Final report for FNC20-1204
Project Information
We are a certified Organic farm operating 260 acres in total. Our main enterprises include grassfed beef, pastured heritage hogs, pastured laying hens, and organic vegetables. The farm has been in operation for over 100 years and organic for the past 30, but is undergoing a change in structure as we are in the process of transitioning to a cooperative ownership model along with a non-profit educational and advocacy arm.
Soil health is a key tenet in organic agriculture. Without healthy soils production and ecosystem diversity suffer. Many organic vegetable farming techniques require intensive tillage for initial bed preparation in order for the myriad mechanical weed control techniques to be effective. The downside is obvious, soil health suffers due to intensive plowing and tillage. While steps have been taken to incorporate no-till methods from organic row-cropping systems into vegetable systems, these methods are often only usable in highly competitive crops with wide spacing and relatively low value. Our goal is to utilize a combination of tractor mounted tools (deep shank and power harrow), which have hand tool analogues (broad fork), to prepare high rotation vegetable beds of higher value crops (lettuce, beets, carrots, and other leafy greens) compared to using a rototiller for bed preparation.
Hypothesis 1: There will be a significant difference in total organic matter, soil compaction, and/or meso-fauna diversity between treatments.
Hypothesis 2: Final levels of total organic matter, soil compaction, and/or meso-fanua diversity will be significantly different than at the start of the experiment.
Research
The two major methods we will explore are subsoiling and power harrowing. We will scale up each practice to be tractor mounted and useable on more than 5 acres. There will be four treatment groups:
- Negative control (rototiller only),
- deep shank + rototiller,
- power harrow alone,
- and deep shank + power harrow.
Each treatment will be done preceding establishment of each crop. Composted cow manure, made on the farm and certified organic by MOSA, will be applied at recommended amounts for each crop prior to planting. Termination of the crops using a flail mower will follow final harvest window for each one.
The high value crop sequences we will use are lettuce (salanova, baby leaf salad mix, or head lettuce), spinach, and quick rotation root crops (beets, carrots, turnips, and radish). We will incorporate a crop rotation sequence that allows for different families of plants to be grown in the same season without risking disease and nutrient deficiencies (Table 1). Between row and within row plant spacing can be found in Table 2.
Preliminary soil samples of each bed will be taken prior to planting. These tests will examine total organic matter, soil compaction, and meso-fauna diversity and abundance (earthworms, arthropods, etc.) along with standard macro and micronutrient profiles. The same set of tests will be conducted at the end of each growing season for two straight years as well as the start of the second year. Samples will be sent to the University Wisconsin (UW) - soils lab and collected according to the standard pooled sampling guidelines. Replicated data sets from the UW-soils lab will be retained and used for ANOVA analysis to compare differences in test variables by treatment type, and before and after analysis of each variable. These tests will be run using the R-project software package.
Table 1: Years 1 and 2 crop rotation strategies.
|
April 2020 - July 2020 |
Lettuce (spring/summer) |
|
July 2020 - November 2020 |
Carrots (late season) |
|
April 2021 - May 2021 |
Spinach (spring) |
|
May 2021 - August 2021 |
Beets/Radish (summer/fall) |
|
August 2021 - December 2021 |
Green Manure Cover Crop |
Table 2: Crop type, in-row spacing between seeds, between-row spacing. Twelve inches between rows indicates three rows per thirty-six inch bed and six inches between rows indicates five rows per thirty-six inch bed.
|
Crop |
In-row spacing |
Between-row spacing |
|
Beets |
2 “ |
12” |
|
Carrots |
2” |
12” |
|
Lettuce (Loose Leaf) |
1” |
6” |
|
Lettuce (Salanova/Head) |
6” |
12” |
|
Radish |
2” |
6” |
|
Spinach |
1” |
6” |
The plan was to purchase a TS48 Compact Power harrow with seedbed roller by R2 Rinaldi. Due to the COVID19 pandemic, Rinaldi was unable to ship a power harrow so I sourced an Ibex TX40 from Tractor Tools Direct instead. The mechanical parameters are almost identical so this change does not have any impact on the stated outcomes of the project.
The original plan also included the purchase of a Buckeye Tractor Company Subsoiler Center Shank. Buckeye Tractor Co. was also having major difficulties due to the COVID pandemic so I was not able to purchase a center shank subsoiler from them. Instead, we custom fabricated one using an old three point mount along with a 5/8" thick steel plate. Again, the function of the project was not impacted because of this change. In fact, this course of action is what I would recommend to other farmers looking for a deep shank subsoiler on their own farm.
My results showed no significant difference between treatments in 2021, but I think it may be due to the late start of the project, due to supply issues at the start of the pandemic, and our project would benefit from another season's data. For these reasons, I requested an received an extension until 12-31-22.
Educational & Outreach Activities
Participation Summary:
We have not completed the project yet and due to COVID, all on-farm demonstrations and conference presentations have been put on hold. The only other farmers that have seen the project in action are those in our cooperative who are also thinking of implementing these practices. Our plan is that the fall and winter season (2021 - 2022) will be the start of our educational offerings with plans to continue them long into the future as we fine-tune the practices started during the grant cycle.
Presentation at MOSES organic farming conference in February 2022 was done but because of the extension of the grant only preliminary results were presented. A followup presentation is planned for February 2023 with final results and expanded examples for future uses and improvements. Another presentation is planned virtually for August 2022 in the "Farming Matters" series. I will also send applications in to speak at the Organic Vegetable Growers Conference and the Practical Farmers of Iowa conferences for the 2022/23 winter season.
Our plan was to host at least one field day highlighting the power harrow during the 2020 growing season. However, due to the pandemic we decided to forgo this gathering and will have farm events during the 2021 and 2022 growing seasons.
We had one farm event on June 4th of 2022 where 100 CSA members and other community members came to the farm for a dinner and tour. During the tour I highlighted the use of the power harrow in our field preparations and how the purchase of it was facilitated through a grant from NCR-SARE. A few of the participants who work in local government and others who have small farms of their own took special interest in the grant program and will either encourage people they know or will themselves apply for projects of their own. There were some members of the City of Green Bay's sustainable development commission who noted the importance of grant programs like SARE and will likely include recommendations of similar funding circles for food system development in the city to the mayor.
Learning Outcomes
There were many lessons learned, both novel and relearned, throughout the time of the grant. One of the most obvious lessons was the importance of having an effective way of breaking down and turning over existing organic matter in the bed that needs to be worked. The expected outcomes of the power harrow/deep shank system were not reflected in the data as there was no significant difference in the physical parameters of the soil when compared to a rotavator. However, the lack of difference in the systems may have been a result of improper organic matter termination the first year which resulted in significant weed mass the following year. The issues with the power harrow were evident when there were intact plants left on the soil surface as the mechanical action of the harrow was not to bury or chop the material, in the manner of a rototiller, but rather bring it to the surface. This necessitated multiple passes with the power harrow and an additional pass to hand rake out any weeds leftover. The extra passes with the harrow likely affected the aggregate stability of the O-horizon in the soil which defeated the purpose and benefit of the power harrow in the first place.
In other plots on the farm, where there was little to no surface organic matter due to use of a flail mower or chisel plow. The power harrow did a much better job with a single pass in preparing the soil for planting. Additionally, the timeframe of the experiment did not seem to permit the details of longer term management strategies to become evident. Therefore, we will continue to gather and collect data for years to come to demonstrate the effects of this tillage method on soil health and quality. I have had many farmers reach out regarding the efficacy of implementing a power harrow for final seedbed preparation on their farm. My recommendation to them has always been the same: don't outright change what you are doing, rather use the power harrow as a final seedbed prep instead of a rototiller on a few acres and be ready to till if it doesn't work right away. You need to practice with this method before you can be completely confident that it will work the way you need it to. There have been some farmers with glacial till soils that are extremely abundant with fist-sized rocks who I have specifically advised to either not get a power harrow or at least the Ibex brand because those rocks would regularly find their way into the teeth of the harrow and break shear bolts all the time, resulting in a lot of headaches and time getting on and off the tractor.
Project Outcomes
Multiple Farmers at 2022 MOSES Organic Farming Conference: Everyone in the room (at least 100 people) said that they were excited to see someone using this method and have gone through the trials to see what works and doesn't. They all said they would be interested in incorporating something like it on their farm.
I will continue to collect soil health and physical attribute changes as long as we use the power harrow and deep shank system on our farm. It may be advantageous to keep an eye out for any other projects that come up that wish to explore more detailed effects (parent soil type, working depth, number of passes throughout the season, time after a soaking rain event, different brands and their resilience or different modes of action, etc.).
This was a very preliminary study and should not be taken outright to indicate that there is no difference between power harrow and rototiller or use or lack of use of a deep shank ripper on soil health.