Growing organic soybeans


My wife and I have about an acre of land by our house that we want to grow soybean on. There are at least two other growers in our area but they do make use of pesticides. We want to do this completely organically and avoid the use of herbicide. What are the best ways of keeping the weeds down on this scale? We’d really appreciate any advice before we take take this on.

Posted by: George Gifford (3 points) George Gifford
Posted: February 20, 2013

George Gifford commented,
Dave and Steven, thank you very much for your insights it was exactly what I was looking for and extremely helpful. Given that I do not yet have access to some of the equipment needed I fear that this may be a more realistic project to start next year. Is it considered good practice to plant corn before planting the soybean or could the soybean be the first crop to be sown?
almost 8 years ago.


The typical practice for organic weed management in soybean involves several steps. First, work out a rotation plan that helps build soil health and avoids selecting for weeds adapted to summer crops like soybean. For example, it's quite common to grown a winter cereal and an earlier planted summer crop (vegetable or corn for example) in rotation with soybean. Since different weeds are adapted to differing conditions, you avoid selecting for those that are most adapted to germinate and compete with soybean. Once the soybean crop is in the ground, there are specific tools that organic growers would use in soybean. Early on, before any plants (weeds or crop) have emerged, it's common to pull a rake like device across the field (attached to a small tractor), that device is called a tine weeder. The tines (scratch the soil uprooting "white thread" stage weed seedlings leaving the larger seeded soybean undisturbed. Some growers would follow the tine weeding with a rotary hoe (another tool designed to uproot small weeds) up through the first trifoliate leaf stage of soybean. Then, when the soybeans are 6-10 inches tall you'd pull a row cultivator through the field uprooting weeds in the interrow and throwing soil to the crop row. I'd be happy to send more details if it's helpful.

Posted by: Dave Mortensen (7 points) Dave Mortensen
Posted: February 21, 2013

Dave's approach is generally what has worked for us as well. The first line of attack in all organic weed management is to diversify your crop rotation so that the crops you plant differ in their phenology (fall planted, spring planted, summer planted crops, and perennials). This will diversify the selection pressure on weeds and prevent any species of weeds from completely dominating and its populations from rapidly growing. After focusing on your crop rotation, standard approaches to mechanical weed control in organic soybean production includes 2-5 blind cultivations (tine weeders and rotary hoes) and 2-3 between row cultivations (s-tine cultivators, wide singe sweep cultivators). The blind cultivations should be done the day of planting to try and create a soil dust mulch (loose soil that decreases optimal conditions for weed germination). After at-planting tine weeding or rotary hoeing, try and get in 1-2 more blind cultivations on 3-4 day intervals. Be careful not to blind cultivate when soybeans are in the crook stage (just emerging). They are easily snapped off. Once soybeans are 6-10 inches tall and blind cultivation will begin to do a lot of damage, switch to inter-row cultivators. Try and use an inter-row cultivator that has shields for the first pass or you can move a lot of soil on the row and bury plants. At last cultivation, many growers will use hillers to throw a lot of soil around the base of the soybean plants and bury weeds. An acre is not that much land, so it would not hurt to go out with a pair of clippers and take the tops off the really big weeds before they produce mature seed heads. That will keep weed seed production down and lower weed populations in your crops over time.

Good luck.

Posted by: Steven Mirsky (3 points) Steven Mirsky
Posted: February 22, 2013

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