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Farm Scale Study: Weed Management

July 10, 2009
Weed Management

Weed management with hand tools (Benjamin Austin, foreground) and a tractor (Tony Silvernail, background).

At the beginning of July 2008 I posted pictures of the farm scale study at Kentucky State University. Here are some pictures of the same study, repeated in 2009. The plot diagram that I posted in 2008 is identical for 2009, except that we have rotated the crops:

  • Last year’s soybean rows are this year’s corn.
  • Last year’s corn is this year’s sweet potato.
  • Last year’s sweet potato is this year’s sweet sorghum.
  • Last year’s sweet sorghum is this year’s soybean.

To get the crops off to a good start we are focussing on weed management.

Last year I posted a vibrant picture of a blooming mustard cover crop. This year I’ll post a picture of heritage tomatoes growing among a blooming buckwheat cover crop. As I walk through this field, hoe in hand, I’m surrounded by the buzzing of bees, hard at work in the buckwheat. We planted wide strips of buckwheat between the tomato rows to help prevent cross-pollination between different heritage varieties of tomato that we’re using for seed production. Buckwheat grows vigorously, crowding out weeds.

Michael Bomford walks between a row of heritage tomatoes and a blooming buckwheat cover crop.

Michael Bomford walks between a row of heritage tomatoes and a blooming buckwheat cover crop at the Kentucky State University Research Farm.

Our Biointensive and Market Garden scale plots are much more advanced than at this time last year. The following two photos show plots that I photographed on July 7th last year, from the same perspective. Last year the corn was knee-high and the sweet sorghum was barely emerging on July 7th. This year the corn is already tasselling in the biointensive plots. We hand-pollinated corn in the biointensive plots to ensure the ears would fill despite the fact that the larger plots in the vicinity have not yet started producing pollen.

A biointensive plot in the east corner of Rep 2, looking west. From left to right the crops are soybean, corn, sweet sorghum, and sweet potato. One corn variety already has tassels.

A biointensive plot in the east corner of Rep 2, looking west. From left to right the crops are soybean, corn, sweet sorghum, and sweet potato. The corn is tasseling.

A market garden plot in the south corner of Rep 3, looking north. From left to right, the crops are soybean, sweet sorghum, sweet potato and corn. A biointensive plot growing the same crops on a smaller scale is in the background, with a buckwheat cover crop blooming behind it.

A market garden plot in the south corner of Rep 3, looking north. From left to right, the crops are soybean, sweet sorghum, sweet potato and corn. A biointensive plot growing the same crops on a smaller scale is in the background, with a buckwheat cover crop blooming behind it.

Weeds have been less of a problem in our biointensive and market garden plots in 2009 than in 2008, but more of a problem in our small farm plots. We are using an old Farmall 130 tractor as our main weed management tool in the small farm plots. These little tractors are ubiquitous on Kentucky’s old tobacco farms, they are an appropriate size for small farms, and they feature an offset engine block and belly-mounted colters in front of the driver, helping the operator to get close to the crop row without damaging the crop.

When the tractor is done we come through with a hoe to clean up any weeds in the crop rows. We mostly end up hand-hoeing our sweet potatoes — even in the small farm plots — because their vining growth habit makes them susceptible to damage by the tractor.

Hoe and tractor

Benjamin Austin hoes sweet potatoes while Tony Silvernail weeds between corn rows with a Farmall 130 tractor. Mr. Austin is a high school student completing an internship at Kentucky State University through the Research and Extension Apprenticeship Program.

There’s plenty of weeding for everybody.

Michael Bomford hoes weeds between sweet potatoes.

Michael Bomford hoes weeds between sweet potatoes.

Michael Bomford provides research and extension services related to organic agricultureand small-scale renewable energy production through Kentucky State University’s Land Grant Program. He thanks Tony Silvernail, Benjamin Austin, Brian Geier and John Rodgers for their help with maintaining the organic land at the KSU Research Farm in recent weeks.

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One Comment leave one →
  1. Sharon permalink
    September 28, 2009 7:23 pm

    Thanks to you and your group for doing this wonderfully interesting experiment.

    In looking over the information you posted, I saw a few things that might be affecting your experiment unexpectedly.

    In the biointensive plots and to a lesser degree in the market garden and small farm plots, the yields might be affected by the degree to which the grass/cover crop on the edges is using the water and nutrients in the garden plots or using up soil fertility and water in areas where the biointensive bed plants would be trying to send out roots. In most of the market and small farm plots the plants aren’t competing with the grass/cover crop. It looks to me from some of the pictures that at least 50% of the biointensive plants would be affected by this. In your market and small farm plots the crops that run parallel to the edges would be most affected by the adjacent vegetation. I mention this because I have noticed that the rows of crops next to a farmer’s lawn or dirt farm roads or paved roads often produce much less than crops 10 feet or so into the garden. And actually it’s possible that the entire biointensive garden is in this lower productivity zone.

    In the biointensive gardens was the vegetation that was removed composted and brought back to the biointensive garden a few weeks later? If not some of the soil fertility that was plowed and composted into the market and small farm plots would be missing from the biointensive plots. At this point to compensate the only thing I can think of would be in 2010 to remove the sod/cover crop and the equivalent amount of soil that was removed in the first year’s prep from a similar area, chop it up into small cubes (maybe with a machete–and all this would add to plot time) such as would happen with a tiller, and compost it for a few weeks (perhaps in a raised twin compost tumbler to protect the nutrients from leaching) and then return it to the garden along with the regular compost that would have gone into those plots anyway.

    You mentioned the first year being complicated by drought. I wasn’t sure if you watered all the plots or not, but if not this does have a big impact on biotensive gardens. (Steve Soloman’s books have a good perspective on this.) If you aren’t watering and have the resources, it might be worth having a fourth garden style with the same number of plants as the biointensive garden and planting them in a waffle style garden which would take 2-4 times the space of the biointensive garden depending on the severity of the usual drought. If you mix the crops in each waffle it might help to start with the potatoes at mid waffle and let them run between corn and beans in the lower section of the waffle and then to do some the opposite. That way if you get little rain some of the potatoes will do well, and if you get a lot the higher ones will be less apt to rot.

    Looking forward to hearing more about the 2009 adventures with the experiment.

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