Progress report for FNE23-068
Project Information
This project seeks to develop a production method for direct-seeded carrots that will improve germination and reduce in-row weeds by seeding into strips of finished compost.
In year one, objectives were:
- To determine an efficient system for preparing compost strips on a small scale.
- To compare results in in-row weed control using different depths of applied compost strips and different compost products.
- To compare results in germination, and in weed species present, using different compost products.
In year two, objectives will be:
- To develop a mechanized system to apply compost strips
- To determine the optimal compost product and compost strip depth by comparing the most promising four treatments from Year 1 in a replicated field trial and analyzing the data.
- To assess the financial feasibility of using this system by comparing the input and labor costs of planting into compost strips with the costs of using our standard system of producing carrots.
Carrots have been a challenging crop for us at Hearty Roots for all of the 19 seasons we have farmed, whether on a tiny scale or on a larger scale. Although we have had some great success, there have also been many frustrations and failed plantings. We face two primary challenges:
- Weed pressure. Because carrots are slow to germinate, and must be direct seeded, weeds have an opportunity to get ahead of carrot seedlings. While weeds between rows can be managed through cultivation, weeds in the row must be hand-weeded, usually at a peak time of the season when labor hours are stretched thin. We have also used flame weeding to attempt to control weeds in the row, by burning the newly germinated weeds before the carrots emerge. However, this method has several drawbacks: it is risky, as carrot seedlings can be burned inadvertently; it is fossil fuel intensive, as it relies on propane; and it is an unpleasant and time-consuming task.
- We farm sandy and gravelly soils, which do not hold moisture for long. To encourage carrots to germinate, we need to irrigate with sprinklers almost daily. However, this practice also encourages weeds to germinate, and can also lead to crusting of the soil which prevents carrots from sprouting up.
When we have good germination and we are able to control in-row weeds by hand weeding, a clean bed of carrots is a joy to harvest, yielding quickly picked bunches of profitable, high-quality roots.
We will trial a system for growing carrots that we believe will improve both the in-row weeds problem and the germination problem. After creating narrow trenches on the vegetable bed top for each carrot row, we will fill the trench with finished compost, and then seed directly into the strip of compost. The compost strip will serve three purposes:
- The weed-free compost will smother weed seeds that are in the soil below the strip, preventing germination of weeds in the carrot row.
- The friable texture of the finished compost and its ability to hold moisture will improve carrot seed germination by resisting crusting at the surface and by keeping the seeds moist.
- The application of compost will also provide fertility to the growing carrots, a method we already use on the farm on a broadcast basis. This system will use a similar quantity of compost, but carefully targeted in its application, to provide the additional benefits listed above.
If we are able to demonstrate a reliable system for germinating and growing carrots with minimal in-row weeds through planting into compost strips, the benefits to the farm will be many. We could reliably seed carrots through the summer, without losing plantings that get too weedy because we are too busy with peak season chores; we could improve harvest efficiency as beds with fewer weeds are much faster and easier to harvest than weedy beds; and we could improve our efficiency of land use, with higher yields per foot due to improved germination rates.
We are optimistic about the potential for this project, but also aware of possible pitfalls, which is why running a careful trial is important. Possible complications that we will be on alert for as we progress through the trial include: might some of the compost products have weed seeds that end up germinating in the row? Will the high organic matter of pure finished compost cause carrots to fork? Our hypothesis is that this system will be an improvement in all of these areas over the traditional system, and this trial will give us the data to test that hypothesis.
Cooperators
- - Technical Advisor
- - Technical Advisor
Research
This project will be carried out in two phases, over two years.
Phase 1 will took place in 2023, to carry out the Year 1 objectives:
- To determine an efficient system for preparing compost strips on a small scale:
- To make trenches, we will prepared a vegetable bed as we usually do with our tractor mounted bed former, and then passed over the bed with a farm-fabricated tool in order to open a 3” wide trench of the desired depth at the location of the planting row. For this phase of the trial, we applied the compost into the trench by hand.
- We planted carrot seeds into the compost strips using a Jang hand-pushed seeder, regarded as the most precise tool to use for seeding carrots on a smaller scale.
- The carrot variety Napoli was planted, a standard variety for fall fresh market carrots. Carrots were seeded on July 26.
- We tracked the time spent and the results of this less mechanized system of preparing compost strips on beds, in order to determine the feasibility of this system for small scale growers, and will perform a cost benefit analysis of using this system on a smaller scale.
- To compare results in in-row weed control using different depths of applied compost strips and different compost products, and to compare results in germination, weed suppression, and weed seed content of different compost products:
- 18 plots were be prepared, each plot was a 10’ long section of a 6’ wide raised bed, with 2 rows of carrots to be planted per bed, in rows 32” apart.
- Nine treatment types were trialed, based on the following variables:
- Five types of planting strips were prepared:
- 3” wide x 1” deep
- 3” wide x 2” deep
- 3” wide x 3” deep
- A control area with no trench and compost scattered on the surface
- A control area with no trench and no compost
- Each depth of planting strip was prepared using each of the two types of compost to be trialed:
- McEnroe Organic Compost
- Hudson Soil Co. Compost *
- Five types of planting strips were prepared:
- Each of the 9 treatments was used on 2 plots, in a randomized arrangement, for a total of 18 plots planted.
- Plots were irrigated with micro sprinklers so that soil surface did not dry out before germination.
- 2-3 weeks after planting, the number of weeds that had germinated was assessed. Weeds were be counted within the 3” wide planting row in a defined area of each plot. Carrot seedlings were also counted in a defined area in each plot to determine an average germination percentage for each plot.
- 3-4 Weeks after planting, half of each plot was hand weeded.
- All beds were tractor cultivated between rows, as is typical with organic carrot production, first with a basket weeder and then with sweeps.
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- *We had intended to trial municipal compost from Ulster County Resource Recovery Agency due to its low cost, but we were informed by our organic certifier, NOFA-NY, that it is not approved for organic application. We considered replacing it with Vermont Compost, but we determined that this pricier product, coupled with long shipping distence. could not be an economical choice even if it worked perfectly.
After the completion of Phase 1, data was assessed, and recommendations have been made based on the following considerations:
- Relationship between depth of compost trench and in-row weed control
- Relationship between compost product used and in-row weed control and yield and quality of harvested carrots.
The most promising treatments will be selected for further study in Phase 2.
Phase 2 will take place in 2024, to carry out the Year 2 objectives:
- To develop a mechanized system to apply compost strips:
- Working with our farm’s Mechanic, we will modify our existing Kennco Bed Shaper, which has a hydraulically driven hopper with a conveyor system, to create trenches of the desired depth and fill the trenches with finished compost flowing from the hopper.
- Working with our farm’s Mechanic, we will adjust our existing MaterMacc Vacuum Seeder with mechanical guidance to follow the edges of our raised beds, to allow our seeder to seed carrots precisely into the compost strips.
- We will track the cost of the modifications and the time spent creating beds using these modified implements in order to determine the feasibility of this system for larger growers who might wish to implement this system on a mechanized scale.
- To determine the optimal compost product and compost strip depth by comparing the most promising four treatments from Year 1 in a replicated field trial and analyzing the data:
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- Twenty plots will be prepared, each plot will be a 50’ long section of a 6’ wide raised bed, with 2 rows of carrots to be planted per bed, in rows 32” apart.
- The four most promising treatments (combinations of trench depth and compost product) from Phase 1 will be used in Phase 2. Each of the four treatments will be planted into four plots, using a randomized design to allow for statistical analysis. The final four plots will be prepared as control plots, without compost strips.
- We will repeat the methods from Phase 1 for irrigating, cultivating, analyzing numbers of weeds in row, and calculating carrot germination percentage and yields.
- To assess the financial feasibility of using this system by comparing the input and labor costs of planting into compost strips with the costs of using our standard system of producing carrots:
- With the help of our Technical Advisor, statistical analysis will be performed to identify the most promising treatments from the Phase 2 trials.
- Cost of labor and compost for making trenches, any savings in hand weeding labor, and any value gained from any improvements in yield, will be analyzed to determine if this system is recommended for future use in carrot production. The data for implementing the system on a hand scale (from Year 1) and on a mechanized scale (from Year 2) will be considered in order to be able to advise growers of different scales on their options.
On August 16th, 2023, Ethan Grundberg and an assistant (Cornell Cooperative Extension) measured the following in one 2-foot section of each treatment plot:
- Number of weeds
- Number of carrots
- Species of weeds (broadleaf vs. grass)
The main takeaways from the data gathered in Year 1 are:
- Compost source did not have a significant effect on carrot stand or weed densities.
- Compost depth had a significant impact on weed densities. Broadcast applications of compost had significantly higher weed pressure than banded applications of any depth. There was a trend toward greater reduction in weed pressure with deeper applications of banded compost.
The reduction in weeds was very significant, with the 3" deep bands of compost averaging 18 weeds per 2 row feet, while the control area averaged 80.8 weeds per 2 row feet. (see chart)
While carrots at the lowest weed density would still require hand weeding, the reduction in weeds from the control would result in significant labor hours saved over the course of the season, at least 4 fewer hours per 500' bed of hand weeding, assuming that 1 weed is pulled per second. We expect that the hand weeding is also done more quickly at this lower density because carrots are easier to see and there is less likely to be damage to the carrots from pulling out adjascent weeds.
While the cost of compost is not inexpensive (approximately $3,150 per acre),