cover crops

[c-ray]

going to lay down some info in this thread about cover crops...for starters here is an interesting study about hairy vetch

from http://www.organic-center.org/science.antiox.php?action=view&report_id=13

Cover Crops Trigger Unique Gene Expression Patterns That Promote Plant Health
July 2004

In an elegant study that is the first of its kind, scientists working at USDA’s Henry A Wallace Beltsville Agricultural Research Center used the tools of biotechnology to trace how plants respond to a common organic farming practice – the planting of crops in a hairy vetch (HV) mulch-based system. The study compared the genetic response and health of tomato plants growing in a HV system to tomatoes grown with black plastic (BP) and typical chemical fertilizers and pesticide inputs. The plants grown in the HV mulch-system grew longer and had delayed senescence (beginning at 65 days post-transplanting in the BP system versus 84 days with HV), expressed higher levels of several health-promoting proteins and secondary plant metabolites, and were more resistant to common foliar plant diseases (bacterial spot, early blight, Septoria leaf spot). Disease symptoms were apparent in the BP plants from 65 days post-transplanting and grew worse steadily, but did not appear until 84 days after transplanting in the HV system and never became as severe.

The authors report “a distinct expression profile of gene transcripts and proteins...” that reflect changes in hormone signaling in the hairy vetch-grown plants. The impacts of these changes are significant, resulting in “...efficient utilization and mobilization of N, higher photosynthetic rates and, thus, of carbon mobilization...and defense promotion.” The HV plants had larger, healthier root systems, grew slower and longer and produced fruit and foliage more tolerant to disease pressure.

Source: “An alternative agriculture system is defined by a distinct expression profile of select gene transcripts and proteins,” Proceedings of the National Academy of Sciences, Early Edition, July 2004

Authors: Vinod Kumar, Douglas Mills, James Anderson, and Autar Mattoo

[c-ray]

here's a related thread about Dynamic Accumulator Plants, which is basically what cover crops are:
https://www.cannabis-world.org/cw/showthread.php?t=1788&highlight=dynamic+accumulator+plants

also check out the wikipedia page on cover crops it sums them up pretty well:
http://en.wikipedia.org/wiki/Cover_crop

and last but not least 'Choosing the best cover crops for your organic no-till vegetable system - A detailed guide to using 29 species'
http://www.newfarm.org/features/0104/no-till/chart.shtml

[c-ray]

UC SAREP Cover Crop Resource Page
http://www.sarep.ucdavis.edu/ccrop/index.htm
^
:smile2:

[c-ray]

from http://www.snow-pond.com/
also check out their pdf Chart of Soil Seed Uses and Characteristics (http://www.snow-pond.com/SoilSeed/sschart.pdf) and code breaker (http://www.snow-pond.com/SoilSeed/sscodes.pdf)



Soil Seed Primer

Soil Seed is a term we use to describe seed that's planted with the specific goal of improving the soil by plowing, tilling or digging the crop back into the earth. Soil crops create a better environment for subsequent vegetable, grain and flower crops by:
adding organic matter
increasing microbial activity
providing food and habitat for larger soil creatures
aerating compacted soils
increasing the retention of soil moisture
bringing minerals from the subsoil up to the root zone
fixing nitrogen from the atmosphere

Each crop has some special characteristics that make it well-suited to accomplishing a specific purpose. Those purposes can be divided into several broad categories which are discussed below and referenced in the soil seed information chart.


Allelopathic properties Weeds can be controlled by planting crops whose roots produce natural toxins which inhibit the germination and growth of weed seeds. Winter rye, a commonly used plant with allelopathic characteristics, must be allowed to decompose for several weeks before planting the following crop. Sunflowers, oats and wheat are other examples. The allelopathic effect diminishes fairly rapidly for most plants once they are incorporated into the soil.


Beneficial insect habitat Beneficial insects flock to a garden with a broad diversity of plants. Some insects seek nectar to get through a period when their preferred food source is scarce. For example, clover blossoms produce nectar that attracts hungry lacewings, honey bees, lady bugs, and wasps. Often, beneficial insects will be lured in to prey on the pest of a soil crop but then remain to control other pests on your vegetable crop.


Break crop Different plants harbor different populations of insect pests. If populations build to harmful levels in one crop, a different crop that does not harbor those pests or actually diminishes their population may be planted to interrupt the pest's life cycle. After the break crop has done its work, the rotation may include the vulnerable crop once again. Reducing pest populations is one of the best reasons to rotate crops in the garden and on the farm.


Catch crop (aka trap crop) Plants with a particularly strong ability to capture, store, and slowly release nutrients are called catch crops. They are traditionally planted in late summer or early fall to trap nutrients from freshly spread manures, previously turned under legumes or decomposing vegetation. They also protect the soil from winter erosion and nutrient losses. Crops such as annual ryegrass, have heavy, fibrous root systems that capture nutrients and protect the land. Catch crops should be planted when there are 4-6 weeks of 55° days remaining before last frost, i.e., early September in the Northeast.


Cover crops Land exposed to the weather over a fallow season without a protective mantle of plants (dead or alive) can lose both topsoil and nutrients and suffer erosion damage. Any cover is better than no cover. If you need to get on the soil quickly in the spring or have limited tillage equipment, you may want to plant something that will winter-kill like oats or a non-hardy vetch. If early access to the land is not a priority, a winter hardy crop like winter rye does a good job of holding everything in place. If the soil will be fallow the next season and does not have lots of available nutrients, a late summer legume (vetch/rye mix) provides protection from weather and will return an added bonus of nitrogen to those crops that follow.


Erosion control Some plants grow especially well in areas vulnerable to erosion and hold soil in place even under adverse conditions. Annual ryegrass and brome grass produce huge amounts of root mass. Subterranean clover not only provides a dense mat of vegetation to control water runoff, but also produces seed on peduncles that bury themselves deep into the soil where they avoid foragers and washout from heavy rains.


Intercropping Planting a crop between rows of actively growing row crops is also referred to as intercropping. Benefits include prevention of soil compaction by machinery, loss of soil from heavy rains or winds, and an established, protective cover for the soil after the row crop is harvested. Many of the soil seeds work well in this capacity.


Nitrogen fixers Leguminous plants, such as clover and soybeans, can form a symbiotic relationship with certain soil bacteria called rhizobia. If these bacteria are present in the root zone of the plant, they will set up housekeeping in "nodules" on the roots. There they extract nitrogen from the air and change it into a form plants can use. Many of these plant/bacteria combinations fix so much nitrogen that they eliminate the need for any further nitrogen inputs on the part of the grower.

It is common practice to coat seeds with the particular species of rhizobia that the legume prefers just prior to planting. This process is called inoculation. Most of our legume seed is raw, meaning it's not already inoculated. We sell inoculant for all of the common legumes; varieties which require an uncommon inoculant, are sold in a pre-inoculated (aka - rhizocoated) form. Inoculants have a limited shelf life. Therefore, it's best to buy fresh inoculant each season. Well inoculated legumes get 70-80% of their nitrogen from the rhizobia and very little from the soil. In fact, soils with excessively high nitrogen can retard the nitrogen fixing ability of legumes. All plants liberate some nitrogen when they decompose, but legumes such as alfalfa, cowpeas, field peas, soybeans and all the vetches create a net gain in soil nitrogen.


Nurse crops A nurse crop assists the development of a slower maturing crop. For example, oats can be planted with clover to provide the clover with shelter from the wind, rain and sun. The oats germinate first, out compete weeds for available resources and can be mowed when clover starts to emerge. Other crops are more productive if they have a support to climb. Vetch and field peas, for example, do better when they can twist themselves around a stiff-stalked nurse crop such as oats or rye.


Scavenger crops Topsoil that has been heavily cropped with shallow-rooted plants such as corn becomes deficient in certain nutrients. In order to restore these removed nutrients the grower must add them or use a plant that is adept at reaching deep into the subsoil to bring minerals to the surface. Scavenger crops such as alfalfa, red clover and sweet clover also break up compacted soils. When the deep-rooted plants die, their decaying roots leave holes in the soil. These holes provide a pathway for roots of less aggressive plants to follow and for water to drain from the surface.

Smother crops such as buckwheat, Japanese millet and sorghum-Sudan grass control weeds with a thick canopy that excludes the sun and a fibrous, shallow root system that out competes weeds for water and nutrients. Smother crops usually grow quite tall at a fast rate or quickly produce broad leaves that shade out the lower growing weeds. Growing different crops in a single season is the most effective strategy. If the weed problem is severe, it may take more than one season to reach the desired level of control. An effective and common sequence of smother crops is oats in spring, buckwheat in mid-summer and winter rye in the fall.

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A Brief Introduction to Clovers

Clovers are effective builders of soil because they 1) improve soil aeration; 2) enhance soil microbial life; 3) increase soil water-holding capacity and permeability; 4) reduce wind and water erosion of light soils and the baking of heavy soils.

Ideally, clover should be seeded with an alfalfa drill. Most folks don't have one and will need to prepare a seed bed, broadcast the seed and use a roller or some type of drag to cover the seed. Soil cover reduces depredations by birds and rodents, provides better moisture conditions for seedling development, and reduces exposure to heat and sunlight which ensures better survival of the Rhizobia with which the seed should have been inoculated. In the Northeast, seeding directly into a late spring snow or onto a field that is heaving and cracking from late spring frosts can often establish a stand in an existing field with little or no tillage effort. This practice is called frost seeding and can be very effective.

Prior use of smother crops like Sorghum-Sudan grass, oats, rye or buckwheat can reduce competition from weeds and provide a firm seed bed for the clover. Clover should be seeded no more than a half-inch deep or seedlings will be unable to reach the soil surface. Smooth, firm seedbeds will assure uniformly shallow seeding. The first year following seeding is critical for a clover stand. The stand must produce abundant seed to ensure its renewal. Ample potassium and phosphorus reserves are necessary as is sulfur. Have your soil tested and if soil phosphorus levels are below 20 ppm, amendments are in order.

Grazing or mowing keeps faster-growing weeds and grasses from overtopping the clover. Ideally, a new field should be kept grazed or mowed to about 3 inches until seed heads appear on any annual grasses. Thereafter, livestock feed selectively on clover and should be removed from the range until clover seeds have matured. Clover growth is generally best in the soil pH range of 6-7.

Many clovers produce a certain percentage of seed that won't germinate in the first year, but will germinate in following years. This type of seed is called hard seed and is a characteristic of legumes (particularly alfalfa, clover and vetch) that ensures their survival. In a year with adverse conditions, the hard seed that didn't previously germinate will be ready to perpetuate the stand the following year.

[crazy cooter]

C-ray... have you ever purchased hairy vetch seed? Know where it's available? I just have a few small raised beds for veggies but plan to do a cover crop this winter.

[c-ray]

I got some from the feed store...it is pretty common around these parts
look for seed that is preinnoculated with rhyzobium or buy some to coat the seeds
you should consider planting other winter hardy legumes like austrian peas and faba beans with the vetch, to increase the biological and nutritional diversity

[c-ray]

from http://www.newfarm.org/features/2007/0707/ccsummit/bialon.shtml
Cover crops offer benefits from fertility to weed management
Penn State’s “cover crop summit” lays out species options and soil health tests for hands-on farmer learning.

By Ed Bialon

Posted July 13, 2007: As a new farmer—new to both rural living and Pennsylvania—I was glad to attend Pennsylvania’s Cover Crop Research and Management Summit last month. I found a tremendous amount of information about cover crops in sustainable and organic farming systems.

My wife, Joan, and I purchased our 91-acre farm near Huntingdon, Pennsylvania, in January 2005. We spent the next two years moving from St. Louis, Missouri, upgrading some of the farm’s infrastructure, and obtaining an organic crop certification. At this point we are most interested in producing organic vegetables and hay, and at some future date having an on-farm produce market. I have also given some thought to growing organic grain and forages to sell to the increasing number of organic dairy farms in the area.

We want our farm to be both sustainable and organic. We are engaged in constant discussion and debate on where we want to go with this farm in terms of our mission and goals. We also lack basic farming skills and experience, a situation which puts our farm at risk. I’m looking for wisdom in others’ experiences. To learn a bit about our challenges this spring, see the sidebar “Our farm year so far.”

This planting season I moved in the direction of solving a soil-fertility issue of low nitrogen in my commercial vegetable garden. In reviewing seed catalogs, we saw cover-crop seed mixes were being marketed as green manure to enrich the soil with nitrogen and organic matter. My wife and I were drawn to a spring-planted, green-manure mix of 60 percent field peas, 25 percent oats and 15 percent hairy vetch.

We decided to create our own green-manure mix using chickling vetch, forage peas and soybeans based on information from a seed salesman from the Midwest. However, as we explored this alternative and prepared to execute it, we realized how little we knew about managing cover crops to assure us of a successful outcome. We decided not to sow the early-season mix until we understood things better. The summit looked like a great way to learn about improving soil nitrogen with cover crops.


Cover crop selection

Held at the Penn State University agronomy farm at Rock Springs, the event turned out to be a great day for those of us who wanted to use cover crops in sustainable farming systems. Penn State and Rodale Institute staff paired up to give four presentations.

Dave Wilson, agronomist at Rodale, and Ron Hoover of Penn State discussed cover-crop species attributes and selection. Cover crops serve multiple purposes, and their incorporation into your crop rotation provides multiple benefits in a comprehensive approach to soil fertility and quality issues. Dave Wilson’s handout titled “Cover Crops for the Northeast” is a must-read resource on this topic. [ Can we link to this? ]

Cover crops discussed or displayed in research plots included rye grass, winter rye, sweetclover, sorghum-sudan grass hybrids, red clover, hairy vetch, alfalfa, berseem clover, crimson clover, white clover, peas, forage radish, oilseed radish, daikon radish, oats, buckwheat, bahiagrass, sun hemp, mucuna, teff, wheat, fava and bell beans, rapeseed, canola, millets and lab lab. What I heard and saw made me aware of the many cover crop options and their contribution to improving soil quality, combatting weeds, managing pests and fighting crop diseases.

The summit presentation by Wilson and Hoover gave me, a new organic planter, an understanding of the why, what and when of cover crops I should implement in my crop rotation in order to improve my soil. I’m planning to use a cover crop in my commercial garden after the snow peas and English shell peas finish in mid-July, which will probably be a non-legume such as rye. In my sweet corn plots, as the harvests are completed sequentially between late July September, I plan to use hairy vetch to rebuild my nitrogen for the next season.


Monitoring soil change

Professor Mary Barbercheck prepares to place a drop of soil solution (made mixing water and soil) onto a test paper to determine the soil’s pH level.

Mary Barbercheck, a Penn State professor of entomology, demonstrated four low-tech ways to monitor changes in soil quality:

Use test meters and test strips to monitor soil pH. The optimum range for most crops is between 6 and 7.5.

Use test strips to monitor soil nitrate which will show the amount of nitrogen in nitrate form that is available for use by plants.

Use a plastic barrier, water, a watch and a form that holds at least an inch of water to monitor the soil’s ability to take in water through the surface over time (infiltration). One inch of water soaking in per 30 minutes is considered to be moderately rapid.

Assess how easily an object can be pushed into the soil to monitor soil compaction. A penetrometer will actually measure the force being applied.

Also key to success is keeping records of these soil tests to have them for comparison later. In her presentation, Barbercheck introduced a soil-quality health card which I plan to use in my record keeping. This card lists items that can be assessed without the aid of technical or laboratory equipment, including soil tilth, compaction, water infiltration and generation, erosion, subsurface cover, soil life, soil organic matter, plant growth and plant roots.

There are three assessment description ranges (good, medium and poor). Within the ranges a numbered rating can be applied for more detail. Using a comparative approach, I can learn a lot about my soil. You can easily compare fields on your own farm or compare your fields with other farms' fields. For example, I could observe and assess that the Penn State fields would have a “good” rating compared to the same indicators in my farm fields—which I would place in the “poor” range.


Keeping natural N where it belongs

Robert Gallagher, an associate professor of cropping systems at Penn State, along with his students Justine Cook and Anna Starovoytov, presented management alternatives to improve nitrogen utilization from hairy vetch. They explained the need to manage excessive nitrogen from hairy vetch to prevent nitrogen leaching and environmental damage. This was surprising to me, because I wasn’t aware that N leaching was possible from a cover crop. I realized I needed to know: How much N does the vetch produce? What makes it leach away? How can you have a great crop of vetch, and keep it from becoming a pollutant?

Under good growing conditions and proper management, hairy vetch can supply enough N to even heavy nitrogen feeders. As a legume, it’s able to fix nitrogen from the atmosphere and convert it into a form that’s available to other plants. Vetch is managed to grow long enough to produce a huge amount of biomass, since the residue of the above-ground plant contributes significant nitrogen, in addition to what’s in the nodules on the roots.

Having a good crop of vetch depends on timely planting within the late summer to early fall sowing window, the weather in winter and spring, and the sowing date of the cash crops that follows. Heavy rains in the fall and spring can cause soil nitrogen to leach. Rye or other grains planted with the vetch can act as a “catch crop” for the nutrient nitrogen. These non-legumes take up nutrient N and prevent it from moving downward to below the root zone where it can become a pollutant.


Got your weed management covered?

Timothy Leslie briefed us on beneficial macro-organisms relative to soil quality and weed suppression. He explained that some beetle species, known as granivores, feed exclusively on weed seeds, and demonstrated a low-tech insect trap he uses to assess and identify insect populations in the field.

Bill Curran, a professor of weed science, with team members Ruth Mick, Steven Mirsky and Matt Ryan, discussed cover crops in weed management. The highlights of their presentation were the mechanical tactics of mowing and the use of roller/crimper technology to create a barrier of mulch and residue for weed suppression.

I gained much insight about how cover crops will help us achieve our productivity goals in the coming years by improving soil quality and helping us manage weeds.

Ed Bialon farms 34 tillable acres 3.4 miles from Huntingdon, Pennsylvania. His cash crops are sweet corn, snow peas, English shell peas and mixed grass hay.

[caddis]

Clovers, white, single cut red, and for your wetter areas alsike.....also a nice vetch throwing some purple flowers.

Gotta love plants that put nitrogen back in your soil.

Taker easy