It is rare for August to serve up days as pretty as the 15th. The Twilight Tour was a great chance to pass the time outdoors and learn about the latest organic farming research being conducted at the Central Maryland Research and Education Center in Upper Marlboro. I joined 30+ farmers, including about a dozen new and beginning farmers on the tour. Surveys indicate that most new and beginning farmers are interested in growing organically.
Dr. Jerry Brust spoke at the first stop on the tour. This year, as an experiment, he planted tomatoes into a
barley/crimson clover cover crop that had been crimped in the spring. The tomato plants still looked healthy.
The study focus was on weed management. The vegetative mat formed by the decaying covercrop did not control the weeds the entire year (as evidenced in the photo). Jerry had mowed the weeds twice during the growing season on the near side of the row and the weeds were under control. On the other side, he dragged a 4’wide weed barrier every one-two weeks along the row to smother the weeds. The weeds on that side of the row (not shown in the photo) were under control as well.
Farmer Mike Klein was also asked to explain how he controlled weeds organically in his high tunnels. He reported that this year he is using 6′ weed barrier mats, which he applies the same time that he installs the drip line and plants the tomatoes. He was pleased with the results.
At the next stop we joined Lauren G. Hunt and Armando Rosario-Lebron in a corn plot. Their experiments involved the planting of insectary “companion plants”, such buckwheat and purple tansy, to attract natural enemies of the Brown Marmorated Stink Bug and other pests that feed on corn and many other crops. Buckwheat and purple tansy attract parasitiod wasps. According to Lauren, the parasitoid lays its eggs inside the stink bug’s eggs and the stink bugs are unable to emerge. While the buckwheat grew well, the purple tansy did not, so they will replace it in next year’s experiment. The hope is that strategic planting of a variety of these beneficial plants can attract enough native parasitoids to sufficiently curb the populations of the pests naturally.
A few hundred yards away, we joined researchers Peter Lynagh and Greg Polley who are a investigating the effects of different tillage systems on soil temperature, moisture, nitrogen mineralization, pests, greenhouse gas emissions, plant growth and economics. The crop was sweet corn and the tillage systems investigated were conventional tillage (Bare Ground), black plastic, strip tillage and no tillage. The latter two tillage systems involved planting corn in the residue of a cover crop mixture of forage radish, crimson clover and rye.
Preliminary results showed that strip tillage produced the highest yield and the second lowest weed density. The greenhouse gas emission data is not available at this time.
At the next stop, Dave Myers (Extension Agent and Ice Cream Maker Extraordinaire) presented the Meadow Orchard project. Conceived by the Southern Maryland Fruit Team, the Meadow Orchard is intended to provide small-scale farmers with a new income source. The hope is that by finding fruit varieties that have fewer pests and higher
tolerance of diseases in the Southern Maryland region, the farmers will be able to add fruit to their offerings. So far, Dave noted that a number of varieties show promise, including fall raspberries, fall blackberries and brown turkey figs.
As the sun was just hanging over the horizon, we arrived at the crookneck squash patch where we joined researcher Amanda Buchanan. The objective of her study was to use different cover crop treatments and look for their impact on insect pests, weeds, soil nutrients, and crop yield. The treatments were: no cover crop (bare ground), barley, crimson clover, and barley and crimson clover. The barley + crimson clover treatment had the most biomass, the lowest weed density, the highest soil nitrate and the highest yield. The barley plots had the lowest arthropod counts (squash bugs, squash bug egg masses and
cucumber beetles), closely followed by the barley + crimson clover.
She also noted that hand weeding was necessary with all of the cover crop treatments, but that bare ground weeding time was much higher than the other three treatments. The barley + crimson clover treatment required the least weeding time.
Organic vegetable farmers know that their products can command higher prices from consumers. Many grow organically out of a commitment to minimize their impact on the environment. Others grow organically because they refuse to work with chemical pesticides, herbicides, and fungicides. However, growing many of these crops organically in Southern Maryland’s wet, humid climate may sometimes feel like trying to sail across the ocean without a sail, a motor and a rudder. Therefore, organic farmers are always grateful for any ideas that reduce weed pressure, improve soil health and increase yield.