scholarly journals Increase in Populations of Rhizoctonia solani and Wirestem of Collard with Velvet Bean Cover Crop Mulch

Plant Disease ◽  
2003 ◽  
Vol 87 (6) ◽  
pp. 719-725 ◽  
Author(s):  
Anthony P. Keinath ◽  
Howard F. Harrison ◽  
Paul C. Marino ◽  
D. Michael Jackson ◽  
Thomas C. Pullaro

Velvet bean has been used traditionally as a summer cover crop in the southeastern United States. We investigated the use of killed velvet bean as a cover crop mulch left on the soil surface before collard was transplanted in the fall. Control treatments were weed-free fallow and velvet bean that was killed and disked into the soil before transplanting. Incidence of wirestem, caused by Rhizoctonia solani, reached a maximum of 25% in 2000 but only 4% in 2001 in cover crop mulch treatments. Nevertheless, in both years, the infection rate, area under the disease progress curve, and final incidence were significantly greater with cover crop mulch than in the fallow or disked treatments. Wirestem incidence did not differ between the disked and fallow treatments in either year. Populations of R. solani in soil were greater after cover crop mulch than in fallow plots in both years and greater in the disked treatment than in fallow soil in 2000 but not 2001. Velvet bean does not appear to be suitable as an organic mulch for fall collard production, but could be used as a summer cover crop if disked into the soil before transplanting collard.

2012 ◽  
Vol 104 (5) ◽  
pp. 1321-1335 ◽  
Author(s):  
Maheteme T. Gebremedhin ◽  
Henry W. Loescher ◽  
Teferi D. Tsegaye

2015 ◽  
Vol 29 (4) ◽  
pp. 861-867
Author(s):  
W. Carroll Johnson ◽  
Thomas R. Way ◽  
David G. Beale

Yellow and purple nutsedge are common in the southeastern United States, and both perennial species are difficult to control in organic crop-production systems. Tubers are generally confined to the upper portions of the soil profile and are vulnerable to desiccation when brought to the soil surface. A peanut digger is a common implement found in the coastal plain region of the southeastern United States and has shown promise controlling perennial nutsedges in fallow sites. The peanut digger undercuts perennial nutsedges, deposits weeds on the soil surface, and exposes weeds to desiccation. However, rainfall after tillage with the peanut digger allows displaced nutsedges to survive. As part of a senior-level class project, undergraduate mechanical engineering students from Auburn University designed and constructed a cart attached to a peanut digger that collected nutsedges. Key features included a custom hitch that allowed the correct plane of movement and a hydraulic conveyor system that discarded the perennial nutsedges off-site, away from the field. The prototype was tested in a fallow location in the summer of 2014 with a yellow nutsedge infestation averaging 148 plants m−2. One week after the initial field test, tillage using the peanut digger with specialized cart reduced yellow nutsedge densities in the tilled area by > 99%.


1999 ◽  
Vol 9 (3) ◽  
pp. 359-365 ◽  
Author(s):  
Warren Roberts ◽  
James Shrefler ◽  
James Duthie ◽  
Jonathan Edelson ◽  
Bob Cartwright ◽  
...  

We conducted several experiments to determine the best system for production of spring cabbage (Brassica oleracea L. Capitata group) with conservation tillage (CT) in the southern plains of the United States. Rye (Secale cereale L.) was selected as the best cover crop to cover the soil in a short time. Raised beds were formed in the fall and planted with rye. With most studies, the rye was allowed to remain on the soil surface rather than being tilled into the soil. Planting densities, rates of nitrogen fertilizer, and herbicide materials were evaluated to determine the best system for cabbage production. In each study, various cover crop practices were compared with bare soil production systems. Soil erosion was reduced by the use of rye cover crops. Cabbage was produced in the CT system, but cabbage yields were higher in bare soil plots than in the rye-covered plots. We are also in the process of developing a system of CT that involves permanent bermudagrass [Cynodon dactylon (L.) Pers.] pastures and watermelon [Citrullus lanatus (Thunb.) Matsum. & Nakai]. This system allows both crops to be grown simultaneously on the same land.


HortScience ◽  
2000 ◽  
Vol 35 (3) ◽  
pp. 442B-442 ◽  
Author(s):  
J.P. Mitchell ◽  
C. Summers ◽  
T.S. Prather ◽  
J. Stapleton ◽  
L.M. Roche

Observations that tomato transplants died or were severely stunted when set into unincorporated sorghum-sudan hybrid surface mulch led us to further investigate the potential allelopathic impacts of this warm-season cover crop in a series of field experiments. Survival and dry weights of tomato, lettuce, and broccoli transplants were determined in fallow, incorporated sorghum-sudan-, and unincorporated sorghum-sudan-mulched soils. All three species transplanted into plots in which the sorghum-sudan had been cut and left on the soil surface had a significantly lower dry weight than plants transplanted into fallow soil or into soil where the sorghum-sudan had been incorporated. Additionally, fewer transplants survived in the mulch treatment. The surface mulch plots also significantly reduced weed biomass nearly 10-fold. We believe that a water-soluble compound that is leached out of the sorghum-sudan hybrid is toxic to all three of the plants tested. Further laboratory and greenhouse tests are under way to determine the exact nature of the toxic substance.


Plant Disease ◽  
2012 ◽  
Vol 96 (7) ◽  
pp. 973-978 ◽  
Author(s):  
C. L. Rivard ◽  
S. O'Connell ◽  
M. M. Peet ◽  
R. M. Welker ◽  
F. J. Louws

Bacterial wilt, caused by Ralstonia solanacearum, can result in severe losses to tomato (Solanum lycopersicum) growers in the southeastern United States, and grafting with resistant rootstocks may be an effective strategy for managing this disease. However, R. solanacearum populations maintain considerable diversity, and little information is known regarding the efficacy of commercially available rootstocks to reduce bacterial wilt incidence and subsequent crop loss in the United States. In this study, tomato plants grafted onto ‘Dai Honmei’ and ‘RST-04-105-T’ rootstocks had significantly lower area under the disease progress curve (AUDPC) values compared with nongrafted plants (P < 0.05). Across three locations in North Carolina, final bacterial wilt incidence for non- and self-grafted plants was 82 ± 14 to 100%. In contrast, bacterial wilt incidence for the grafted plants was 0 to 65 ± 21%. Final bacterial wilt incidence of plants grafted with Dai Honmei rootstock was 0 and 13 ± 3% at two locations in western North Carolina but 50 ± 3% at a third site in eastern North Carolina. Similarly, grafting onto RST-04-105-T rootstock significantly reduced AUDPC values at two of the three locations (P < 0.05) compared with that of the nongrafted plants, but performed poorly at the third site. Total fruit yields were significantly increased by grafting onto resistant rootstocks at all three sites (P < 0.05). Regression analyses indicated that yield was significantly negatively correlated with bacterial wilt AUDPC values (R2 was 0.4048 to 0.8034), and the use of resistant rootstocks enabled economically viable tomato production in soils naturally infested with R. solanacearum.


1969 ◽  
Vol 90 (3-4) ◽  
pp. 215-220
Author(s):  
Nelson Semidey ◽  
Luisa E. Flores-López

Velvet bean [Mucuna deeringiana (Bort.) Meer.], pigeon pea [Cajanus cajan (L.) Huth], sorghum [Sorghum bicolor (L.) Moench.] and tropical pumpkin or calabaza [Cucurbita moschata (Duchesne) Poir.] were evaluated as cover crops for the control of nutsedges in rotation with onion (Allium cepa L.) at the Lajas Agricultural Experiment Station during the years 1998-99 and 1999-2000. In each year of study, the four cover crops were grown until mature stage, and plant residue was disked or removed from soil surface before onion planting. Cover crop species had no significant influence (P < 0.05) on nutsedge density, mainly represented by Cyperus rotundus L. and C. esculentus L., neither six weeks before onion planting nor after nine weeks of cropping during 1998-99. Disc incorporation of all cover crops suppressed nutsedge density more than removal of plant residues from soil surface. Onion produced greater yield (30,030 kg/ha) after calabaza rotation than after pigeon pea (21,090 kg/ha) or sorghum (18,940 kg/ha) in 1998-99. In 1999-2000, plots grown with velvet bean, pigeon pea and calabaza had less nutsedge than the untreated controls two weeks before incorporation of plant residues. Plots with these three cover crops also had lower density of nutsedges than plots with sorghum. Nutsedge density was not significant at three, six, and 10 weeks after onion planting. In 1999-2000, onion yields among cover crop rotations were not significantly different, with an average of 5,837 kg/ha. Cover crop allelopathy, as well as nutsedge interference, may have reduced onion production during the second year of planting. 


2019 ◽  
Author(s):  
Jorge Noguera

This study was conducted to determine the effectiveness of a novel mind perception manipulation. Mind perception is currently theorized to be an essential aspect of a number of human social psychological processes. Thus, a successful manipulation would allow for the causal study of those processes. This manipulation was created in an attempt to explore the downstream impact of mind perception on the endorsement of conspiracy theories. Conspiracy theories are steadily becoming more and more prominent in social discourse. Endorsement of conspiracy theories are beginning to show real world ramifications such as a danger to human health (e.g., in the anti-vaccination movement). A sample of college students (valid N = 53) from a large rural institution in the southeastern United States participated for course credit. These participants completed a mind perception pretest, were randomly assigned to either the manipulation in question (in which participants are asked to consider the ‘mind’ of several targets and write their thoughts about them) or the control condition, and then they completed a posttest. The mixed ANOVA revealed that the interaction term between Time and Condition was not significant. Because the manipulation did not work, other analyses were aborted, in accord with the pre-registration. My Discussion focuses on the procedures and potential shortcomings of this manipulation, in an effort to lay the groundwork for a successful one.


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