scholarly journals Phytotoxicity and Benzoxazinone Concentration in Field Grown Cereal Rye (Secale cerealeL.)

2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
C. La Hovary ◽  
D. A. Danehower ◽  
G. Ma ◽  
C. Reberg-Horton ◽  
J. D. Williamson ◽  
...  
Keyword(s):  
Indicator Species ◽  
Cover Crop ◽  
Weed Suppression ◽  
Winter Rye ◽  
Cereal Rye ◽  
Shoot Tissue ◽  
Effective Use ◽  
Phytotoxic Compound ◽  
Insight Into ◽  
Germination Bioassays

Winter rye (Secale cerealeL.) is used as a cover crop because of the weed suppression potential of its mulch. To gain insight into the more effective use of rye as a cover crop we assessed changes in benzoxazinone (BX) levels in rye shoot tissue over the growing season. Four rye varieties were planted in the fall and samples harvested at intervals the following spring. Two different measures of phytotoxic compound content were taken. Seed germination bioassays were used as an estimate of total phytotoxic potential. Dilutions of shoot extracts were tested using two indicator species to compare the relative toxicity of tissue. In addition, BX (DIBOA, DIBOA-glycoside, and BOA) levels were directly determined using gas chromatography. Results showed that rye tissue harvested in March was the most toxic to indicator species, with toxicity decreasing thereafter. Likewise the BX concentration in rye shoot tissue increased early in the season and then decreased over time. Thus, phytotoxicity measured by bioassay and BX levels measured by GC have a similar but not identical temporal profile. The observed decrease in phytotoxic potential and plant BX levels in rye later in the season appears to correlate with the transition from vegetative to reproductive growth.

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

2018 ◽  
Vol 35 (3) ◽  
pp. 227-233 ◽  
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.

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

Agronomy ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 319 ◽  
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.

Comparison of Conventional and Alternative Nursery Weed Management Strategies

1995 ◽  
Vol 9 (4) ◽  
pp. 761-767 ◽  
Author(s):  
James B. Calkins ◽  
Bert T. Swanson
Keyword(s):  
Weed Management ◽  
Cover Crop ◽  
Production Systems ◽  
Management Strategies ◽  
Life Cycles ◽  
Weed Suppression ◽  
Winter Rye ◽  
Field Management ◽  
Companion Crop ◽  
Herbicide Management

Soil cultivation (3 to 5 times/yr) and herbicide management (oxadiazon, 3.92 kg ai/ha), agricultural standards for reducing weed competition, were compared to three alternative nursery field management systems regarding weed suppression: ‘Norcen’ bird's-foot trefoil companion crop, ‘Wheeler’ winter rye cover crop/mulch, and grass sod (80% ‘Eton’ perennial ryegrass and 20% ‘Ruby’ red fescue). Field management treatment had a significant effect on observed weed populations. Weed densities were also subject to yearly variations caused by climate and endogenous weed life cycles. Herbicide management (oxadiazon) consistently provided the best control of undesired vegetation (0.3 weeds/m2) followed by the grass sod (0.7 weeds/m2), Wheeler rye cover crop/mulch (1.7 weeds/m2), Norcen bird's-foot trefoil companion crop (8.6 weeds/m2), and cultivated (55.7 weeds/m2) treatments, respectively. Although the grass sod treatment provided excellent control of undesired vegetation, as an alternative to cultivation and herbicide use, it proved to be excessively competitive with the nursery crop. The bird's-foot trefoil treatment quickly became infested with broadleaf weeds the eradication of which proved difficult. The Wheeler winter rye cover crop/mulch field management system provided acceptable weed control combined with other beneficial effects on the plant/soil environment. Results support the effectiveness of Wheeler winter rye and perhaps other allelopathic cover crop/mulch systems in controlling undesired vegetation in horticultural field production systems.

Drill and broadcast establishment methods influence interseeded cover crop performance in organic corn

2020 ◽  
pp. 1-9 ◽  
Author(s):  
John M. Wallace ◽  
Sarah Isbell ◽  
Ron Hoover ◽  
Mary Barbercheck ◽  
Jason Kaye ◽  
...  
Keyword(s):  
Cover Crops ◽  
Cover Crop ◽  
Weed Suppression ◽  
Organic Farms ◽  
N Retention ◽  
Cereal Rye ◽  
Post Harvest ◽  
Organic Systems ◽  
Winter Fallow ◽  
Corn Grain

Abstract Organic grain producers are interested in interseeding cover crops into corn (Zea mays L.) in regions that have a narrow growing season window for post-harvest establishment of cover crops. A field experiment was replicated across 2 years on three commercial organic farms in Pennsylvania to compare the effects of drill- and broadcast-interseeding to standard grower practices, which included post-harvest seeding cereal rye (Secale cereale L.) at the more southern location and winter fallow at the more northern locations. Drill- and broadcast-interseeding treatments occurred just after last cultivation and used a cover crop mixture of annual ryegrass [Lolium perenne L. ssp. multiflorum (Lam.) Husnot] + orchardgrass (Dactylis glomerata L.) + forage radish (Raphanus sativus L. ssp. longipinnatus). Higher mean fall cover crop biomass and forage radish abundance (% of total) was observed in drill-interseeding treatments compared with broadcast-interseeding. However, corn grain yield and weed suppression and N retention in late-fall and spring were similar among interseeding treatments, which suggests that broadcast-interseeding at last cultivation has the potential to produce similar production and conservation benefits at lower labor and equipment costs in organic systems. Post-harvest seeding cereal rye resulted in greater spring biomass production and N retention compared with interseeded cover crops at the southern location, whereas variable interseeding establishment success and dominance of winter-killed forage radish produced conditions that increased the likelihood of N loss at more northern locations. Additional research is needed to contrast conservation benefits and management tradeoffs between interseeding and post-harvest establishment methods.

Timing of Cover-Crop Management Effects on Weed Suppression in No-Till Planted Soybean using a Roller-Crimper

Weed Science ◽  
2011 ◽  
Vol 59 (3) ◽  
pp. 380-389 ◽  
Author(s):  
S. B. Mirsky ◽  
W. S. Curran ◽  
D. M. Mortenseny ◽  
M. R. Ryany ◽  
D. L. Shumway
Keyword(s):  
Weed Management ◽  
Cover Crop ◽  
Crop Management ◽  
Biomass Accumulation ◽  
Weed Suppression ◽  
Hairy Vetch ◽  
Cereal Rye ◽  
No Till ◽  
Termination Date ◽  
Crop Biomass

Integrated weed management tactics are necessary to develop cropping systems that enhance soil quality using conservation tillage and reduced herbicide or organic weed management. In this study, we varied planting and termination date of two cereal rye cultivars (‘Aroostook’ and ‘Wheeler’) and a rye/hairy vetch mixture to evaluate cover-crop biomass production and subsequent weed suppression in no-till planted soybean. Cover crops were killed with a burn-down herbicide and roller-crimper and the weed-suppressive effects of the remaining mulch were studied. Cover-crop biomass increased approximately 2,000 kg ha−1from latest to earliest fall planting dates (August 25–October 15) and for each 10-d incremental delay in spring termination date (May 1–June 1). Biomass accumulation for cereal rye was best estimated using a thermal-based model that separated the effects of fall and spring heat units. Cultivars differed in their total biomass accumulation; however, once established, their growth rates were similar, suggesting the difference was mainly due to the earlier emergence of Aroostook rye. The earlier emergence of Aroostook rye may have explained its greater weed suppression than Wheeler, whereas the rye/hairy vetch mixture was intermediate between the two rye cultivars. Delaying cover-crop termination reduced weed density, especially for early- and late-emerging summer annual weeds in 2006. Yellow nutsedge was not influenced by cover-crop type or the timing of cover-crop management. We found that the degree of synchrony between weed species emergence and accumulated cover-crop biomass played an important role in defining the extent of weed suppression.

scholarly journals Cover Crop Rotation Effects on Growth and Development, Seedling Disease, and Yield of Corn and Soybean

Plant Disease ◽  
2020 ◽  
Vol 104 (3) ◽  
pp. 677-687 ◽  
Author(s):  
Jyotsna Acharya ◽  
Thomas B. Moorman ◽  
Thomas C. Kaspar ◽  
Andrew W. Lenssen ◽  
Alison E. Robertson
Keyword(s):  
Cover Crops ◽  
Cover Crop ◽  
Growth And Development ◽  
Root Disease ◽  
Winter Rye ◽  
Negative Effects ◽  
Winter Cereal ◽  
Cereal Rye ◽  
Soybean Seedlings ◽  
Seedling Roots

The effects of winter cover crops on root disease and growth of corn and soybeans are poorly understood. A 3-year field experiment investigated the effect of winter cereal rye (Secale cereale L.) and winter camelina (Camelina sativa [L.] Crantz), used either in all three years or in rotation with each other, on corn (Zea mays L.) and soybean (Glycine max. [L.] Merr.) growth, root disease, and yield. Corn following a cover crop of camelina had reduced root disease, a lower Pythium population in seedling roots, and greater growth and yields compared with corn following a rye cover crop. Camelina and rye cover crops before soybean had either a positive or no effect on soybean growth and development, root disease, and yield. Moreover, Pythium clade B populations were greater in corn seedlings after a rye cover crop compared with those following a camelina cover crop, whereas clade F populations were greater on soybean seedlings following a camelina cover crop compared with seedlings following a rye cover crop. A winter camelina cover crop grown before corn had less-negative effects on corn seedling growth, root disease, and final yield than a winter rye cover crop before corn. Neither cover crop had negative effects on soybean, and the cover crop in the preceding spring had no measurable effects on either corn or soybean.

Winter Annual Weed Suppression in Rye–Vetch Cover Crop Mixtures

2012 ◽  
Vol 26 (4) ◽  
pp. 818-825 ◽  
Author(s):  
Zachary D. Hayden ◽  
Daniel C. Brainard ◽  
Ben Henshaw ◽  
Mathieu Ngouajio
Keyword(s):  
Cover Crops ◽  
Cover Crop ◽  
Field Experiments ◽  
Dry Weight ◽  
Weed Suppression ◽  
Weed Species ◽  
Cereal Rye ◽  
Winter Annual ◽  
Winter Annual Weeds ◽  
Annual Weeds

Winter annual weeds can interfere directly with crops and serve as alternative hosts for important pests, particularly in reduced tillage systems. Field experiments were conducted on loamy sand soils at two sites in Holt, MI, between 2008 and 2011 to evaluate the relative effects of cereal rye, hairy vetch, and rye–vetch mixture cover crops on the biomass and density of winter annual weed communities. All cover crop treatments significantly reduced total weed biomass compared with a no-cover-crop control, with suppression ranging from 71 to 91% for vetch to 95 to 98% for rye. In all trials, the density of nonmustard family broadleaf weeds was either not suppressed or suppressed equally by all cover crop treatments. In contrast, the density of mustard family weed species was suppressed more by rye and rye–vetch mixtures than by vetch. Cover crops were more consistently suppressive of weed dry weight per plant than of weed density, with rye-containing cover crops generally more suppressive than vetch. Overall, rye was most effective at suppressing winter annual weeds; however, rye–vetch mixtures can match the level of control achieved by rye, in addition to providing a potential source of fixed nitrogen for subsequent cash crops.

Weed Suppression in Cover Crop Monocultures and Mixtures

Weed Science ◽  
2017 ◽  
Vol 66 (1) ◽  
pp. 121-133 ◽  
Author(s):  
Barbara Baraibar ◽  
Mitchell C. Hunter ◽  
Meagan E. Schipanski ◽  
Abbe Hamilton ◽  
David A. Mortensen
Keyword(s):  
Ecosystem Services ◽  
Cover Crops ◽  
Cover Crop ◽  
Biomass Accumulation ◽  
Weed Suppression ◽  
Species Selection ◽  
Grass Species ◽  
Weed Seed ◽  
Crop Species ◽  
Cereal Rye

Interest in planting mixtures of cover crop species has grown in recent years as farmers seek to increase the breadth of ecosystem services cover crops provide. As part of a multidisciplinary project, we quantified the degree to which monocultures and mixtures of cover crops suppress weeds during the fall-to-spring cover crop growing period. Weed-suppressive cover crop stands can limit weed seed rain from summer- and winter-annual species, reducing weed population growth and ultimately weed pressure in future cash crop stands. We established monocultures and mixtures of two legumes (medium red clover and Austrian winter pea), two grasses (cereal rye and oats), and two brassicas (forage radish and canola) in a long fall growing window following winter wheat harvest and in a shorter window following silage corn harvest. In fall of the long window, grass cover crops and mixtures were the most weed suppressive, whereas legume cover crops were the least weed suppressive. All mixtures also effectively suppressed weeds. This was likely primarily due to the presence of fast-growing grass species, which were effective even when they were seeded at only 20% of their monoculture rate. In spring, weed biomass was low in all treatments due to winter kill of summer-annual weeds and low germination of winter annuals. In the short window following silage corn, biomass accumulation by cover crops and weeds in the fall was more than an order of magnitude lower than in the longer window. However, there was substantial weed seed production in the spring in all treatments not containing cereal rye (monoculture or mixture). Our results suggest that cover crop mixtures require only low seeding rates of aggressive grass species to provide weed suppression. This creates an opportunity for other species to deliver additional ecosystem services, though careful species selection may be required to maintain mixture diversity and avoid dominance of winter-hardy cover crop grasses in the spring.

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

Weed Science ◽  
2012 ◽  
Vol 60 (4) ◽  
pp. 624-633 ◽  
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.

scholarly journals Effects of Long-Term Cover Cropping on Weed Seedbanks

2020 ◽  
Vol 2 ◽  
Author(s):  
Virginia Nichols ◽  
Lydia English ◽  
Sarah Carlson ◽  
Stefan Gailans ◽  
Matt Liebman
Keyword(s):  
Cover Crops ◽  
Cover Crop ◽  
Production Systems ◽  
Early Spring ◽  
Weed Suppression ◽  
Winter Rye ◽  
Maize Crop ◽  
Cover Cropping ◽  
Crop Biomass

Cool-season cover crops have been shown to reduce soil erosion and nutrient discharge from maize (Zea mays L.) and soybean [Glycine max (L.) Merr.] production systems. However, their effects on long-term weed dynamics are not well-understood. We utilized five long-term research trials in Iowa to quantify germinable weed seedbank densities and compositions after 10+ years of cover cropping treatments. All five trials consisted of zero-tillage maize-soybean rotations managed with and without the inclusion of a yearly winter rye (Secale cereal L.) cover crop. Seedbank sampling was conducted in the early spring before crop planting at all locations, with three of the five trials having grown a soybean crop the preceding year, and two a maize crop. Two of the trials (both previously soybean) showed significant and biologically relevant decreases (4,070 and 927 seeds m−2, respectively) in seedbank densities in cover crop treatments compared to controls. In another two trials, one previously maize and one previously soybean, no difference was detected in seedbank densities. In the fifth trial (previously maize), there was a significant, but biologically unimportant increase of 349 seeds m−2. All five trials' weed communities were dominated by common waterhemp [Amaranthus tuberculatus (Moq.)], and changes in seedbank composition from cover-cropping were driven by changes in this species. Although previous studies have shown that increases in cover crop biomass are strongly correlated with weed suppression, in our study we did not find a relationship between seedbank changes and the mean amount of cover crop biomass produced over a 10-years period (experiment means ranging from 0.5 to 2.0 Mg ha−1 yr−1), the stability of the cover crop biomass production, nor the amount produced going into the previous crop's growing season. We conclude that long-term use of a winter rye cover crop in a maize-soybean system has the potential to meaningfully reduce the size of weed seedbanks compared to winter fallows. However, identifying the mechanisms by which this occurs requires further research into processes such as seed predation and seed decay in cover cropped systems.

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