scholarly journals (420) Germination and Radicle Elongation Responses of Seven Vegetable Crops to Aqueous Extracts of Hairy Vetch (Vicia villosa) and Cowpea (Vigna unguiculata)

HortScience ◽  
2005 ◽  
Vol 40 (4) ◽  
pp. 1021D-1021
Author(s):  
Erin C. Hill ◽  
Mathieu Ngouajio

Hairy vetch (Vicia villosa Roth) (HV) and cowpea [Vigna unguiculata (L.) Walp.] (CP) are two leguminous cover crops used in vegetable production systems. The residues of both species have been shown to suppress weeds via allelopathic interactions; however, they may also carry a risk of crop injury. A laboratory experiment was designed to study the dose response of carrot, sweet corn, cucumber, lettuce, onion, pepper, and tomato germination and radicle elongation to the aqueous extracts of both HV and CP. Aqueous extracts of fresh, whole plants were lyophilized to obtain a dry powder. Treatments of 0.00, 0.25, 0.50, 1.00, 2.00, 4.00, and 8.00 g dry extract/L of distilled water were applied to 10 seeds on filter paper in petri dishes. The petri dishes were then sealed and placed in the dark at 21 °C for 4 to 7 days, depending on the species germination. After the incubation period, germination rates and radicle lengths were recorded. Each treatment had 4 replications and the full experiment was executed twice. Pepper germination was reduced by increasing concentrations of HV extract; however, all other crops were not affected by HV or CP extracts. The HV extract had a significant effect on radicle elongation in carrot, corn, cucumber, lettuce, onion, and tomato. Inhibition of radical growth at 8 g·L-1 ranged from 42% in cucumber to as high as 81% in carrot. The CP extract had a negative effect on the radicle elongation of carrot, corn, lettuce, and tomato. Inhibition at 8 g·L-1 ranged from 42% in carrot to 67% in tomato. This study shows that both HV and CP extracts hold the potential to negatively affect the listed crops. Therefore, studies need to be done on the persistence of these effects in the field to maximize weed control while avoiding crop injury.

HortScience ◽  
2006 ◽  
Vol 41 (3) ◽  
pp. 695-700 ◽  
Author(s):  
Erin C. Hill ◽  
Mathieu Ngouajio ◽  
Muraleedharan G. Nair

Laboratory experiments were conducted to study the effect of aqueous extracts of hairy vetch (Vicia villosa Roth) and cowpea (Vigna unguiculata (L.) Walp) cover crops on germination and radicle elongation in seven vegetable and six weed species. Lyophilized aqueous extracts of the cover crops were dissolved in reverse osmosis (RO) water to produce seven concentrations: 0.00, 0.25, 0.50, 1.00, 2.00, 4.00, and 8.00 g·L–1. Each treatment had 4 replications and the full experiment was repeated. Experiment 1 (E1) and Experiment (E2) were conducted under similar conditions. In general, seed germination was not affected by extracts of both cover crops. However, radicle growth of all species tested (except common milkweed exposed to cowpea extract) was affected by the cover crop residue extracts. Low concentrations of hairy vetch extract stimulated the radicle growth of carrot, pepper, barnyardgrass, common milkweed, and velvetleaf. Likewise, low concentrations of cowpea extract stimulated the growth of corn, barnyardgrass, and velvetleaf. At higher concentrations all species tested were negatively affected. The order of species sensitivity to the hairy vetch extract, as determined by the IC50 (concentration required to produce 50% radicle inhibition) values, was common chickweed > redroot pigweed> barnyardgrass E1 > carrot E1 > wild carrot > corn > carrot E2 > lettuce > common milkweed > tomato > onion > barnyardgrass E2 > velvetleaf > pepper > cucumber (most sensitive to least sensitive). For cowpea the order was common chickweed > redroot pigweed > corn > tomato > lettuce > wild carrot > pepper > carrot > cucumber > onion> barnyardgrass and velvetleaf. Results suggest that the susceptibility of weeds and vegetable crops to aqueous extracts of hairy vetch and cowpea is dependent on both species and extract concentration.


1996 ◽  
Vol 121 (3) ◽  
pp. 586-591 ◽  
Author(s):  
Vasey N. Mwaja ◽  
John B. Masiunas ◽  
Catherine E. Eastman

The effect of cover-crop management on growth and yield of `Bravo' cabbage (Brassica oleracea var. Capitata L.), `Market Pride' tomato (Lycopersicon esculentum Mill.), and `Mustang' snap bean (Phaseolus vulgaris L.) was determined. Each fall, `Wheeler' winter rye (Secale cereale L.) and `Oregon Crown' hairy vetch (Vicia villosa Roth) were interseeded. The following spring, the cover crops were killed by either applying glyphosate and mowing (CC-G) or mowing and disking (CC-D). Trifluralin was preplant incorporated into bare ground as a conventional tillage (CT) treatment. In 1992 and 1993, a chicken (Gallus gallus L.) based fertilizer was applied to half the subplots. The greatest snap bean and cabbage yields were in CT. The system with the greatest tomato yields varied. In 1991, the greatest tomato yields were in the CT treatment, while in 1992 yields were greatest in the CT and CC-D treatments, and in 1993 the greatest yields were in CT and CC-G. Cabbage yields were greater in the fertilized than the unfertilized treatments. In 1992, infestations of diamondback moth, imported cabbageworm, and cabbage looper were greater in CT than in the CC-G treatment. Three years of the CC-G treatment increased soil organic matter from 3.07% to 3.48% and increased soil pH from 6.30 to 6.51, while neither changed in the CT. Chemical names used: N-(phosphonomethyl) glycine (glyphosate); 2,6-dinitro-N,N-dipro`pyl-4-(trifluoromethyl) benzenamine (trifluralin).


1999 ◽  
Vol 9 (3) ◽  
pp. 373-379 ◽  
Author(s):  
Ronald D. Morse

Advantages of no-till (NT) production systems are acknowledged throughout the world. During the 1990s, production of NT vegetable crops has increased for both direct seeded and transplanted crops. Increased interest in reduced-tillage systems among research workers and vegetable growers is attributed to: 1) development and commercialization of NT transplanters and seeders, 2) advancements in the technology and practice of producing and managing high-residue cover crop mulches, and 3) improvements and acceptance of integrated weed management techniques. Results from research experiments and grower's fields over the years has shown that success with NT transplanted crops is highly dependent on achieving key production objectives, including: 1) production of dense, uniformly distributed cover crops; 2) skillful management of cover crops before transplanting, leaving a heavy, uniformly distributed killed mulch cover over the soil surface; 3) establishment of transplants into cover crops with minimum disturbance of surface residues and surface soil; and 4) adoption of year-round weed control strategies.


HortScience ◽  
1992 ◽  
Vol 27 (6) ◽  
pp. 664c-664 ◽  
Author(s):  
Nancy G. Creamer ◽  
Mark A. Bennett ◽  
Benjamin R. Stinner

Polyculture mixtures of several species of cover crops may be the best way to optimize some of the benefits associated with cover crop use. In the first year of a three year study, 16 polyculture mixtures of cover crops (4 species/mixture) were screened at seven sites throughout the state. Five of the mixtures were seeded at two planting dates. Fall evaluation of the cover crop mixtures included ease of establishment, vigor, percent groundcover, plant height, and relative biomass. The two mixtures with the highest percent groundcover were (1): sudex, rye, mammoth red clover, and subterranean clover (62% and 80% groundcover, one and two months after planting respectively), and, (2), annual alfalfa, hairy vetch, ryegrass, and rye (56% and 84% groundcover one and two months after planting respectively). The six mixtures with the highest percent groundcover did consistently well, relative to other mixtures, at all locations. Mixture (1) above also had the highest relative biomass throughout the state. Yellow and white sweet clovers, hairy vetch, winter oats, subterranean clover, red clover, rye and barley established well and maintained high vigor ratings throughout the fall. Ladino clover, timothy, and big flower vetch consistently had poor vigor ratings.


HortScience ◽  
1995 ◽  
Vol 30 (4) ◽  
pp. 806C-806
Author(s):  
Kathryn E. Brunson ◽  
Sharad C. Phatak ◽  
J. Danny Gay ◽  
Donald R. Sumner

Velvetbean (Mucuna deeringiana L.) has been used as part of the crop rotation in low-input vegetable production in southern Georgia to help suppress populations of root-knot nematode (Meloidogyne incognita) for the past 2 years. Over-wintering cover crops of crimson and subterranean clovers were used the low-input plots and rye was the plow-down cover crop in the conventional plots. Tomatoes, peppers, and eggplant were the vegetable crops grown in these production systems. Following the final harvest in 1992, use of nematicides in the low-input plots was discontinued and velvetbean was then planted into the low-input plots and disked in after 90 days. Results from the 1993–94 soil samples taken before and after velvetbean showed a continuing trend of reduced nematode numbers where velvetbean had been, while most conventional plots that had nematicides applied resulted in increases in nematode populations.


HortScience ◽  
2000 ◽  
Vol 35 (4) ◽  
pp. 600-603 ◽  
Author(s):  
Nancy G. Creamer ◽  
Keith R. Baldwin

Summer cover crops can produce biomass, contribute nitrogen to cropping systems, increase soil organic matter, and suppress weeds. Through fixation of atmospheric N2 and uptake of soil residual N, they also contribute to the N requirement of subsequent vegetable crops. Six legumes {cowpea (Vigna unguiculata L.), sesbania (Sesbania exaltata L.), soybean (Glycine max L.), hairy indigo (Indigofera hirsutum L.), velvetbean [Mucuna deeringiana (Bort.) Merr.], and lablab (Lablab purpureus L.)}; two nonlegume broadleaved species [buckwheat (Fagopyrum esculentum Moench) and sesame (Sesamum indicum L.)]; and five grasses {sorghum-sudangrass [Sorghum bicolor (L) Moench × S. sudanense (P) Stapf.], sudangrass [S. sudanense (P) Stapf.], Japanese millet [Echinochloa frumentacea (Roxb.) Link], pearl millet [Pennisetum glaucum (L). R. Br.], and German foxtail millet [Setaria italica (L.) Beauv.)]}, were planted in raised beds alone or in mixtures in 1995 at Plymouth, and in 1996 at Goldsboro, N.C. Biomass production for the legumes ranged from 1420 (velvetbean) to 4807 kg·ha-1 (sesbania). Low velvetbean biomass was attributed to poor germination in this study. Nitrogen in the aboveground biomass for the legumes ranged from 32 (velvetbean) to 97 kg·ha-1 (sesbania). All of the legumes except velvetbean were competitive with weeds. Lablab did not suppress weeds as well as did cover crops producing higher biomass. Aboveground biomass for grasses varied from 3918 (Japanese millet) to 8792 kg·ha-1 (sorghum-sudangrass). While N for the grasses ranged from 39 (Japanese millet) to 88 kg·ha-1 (sorghum-sudangrass), the C: N ratios were very high. Additional N would be needed for fall-planted vegetable crops to overcome immobilization of N. All of the grass cover crops reduced weeds as relative to the weedy control plot. Species that performed well together as a mixture at both sites included Japanese millet/soybean and sorghum-sudangrass/cowpea.


HortScience ◽  
2002 ◽  
Vol 37 (3) ◽  
pp. 490-495
Author(s):  
Clydette M. Alsup ◽  
Brian A. Kahn ◽  
Mark E. Payton

Hairy vetch (Vicia villosa Roth) cover crops were grown in a rotation with sweet corn (Zea mays var. rugosa Bonaf.) and muskmelon (Cucumis melo L. Reticulatus group) to evaluate the legume's ability to remove excess P from soils when poultry litter was used as a fertilizer. Fertilizer treatments were: 1) litter to meet each crop's recommended preplant N requirements (1×); 2) litter at twice the recommended rate (2×); and 3) urea at the 1× rate as the control. Following the vegetable crops, hairy vetch was planted on half of each replication, while the other half was fallowed. The vetch was removed from the field in a simulated haying operation in the spring. Soil samples were taken at 0-15 cm and 15-30 cm depths at the onset of the study and after each crop to monitor plant nutrient concentrations. The vetch sometimes raised soil test N concentrations at the 0-15 cm depth. Soil test P concentrations at the 0-15 cm sampling depth in the vetch system were consistently lower numerically, but not statistically, relative to comparable plots in the fallow system. Soil test P at the 0-15 cm depth was usually increased by litter at the 2× rate relative to the urea control, regardless of cropping system. Yields of both vegetable crops were similar among all cover crop and fertilizer treatments.


HortScience ◽  
1998 ◽  
Vol 33 (7) ◽  
pp. 1163-1166 ◽  
Author(s):  
John R. Teasdale ◽  
Aref A. Abdul-Baki

Hairy vetch (Vicia villosa Roth), crimson clover (Trifolium incarnatum L.), and rye (Secale cereale L.) and mixtures of rye with hairy vetch and/or crimson clover were compared for no-tillage production of staked, fresh-market tomatoes (Lycopersicon esculentum Mill.) on raised beds. All cover crops were evaluated both with or without a postemergence application of metribuzin for weed control. Biomass of cover crop mixtures were higher than that of the hairy vetch monocrop. Cover crop nitrogen content varied little among legume monocrops and all mixtures but was lower in the rye monocrop. The C:N ratio of legume monocrops and all mixtures was <30 but that of the rye monocrop was >50, suggesting that nitrogen immobilization probably occurred only in the rye monocrop. Marketable fruit yield was similar in the legume monocrops and all mixtures but was lower in the rye monocrop when weeds were controlled by metribuzin. When no herbicide was applied, cover crop mixtures reduced weed emergence and biomass compared to the legume monocrops. Despite weed suppression by cover crop mixtures, tomatoes grown in the mixtures without herbicide yielded lower than the corresponding treatments with herbicide in 2 of 3 years. Chemical name used: [4-amino-6-(1,1-dimethylethyl)-3-(methylthio)-1,2,4-triazin-5(4H)-one](metribuzin).


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