This project will research, analyze and demonstrate the efficacy of several minimal tillage techniques to manage weeds generally, but especially amaranthus weeds, commonly referred to as pigweed, in fall grown vegetable crops that are usually direct seeded including spinach, beets, and carrots.
Through trials on three certified organic vegetable farms, the project will collect data about the efficacy of various non-chemical and minimal tillage methods to manage weeds, while analyzing the efficiency of labor usage and relationship to soil health, in order to inform growers about optimizing their integrated weed management strategy. In the process, we will also demonstrate how to deploy these techniques on the market garden/small farm scale to growers in the Northeast Kansas and the Great Plains region, and also attempt a wider reach through production of online materials demonstrating the techniques and discussing our findings.
This project will:
- Trial several non-chemical, minimal tillage weed control practices to manage weeds in fall vegetable crops including spinach, beets, and carrots on three farms in Kansas
- Monitor various performance metrics of the different techniques such as soil organic matter, labor time necessary for adequate weed control and harvest yield to provide a detailed picture of management technique performance
- Compile and disseminate information to aid farmers in decision-making for weed management strategies
Demonstrate techniques and communicate results to this region and beyond through on farm field days, presentations at regional conferences and online videos
Multiple bed trials of spinach and beets utilizing occultation, power harrow and flame weeding to create a stale seedbed.
*July 17 – prepped 2 beds and covered with tarp .
*August 9 – tilled and shaped 4 experimental beds and 2 control beds .
*Aug 17 uncovered 2 tarped beds .*Aug 18 fertilized all 8 beds .
*Aug 19 power harrow 2 beds and pressed 6 with power harrow roller to lightly incorporate
*Aug 19 seed 4 beds spinach and 4 beds beets .
*Sept 10 tilled in all beds due to low germination and high weed pressure
Second attemptCould not include occultation as timing was not right to cover a new area for multiple weeks.
*Sept 12 fertilized 3 beds .. power harrowed all 3 beds to incorporate fertilizer
*Sept 19 tilled control bed, power harrowed middle bed, flame
weeded south bed… seeded spinach, 1 control bed, 1 power harrow bed, 1 flame
weed bed .. was unable to implement tarp this round due to insufficient time… set
up mini-wobblers for irrigation
*Oct 1 cultivate with stirrup hoe – control, power harrow, flame … number of weeds and soil moisture made up the difference
between control and other beds… very little pigweed by this point, mostly henbit
**Oct 22 cultivate with stirrup hoe – control, power harrow, flame… Worker fatigue likely made up the difference in times
**Dec 5 two workers harvested all 3 beds…
Farm 2 2018 Report
We were able to plant carrots and spinach in two different setups plus the control. Control consisted on our usual mow cover crop, let foliage die, leave bed alone then till and plant fall crop. We planted spinach on 8/28 and carrots on 8/27.
For the tarp setup, we applied the tarp on 7/20. Removed on 8/27. Ground was very compacted due to water pooling on tarp and weighing down the soil. We used the back roller of the power harrow to try and rough up the top surface enough to use the seeder. Seeding was tough as the roughing up didn’t help much. Spinach and carrots planted as schedule above.
For the power harrow setup, we mowed cover crop and tilled then let ground sit. Once ready to plant we went over with the power harrow. Great tool. Planting same schedule as above.
We used constant irrigation to aid in germination of all beds. We got a late heat wave and the spinach did not germinate in any bed enough to keep. We tilled in 9/13.
We recorded harvest f in the fall. Started on 11/20 and went until just a few weeks ago when the ground finally froze under the row cover. We covered them in November and will report harvest totals after completion in spring 2019
The trial bed is about 70 feet long by about three feet, with two dense plantings of carrots in that bed. It is currently covered with row cover but we’ve had trouble keeping the cover down as winter progresses.
With such a dry season, we didn’t try to work the bed the end of July. We tilled, watered several times to try to get the pig weed to sprout because the soil was so dry. On August 2, we determined we had enough sprouts to try to cover it. We covered the bed with the cover white
side up and weighted it down.
On Sept. 4, we removed the cover because even though 6 weeks covered would have been ideal, we were running out of time for fall production. We planted in one bed, 70 feet long by three feet wide, with two plantings at either edge.
On Oct. 1, there are two photos that show pig weed in the row along with other weeds. Believe it or not, this was substantially less than what we would have otherwise had. The carrots sprouted and grew to about four inches. We weeded down the middle and the edges for about three hours by hand.
On Nov. 8, with cold weather approaching, we spent three hours weeding again, then mulching them throughly with straw and putting row cover over them. The carrots were only about two to three inches long so we wanted to see if we could get through winter with them and thin again in the spring to encourage larger growth.
Wildlife, a few errant chickens and wind have played havoc on the cover, but final data will be reported in spring 2019 at harvest.
Observations and preliminary thoughts.
On flame weeding as a control
Flame weeder worked well for small pigweed, typically our worst fall weed.
In areas where volunteer wheat spouted, the flame weeder did not affect the wheat that sprouted as a weed.
On the power harrow
The power harrow makes very nice seed beds, better than the tiller… but it appeared to sprout more weeds than the tiller as the more viable seed bank doesn’t get buried.
The tarp can be a challenge to manage and sometimes catches and holds water on top which
causes some soil compaction.
In year one we had a great deal of trouble. An extreme drought persisted in our region until early October and hot dry weather inhibited the establishment of fall crops in early to mid-August which is the normal window. Several trials failed due to poor crop germination and had to be repeated a few weeks later as soil temperatures dropped. Overall using these methods alone seemed to show poor results with high weed pressure in test beds, however I suspect that using them together would more effective than using them by themselves.
Overall, timing was the biggest challenge for using these weed suppression methods.If timed correctly flame weeding appeared to be very effective.. In a perfect world a better process might beusing these methods together would be a 2+ month process: 1) start with a relatively clean field with minimal plant material; 2) fertilize and prepare beds with power harrow; 3) if no rain comes, overhead irrigate, then cover with tarp and leave for 6 weeks to kill most viable surface weed seed; 4) pull back tarp, overhead irrigate again to sprout any remaining weed seeds and wait for a week or so; 5) flame weed any weed seeds that sprouted from irrigation; and 6) seed crop into flame weeded beds.
Educational & Outreach Activities
For outreach in the first year of this project we had four main outreach efforts. One on farm demonstration and discussion held in September at Mellowfields Farm. Six farmers attended, and we demonstrated the weed management equipment and discussed the course of the project this year. Attendees were able to observe the trial plots. Red Tractor Farm was a stop on the Kaw Valley Farm Tour in October, so we made signs for the trial beds that described the project and the trial technique- occultation. IN the fall and winter Tom Buller was able to make two presentations using information gathered in the first year. One was a presentation on Conservation Agriculture at the Great Plains Growers Conference on January 11, 2019 that incorporating observations from this project. Another presentation occurred at the Nebraska Sustainable Agriculture Society’s Annual Meeting on February 8, 2019. This presentation covered the whole course of the project to date, from initial conception to the end of the first year.
In year one of this project, it seems as though we went through a trial that exposed some of the challenges we had not expected. We hope to learn from those challenges and with our second year of field trials find more conclusive evidence and share with more fellow farmers.