11.12: A Case Study, Celia Barss
- Page ID
- 25058
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\(\newcommand{\avec}{\mathbf a}\) \(\newcommand{\bvec}{\mathbf b}\) \(\newcommand{\cvec}{\mathbf c}\) \(\newcommand{\dvec}{\mathbf d}\) \(\newcommand{\dtil}{\widetilde{\mathbf d}}\) \(\newcommand{\evec}{\mathbf e}\) \(\newcommand{\fvec}{\mathbf f}\) \(\newcommand{\nvec}{\mathbf n}\) \(\newcommand{\pvec}{\mathbf p}\) \(\newcommand{\qvec}{\mathbf q}\) \(\newcommand{\svec}{\mathbf s}\) \(\newcommand{\tvec}{\mathbf t}\) \(\newcommand{\uvec}{\mathbf u}\) \(\newcommand{\vvec}{\mathbf v}\) \(\newcommand{\wvec}{\mathbf w}\) \(\newcommand{\xvec}{\mathbf x}\) \(\newcommand{\yvec}{\mathbf y}\) \(\newcommand{\zvec}{\mathbf z}\) \(\newcommand{\rvec}{\mathbf r}\) \(\newcommand{\mvec}{\mathbf m}\) \(\newcommand{\zerovec}{\mathbf 0}\) \(\newcommand{\onevec}{\mathbf 1}\) \(\newcommand{\real}{\mathbb R}\) \(\newcommand{\twovec}[2]{\left[\begin{array}{r}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\ctwovec}[2]{\left[\begin{array}{c}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\threevec}[3]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\cthreevec}[3]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\fourvec}[4]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\cfourvec}[4]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\fivevec}[5]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\cfivevec}[5]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\mattwo}[4]{\left[\begin{array}{rr}#1 \amp #2 \\ #3 \amp #4 \\ \end{array}\right]}\) \(\newcommand{\laspan}[1]{\text{Span}\{#1\}}\) \(\newcommand{\bcal}{\cal B}\) \(\newcommand{\ccal}{\cal C}\) \(\newcommand{\scal}{\cal S}\) \(\newcommand{\wcal}{\cal W}\) \(\newcommand{\ecal}{\cal E}\) \(\newcommand{\coords}[2]{\left\{#1\right\}_{#2}}\) \(\newcommand{\gray}[1]{\color{gray}{#1}}\) \(\newcommand{\lgray}[1]{\color{lightgray}{#1}}\) \(\newcommand{\rank}{\operatorname{rank}}\) \(\newcommand{\row}{\text{Row}}\) \(\newcommand{\col}{\text{Col}}\) \(\renewcommand{\row}{\text{Row}}\) \(\newcommand{\nul}{\text{Nul}}\) \(\newcommand{\var}{\text{Var}}\) \(\newcommand{\corr}{\text{corr}}\) \(\newcommand{\len}[1]{\left|#1\right|}\) \(\newcommand{\bbar}{\overline{\bvec}}\) \(\newcommand{\bhat}{\widehat{\bvec}}\) \(\newcommand{\bperp}{\bvec^\perp}\) \(\newcommand{\xhat}{\widehat{\xvec}}\) \(\newcommand{\vhat}{\widehat{\vvec}}\) \(\newcommand{\uhat}{\widehat{\uvec}}\) \(\newcommand{\what}{\widehat{\wvec}}\) \(\newcommand{\Sighat}{\widehat{\Sigma}}\) \(\newcommand{\lt}{<}\) \(\newcommand{\gt}{>}\) \(\newcommand{\amp}{&}\) \(\definecolor{fillinmathshade}{gray}{0.9}\)Athens, Georgia
When Celia Barss became the farm manager of Woodland Gardens Organic Farm, she knew cover crops were going to be a big part of the rotation from the start, a decision she’s grateful she stuck with. “We built up slowly,” she says. “Even the open ground, we just cover cropped it until we had time to start producing cash crops. Some fields got to be cover cropped for three years before we started growing in them.”
The cover crops play a key role in diversifying the 12-acre operation’s rotation, which now includes more than 80 different types of fruits and vegetables, as well as cut flowers, that are sold either to restaurants in Atlanta, to a local farmers’ market or through their CSA. Cover cropping is also done in the greenhouses and hoop houses, which make up 1.5 acres of their eight tillable acres. The remaining acreage is in perennial production, which consists of blueberries, figs, muscadines (a native grapevine) and asparagus. The perennials are grown in their own separate areas on heavy slopes, with grass in between them to protect the soil instead of cover crops.
Barss uses cover crops primarily to build up soil organic matter, which, she says, they are “burning through” due to their climate and tillage practices. She explains that she tills because of their intensive planting schedule and tight crop spacing, but she is trying no-till on two open fields that get planted the earliest. With heavy clay soils and wet springs, Barss felt she was doing too much damage tilling under those conditions, so she decided to create beds, leave them fallow for two months, then cover them with silage tarps for a month prior to production. While it was a compromise for her to leave the soils bare like that, she was impressed with how ready to go the fields were after pulling off the silage tarps. She also makes sure to do a heavy summer cover crop on those fields since they are left bare longer than she prefers. Everything else gets planted with cover crops between cash crops.
The cover crops are also key to dealing with some production challenges, primarily weeds and nematodes. Amaranth has become the farm’s biggest weed challenge in the summer, and Barss is also utilizing landscape fabric to help with suppression. “Weeds are all about prioritizing how you do stuff on the farm,” she says. “Timing of getting [fields] weeded or into cover is everything, and just not letting [weeds] go to seed.”
Nematodes, on the other hand, are a challenge that slowly crept up over the years. Barss started seeing nematode pressure around the tenth year of production in their stationary houses. All of those stationary houses have some level of pressure: the newest ones less, the oldest ones the most. Barss admits this problem occurred from not maintaining a longer period out of a host crop in the houses. But in order to reduce nematodes through rotation, she wouldn’t be able to grow a cash crop for six months, because all of them are hosts for nematodes, she explains.
To help combat the nematodes, they were advised by Elizabeth Little, an Extension plant pathologist at the University of Georgia, to try sunn hemp as a cover crop for its nematicidal traits. But Barss can only have sunn hemp grow and break down before a cash crop in the houses for three months, which she’s realizing is not long enough to break the life cycle. She has been solarizing too, which helps suppress the nematodes long enough for their tomato crops, but after tomatoes and most summer crops, the nematode populations have built back up enough to damage the crops that follow in the fall.
While Barss would be happy to do more cover cropping in the houses because of the difference they make in soil tilth—“it’s amazing the difference when we go in after a cover crop,” she says—the farm can’t afford to be out of production for longer than three months. Instead, she’s moving from solarizing to soil steaming so she can cover crop and treat for nematodes. This approach will still allow her to do more cover cropping because while solarizing takes six weeks, steaming only takes half an hour. “I can do a quick cover crop and then do the steamer before going into a cash crop, instead of solarizing in addition to the cover crop,” Barss explains. But soil steaming requires a lot of energy and can be a big financial investment for the steamer, so it’s considered an alternative when other options aren’t available.
In addition to sunn hemp, Barss uses a lot of cowpeas and sorghum-sudangrass together in the summer because they do well in the heat. In areas where she has a shorter window, like six weeks, she’ll use millet or buckwheat instead, since it’s not enough time to let the cowpeas and sorghum-sudangrass grow. In the winter and cooler seasons, she’ll use rye, hairy vetch and Austrian winter peas in fields that will be in cover for longer periods. In fields where she’ll be planting early or needs to fill in shorter gaps in the spring and fall, she’ll use oats because they’re easier to terminate.
Oats will also follow in the spring in places where brassicas may have gone too late. Unlike the hoop houses, fields have a good three- or four-year rotation between plant families, Barss says, which is mostly dictated by the brassicas. “The brassicas really push the rotation, and that’s the family I’m finding myself always doing less than I want to because of rotation.” Her rotations vary by field, as she has to stay out of some later than others because they’re too wet in the spring, but a typical rotation might include early spring brassicas, followed by the field peas and watermelons split 50/50 across the field, then two cycles of a cover crop.
Barss tries to get as much out of the cover crops as possible while they’re growing by mowing sorghum-sudangrass, for example, to about a foot and letting them regrow. This extends their life while preventing them from going to seed. “Our goal is to have [the cover crops] go as
long as possible and keep the ground covered because we have such a long summer,” she says. When it is time to terminate them, she’ll flail-mow and incorporate them into the soil.
Her focus on cover cropping has paid off. Barss says initially there were fields she didn’t want to plant certain crops in because she didn’t think the soil quality was good enough. Instead she would plant a crop that didn’t need a lot of nutrients, such as field peas, and then focus on
cover cropping it. Now she can plant any of their crops in those fields, stating: “it’s amazing the difference in a field that I went into 10 years ago that hadn’t been cover cropped.”
“I attribute everything to the cover cropping, honestly, for the quality of our soils,” Barss says. “I could grow a lot more, but I wouldn’t be able to do the cover cropping the way I am. Just forcing yourself to stick to those ideals that you set up and making sure you stick to those rotations and
not just trying to plant more and more. Because it’s easy to start doing, but then you definitely see your soil quality start to go down.”
| Field | Season | 2019 Season | 2020 Season |
|---|---|---|---|
| 2 | Winter | strawberries, onions, flowers | Covers: rye/peas/vetch |
| Spring | strawberries, onions, flowers | Covers: sorghum-sudangrass/cowpeas | |
| Summer | cover crop | Covers: sorghum-sudangrass/cowpeas | |
| Fall | cover crop | Brassicas | |
| 5 | Winter | cover crop | Herbs |
| Spring | herbs | Herbs | |
| Summer | herbs | cover crop | |
| Fall | herbs | cover crop | |
| 6 | Winter | cover crop | cover crop |
| Spring | cover crop | cover crop | |
| Summer | cover crop | beans/beets/flowers | |
| Fall | Brassicas | beans/beets/flowers | |
| 7-A | Winter | cover crop | cover |
| Spring | cover crop | tomatoes/flowers | |
| Summer | sunchoke, edamame, flowers | tomatoes/flowers | |
| Fall | cover crop | cover crop | |
| 7-B | Winter | cover crop | cover crop |
| Spring | peppers, eggplant | cover crop | |
| Summer | peppers, eggplant | cover crop | |
| Fall | cover crop | brassicas | |
| 8-A | Winter | cover crop | cover crop |
| Spring | cover crop | peppers, eggplants, herbs | |
| Summer | watermelons, flowers, beans, cukes | peppers, eggplants, herbs | |
| Fall | cover crop | cover crop, herbs | |
| 8-B | Winter | cover crop | cover crop |
| Spring | brassicas, scallions, beets | flower/cover crop | |
| Summer | squash, beans | unknown | |
| Fall | cover crop | cover crop | |
| 9-A | Winter | cover crop | strawberries/onions/flowers |
| Spring | potatoes | strawberries/onions/flowers/beans | |
| Summer | cover crop | cover crop | |
| Fall | strawberries, onions, flowers | cover crop | |
| 9-B | Winter | cover crop | cover crop |
| Spring | cover crop | cover crop | |
| Summer | cover crop | cover crop | |
| Fall | cover crop | brassicas | |
| 9-C | Winter | cover crop | cover crop |
| Spring | cover crop | cover crop | |
| Summer | cover crop | cover crop | |
| Fall | cover crop | brassicas | |
| 10 | Winter | cover crop | cover crop |
| Spring | flowers, melons, corn, cukes | potatoes | |
| Summer | cover crop | cover crop | |
| Fall | bedded up for spring | cover crop | |
| 11 | Winter | cover crop | cover crop |
| Spring | brassicas | cover crop | |
| Summer | field peas, watermelon | corn, beans, squash | |
| Fall | cover crop | cover crop | |
| 12 | Winter | cover crop | cover crop |
| Spring | cover crop | cover crop | |
| Summer | cover crop | field peas/flowers | |
| Fall | brassicas, chicories | cover crop | |
| 13 | Winter | garlic, cover crop | fallow |
| Spring | garlic, cover crop | brassicas, scallions, lettuce | |
| Summer | cover crop | squash, corn | |
| Fall | prep for spring | cover crop | |
| 14 | Winter | cover crop | garlic, cover crop |
| Spring | cover crop | garlic, cover crop | |
| Summer | tuberoses, field peas to cover crop | cover crop | |
| Fall | garlic, cover crop | cover crop/prep for spring | |
| 15 | Winter | cover crop | cover crop |
| Spring | cover crop | squash, corn | |
| Summer | sweet potatoes, melons | cover crop | |
| Fall | cover crop | garlic, cover crop | |
| 17-A | Winter | cover crop, herbs | cover crop |
| Spring | peppers, herbs | sweet potatoes, tuberoses | |
| Summer | peppers, cover crop | sweet potatoes, tuberoses | |
| Fall | cover crop, brassicas | cover crop | |
| 17-B | Winter | cover crop | fallow |
| Spring | squash, corn, beans | brassicas | |
| Summer | cover crop | field peas, watermelons | |
| Fall | prep for early spring | cover crop | |
| 18 | Winter | cover crop | cover crop |
| Spring | cover crop | cukes, melons, winter squash | |
| Summer | tomatoes, okra, flowers | cukes, melons, winter squash | |
| Fall | cover crop | brassicas | |
| 19 | Winter | cover crop | cover crop |
| Spring | cover crop | cover crop | |
| Summer | winter squash, corn, beans, summer squash | melons, watermelons, edamame, okra, beans, tuberoses | |
| Fall | brassicas | cover crop |