27 dairy farmers improve nitrogen management on 1,500 acres of corn (100 fields) by increasing yield, reducing fertilizer rate, or reducing nitrogen losses from planting cover crops by September 15, resulting in a total annual savings of $54,000.
Many dairy farms store cow manure in a centralized area, and must then transport manure long distances in order to spread it over soils at sustainable rates. Transporting manure is resource intensive and economically prohibitive so farmers apply as much manure as possible to fields closer to major operations in order to reduce costs. If moisture conditions are unfavorable in some areas, more manure might be spread in dry areas compared to wet areas, creating an uneven distribution of nutrients within and among fields. When sampling soils for fertility recommendations, this uneven distribution of nutrients may not be apparent in measurements and testing, which results in misleading fertility recommendations for corn fields where manure is applied.
In order to help dairy farmers in Connecticut, Massachusetts, and Maine improve nutrient management on corn fields, we will collect soils form multiple fields in those states and present the results to participating farmers. Fields will be partitioned into wet and dry areas and nutrient analyses will be accompanied by biological soil tests, and aerial imagery to provide farmers with a more accurate representation of the fertility of their soils. We will also conduct workshops with farmers to have direct discussions about the implications of our results and encourage farmers to better optimize nutrient management in their corn fields.
- (Educator and Researcher)
- (Educator and Researcher)
1. Soil chemical and biological test results from manured corn fields differ between wet and dry areas in the fields.
2. Current soil sampling protocols do not adequately describe the variability of soil nutrients in manured corn fields.
3. Revised soil sampling protocols for manured corn fields will indicate a minimum distance between soil
samples that would provide independent chemical and biological test results.
4. Sampling of partitioned manured cornfields based on drainage and revised soil sampling protocols will result in less variable soil test results and more accurate fertilizer recommendations.
Farmer recruitment was a coordinated effort between extension at University of Connecticut, University of Massachusetts, and University of Maine. Extension programs in each state contacted farmers that previously participated in extension activity and seemed like reliable participants for this research. Farmers and agricultural consultants were all recruited in fall 2018. In order to participate in the project, farmers were asked to allow us to survey 2-3 of their silage corn fields receiving dairy cow manure.
Silage corn fields throughout Connecticut, Massachusetts, and Maine were selected for the research based on existing soil nutrient concentrations and management history with dairy cow manure applications. We specifically requested from farmers, one field that typically receives less dairy cow manure than average and another field that receives more dairy cow manure than average. In any given year from 2018-2020, there were between 60-65 fields involved in the research.
Among fields volunteered for the project, we selected nine fields for a detailed analysis of the spatial distribution of nutrients. Fields were selected to fulfill a diverse range of sizes, nutrient concentrations, and conservation practices. In these fields, we sampled in grid patterns with a grid-cell size of 150 x 150 ft, which is approximately 0.5 acre. The number of grid cells varied based on the size of the field. We then used farmer recommendations to select two grid cells in each field that have been managed differently in the past based on the amount of manure applied. Within the selected grid cells we conducted intensive sampling in transects through the center lines going North-South and West-East through the grid.
Soil Sampling and analysis
We collected soil samples in fall of each year after corn was harvested. Soil samples were collected using a 2-inch diameter auger to a depth of 6 inches. All soils were air-dried and sieved through a 2-mm mesh. Soils nutrients were measured in two ways, after extraction with the Modified Morgan procedure, and after extraction with the Mehlich 3 procedure. Soil nitrate was measured independently. In addition to nutrient measurements, we measured C, N, organic matter, and used two biological tests referred to as the CO2 burst and Solvita® labile amino N.
Aerial images of fields were collected when silage corn was at peak stages of the transition from vegetative growth to reproductive growth. Most images were collected in either August or early September of the year. Images were captured using an automated drone flying 400 ft above ground. The images were composited and shared with farmers for reference.
Workshops were conducted in winter 2019, 2020, and planned for a virtual workshop in winter 2021. During the workshops we start off by asking farmers to complete a survey about their field activities for the past corn season. Their surveys are then used to explain observations from soil sample data and aerial images. During workshops farmers interacted with researchers, educators, and each other in conversations attempting to convince farmers to manage nutrients from dairy cow manure more efficiently among their fields. If farmers decided to make changes to management of the fields, we would consult with them and effects from the changes would likely be captured in soil samples and aerial imagery the next year.
Our data showed clear trends between available soil nitrate and the amount of rainfall during the growing season. In Connecticut and Maine, when rainfall was greater, less nitrate was available in soil and when rainfall was less, there was more nitrate available in soil. We did not see this trend for 2018-2019 in Massachusetts and we are awaiting 2020 data to learn if this is still true. We had initially used the Adapt-N model for tracking nitrate throughout the growing season, but the program was not as well received as conventional soil sampling data. This data provides farmers with clear numbers showing them how they should be managing nitrate to respond to weather each year and may influence farmers to take more steps to actively manage fields mid-season.
Soil P was also a large issue among dairy farm corn fields. Optimum amounts of P for silage corn growth are between 14-20 lb P ac-1 based on Modified Morgan extraction. In our study, over 70% of fields are above that optimum range and have more P than needed. We suspect this is because farmers generally apply manure to match N needs, and as a result, they apply more P than corn uptakes. Based on our data, P will be a significant concern in the future if farms do not move P more efficiently.
Biological tests were applied to the study to better understand the “activity” of organic matter in silage corn fields. Dairy farms add lots of organic matter to their fields in the form of dairy cow manure, and inside that manure is lots of stored nutrients that could be mineralized into available nutrients for corn. Our use of SLAN implies that more N is mineralized when there is more organic matter present. The CO2 burst test shows how easily mineralized some organic matter is. When painting the full picture, this data shows that organic matter comes in different forms. When farmers increase labile C in their fields by using cover crops or no-till agriculture, the organic matter is easier to convert to plant-available nutrients.
We compiled aerial images into a presentation to show farmers during workshops. We had back and forth discussions with farmers about ideal situations for managing manure and being able to use nutrients more efficiently. The images showed combinations of what it looks like to have healthy corn and what it looks like when corn is clearly deficient. Giving farmers this perspective opened their eyes to some inefficient management practices that they could probably afford to improve upon and might also encourage farmers to embrace new practices on their fields. During some meetings, farmers that implemented conservation practices on their fields like no-till and cover cropping spoke with other farmers about the benefits and detriments of conservation management. Getting farmers to discuss these practices more openly was a nice bonus to our workshops and may help gain support for more workshops in the future.
Conclusions are still pending as of January 2021.
Our edcuational approach included regular visits to farmers during the growing season and workshops with large farmer groups during winter.
In winter 2019 we conducted 3 separate workshops in the 3 states involved in the project. Workshops were lead by the dairy farm externsion expert in each state. Workshops involved a general presentation to all farmers where we showed aerial images and data from soils collected the previous fall.The general presentation was followed by group discussions about management practices farmers were concerned about.
In winter 2020, we conducted workshops similar to those in 2019, expect in this year we were able to engage with farmers more because of the aerial photographs of their fields that had been captured the previous summer. During this workshop, we educated farmers about how the aerial images related to management practices recorded for their fields. Farmers also talked to each other about how conservation management practices had affected their efficiency in the past.
In winter 2021, we are planning some form of digital communication with farmers because of the Covid-19 pandemic restricting our ability to meet with farmers in large groups.
1. Farmers and Service Providers are recruited in each state by email, phone or in person using existing contacts from previous collaborations and by contacts made at CCA meetings. One service provider and 12 farmers from each state agree to work with project. 9 of the farms agree to intensive sampling of one corn field. Completed by September 1, 2018.
Progress on this and other milestones was delayed because of heavy rainfall throughout the months of September and October 2018. More than 10 inches (254 mm) of rain was recorded in September, which is more than twice the historical average of rainfall for the month.
Despite delays, 32 farms (64 fields) across the three states agreed to participate in this research. Soil samples from farm fields were collected by the end of November 2018 and are currently being analyzed using standard nutrient analysis and biological assessments using Solvita® CO2 Burst and labile amino nitrogen.
2. 36 farmers, 12 each state, and 3 service providers, 1 each state, attend a half-day, first-year workshop in each state (2 identical workshops in each state each winter to reduce travel by farmers) to learn protocols/use of tools: aerial images, Adapt N, fall soil nitrate concentrations, the SLAN soil biological test and other soil biology tests, soil sampling procedures, and effect of planting date on recovery of residual nitrate by cover crops. January 2019.
During Winter 2019 one workshop was conducted in Maine on February 20, one workshop in Massachusetts on March 11, and workshops in Connecticut on March 13 and March 14. 20 of the 32 farmers involved attended workshops. We informed farmers about results for their soils that were sampled in Fall 2018. Farmers attending meetings had already volunteered fields they believed were low in P and fields they believed were high in P. We presented information about standard nutrient tests with a focus on N and P, and we also included information about CO2 respiration and N mineralization to incorporate biological components of soil nutrient management.
We presented farmers with information about potential future nutrient management challenges for dairy farms in New England and juxtaposed that with current nutrient results for their fields. Farmers asked for comments about their existing management practices and wondered how likely existing practices would be able to sustain without causing concern. After the presentation and discussion we asked farmers to consider volunteering fields for intensive sampling study, and we were able to obtain enough fields for that part of the research. As of November 2019, 9 corn silage fields managed by dairy farms (5 in Connecticut and 4 in Massachusetts) were intensively sampled to analyze nutrient variability and the samples are being processed in the UConn soil nutrient analysis laboratory.
Farmers were informed about plans for winter 2020 meetings before being dismissed
3. 30 Farmers create a learning plan for themselves and a nitrogen management plan for the 4 fields they enroll in the program in the winter meetings. January 2019.
This part of the research proved to be too ambitious as most farmers make decisions based on the amount of time and money they have in the moment. We coordinated with some farmers during spring and summer 2019 to assist in their N management decisions using the Adapt-N software, but in most cases farmers ultimately decided to either follow their previous plans or use a hired consultant to manage nutrients throughout their fields. Farmers also prefer to move manure from their pits when and where it is convenient for them rather than waiting for software to inform them of that decision. We were not successful at convincing farmers to follow specific plans for these four fields during the 2019 corn season, but we are hoping that data we present for 2018 and 2019 soil samples and aerial images will convince some farmers to change management to be more efficient in some way.
In 2020, many farmers adjusted farm management practices to account for losses in revenue and resources during the covid-19 pandemic. Although the change in management planning was not intentional, data from 2020 will likely give us a chance to show farmers data from their fields in years when they allocate resources more efficiently (or with more frugality). We can use this year to explore what farmers learned when they had to be more precise with N and P management.
5. 30 Farmers notify project leaders about when their fields will be expected to tassel to ensure correct timing of collection of aerial images of the corn fields. Early July 2020.
We collected aerial images in summer 2019 and summer 2020 with assistance from farmers who informed us about the status of their corn. Images from 2019 were shared with farmers during Winter 2020 workshops and images collected in 2020 will be shared with farmers during 2021 workshops. We have not yet scheduled 2021 workshops because of the covid-19 pandemic, but this task is complete because we collected aerial images of corn silage fields as desired.
6. 33 farmers/3 service providers meet in winter in each state in second year to review concepts and discuss results of objective tests from their individual fields, from their state, and aggregate results from the three states in first year. Based on the new knowledge the farmers learn from this meeting, learning plans and nitrogen management plans are updated by farmers in consultation with project team. January 2020.
Farmer meetings were completed in February 2020. We discussed aerial images with farmers as well as different nutrient deficiency or nutrient excess issues that fields in the project seemed to have. Agricultural consultants were present at meetings and we advocated for consultants to adopt more top-down strategies for nutrient management whenever possible. Many farmers had not yet seen aerial images of their corn fields, and this was a new perspective for them. For farmers that make a change in management in 2020, we hope that the summer 2020 aerial images will provide them a reliable comparison for how changes in management can affect their fields.
7. 5 farmers make changes to their nitrogen management; 3 farmers plant cover crops by September 15 to ensure good recovery of residual nitrate. April to September 2019.
After showing farmers 2 years of soil data and 1 summer of aerial images, there were trends to show that nitrate was in excess in some fields and deficient in some fields. We had 7 farmers across the 3 states agree to shift their manure applications to place more manure where it may be needed. We complemented nitrate data with P data to show farmers whether their fields had enough residual nutrients after many years of dairy manure applications.
We are not sure how many followed through with their plans throughout the 2020 corn season because of issues with covid-19 pandemic. We will reconnect with farmers in winter 2021 to learn what they did after harvesting corn during the 2020 season.
8. 30 farmers/3 service providers meet in winter in each state in third year to review concepts and discuss results of objective tests of the nitrogen status of their individual fields, results from their state, and aggregate results from the three states in first and second year. Based on the new knowledge the farmers learn from this meeting, learning plans and nitrogen management plans are updated by farmers in consultation with project team. January 2021.
Due to the covid-19 pandemic, we have not scheduled in-person meetings with farmers for winter 2021. We are currently considering virtual conferences or meeting with farmers in smaller groups that can accommodate current guidelines to avoid spreading the virus.
4. 30 Farmers review their nitrogen management plan with the project leader in their state either through phone calls or email. March 2021.
Farmers did not develop N management plans specific for the project, but many agreed to reduce or increase manure application by an unspecified amount to 1 of their 2 fields based on aerial images collected during the 2019 corn season. We have kept regular communication with farmers in each state about nutrient inputs to their fields through yearly surveys and checking in before and after corn season.
We will check with farmers in 2021 to review what they changed and whether the 2020 results reflect what they expected based on changes made.
9. An additional 15 farmers make changes to their nitrogen management and 5 plant cover crops by September 15. April to September 2020.
Because of the covid-19 pandemic of 2020, farmers may be risk averse and hesitant to make significant changes in field management that would increase management costs. A significant number of farmers reduced their output and likely applied less nitrogen and manure as a result. We are not yet sure how many followed through with cover crops. We will discuss with farmers in 2021 to convince them to change management based on our results and possibly plant cover crops in 2021. Many farmers in our group already prefer planting cover crops and we hope their testimony (and possibly finances) will convince other farmers to adopt cover crops as well.
10. 12 Certified Crop Consultants from New England learn about objective tests and the results of the project at the annual CCA meeting in New Hampshire in late January 2021.
We will present results of our 2018-2020 soil analysis and imagery compilations during the 2021 Maine In-service training for agricultural service providers, which will be a virtual event this year. We expect that many certified crop consultants will be in attendance. We have also presented the data to an audience attending the 2020 New York certified crop advisor training, which was a virtual event in December 2020.
Milestone Activities and Participation Summary
Our meetings with farmers went very well because we had soil analyses and aerial images. The aerial images were very convincing physical evidence of certain management patterns that farmers preferred to avoid. During our sessions with observed nutrient deficient corn fields, nutrient excessive corn fields, and some that were between then two. With this evidence and testimony from other farmers, we convinced other farmers that it would be worth exploring their options for cover crops and no-till farming.
There was one agricultural service provider present who had not explored adding cover cropping as a service, but we believe that this service provider will open his business up to adding cover cropping as a nutrient management service in the future.