in oat residue and no cover crop. Over the years, Palmer amaranth density increased 333% without cover crops and 28% with cover crops. Rice flatsedge density increased four to five times in oat and sorghum-sudangrass residues but remained the same in Italian ryegrass residue. In general, Italian ryegrass residue suppressed the most weeds. Oat residue was least suppressive. Italian ryegrass and sorghum-sudangrass also reduced southern pea stand. Regardless of cover crop and year, half and full rates of imazethapyr followed by sethoxydim equally reduced density of Palmer amaranth, goosegrass, large crabgrass, southwestern cupgrass, and rice flatsedge compared with the untreated check. Residual control of Palmer amaranth by imazethapyr was higher at the full rate than the reduced rate, regardless of cover crop. Half rate of imazethapyr followed by sethoxydim controlled 94 to 100% of Palmer amaranth, rice flatsedge, large crabgrass, and southwestern cupgrass late in the season, regardless of cover crop in 1992 and 1993. Southern pea yield in untilled plots with cover crops was two to three times lower than yield in plots with preplant tillage and no cover crops mostly because of reduction in crop stand in the presence of cover crops.

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