Using Reduced Tillage and Cover Crop Residue to Manage Weeds in Organic Vegetable Production

2017 ◽  
Vol 31 (4) ◽  
pp. 557-573 ◽  
Author(s):  
Guihua Chen ◽  
Lauren Kolb ◽  
Alan Leslie ◽  
Cerruti R. R. Hooks

Adoption of conservation tillage practices has been slow in organic vegetable production, partially due to producers’ concerns regarding weed management. Integrating cover crops into a conservation tillage program may provide organic producers a viable weed management option enabling growers to practice conservation tillage. A four-year study was conducted to evaluate the influence of different tillage methods (two conventional and two conservation practices) jointly with a mixed winter cover crop for weed suppression, time required for hand weeding, and crop yield in organically managed eggplant (2012 and 2014) and sweet corn (2013 and 2015) production systems. Tillage treatments were conventional tillage without surface mulch (CT-BG) and with black polyethylene (plastic) mulch (CT-BP), strip-tillage (ST), and no-tillage (NT) with cover crop residue. At 2 and 7 WAT/P (weeks after transplanting/planting), intra-row weed density was higher in CT-BG and ST, and inter-row weed density was higher in CT-BG and CT-BP treatments. Time required for hand-weeding was greatest in CT-BG and least in CT-BP and NT treatments. Eggplant yield was lowest in NT treatment in 2012 but similar among treatments in 2014. Sweet corn yield was similar among treatments in 2013 but highest in ST in 2015. Though both CT-BP and NT treatments showed greater potential for weed suppression, production input was highest in CT-BP but least in NT. Implications of these findings suggest that there is a potential to use strip tillage integrating with stale seedbed tactic for weed management in organic vegetables, which reduces herbicide use, hand-labor, and overall weed management cost while maintaining high yield potential.

HortScience ◽  
2005 ◽  
Vol 40 (3) ◽  
pp. 888d-888
Author(s):  
Warren Roberts ◽  
Jonathan Edelson ◽  
Benny Bruton ◽  
Jim Shrefler ◽  
Merritt Taylor

Plots were established at the Lane Agricultural Center in Lane, Okla., in 2003 for the purpose of conducting research in certified organic vegetable production. A field was selected that had been in pine timber since 1985. The field was cleared, plowed, disked, and land-planed. To establish a baseline for future reference, soil samples were collected on a 30 × 30 ft grid. Lime was added to adjust the pH. Poultry litter was added to the field as a fertilizer, and was incorporated by disking. Turnips were grown as a cover crop during the winter of 2003–04. In Spring 2004, the field was divided into four equal sections, which were planted with either tomatoes, sweet corn, watermelons, or southern peas. Tomatoes were planted using both determinate and indeterminate types. Plants were selected based on reported properties of interest to organic growers, such as disease resistance, pest resistance, or heat-set capabilities. The cultivars with greatest yield were Sunny, Solar Set, Classica, Sun Leaper, and Mountain Fresh. Visual disease ratings were taken throughout the season. Copper sulfate was used as a fungicide. The cultivars with the lowest disease ratings were Amelia, Peron, Celebrity, Florida 91, and Mountain Fresh. The major insect pest throughout the season was aphids. Aphid counts reached 6.9 aphids per leaf on 11 June. Two applications of AzaDirect, a neem extract, reduced aphid populations to 1.0 aphid per leaf on 17 June, 0.1 aphid per leaf on 25 June, and 0 aphids on 9 July.


HortScience ◽  
1997 ◽  
Vol 32 (3) ◽  
pp. 539F-540
Author(s):  
John Luna ◽  
Mary Staben ◽  
Tim O'Brien

Five on-farm trials were conducted in the Willamette Valley of western Oregon in 1996 to evaluate the potential for integrating winter-annual cover crops and rotary strip-tillage in vegetable productions systems. Two kinds of rotary strip tillers were used to till strips into killed winter cover crops or wheat stubble. Strip-tillage systems were compared to the “standard tillage” practices of the participating growers. In two sweet corn trials, yield of sweet corn was reduced ≈1 MT/ha in the strip-tillage treatments, compared to the standard tillage practices used by the growers. In these trials, the number of tillage operations was reduced by four to five passes with the strip-tillage system. In two other sweet corn trials, corn yield was reduced by ≈4.5 to 5.6 MT/ha in the strip-till treatments compared to the standard tillage treatments. In a transplanted broccoli trial, the strip-tillage and standard tillage treatments produced comparable yields. Possible factors reducing crop yield in the strip till systems include reduced soil temperature at planting and during early growth, soil moisture depletion in the undisturbed cover crop areas, soil compaction, nitrogen immobilization by the cover crop, weed competition, and possible glyphosate/microbiological interactions. Although an economic analysis of this project has not yet been completed, a rough estimate of tillage costs at $25/40 per pass per ha suggests that, in the field with only a 1 MT/ha yield reduction, the reduction in tillage costs would offset the yield reduction in corn (valued at about $88/MT). If yield reducing factors can be understood and a predictable, manageable system of strip-till vegetable production developed, there is a potential to dramatically reduce tillage costs and enhance soil quality through conservation of soil organic matter and biological diversity.


HortScience ◽  
2006 ◽  
Vol 41 (3) ◽  
pp. 505A-505
Author(s):  
Carlene A. Chase ◽  
Rosalie L. Koenig ◽  
Jeffery E. Pack ◽  
Clinton C. Warren

Weed management is a major constraint of organic vegetable production and perennial weeds such as purple nutsedge (Cyperus rotundus) are particularly difficult to control. A study was initiated in 2005 to determine how summer fallow techniques impact purple nutsedge population density, tuber number and tuber viability; and to evaluate the impact of the treatments on the yields of two fall crops differing in canopy size and rate of development. Clean fallow treatments accomplished with weekly tillage or weekly flaming were conducted for 12 weeks. Two sets of summer cover crop treatments of sunn hemp (Crotalaria juncea) were established by broadcasting 40 lb of seed per acre and were undercut at 13 weeks after seeding. Cover crop residue was either incorporated before transplanting or retained on the surface as mulch for the fall crops of lettuce and broccoli. Soil solarization was initiated on 2 July and the transparent solarization film was maintained in place until mid-October. A weedy fallow treatment was included as a control, which was tilled before establishing the fall crops. Before the initiation of the summer fallow treatments, no difference in viable tubers or nutsedge shoot density was observed. After fallow, flaming had the highest number of viable tubers, with all other treatments similar to the weedy control. Nutsedge shoot density was suppressed by all fallow treatments to lower levels than with the weedy control, but solarization was the least effective. Leaf-cutting insects eliminated the crops in the sunn hemp mulch treatment within days of being transplanted. Lettuce stands with all other treatments were similar and greater than with the weedy control. Highest broccoli stands were obtained with flaming, solarization, and tillage; but broccoli stand with incorporated sunn hemp was similar to the weedy control. Highest lettuce yields occurred with incorporated sunn hemp, solarization, and weekly tillage. However, lettuce yields with flaming and the weedy control did not differ statistically. Broccoli yields were greatest with flaming, solarization, and tillage. Broccoli development was delayed with the weedy control and incorporated sunn hemp treatments and no significant yield was obtained.


HortScience ◽  
2000 ◽  
Vol 35 (3) ◽  
pp. 440A-440 ◽  
Author(s):  
G.D. Hoyt ◽  
J.E. Walgenbach ◽  
P.B. Shoemaker

This experiment was designed to compare best management practices for conventional and conservation tillage systems, chemical IPM vs. organic vegetable production, and rotation effect on tomatoes. Three vegetables were grown under these management practices with sweet corn (1st year) and fall cabbage or cucumber (2nd year), and fall cabbage on half of the field plots and tomatoes on the other half. The treatments were: 1) conventional-tillage with chemical-based IPM; 2) conventional-tillage with organic-based IPM; 3) conservation-tillage with chemical-based IPM; 4) conservation-tillage with organic-based IPM; and 5) conventional-tillage with no fertilizer or pest management (control). This poster describes sweet corn, cabbage, and cucumber yields from the various treatments over two 3-year rotations. Sweet corn yields were 34% higher in treatments with chemical fertilizer and pest control than with organic methods. Ear worm damage was high (58%) in the organic treatment compared to the chemical IPM program (14%). Fall cabbage was planted after sweet corn and cucumber harvest (all treatments were reapplied). Marketable cabbage yields were in the order: conventional-tilled-organic > strip-tilled-chemical > conventional-tilled-chemical > strip-till-organic > control for both years. Percent culls (< .9 kg heads) were in reverse order of marketable heads. Cabbage insect control was similar in chemical IPM and organic management. Cucumber yields were in the order: conventional-tilled-chemical > conventional-tilled-organic = strip-till-chemical > strip-tilled-organic > control for both years. Insect damage on cucumber fruit was 51% for organic systems and 1% for chemical methods of production. No differences were seen between tillage system within the same production system (chemical vs organic).


2019 ◽  
Vol 34 (3) ◽  
pp. 383-393
Author(s):  
Erin R. Haramoto ◽  
Carolyn J. Lowry ◽  
Robert Pearce

AbstractWinter cover crops (CCs) provide soil conservation benefits for strip-tillage tobacco producers, but soil-residual herbicides may interfere with their establishment and growth. Tobacco is planted later than many agronomic crops, but growers often terminate CCs early to minimize CC residue at planting, and this may reduce weed suppression potential. We examined residual herbicide effects on CCs across two seasons and the potential for CC-based weed suppression within strip-tilled tobacco. Mixtures of wheat plus crimson clover and cereal rye plus crimson clover were examined, with a no-CC control. Herbicides included two rates of PRE sulfentrazone (177 or 354 g ai ha–1) plus carfentrazone (20 or 40 g ai ha–1); the higher rate was also followed by POST clomazone (840 g ai ha–1) or mixed with PRE pendimethalin (1,400 g ai ha–1). Controls with no weed management and hand weeding were also included. CC density and biomass were not reduced by weed management (WM) treatments with residual herbicides. However, CCs did not reduce density of annual grasses, small-seeded broadleaves, or perennials in the tilled in-row or untilled between-row zones. Cereal rye plus crimson clover resulted in lower weed biomass at tobacco harvest in the untilled between-row zone in 2017. WM effects were variable between the years, weed groups, and zones. Adding clomazone or pendimethalin was more consistent for reducing weed density and biomass compared to the low rate of sulfentrazone plus carfentrazone. Tobacco yield was unaffected by CCs in 2017 but lower in some WM treatments in 2018. In this study, tobacco herbicides did not interfere with wheat, cereal rye, or crimson clover establishment, but additional research should determine if these results apply to other environments and soil types. However, when these CC species were terminated 5 to 6 wk before transplanting, they did not consistently contribute to weed control.


HortScience ◽  
1999 ◽  
Vol 34 (3) ◽  
pp. 522A-522
Author(s):  
J.P. Mitchell ◽  
W.T. Lanini ◽  
S.R. Temple ◽  
E.V. Herrero ◽  
E.M. Miyao ◽  
...  

Conservation tillage (CT) row crop production is currently not widely adopted in California. Recently, however, interest in evaluating the potential of CT systems to reduce production costs and improve soil quality is growing in many areas in the state. In 1997 and 1998, we evaluated four cover crop mulches (rye/vetch, triticale/vetch, Sava medic, and Sephi medic) in a CT-transplanted tomato system relative to the conventional winter fallow (CF) practice. In both years, yields were comparable to the CF under the triticale/vetch and rye/vetch mulches. Earthworm populations after 2 years of CT production were increased 2- to 5-fold under mulches relative to the CF system. Soil carbon was increased by 16% and 6% after 2 years of CT production under the triticale/vetch and rye/vetch mulches, respectively. Weed suppression under the triticale/vetch and rye/vetch was comparable to the CF with herbicide system early in the season in both years but was maintained through harvest in only one season. Soil water storage (0-90 cm) was similar at the beginning of the tomato season in triticale/vetch, rye/vetch, and fallow plots but was higher under the mulches during much of the last 45 days of the 1998 season. Further refinement of CT practices in California's vegetable production regions is needed before wider adoption is likely.


2016 ◽  
Vol 32 (4) ◽  
pp. 349-357
Author(s):  
Eric Bietila ◽  
Erin M. Silva ◽  
Anne C. Pfeiffer ◽  
Jed B. Colquhoun

AbstractCover crop-based reduced tillage (CCBRT) has achieved positive impacts in organic row crop systems, contributing to the conservation of soil resources and the facilitation of weed management. This technique, which uses cover crop residues as mulches to suppress weeds, has shown more variable success in organic vegetable production systems. This experiment examined CCBRT for small-scale organic vegetable production in the upper Midwestern USA, specifically evaluating weed suppression, labor inputs and crop yields. Cereal rye (Secale cerealeL.) and winter wheat (Triticum aestivumL.) were fall-sown in 2012 and 2013 in a strip-plot design, including control treatments with no cover crop and spring-applied oat straw mulch. Cover crop plots were strip-tilled in mid-April to establish a planting zone, with cover crops terminated in late May at anthesis with a hand-tractor mounted sickle-bar mower. Bell peppers (Capsicum annuumL. var. ‘Revolution’), snap beans (Phaseolus vulgarisL. var. ‘Tavera’), and potatoes (Solanum tuberosumL. var. ‘Red La Soda’) were hand-planted either as transplants or seed in each treatment immediately following cover crop termination. During each summer growing season, weeds were completely eliminated from each plot by hand approximately every 10–14 days, with time for manual weeding recorded for each treatment. Vegetable crop yields and quality were measured at harvest during 2013 and 2014. Cereal rye and winter wheat produced similar biomass at the time of termination. Greater weed biomass was collected in the wheat treatment as compared with the cereal rye, increasing the in-season labor required for manual weeding. Bean yields were decreased in the all CCBRT treatments compared with control treatments in both years of the study. Pepper yields did not differ in CCBRT treatments as compared with the control in both 2012 and 2013, although the CCBRT treatments did yield lower marketable peppers compared with the straw mulch plots. Potato tuber yields were not different in the CCBRT treatments as compared with the control in 2012, but were lower in 2013. These data indicate that, if CCBRT is to be more widely adopted in small-scale vegetable production, further optimization of the system must be achieved to ensure consistent and adequate weed suppression while maintaining crop yield and quality.


2016 ◽  
Vol 5 (4) ◽  
pp. 46 ◽  
Author(s):  
Mona Ahmadiani ◽  
Chun Li ◽  
Yaqin Liu ◽  
Esendugue Greg Fonsah ◽  
Christine Bliss ◽  
...  

<p class="sar-body"><span lang="EN-US">There are little economic data concerning the profitability of organic vegetable crops in the Southern Coastal Plain, especially in reference to sod-based rotation and tillage alternatives.  A three-year experiment was conducted at the North Florida Research and Education Center-Quincy involving a crop rotation sequence of oats and rye (winter), bush beans (spring), soybean (summer) and broccoli (fall). Bush beans and broccoli were the cash crops. This paper presents analyses of the riskiness of organic production utilizing years in bahiagrass prior to initiating the crop rotation sequence and conventional tillage (CT) versus strip tillage (ST). Methods of “Risk-rated enterprise budget” and “Analyses of Variance-Covariance Matrix (ANOVA)” were utilized for determining relative profitability, and coefficient of variation was applied for measuring riskiness of each treatment. Three years of bahiagrass prior to initiating the crop rotation sequence, in combination with conventional tillage, had the highest profitability and ranked as the least risky scenario.  The second most profitable treatment was conventional tillage with four years of bahiagrass. Focusing on strip tillage, four years of bahiagrass with strip-tillage ranked third in term of profitability.</span></p>


Weed Science ◽  
2021 ◽  
pp. 1-26
Author(s):  
Roberto Botelho Ferraz Branco ◽  
Fernando de Carvalho ◽  
João Paulo de Oliveira ◽  
Pedro Luis da Costa Alves

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.


2018 ◽  
Vol 34 (5) ◽  
pp. 439-446 ◽  
Author(s):  
David Robb ◽  
Geoff Zehnder ◽  
Robin Kloot ◽  
William Bridges ◽  
Dara Park

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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