Conservation tillage for organic agriculture: Evolution toward hybrid systems in the western USA

2012 ◽  
Vol 27 (1) ◽  
pp. 21-30 ◽  
Author(s):  
John M. Luna ◽  
Jeffrey P. Mitchell ◽  
Anil Shrestha

AbstractOrganic farming has been historically dependent on conventional tillage operations to convert perennial pasture leys to annual crop rotations, incorporate crop residues, compost and cover crops, as well as to mechanically kill existing vegetation. Conventional tillage, however, has long been known to lead to soil degradation and erosion. A recently developed no-till organic production system that uses a roller–crimper technology to mechanically kill cover crops was evaluated in two states in the western United States. In Washington, pumpkins (Cucurbitaspp.) grown in a no-till roller–crimper (NT-RC) system produced yields 80% of conventional tillage, but with fewer weeds. However, in California on-farm research trials in organic cotton (Gossypium barbadenseL.), tomato (Lycopersicon esculentumMill.), eggplant (Solanum melongenaL.) and cowpea (Vigna unguiculata(L.) Walp.), the no-till system produced virtual crop failure, or yields less than 20% of the standard production method. The major problems associated with rolled cover crops in California included reduced crop seedling emergence, planter impediment with excessive residue, lack of moisture and delay in transplanting of vegetable crops due to continued growth of cover crops, in-season crop competition from cover crop regrowth and impracticability of using cultivators. Further, excessive dry residue during summer in California can present the risk of fire. In both California and Oregon, considerable success has been demonstrated with zone tillage (strip tillage) in conventionally produced field and vegetable crops. In a replicated Oregon trial, the organic strip tillage treatment produced 85% of the broccoli (Brassica oleraceaL.) yield compared to a conventional tillage treatment. Our studies suggest that the zone tillage concept may offer opportunities to overcome many of the agronomic challenges facing no-till.

2012 ◽  
Vol 27 (1) ◽  
pp. 60-67 ◽  
Author(s):  
Steven J. Shirtliffe ◽  
Eric N. Johnson

AbstractOrganic farmers in western Canada rely on tillage to control weeds and incorporate crop residues that could plug mechanical weed-control implements. However, tillage significantly increases the risk of soil erosion. For farmers seeking to reduce or eliminate tillage, potential alternatives include mowing or using a roller crimper for terminating green manure crops (cover crops) or using a minimum tillage (min-till) rotary hoe for mechanically controlling weeds. Although many researchers have studied organic crop production in western Canada, few have studied no-till organic production practices. Two studies were recently conducted in Saskatchewan to determine the efficacy of the following alternatives to tillage: mowing and roller crimping for weed control, and min-till rotary hoeing weed control in field pea (Pisum sativum L.). The first study compared mowing and roller crimping with tillage when terminating faba bean (Vicia faba L.) and field pea green manure crops. Early termination of annual green manure crops with roller crimping or mowing resulted in less weed regrowth compared with tillage. When compared with faba bean, field pea produced greater crop biomass, suppressed weeds better and had less regrowth. Wheat yields following pea were not affected by the method of termination. Thus, this first study indicated that roller crimping and mowing are viable alternatives to tillage to terminate field pea green manure crops. The second study evaluated the tolerance and efficacy of a min-till rotary harrow in no-till field pea production. The min-till rotary hoe was able to operate in no-till cereal residues and multiple passes did not affect the level of residue cover. Field pea exhibited excellent tolerance to the min-till rotary hoe. Good weed control occurred with multiple rotary hoe passes, and pea seed yield was 87% of the yield obtained in the herbicide-treated check. Therefore, this second study demonstrated that min-till rotary hoeing effectively controls many small seeded annual weeds in the presence of crop residue and thus can reduce the need for tillage in organic-cropping systems.


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>


2004 ◽  
Vol 18 (4) ◽  
pp. 1023-1030 ◽  
Author(s):  
R. Edward Peachey ◽  
Ray D. William ◽  
Carol Mallory-Smith

The effect of planting system and cover crop residues on weed emergence in irrigated vegetable row crops was studied in field experiments from 1995 through 1997. Vegetable crops were either no-till planted (NTP) through cover crop residues or conventionally planted (CP) into soil with cover crop residues incorporated. NTP reduced emergence of hairy nightshade by 77 to 99% and Powell amaranth emergence by 50 to 87% compared with CP. Cover crop treatments were much less important than planting system in regulating weed emergence. Tillage in the spring did not increase the number of viable seeds near the soil surface. Hairy nightshade emergence ranged from 0.6 to 9.8% of the intact seeds in CP compared with 0 to 0.1% emergence of the seeds in the NTP plots. Powell amaranth emergence ranged from 4.9 to 6.5% of the intact seeds in CP contrasted with only 0.4 to 0.9% emergence of the seeds in NTP plots.


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.


Agronomy ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 257 ◽  
Author(s):  
Husrev Mennan ◽  
Khawar Jabran ◽  
Bernard H. Zandstra ◽  
Firat Pala

Vegetables are a substantial part of our lives and possess great commercial and nutritional value. Weeds not only decrease vegetable yield but also reduce their quality. Non-chemical weed control is important both for the organic production of vegetables and achieving ecologically sustainable weed management. Estimates have shown that the yield of vegetables may be decreased by 45%–95% in the case of weed–vegetable competition. Non-chemical weed control in vegetables is desired for several reasons. For example, there are greater chances of contamination of vegetables by herbicide residue compared to cereals or pulse crops. Non-chemical weed control in vegetables is also needed due to environmental pollution, the evolution of herbicide resistance in weeds and a strong desire for organic vegetable cultivation. Although there are several ways to control weeds without the use of herbicides, cover crops are an attractive choice because these have a number of additional benefits (such as soil and water conservation) along with the provision of satisfactory and sustainable weed control. Several cover crops are available that may provide excellent weed control in vegetable production systems. Cover crops such as rye, vetch, or Brassicaceae plants can suppress weeds in rotations, including vegetables crops such as tomato, cabbage, or pumpkin. Growers should also consider the negative effects of using cover crops for weed control, such as the negative allelopathic effects of some cover crop residues on the main vegetable crop.


1999 ◽  
Vol 79 (1) ◽  
pp. 217-220 ◽  
Author(s):  
M. S. Burgess ◽  
G. R. Mehuys ◽  
C. A. Madramootoo

A 3-yr field study in Quebec assessed effects of tillage (no-till, reduced, or conventional) × crop residues (removed or retained) on soil nitrate under corn production. Fall nitrate levels were greatest in plots without residues 1 yr after treatments began, but not thereafter. No-till and conventional tillage had similar values, but sometimes differed from reduced tillage. Key words: Nitrate, corn, no-till, reduced tillage, conventional tillage, crop residues


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.


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 ◽  
2007 ◽  
Vol 42 (7) ◽  
pp. 1568-1574 ◽  
Author(s):  
E. Ryan Harrelson ◽  
Greg D. Hoyt ◽  
John L. Havlin ◽  
David W. Monks

Throughout the southeastern United States, vegetable growers have successfully cultivated pumpkins (Cucurbita pepo) using conventional tillage. No-till pumpkin production has not been pursued by many growers as a result of the lack of herbicides, no-till planting equipment, and knowledge in conservation tillage methods. All of these conservation production aids are now present for successful no-till vegetable production. The primary reasons to use no-till technologies for pumpkins include reduced erosion, improved soil moisture conservation, long-term improvement in soil chemical and microbial properties, and better fruit appearance while maintaining similar yields compared with conventionally produced pumpkins. Cover crop utilization varies in no-till production, whereas residue from different cover crops can affect yields. The objective of these experiments was to evaluate the influence of surface residue type on no-till pumpkin yield and fruit quality. Results from these experiments showed all cover crop residues produced acceptable no-till pumpkin yields and fruit size. Field location, weather conditions, soil type, and other factors probably affected pumpkin yields more than surface residue. Vegetable growers should expect to successfully grow no-till pumpkins using any of the winter cover crop residues tested over a wide range in residue biomass rates.


HortScience ◽  
1997 ◽  
Vol 32 (3) ◽  
pp. 511A-511
Author(s):  
Alan W. McKeown ◽  
John W. Potter ◽  
R.F. Cerkauskas ◽  
L. Van Driel

A long-term experiment in the same site was planted to evaluate potential yield, nematode, and disease problems with tomatoes (Lycopersicon esculentum Mill.) in a strip-till system. Treatments consisted of conventional tillage (CT) and strip tillage (ST), rye (Secale cereale L.), wheat (Triticum aestivum L.), and perennial ryegrass (Lolium perenne L.) cover crops and a 2-year rye–tomato rotation. Results of the first 5 years indicate a decrease in tomato yield over time for both tillage treatments and cover crops. Tomato yields were lower following wheat and perennial ryegrass than rye. Strip-tillage reduced yield compared to conventional tillage in only 1 year out of 6. Yield increased overall for treatments in 1992, with highest yield in the rye–tomato rotation. Bacterial speck/spot symptoms on foliage, although minor, were significantly greater in ST than in CT plots during the last 3 years. No major consistent trends in incidence and severity of bacterial and fungal diseases and of disorders of fruit were evident during the 5-year period, and neither fruit yield nor quality were significantly affected by these factors. Root-knot nematodes (Meloidogyne hapla Chitwood) were numerically less numerous in the rye–tomato rotation than in other treatments; both root-knot and root lesion nematodes [Pratylenchus penetrans (Cobb)] tended to be less numerous under CT than under ST. Tomatoes grown under reduced tillage appear more sensitive to plant parasitic nematodes and preceding cover crops than in conventional tillage.


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