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 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
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
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
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.