001 COLLABORATIVE LEARNING AND PARTICIPATORY ON-FARM RESEARCH: COVER CROPS AND VEGETABLE PRODUCTION SYSTEMS

A participatory, on-farm research project was initiated in 1992 in an effort to enhance mutual learning, knowledge, and experience of integrating cover crops into western Oregon vegetable production systems. A major goal of the project was to include growers, agribusiness representatives, governmental agency, Extension and university researchers in a collaborative learning process, emphasizing grower participation in the design and implementation of on-farm research and demonstration projects. To facilitate this participation from the planning stage forward, four “focus sessions” were hosted by lead farmers in different areas of the Willamette Valley to define growers' needs and interests relating to on-farm research and demonstration trials. Based on individual growers' specific experimental objectives, cover crop evaluation trials were established on ten farms. Typically on each farm, 5 to 10 cover crop species or mixtures (grain and legume) were planted in large plot strips. Twenty five different cover crop species, varieties, and mixtures were planted. Seasonal cover crop biomass and nitrogen accumulation rates were determined, with cover crop impacts on crop yields and economic returns evaluated at selected sites.

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Herbicide Programs for the Termination of Various Cover Crop Species

Weed Technology ◽

10.1017/wet.2017.20 ◽

2017 ◽

Vol 31 (4) ◽

pp. 514-522 ◽

Cited By ~ 5

Author(s):

Cody D. Cornelius ◽

Kevin W. Bradley

Keyword(s):

Cover Crops ◽

Cover Crop ◽

Field Experiments ◽

Crop Yields ◽

Production Systems ◽

Annual Ryegrass ◽

Crop Species ◽

Cereal Rye ◽

Crimson Clover ◽

Herbicide Treatments

The recent interest in cover crops as a component of Midwest corn and soybean production systems has led to a greater need to understand the most effective herbicide treatments for cover crop termination prior to planting corn or soybean. Previous research has shown that certain cover crop species can significantly reduce subsequent cash crop yields if not completely terminated. Two field experiments were conducted in 2013, 2014, and 2015 to determine the most effective herbicide program for the termination of winter wheat, cereal rye, crimson clover, Austrian winter pea, annual ryegrass, and hairy vetch; and cover crops were terminated in early April or early May. Visual control and above ground biomass reduction was determined 28 d after application (DAA). Control of grass cover crop species was often best with glyphosate alone or combined with 2,4-D, dicamba, or saflufenacil. The most consistent control of broadleaf cover crops occurred following treatment with glyphosate +2,4-D, dicamba, or saflufenacil. In general, control of cover crops was higher with early April applications compared to early May. In a separate study, control of 15-, 25-, and 75-cm tall annual ryegrass was highest with glyphosate at 2.8 kg ha−1or glyphosate at 1.4 kg ha−1plus clethodim at 0.136 kgha−1. Paraquat- or glufosinate-containing treatments did not provide adequate annual ryegrass control. For practitioners who desire higher levels of cover crop biomass, these results indicate that adequate levels of cover crop control can still be achieved in the late spring with certain herbicide treatments. But it is important to consider cover crop termination well in advance to ensure the most effective herbicide or herbicide combinations are used and the products are applied at the appropriate stage.

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The Correct Cover Crop Species Integrated with Slurry Can Increase Biomass, Quality and Nitrogen Cycling to Positively Affect Yields in a Subsequent Spring Barley Rotation

Agronomy ◽

10.3390/agronomy10111760 ◽

2020 ◽

Vol 10 (11) ◽

pp. 1760

Author(s):

Paul Cottney ◽

Lisa Black ◽

Ethel White ◽

Paul N. Williams

Keyword(s):

Cover Crops ◽

Cover Crop ◽

Crop Yields ◽

Spring Barley ◽

C:N Ratio ◽

Brassica Species ◽

Carbon Accumulation ◽

Soil Mineral Nitrogen ◽

Crop Species ◽

N Accumulation

The aim of this study is to identify species of cover crops that cause an increase in biomass and total nutrient accumulation in response to manure/slurry. This could improve nutrient efficiency and intensify the benefits from over-winter cover crops in arable rotations and improve following commercial crop yields. In a pot experiment, sixteen cover crops were grown for 100 days in response to slurry. Growth and nutrient (N, P, K, Mg and S) accumulation were measured, and then residue was reincorporated into the soil with spring barley (Hodeum vulgare L.) sown and harvested for yield. In response to slurry, tillage radish (Raphanus sativus L.) increased N accumulation by 101% due to a significant increase in biomass and % N (p < 0.05) over its relative control plots. Significant interactions between species and the application of slurry were found in cover crop biomass, cover crop and spring barley nutrient uptake, as well as cover crop carbon accumulation, particularly in the brassica species used. Slurry integrated with cover crops both reduced the cover crop C:N ratio and enhanced nutrient cycling compared to the control when soil mineral nitrogen (SMN) and spring barley crop N offtake were pooled. However, this was not observed in the legumes. This study shows that slurry integration with cover crops is a promising sustainable farming practice to sequester N and other macro-nutrients whilst providing a range of synergistic benefits to spring barley production when compared to unplanted/fallow land rotations. However, this advantage is subject to use of responsive cover crop species identified in this study.

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Carryover of Common Corn and Soybean Herbicides to Various Cover Crop Species

Weed Technology ◽

10.1614/wt-d-16-00062.1 ◽

2017 ◽

Vol 31 (1) ◽

pp. 21-31 ◽

Cited By ~ 19

Author(s):

Cody D. Cornelius ◽

Kevin W. Bradley

Keyword(s):

Cover Crops ◽

Cover Crop ◽

Production Systems ◽

Italian Ryegrass ◽

Hairy Vetch ◽

Crop Species ◽

Cereal Rye ◽

Crimson Clover ◽

Crop Establishment ◽

Biomass Reduction

The recent interest in cover crops as component of Midwest corn and soybean production systems has led to the need for additional research, including the effects of residual corn and soybean herbicide treatments on fall cover crop establishment. Field studies were conducted in 2013, 2014, and 2015 in Columbia, Missouri to investigate the effects of common residual herbicides applied in corn and soybean on establishment of winter wheat, tillage radish, cereal rye, crimson clover, winter oat, Austrian winter pea, Italian ryegrass, and hairy vetch. Cover crops were evaluated for stand and biomass reduction 28 d after emergence (DAE). Rainfall from herbicide application to cover crop seeding date was much greater in 2014 and 2015, which resulted in less carryover in these years compared to 2013. When averaged across all herbicides evaluated in these experiments, the general order of sensitivity of cover crops to herbicide carryover, from greatest to least was Austrian winter pea=crimson clover>oilseed radish>Italian ryegrass>hairy vetch>wheat >winter oat>cereal rye. Cereal rye had the fewest instances of biomass or stand reduction with only four out of the 27 herbicides adversely effecting establishment. Pyroxasulfone consistently reduced Italian ryegrass and winter oat biomass at least 67% in both the corn and soybean experiments. In the soybean experiment, imazethapyr- and fomesafen-containing products resulted in severe stand and biomass reduction in both years while flumetsulam-containing products resulted in the greatest carryover symptoms in the corn experiment. Results from these experiments suggest that several commonly used corn and soybean herbicides have the potential to hinder cover crop establishment, but the severity of damage will depend on weather, cover crop species, and the specific herbicide combination.

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Cover crop management effects on soybean and corn growth and nitrogen dynamics in an on-farm study

American Journal of Alternative Agriculture ◽

10.1017/s0889189300003891 ◽

1991 ◽

Vol 6 (2) ◽

pp. 71-82 ◽

Cited By ~ 32

Author(s):

D. L. Karlen ◽

J. W. Doran

Keyword(s):

Cover Crops ◽

Cover Crop ◽

Root Zone ◽

Winter Rye ◽

Nitrogen Accumulation ◽

Fertilizer N ◽

Hairy Vetch ◽

Early Season ◽

On Farm ◽

Ridge Tillage

AbstractCombining cover crops and conservation tillage may result in more sustainable agricultural production practices. Objectives of this on-farm study were to quantify effects of cover crops on growth and nitrogen accumulation by soybean [Glycine max (L.) Merr,] and corn (Zea mays L.) on a Nicollet loam (fine-loamy, mixed, mesic Aquic Hapludoll) near Boone, Iowa, Our farmer-cooperator planted soybean in 1988 using ridge tillage into an undisturbed strip with a hairy vetch (Vicia villosa L. Roth) cover crop and into a strip where previous crop residue and a negligible amount of cover crop had been incorporated by autumn and spring disking. In each strip, we established four plots for soil and plant measurements. Our cooperator planted corn on the same strips in 1989 into a cover crop that consisted of both hairy vetch and winter rye (Secale cereale L.). We determined the source of N accumulated by the corn by applying 67 kg N/ha of 15N depleted NH4NO3 fertilizer. In the absence of cover crops, early season soil NO3-N levels in the top 30 cm were higher, and corn growth and N accumulation were more rapid. At harvest, the corn grain, stover, and cob together accounted for 36 and 39 percent of the 15N fertilizer for the ridge tillage and disked treatments, respectively. We suggest that lower net mineralization of organic matter or greater denitrification losses before planting reduced the availability of soil N, This created an early season Nstress in corn grown with cover crops that was not overcome by broadcast fertilizer N applied three weeks after planting. Our on-farm research study has helped focus continuing efforts to determine if non-recovered fertilizer N is being immobilized in microbial biomass, lost by denitrification, or leached below the plant root zone.

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Evaluating Fall Cover Crops Following Early Harvested Vegetables

HortScience ◽

10.21273/hortsci.30.4.807b ◽

1995 ◽

Vol 30 (4) ◽

pp. 807B-807

Author(s):

Lydia Stivers-Young

Keyword(s):

Cover Crops ◽

Cover Crop ◽

Dry Matter ◽

Above Ground Biomass ◽

Crop Species ◽

Yellow Mustard ◽

Brassica Hirta ◽

Early Planting ◽

Oilseed Radish ◽

On Farm

Vegetable growers in the northeastern United States who want to use cover crops are limited by the relatively short growing season and by a lack of cover crop species options. Seven cover crops that winter-kill under NE US conditions were evaluated in on-farm trials for their suitability for following early harvested vegetables. Plots of oilseed radish (Raphanus sativus), white senf mustard (Brassica hirta), phacelia (Phacelia tanacetifolia), oats (Avena sativa), and a bare control were planted on 25 Aug. and 8 Sept. 1993, following a lettuce crop. In the early planting, oilseed radish, white senf mustard, and phacelia produced more than 3000 kg·ha–1 dry matter in 11 weeks, while oats produced just more than 2000 kg·ha–1. A smaller proportion of the accumulated biomass from these cover crops remained on the surface in the spring compared to oats. In the first planting, 80–107 kg·ha–1 N were accumulated in the above-ground biomass of the cover crops. On 3 and 16 Sept. 1994, plots of oilseed radish, white senf mustard, oats, yellow mustard (Brassica hirta), forage kale (Brassica oleracea), forage turnip (Brassica rapa), canola (Brassica napus cv. Sparta), and a bare control were established following potatoes. All cover crops except kale produced more than 3800 kg·ha–1 dry matter by late November in the early planting.

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Evaluation of cover crop sensitivity to residual herbicides applied in the previous soybean [Glycine max (L.) Merr] crop

Weed Technology ◽

10.1017/wet.2019.10 ◽

2019 ◽

Vol 33 (2) ◽

pp. 312-320 ◽

Cited By ~ 1

Author(s):

Derek M. Whalen ◽

Mandy D. Bish ◽

Bryan G. Young ◽

Aaron G. Hager ◽

Shawn P. Conley ◽

...

Keyword(s):

Cover Crops ◽

Cover Crop ◽

Crop Production ◽

Production Systems ◽

Ground Cover ◽

Crop Species ◽

Cereal Rye ◽

Crimson Clover ◽

Crop Establishment ◽

Study Results

AbstractIn recent years, the use of cover crops has increased in U.S. crop production systems. An important aspect of successful cover crop establishment is the preceding crop and herbicide program, because some herbicides have the potential to persist in the soil for several months. Few studies have been conducted to evaluate the sensitivity of cover crops to common residual herbicides used in soybean production. The same field experiment was conducted in 2016 in Arkansas, Illinois, Indiana, Missouri, Tennessee, and Wisconsin, and repeated in Arkansas, Illinois, Indiana, Mississippi, and Missouri in 2017 to evaluate the potential of residual soybean herbicides to carryover and reduce cover crop establishment. Herbicides applied during the soybean growing season included acetochlor; acetochlor plus fomesafen; chlorimuron plus thifensulfuron; fomesafen; fomesafen plus S-metolachlor followed by acetochlor; imazethapyr; pyroxasulfone; S-metolachlor; S-metolachlor plus fomesafen; sulfentrazone plus S-metolachlor; sulfentrazone plus S-metolachlor followed by fomesafen plus S-metolachlor; and sulfentrazone plus S-metolachlor followed by fomesafen plus S-metolachlor followed by acetochlor. Across all herbicide treatments, the sensitivity of cover crops to herbicide residues in the fall, from greatest to least, was forage radish = turnip > annual ryegrass = winter oat = triticale > cereal rye = Austrian winter pea = hairy vetch = wheat > crimson clover. Fomesafen (applied 21 and 42 days after planting [(DAP]); chlorimuron plus thifensulfuron and pyroxasulfone applied 42 DAP; sulfentrazone plus S-metolachlor followed by fomesafen plus S-metolachlor; and sulfentrazone plus S-metolachlor followed by fomesafen plus S-metolachlor followed by acetochlor caused the highest visual ground cover reduction to cover crop species at the fall rating. Study results indicate cover crops are most at risk when following herbicide applications in soybean containing certain active ingredients such as fomesafen, but overall there is a fairly low risk of cover crop injury from residual soybean herbicides applied in the previous soybean crop.

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Winter-killed Cereal Rye Cover Crop Influence on Nitrate Leaching in Intensive Vegetable Production Systems

HortTechnology ◽

10.21273/horttech.24.5.502 ◽

2014 ◽

Vol 24 (5) ◽

pp. 502-511 ◽

Cited By ~ 8

Author(s):

Aaron Heinrich ◽

Richard Smith ◽

Michael Cahn

Keyword(s):

Nitrate Leaching ◽

Cover Crops ◽

Cover Crop ◽

Production Systems ◽

Early Spring ◽

Late Winter ◽

Vegetable Production ◽

Residual Soil ◽

Cereal Rye ◽

Bare Fallow

High levels of residual soil nitrate are typically present in cool-season vegetable fields in coastal regions of California in the fall, after the production of multiple crops over the course of the growing season. This nitrate is subject to leaching with winter rains when fields are left fallow. Although the benefits of growing nitrate scavenging cover crops on soil and water quality are well documented, the portion of vegetable production fields planted to winter cover crops in this region is low. Most growers leave their fields unplanted in bare-fallow beds because the risk of having too much cover crop residue to incorporate may delay late winter and early spring planting schedules. A possible strategy to derive benefits of a cover crop yet minimize the amount of residue is to kill the cover crop with an herbicide when biomass of the cover crop is still relatively low. To evaluate whether this strategy would be effective at reducing nitrate leaching, we conducted field studies in Winter 2010–11 (Year 1) and Winter 2011–12 (Year 2) with cereal rye (Secale cereale). Each trial consisted of three treatments: 1) Fallow (bare fallow), 2) Full-season (cover crop allowed to grow to full term), and 3) Partial-season (cover crop killed with herbicide 8 to 9 weeks after emergence). In Year 1, which received 35% more rainfall than the historical average during the trial, the Full-season cover crop reduced nitrate leaching by 64% relative to Fallow, but the Partial-season had no effect relative to Fallow. In Year 2, which received 47% less rainfall than the historical average during the trial, the Full- and Partial-season cover crops reduced nitrate leaching by 75% and 52%, respectively, relative to Fallow. The Full-season cover crop was able to reduce nitrate leaching regardless of yearly variations in the timing and amount of precipitation. Although the Partial-season cover crop was able to reduce leaching in Year 2, the value of this winter-kill strategy to reduce nitrate leaching is limited by the need to kill the crop when relatively young, resulting in the release of nitrogen (N) from decaying residues back into the soil where it is subject to leaching.

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Cover Crop Benefits for South Florida Commercial Vegetable Producers

EDIS ◽

10.32473/edis-ss461-2006 ◽

2006 ◽

Vol 2006 (11) ◽

Author(s):

Yuncong Li ◽

Edward A. Hanlon ◽

Waldemar Klassen ◽

Qingren Wang ◽

Teresa Olczyk ◽

...

Keyword(s):

Organic Matter ◽

Soil Organic Matter ◽

Cover Crops ◽

Cover Crop ◽

Production Systems ◽

South Florida ◽

Vegetable Production ◽

Science Department ◽

Nutrient Conservation ◽

Soil And Water

SL-242, an 8-page illustrated fact sheet by Y. Li, E. A. Hanlon, W. Klassen, Q. Wang, T. Olczyk, and I. V. Ezenwa, describes how and why to use cover crops in South Florida vegetable production systems, and identifies several cover crops that work in Florida's climate, that contribute to nutrient conservation, and whose biomass can be incorporated to improve soil organic matter. Published by the UF Soil and Water Science Department, June 2006. SL-242/SS461: Cover Crop Benefits for South Florida Commercial Vegetable Producers (ufl.edu)

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Fall Cover Crops for Reducing Nitrate Leaching in Cool Season Vegetable Production in the Salinas Valley

HortScience ◽

10.21273/hortsci.40.4.1110b ◽

2005 ◽

Vol 40 (4) ◽

pp. 1110B-1110

Author(s):

Richard F. Smith ◽

Louise E. Jackson ◽

Tiffany A. Bensen

Keyword(s):

Nitrate Leaching ◽

Cover Crops ◽

Cover Crop ◽

Production Systems ◽

Indian Mustard ◽

Vegetable Production ◽

Land Rent ◽

Cereal Rye ◽

Salinas Valley ◽

Bare Fallow

Lettuce growers in the Salinas Valley are often not able to rotate to other crops due to economic pressure, such as high land rent. Winter-grown cover crops (October to March) provide a short-term rotation from lettuce and have been shown to reduce nitrate leaching by 75%. However, the use of winter-grown cover crops is low due to the extended time these cover crops tie up the ground. As a result, growers are interested in the potential of fall-grown cover crops (September to October) to reduce nitrate leaching through the winter. Fall-grown cover crops are incorporated into the soil prior to the onset of winter rains and leave the soil bare over the winter; however, during fall growth, the cover crop has the potential to capture excess nitrate that may leach during the fallow period, but how much has not been previously measured. A long-term trial was established in Fall 2003 using treatments of Indian mustard (B. juncea) `ISCI 61', White mustard (S. alba) `Ida Gold', Cereal rye (Secale cereale) `Merced', and a no cover crop control. All cover crops contained ≈224 kg·ha-1 N upon incorporation. Anion resin bags were installed 90 cm deep in the soil following incorporation to trap leaching nitrate; they were left in place until planting of the lettuce the following spring. First-year results indicated that the mustard cover crops and `Merced' rye all reduced nitrate leaching to the 90-cm depth by 67% to 82% over the bare fallow treatment. These results indicate that fall-grown cover crops have the potential to reduce nitrate leaching in lettuce production systems in the Salinas Valley.

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USE OF COVER CROPS IN VEGETABLE PRODUCTION

HortScience ◽

10.21273/hortsci.28.4.260f ◽

1993 ◽

Vol 28 (4) ◽

pp. 260F-260

Author(s):

Francis X. Mangan ◽

Stephen J. Herbert ◽

Mary Jane Else

Keyword(s):

Organic Matter ◽

New England ◽

Cover Crops ◽

Cover Crop ◽

Nitrogen Fertilizers ◽

Winter Rye ◽

Vegetable Production ◽

Crop Season ◽

Crop Species ◽

Northern New England

Cover crops have been used in agricultural systems for thousands of years and are still an important part of vegetable production in the Northeast. Winter rye (Secale cereale) is by far the dominant cover crop species on conventional vegetable farms in the New England states. It is use is primarily for erosion control. Winter rye is popular since it is cheap, easy to establish, can overwinter in the harsh winters of northern New England, is efficient in “capturing” excess nitrogen at the end of the cash crop season, and it can produce substantial amounts of organic matter in the spring. As many positive attributes that winter rye has, it is important to be aware of many of the other potential cover crop species that are available to us. For example, many conventional growers are exploring the use of leguminous cover crops as an alternative to chemical nitrogen fertilizers which are more readily leached and are only going to get more expensive. Cover crops can also be seeded and managed in innovative ways to suppress weeds and other pests, add organic matter and conserve soil moisture.

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