A 2-Year Small Grain Interval Reduces Need for Herbicides in No-Till Soybean

2009 ◽  
Vol 23 (3) ◽  
pp. 398-403 ◽  
Author(s):  
Randy L. Anderson

This study measured weed interference in soybean and corn as affected by residue management tactics following a sequence of oat and winter wheat. Residue management tactics compared were conventional tillage, no-till, and no-till plus cover crops. Treatments were split into weed-free and weed-infested conditions; prominent weeds were green and yellow foxtail and common lambsquarters. Grain yield of soybean did not differ between weed-free and weed-infested conditions with no-till, whereas weeds reduced yield 25% in the tilled system. Corn responded inconsistently to treatments, with more than 40% yield loss due to weed interference in 1 yr with all treatments. Cover crops did not improve weed management compared with no-till in either crop. Seedling emergence of the weed community differed between tillage and no-till; density of weed seedlings was fivefold higher with tillage, whereas seedling emergence was delayed in no-till. The initial flush of seedlings occurred 2 to 3 wk later in no-till compared with the tilled system. Designing rotations to include cool-season crops in a no-till system may eliminate the need for herbicides in soybean to manage weeds.

2014 ◽  
Vol 30 (4) ◽  
pp. 392-398 ◽  
Author(s):  
Randy L. Anderson

AbstractOrganic producers are seeking alternative tactics for weed control, so that they can reduce their need for tillage. In this study, we examined cultural strategies for controlling weeds during the transition from a cool-season crop to soybean. The study was arranged as a two-way factorial, with factors being choice of cool-season crop and tillage treatments. The cool-season crops were either spring wheat harvested for grain or an oat–pea mixture harvested for forage. Five tillage treatments, ranging from intensive tillage to no-till, were established following each cool-season crop. Two tillage treatments included the cover crops, oat plus oilseed radish. Soybean was planted the following growing season. Each soybean plot was split into two subplots: weed-free and weed-infested. A cultural system comprising oat/pea as a preceding crop with no-till and cover crops reduced weed biomass in soybean 63% compared to intensive tillage. Reduced weed biomass resulted because of delayed weed emergence and lower weed community density. Consequently, soybean yielded 14% more in this treatment than with the intensive tillage treatment when weeds were present. Weed community composition also differed between the two systems; horseweed and field dandelion were prominent in no-till, whereas common lambsquarters, redroot pigweed and buffalobur were prevalent in the tillage control. Other treatments did not control weeds better than intensive tillage. A cultural system approach may minimize the need for tillage during the interval between cool-season crops and soybean.


Weed Science ◽  
2010 ◽  
Vol 58 (3) ◽  
pp. 300-309 ◽  
Author(s):  
Adam S. Davis

Termination of cover crops prior to no-till planting of soybean is typically accomplished with burndown herbicides. Recent advances in cover-crop roller–crimper design offer the possibility of reliable physical termination of cover crops without tillage. A field study within a no-till soybean production system was conducted in Urbana, IL, from 2004 through 2007 to quantify the effects of cover crop (cereal rye, hairy vetch, or bare soil control), termination method (chemical burndown or roller–crimper), and postemergence glyphosate application rate (0, 1.1, or 2.2 kg ae ha−1) on soybean yield components, weed–crop interference, and soil environmental variables. Biomass of weeds surviving management within a soybean crop following either a vetch or rye cover crop was reduced by 26 and 56%, respectively, in the rolled system compared to the burndown system. Soybean yield loss due to weed interference was unaffected by cover-crop termination method in soybean following a rye cover crop, but was higher in the rolled than burndown treatment in both hairy vetch and bare soil treatments. In soybean following a rye cover crop, regardless of termination method, yield loss to weed interference was unaffected by glyphosate rate, whereas in soybean following a vetch cover crop or bare soil, yield loss decreased with glyphosate rate. Variation in soybean yield among cover crops and cover-crop termination treatments was due largely to differences in soybean establishment, rather than differences in the soil environment. Use of a roller–crimper to terminate a cover crop preceding no-till soybean has the potential to achieve similar yields to those obtained in a chemically terminated cover crop while reducing residual weed biomass.


2006 ◽  
Vol 21 (2) ◽  
pp. 124-133 ◽  
Author(s):  
Krishna P. Paudel ◽  
Luanne Lohr ◽  
Miguel Cabrera

Cotton production is the number one crop enterprise in Georgia in terms of revenue generation. However, due to continuous deterioration of soil quality with conventional tillage and chemical fertilizer application, the economic viability and sustainability of cotton production in Georgia are questionable. Residue management systems (RMSs) comprising winter cover crops were analyzed as an alternative to the existing system, which consists of conventional tillage and chemical fertilizer using yield benefit, net revenue, carbon sequestration, and yield efficiency criteria. Four different RMSs were examined for profitability and input efficiency. Four RMSs encompassing tillage versus no-till and chemical versus organic sources of plant nutrients were compared for their yield and net return differences. No-till and poultry litter with a cover crop was the only system with a positive return and crop yield based on the results from experimental data. Limited results from the experimental field were reinforced using a simulation study. When cotton yield is simulated with an alternative level of organic matter and nitrogen application, production function shows efficiency in input application at the higher level of organic matter. Regression results based on an erosion productivity impact calculator/environmental policy integrated climate (EPIC) simulation indicated that, in the long term, a no-till and poultry litter system may have promise in the region. The results from simulation confirm the results from the experimental study. This study reflected a need to change the cotton management system from the 200-year-old practice of employing intensively cultivated conventional tillage and chemical fertilizers to a new renewable resource-based system where residue management and organic sources of nutrients would be the key components.


2008 ◽  
Vol 22 (4) ◽  
pp. 736-740 ◽  
Author(s):  
Randy L. Anderson

This study measured impact of cool-season crops on seedling emergence, survival, and seed production of weeds common in corn and soybean. Weed dynamics were monitored in permanently marked quadrats in winter wheat, spring wheat, and canola. Three species, green foxtail, yellow foxtail, and common lambsquarters, comprised more than 80% of the weeds observed in the study. Seedling emergence was reduced by winter wheat, but not by spring wheat or canola, when compared with adjacent quadrats without a crop canopy. Approximately 10% of seedlings in spring wheat and canola developed into seed-bearing plants, but no seed-bearing plants were present in winter wheat at harvest. Common lambsquarters produced more than 1,100 seeds/plant, whereas a foxtail plant produced 85 seeds, averaged across spring wheat and canola. At harvest, new seedlings were present in all crops; thus, control after harvest will be required to prevent seed production in the fall. Winter wheat may provide an opportunity to disrupt population dynamics of weeds common in corn and soybean without requiring herbicides.


Weed Science ◽  
2009 ◽  
Vol 57 (4) ◽  
pp. 417-426 ◽  
Author(s):  
Vince M. Davis ◽  
Kevin D. Gibson ◽  
Thomas T. Bauman ◽  
Stephen C. Weller ◽  
William G. Johnson

Horseweed is an increasingly common and problematic weed in no-till soybean production in the eastern cornbelt due to the frequent occurrence of biotypes resistant to glyphosate. The objective of this study was to determine the influence of crop rotation, winter wheat cover crops (WWCC), residual non-glyphosate herbicides, and preplant application timing on the population dynamics of glyphosate-resistant (GR) horseweed and crop yield. A field study was conducted from 2003 to 2007 in a no-till field located at a site that contained a moderate infestation of GR horseweed (approximately 1 plant m−2). The experiment was a split-plot design with crop rotation (soybean–corn or soybean–soybean) as main plots and management systems as subplots. Management systems were evaluated by quantifying in-field horseweed plant density, seedbank density, and crop yield. Horseweed densities were collected at the time of postemergence applications, 1 mo after postemergence (MAP) applications, and at the time of crop harvest or 4 MAP. Viable seedbank densities were also evaluated from soil samples collected in the fall following seed rain. Soybean–corn crop rotation reduced in-field and seedbank horseweed densities vs. continuous soybean in the third and fourth yr of this experiment. Preplant herbicides applied in the spring were more effective at reducing horseweed plant densities than when applied in the previous fall. Spring-applied, residual herbicide systems were the most effective at reducing season-long in-field horseweed densities and protecting crop yields since the growth habit of horseweed in this region is primarily as a summer annual. Management systems also influenced the GR and glyphosate-susceptible (GS) biotype population structure after 4 yr of management. The most dramatic shift was from the initial GR : GS ratio of 3 : 1 to a ratio of 1 : 6 after 4 yr of residual preplant herbicide use followed by non-glyphosate postemergence herbicides.


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.


Agronomy ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 840 ◽  
Author(s):  
Ahmed Laamrani ◽  
Paul R. Voroney ◽  
Aaron A. Berg ◽  
Adam W. Gillespie ◽  
Michael March ◽  
...  

The impacts of tillage practices and crop rotations are fundamental factors influencing changes in the soil carbon, and thus the sustainability of agricultural systems. The objective of this study was to compare soil carbon status and temporal changes in topsoil from different 4 year rotations and tillage treatments (i.e., no-till and conventional tillage). Rotation systems were primarily corn and soy-based and included cereal and alfalfa phases along with red clover cover crops. In 2018, soil samples were collected from a silty-loam topsoil (0–15 cm) from the 36 year long-term experiment site in southern Ontario, Canada. Total carbon (TC) contents of each sample were determined in the laboratory using combustion methods and comparisons were made between treatments using current and archived samples (i.e., 20 year and 9 year change, respectively) for selected crop rotations. Overall, TC concentrations were significantly higher for no-till compared with conventional tillage practices, regardless of the crop rotations employed. With regard to crop rotation, the highest TC concentrations were recorded in corn–corn–oats–barley (CCOB) rotations with red clover cover crop in both cereal phases. TC contents were, in descending order, found in corn–corn–alfalfa–alfalfa (CCAA), corn–corn–soybean–winter wheat (CCSW) with 1 year of seeded red clover, and corn–corn–corn–corn (CCCC). The lowest TC concentrations were observed in the corn–corn–soybean–soybean (CCSS) and corn–corn–oats–barley (CCOB) rotations without use of cover crops, and corn–corn–soybean–winter wheat (CCSW). We found that (i) crop rotation varieties that include two consecutive years of soybean had consistently lower TC concentrations compared with the remaining rotations; (ii) TC for all the investigated plots (no-till and/or tilled) increased over the 9 year and 20 year period; (iii) the no-tilled CCOB rotation with 2 years of cover crop showed the highest increase of TC content over the 20 year change period time; and (iv) interestingly, the no-till continuous corn (CCCC) rotation had higher TC than the soybean–soybean–corn–corn (SSCC) and corn–corn–soybean–winter wheat (CCSW). We concluded that conservation tillage (i.e., no-till) and incorporation of a cover crop into crop rotations had a positive effect in the accumulation of TC topsoil concentrations and could be suitable management practices to promote soil fertility and sustainability in our agricultural soils.


Weed Science ◽  
1997 ◽  
Vol 45 (1) ◽  
pp. 85-90 ◽  
Author(s):  
John Cardina ◽  
Heather M. Norquay

The impact of seed production by subthreshold weed populations on future weed problems has impeded the adoption of integrated pest-management principles for weed management. Studies were conducted in fields with no velvetleaf history to determine how seedbanks and seedling populations change following seed production 1 yr or 5 consecutive yr in plow-disk and no-tillage corn. Cumulative seed production by 0.19 velvetleaf plants m−2increased in a linear fashion from 1989 to 1994, with annual additions averaging from 330 seeds m−2for velvetleaf in corn to 2,500 seeds m−2for velvetleaf without competition from corn. Five-year cumulative seed production was 1,480 seeds m−2in plow-disk and 1,810 seeds m−2in no-till corn. In no-till corn, 42 velvetleaf seedlings m−2emerged the 1st year after the 1989 seed rain, but only 35 seedlings m−2emerged over the next 4 yr. In plow-disk plots, annual emergence averaged 12 seedlings m−2. Five years after the 1989 seed rain, the proportion of seeds lost to emergence was about 20% in both tillage treatments. Where velvetleaf seeds were allowed to return to the soil every year, cumulative seedling emergence was lower in plow-disk than in no-till corn, with total emergence of 70 and 360 seedlings m−2, respectively, after 5 yr. Seedbank numbers ranged from 10 seeds m−25 yr after a single seed rain (290 seeds m−2) by velvetleaf in plow-disk corn to 1,020 seeds m−2following 5 consecutive yr of seed rain where 12,580 seeds m−2were returned without corn competition in no-till. Seedbank samples in the fall of the 5th year had 69 to 98% fewer seeds than were accounted for by cumulative seed rain and seedling emergence, with greater apparent seed losses in plow-disk corn than in no-till corn. Over 90% velvetleaf control would be required annually to maintain subthreshold populations for 5 yr following a single seed rain. By comparison, over 95% control would be required annually to maintain subthreshold populations where velvetleaf seed return is permitted each year.


Weed Science ◽  
1999 ◽  
Vol 47 (5) ◽  
pp. 596-601 ◽  
Author(s):  
Mary D. Paulsgrove ◽  
John W. Wilcut

An experiment was conducted at two locations in Georgia and two locations in North Carolina during 1994 and 1995 to evaluate weed management in conventional-tillage bromoxynil-resistantGossypium hirsutumL. (cotton). The weed management systems evaluated included different combinations of fluometuron preemergence (PRE), bromoxynil or bromoxynil plus MSMA early postemergence (EPOST), bromoxynil postemergence (POST), and cyanazine plus MSMA late post-directed (LAYBY). Fluometuron PRE improved control ofAcanthospermum hisptdiumDC. (bristly starbur),Cassia occidentalisL. (coffee senna),Chenopodium albumL. (common lambsquarters),Desmodium tortuosum(Sw.) DC. (Florida beggarweed),Sida spinosaL. (prickly sida),Jacquemontia tamnifolia(L.) Griseb. (smallflower morningglory), andAnoda cristata(L.) Schlecht. (spurred anoda), compared to system that did not use fluometuron PRE. It also improvedG. hirsutumyields at three four locations. Bromoxynil-containing systems provided better weed control and higherG. hirsutumyields than systems without bromoxynil. Bromoxynil EPOST controlledA. hispidium, C. occidentalis, C. album, D. tortuosum, S. spinosa, J. tamnifolia, andA. cristata.Control of these species was frequently improved by a second application of bromoxynil POST. Bromoxynil EPOST, POST, or EPOST plus POST did not controlSenna obtusifolia(L.) Irwin and Barneby (sicklepod), but the addition of MSMA to bromoxynil EPOST improvedS. obtusifoliacontrol. Control of all dicotyledonous weeds was improved by a LAYBY treatment of cyanazine plus MSMA, and yields were improved at three of four locations with this treatment.Gossypium hirsutumwas not injured by POST treatments of bromoxynil, and only temporary injury resulted from POST treatments of MSMA.


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