Progress 09/01/18 to 08/31/22
Outputs
Target Audience:The target audience for this research project is farmers that grow alfalfa for hay production or silage production. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?
Nothing Reported
How have the results been disseminated to communities of interest?Results from this work have been shared at many local extension events and national conferences during the life of this project. Aside from the products listed previously, multiple extension events were attended and presented at by the PI and co-PI's per year. These events did not have proceedings associated with them. The total events presented at were 18 total over the four years of the project. What do you plan to do during the next reporting period to accomplish the goals?
Nothing Reported
Impacts
What was accomplished under these goals?
University of Wisconsin Effort: To quantify the effects of machine traffic on yield a study was conducted at the Arlington Agricultural Research Station in Arlington, Wisconsin. A total of 63 plots with three different tillage levels for a split plot design and replicated RCBD for machine traffic on sub-plots. Tillage treatments consisted of no-tillage, minimum tillage, and extensive tillage that were randomly applied to entire blocks. Yield, plant growth stage, alfalfa quality, moisture content, and compaction measurements were taken on each plot at each harvest for 3 years. GPS data of vehicles involved in the alfalfa harvest process was collected from a commercial dairy in south central Wisconsin in 2019 and 2020. All objectives of the three year study outlined in the proposal were completed and two Master of Science students completed the degree requirements of the University of Wisconsin-Madison and University of Georgia. We are finalizing year 3 data for publication. We expect 3 publications as a result of this effort. University of Georgia Effort: Study Location and Establishment The two varieties of alfalfa were planted into trays containing a standard germination potting mix (Sun Gro®, Agawam, Massachusetts), and the plants were transplanted after 55 days into polyvinyl chloride (PVC) tubes that were 15.2 cm in diameter and 1.25 m in length. To obtain the soil media, three layers of Cecil sandy loam soil type were compacted into each tube. Data Collection Six harvests were completed between April and September 2020, occurring on 14 April 2020, 26 May 2020, 23 June 2020, 14 July 2020, 11 August 2020, and 15 September 2020. Response variables included non-destructive and destructive measures. At each destructive harvest, the response variables measured were total forage (DM) yield, shoots per plant, and damaged shoot number. Before each harvest, growth stage, height of tallest shoot (inches), and moisture readings using a Theta Probe M3 of HH2 Hand Held Meter (Delta-T Devices Ltd, Cambridge, England) were taken. Each plant was then cut with scissors, and the shoots per plant were counted and recorded. Each tube was placed into the pneumatic press at the appropriate times to simulate silage and baling harvests, and then after the application of the appropriate compaction, the number of damaged shoots were counted. Moisture readings were taken at the beginning of the day for each compaction timing. After each harvest and compaction, the alfalfa plants were given ten days to re-grow, then a handheld multispectral sensor (Crop Circle, Holland Scientific) was used to take NDVI measurements. University of Wisconsin Results: The effects of varying amounts of traffic at different times differed for the tillage treatments included in this study but generally followed the same trends. A common trend noticed was that the five-pass hay treatment which received the most traffic at the latest times was consistently the worst yielding treatment. On average five-pass hay was 1.4 Mg/ha lower yielding than the highest yielding treatment. This again confirms the importance of limiting the amount of machine traffic in a field the later it is after the times of cutting. This leads to the conclusion that the loss in yield from machinery traffic is more because of the crown of the plant being crushed and broken than it is from soil compaction. This is believed because although the silage and hay treatments received the same amount of compaction (three and five passes) the hay treatments were consistently lower yielding. It was also interesting to note that the one pass treatment was consistently worse than the control treatments and statistically similar to the yield results of the three and five pass treatments. This shows that even one pass of machine traffic has detrimental effects. On average over both years of harvest the one pass treatment reduced yield estimates by 0.4 Mg/ha from the zero pass or simulated silage treatments. Now knowing that even one pass of machinery traffic can influence alfalfa yield it is important to understand how much of a production field is typically affected by traffic. Using the data loggers and GPS receivers described above, the percent of field affected by machine traffic was able to be calculated. This done by applying a machines footprint (table 1) to the path recorded by GPS. After examining a 31-ha production field from a commercial dairy over six different cuttings it was found that an average of 49% of the field was affected by machinery traffic. Table 8 shows the amount of field affected during each cutting and it was found that at times over half of the field was impacted my machinery traffic. Comparing this to the study by Kroulik et al., (2014) it is somewhat lower as their studies showed up to 64% of the field was impacted by machinery traffic during silage harvest. Table 1. Percentage of field covered by machine traffic by harvest for the seasons of 2019 and 2020. Year: Harvest: Field size (ha) Area covered (ha) Percent covered: 2019 1st 30.9 16.85 55% 2019 2nd 30.9 18.79 61% 2019 3rd 30.9 14.63 47% 2020 1st 30.9 17.59 57% 2020 3rd 30.9 13.35 43% 2020 4th 30.9 10.43 34% Average: 49% Standard Dev: 9% University of Georgia Results: There was no discernable trend in yield over the course of the study. As the season progressed, yield showed a steady decline. This decline is not unusual and is consistent with alfalfa production behavior (e.g., Bula and Massengale, 1972; Rechel et al., 1987). Some metrics on nutritive value were influenced by an interaction (P < 0.001) between the compaction treatment and variety within a harvest. The plants were harvested when the mean stage count of the controls reached ca. 4 as described in Kalu and Fick (1983). There was a significant (P < 0.05) varietal difference for harvests 2 through 6, as Alfagraze was more mature than Ameristand at harvest. For all harvests after harvest 1, the controls of both varieties were the most mature when compared to other the other compaction treatments within varieties. This is consistent with the observations in alfalfa small plots in Wisconsin by Williams (2021) who found that similar compaction timing treatments reduced the maturation of alfalfa at harvest. No consistent trend was detected as to the impact of compaction type or timing on mean stage count at harvest, as they all seemed equally impactful relative to the control. Though there was not a discernable trend when looking at the impact of variety with compaction on yield, the number of shoots per plant was significantly suppressed. From this, it is presumed that because this is a young stand of alfalfa, the plant was resilient enough to compensate for the damage by increasing the width of the shoots as well as the height of each shoot. Therefore, yield was not noticeably affected even with less shoots because the plant had overall taller shoots that have growthier, bigger stems. However, the compaction is likely causing the stand to self-thin once it reaches a certain threshold, and in this study, the threshold was between harvest 3 and harvest 4. This suggests that there is a decline in overall plant vigor as shown in the decrease in the number of shoots per plant as the season progressed. Summary: All objectives of the three-year study outlined in the proposal were completed and two Master of Science students completed the degree requirements of the University of Wisconsin-Madison and University of Georgia. We are finalizing year 3 data for publication. We expect three publications as a result of this effort.
Publications
- Type:
Conference Papers and Presentations
Status:
Accepted
Year Published:
2022
Citation:
Luck, B. D. 2022. Quantifying Machinery Traffic During Alfalfa Harvest & Assessing Yield & Forage Quality Impact. World Alfalfa Congress. San Diego, CA. 14-17 November, 2022. https://alfalfa.org/events/World_Alfalfa_Congress_Agenda.php
- Type:
Conference Papers and Presentations
Status:
Accepted
Year Published:
2021
Citation:
Anderson, R., N. Gaur, and J. D. Hale. 2021. Assessing the Impact of Agricultural Machinery Traffic on Alfalfa Yields. Proceedings of the Annual Conference of the American Forage and Grassland Council (AFGC 2021).
- Type:
Conference Papers and Presentations
Status:
Accepted
Year Published:
2022
Citation:
Luck, B. D., F. Arriaga, D. Hancock, P. Williams, and J. Drewry 2022. Machinery traffic, compaction, and plant damage during alfalfa harvest. 2022 ASABE Annual International Meeting. Houston, TX.
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Progress 09/01/20 to 08/31/21
Outputs
Target Audience:The target audience for this research project is farmers that grow alfalfa for hay production or silage production. University of Wisconsin-Madison: Dr. Luck and Dr. Arriaga participated in multiple extension events that presented data generated from this research to alfalfa and forage growers across Wisconsin. University of Georgia: Dr. Gaur participated in outreach events to discuss the relevant topics to this research and to reach the target audience regionally. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?
Nothing Reported
How have the results been disseminated to communities of interest?Several virtual extension meetings were attended by the PI's and the work and preliminary results were discussed. What do you plan to do during the next reporting period to accomplish the goals?Continuation of the plot work at the University of Wisconsin for the 3rd year to satisfy the objectives outlined in the proposal.
Impacts
What was accomplished under these goals?
Machinery traffic during alfalfa harvest has an impact on yield and nutritive values of the feed produced. The overarching goal of this research is to study the impact of machinery traffic on alfalfa production and identify adjustments in harvest practices that could maintain yield and nutritive values. If implemented, these practices could maintain or increase soil health. Specific objectives for the proposed research are as follows: 1. Quantify the effect of down force on the alfalfa crowns and soil on alfalfa yield and nutritive values; 2. Quantify the effect of machine traffic on yield, nutritive values, and soil properties and collect remote sensing data using commercially available UAV and camera technology; 3. Quantify the spatial distribution of machinery traffic within the field during the growing season on farm; 4. Simulate the potential effect of controlled traffic farming on alfalfa production; 5. Increase producer knowledge and adoption of reduced traffic alfalfa production by hosting field days across Wisconsin and Georgia, developing online material, and extension journal and archival journal publications. Objective 1: The experiment established in 2020 was continued in 2021 at the University of Georgia's J. Phil Campbell Research and Education Center (JPCREC) near Watkinsville, GA (33°872619"N, -83°422988'W) in a hoop-style temporary greenhouse. Two alfalfa varieties--Ameristand 435TQ RR and Alfagraze 600 RR--were planted into trays and transferred to PVC tubes as before. The bottom 6 inches of the top foot of soil was amended with potassium (K), phosphorus (P), and lime, while the top 6 inches of soil was amended with K, P, lime, and organic humus. Some plants were lost in 2021 as were in 2020, but not enough replicates to impede the continuation of the study. The pneumatic compaction machine was again used to compare down force treatments applied to: the top of the crown; the surrounding soil but not to or just above the crown itself; the crown as well as the surrounding soil. The split-split plot factor applies 207 kPa of pressure with 5 timings of application and an untreated control. The level of downforce was chosen based on the availability of the soil-tire interface pressure data and is representative of a mid-sized tractor capable of completing most required field operations. The timing of the down force application stimulates machinery traffic within both silage and hay harvest systems. Once compaction treatments were applied yield, soil bulk density, vegetative index, growth stage, and forage quality were measured at each harvest. There were six harvests collected in 2021. At the end of the season the plants were removed from the tube and root analysis were performed as well. A Master of Science student is finalizing a thesis on this work and will graduate in early 2022. Objective 2: The 2021 field season at the University of Wisconsin-Madison was successful. Yield, compaction measurements, forage quality measurements, and Uncrewed Aerial Vehicle remote sensing data were all collected in the alfalfa plots established in early 2019 for year 2 of this study. The analysis from 2020 showed 0.4 ton/acre and those results seem to be similar for 2021. Results indicate that wheel traffic on alfalfa regrowth has more impact on yield when more time passes between harvest and traffic application. Soil relaxation over the dormant winter period was observed again between 2020 and 2021. Remote sensing data shows damage to the plants increased as the amount of wheel traffic increased when measuring 10 days post-harvest. Objective 3: Location and time-motion data were collected on a cooperating dairy farm again in 2021. This data combined with machinery footprint data for all machines involved in harvest to assess the area of a production field involved with harvest. A maximum field coverage of 63% was observed in second harvest and an average of 49% of the field was covered over two year study. Objective 4: The data collected in Objectives 1 - 3 will be used to develop a model for identifying wheel traffic damage in alfalfa and estimating yield loss. This data analysis is ongoing. Objective 5: Several extension activities were completed and data were presented at an international conference.
Publications
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Progress 09/01/19 to 08/31/20
Outputs
Target Audience:The target audience for this research project is farmers that grow alfalfa for hay production or silage production. University of Wisconsin-Madison: Dr. Luck and Dr. Arriaga participated in multiple extension events that presented data generated from this research to alfalfa and forage growers across Wisconsin. University of Georgia: Dr. Gaur collaborated with Dr. Lisa Baxter, an extension agent at University of Georgia to reach the target audience regionally and the M.S. student, Renee Anderson presented the preliminary findings at a national meeting that is well attended by extension scientists from around the country. Changes/Problems:A preliminary analysis of the NDVI data did not show any meaningful results in the greenhouse study because of the incompatible footprint of the NDVI sensor, Greenseeker, with the size of the tube that the plant was grown in. For consistency, we took 10 measurements of NDVI for the same plant without changing the height above the plant or spatial location of the sensor. We also created a uniform white background around the PVC tube while measuring the NDVI. However, despite this, the sensor outputs were highly varied for the same tube. Hence, we will discontinue NDVI measurements using the Greenseeker and assess the utility of a different NDVI sensor available in Dr. Gaur's group. The COVID-19 pandemic did negatively impact this research, however when protocols were in place the research was able to continue while maintaining social distancing and a safe work environment. What opportunities for training and professional development has the project provided?The project supported the training of an M.S. student at University of Georgia and an M.S. student at the University of Wisconsin-Madison. The UGA student presented her work at one extension and one international conference while the UW-Madison student presented his work at multiple extension events throughout the state. How have the results been disseminated to communities of interest?Several written, online, and in-person events have been attended to disseminate the information gained from this research. Dr. Gaur collaborated with Dr. Lisa Baxter, an extension scientist to disseminate these results to the local and regional alfalfa growers. Specific events and publications are listed below. Luck, B. D. 2020. Conservation practices for crop production: Planter technology and alfalfa wheel traffic. Lafayett Co. Agriculture Sustainability Alliance, Darlington, WI. (150 Participants). Luck, B. D. 2020. Wheel traffic impact on alfalfa regrowth and yield. MFA/WCO/Nutrient Applicators Symposium, Wisconsin Dells, WI. (83 Participants). Williams, P. J. and B. D. Luck. 2020. Alfalfa compaction from wheel traffic. Dodge Co. Forage Council Meeting. (22 Participants). Luck, B. D. 2020. Alfalfa compaction from wheel traffic. Wisconsin Agribusiness Classic, Madison, WI. (70 Participants). Online video "Tread Lightly: Impact of Wheel Traffic on Alfalfa Yield and Soil Compaction." Published 30 Sept. 2020. (61 views on 4 Nov. 2020). https://go.wisc.edu/m13z56 P. Williams, B. D. Luck, F. Arriaga, D. Hancock, and J. Drewry. 2020. How much ground pressure am I applying with my different tire and vehicle configurations? University of Wisconsin Division of Extension Learning Store Article #A4181. Luck, B. D. 2019. Technological modernization for the future of agriculture. 2019 AgriFood Summit - Invited Presentation, Temuco, Chile. (250 Participants). Luck, B. D. 2019. Soils Tour 2019: Badger Ag. Tech. Lab Update. Soil, Water, & Nutrient Mgmt. Area Mtgs. Visited: Madison, Sparta, Eau Claire, Marshfield, Juneau, Kiel, Shawano, and Dodgeville, WI (456 Participants). Luck, B. D. 2019. How much impact does wheel traffic have on alfalfa yield? Researchers at the UW are working to find out! Hay and Forage Grower Magazine. Luck, B. D. 2019. Effect of wheel traffic on alfalfa yield. Midwest Forage Association Forage Focus. What do you plan to do during the next reporting period to accomplish the goals?The data collected in year 1 will be statistically analyzed using a mixed model repeated measures approach. One additional year of data will be collected using the greenhouse study. The hydraulic press saw considerable wear and tear during the first year of the experiment. It will need maintenance which will be provided at University of Georgia. The field research at the University of Wisconsin-Madison will be continued in 2021. At the end of the field season, at least two peer-reviewed journal articles will be developed and published. Also, at least two peer-reviewed extension articles will be developed with results from this research. Multiple extension efforts will also be completed in 2021, either virtually or in-person depending on the status of the COVID-19 pandemic.
Impacts
What was accomplished under these goals?
Objective 1: The experiment was set up at the University of Georgia's J. Phil Campbell Research and Education Center (JPCREC) near Watkinsville, GA (33°872619"N, -83°422988'W) in a hoop-style temporary greenhouse. In the Fall of 2019, the two alfalfa varieties--Ameristand 435TQ RR and Alfagraze 600 RR--were planted into trays. After 55 days, the plants were transplanted into 15.2 cm diameter polyvinyl chloride (PVC) tubes that are 1.25 m in length. To obtain the soil media, three layers of Cecil sandy loam soil type were compacted into each tube. The bottom layer of soil (0.9144 m) was obtained from a soil pit at JPCRC farm (33°875233"N, -83°311888"W) with an average pH of 5.9. The top 1 ft (0.3048 m) of soil was obtained from Iron Horse farm (33°718222"N, -83°422988'W) due to the higher pH of the soil and to ensure the soil was a true representation of Georgia's top soil. The bottom 6 inches of the top foot of soil was amended with potassium (K), phosphorus (P), and lime, while the top 6 inches of soil was amended with K, P, lime, and organic humus. The organic humus was added at 1% dry matter (DM) of soil to represent manure spread on pastures. The two varieties with 3 different treatments and a control were then randomly organized in the greenhouse. These plants were allowed to grow until they were fully mature before initiating the cutting and traffic simulations. Note: We lost ~6 plants due reasons not related to compaction during the course of this study. Using the machine developed by Dr. Luck's group at the University of Wisconsin-Madison, a split plot factor is being used to compare down force treatment applied to: the top of the crown (if the crown is at the soil surface) or just above the crown (if the crown is below the soil surface) with no down force impacting the surrounding soil; the surrounding soil but not to or just above the crown itself; the crown as well as the surrounding soil. The split-split plot factor applies 207 kPa of pressure with 5 timings of application and an untreated control. The level of downforce was chosen based on the availability of the soil-tire interface pressure data and is representative of a mid-sized tractor capable of completing most required field operations. The timing of the down force application stimulates machinery traffic within both silage and hay harvest systems. For the top of the crown (if the crown is at the soil surface) or just above the crown (if the crown is below the soil surface) with no down force impacting the surrounding soil, the footprint of the hydraulic press is 13 cm2 (2 in2) centered over the top of the crown. For the surrounding soil but not the crown downforce treatment, two halves of a 15.2 cm diameter plate with a cutout in the center (13 cm2) are used so that it will allow placement of the plate around the crown but without the uniformly applied force directly impacting the crown. For the crown as well as the surrounding soil downforce treatment, a solid 15.2 cm diameter plate (no cut out) is placed over the center of the tube and a uniformly applied force will impact the crown and the surrounding soil. Application of the different downforce treatments is achieved with the hydraulic press and once the desired applied force is achieved the pressure is immediately released to simulate field conditions. At the initiation, soil tests were conducted using the Mehlich I Extractant method to determine the amount of P, K, Ca, and Mg in the soil. After transplanting, plants were fertilized with P and K at 125% of the recommended amount. For lime, 3750 pounds/acre were added; for phosphorus, 225 pounds per acre were added; for potash, 250 pounds/acre were added to the total soil before dividing the soil into each tube. In the fall 2019, all plants were fertilized with boron (Borosol) at 0.1 ounces each. Grass weeds were controlled weekly by manually removing them from the tube. Mean stage of development was assessed every 2 days once initial stages of bud development were observed to get an average for each variety. Each harvest is made at the late bud stage. Six harvests were made for this alfalfa crop. Changes in bulk density were measured after each harvest by measuring the change in height of the soil in the tube. At each destructive harvest, plots were visually assessed to determine growth stage of alfalfa. Each plant was evaluated for growth stage and the plants were harvested by cutting at 2 inches above the crown. The response variables measured were: total forage (DM) yield, shoots per plant, and damaged shoot number (if the shoot was broken or bent more than 45°). The forage was dried in a forced-air dryer at 60 degrees Celsius until reaching a stable weight, ground to pass a 2 mm screen using a Wiley mill, then ground to pass a 1mm screen using a cyclotec cyclone mill, before being shipped to the University of Wisconsin-Madison for Near Infrared Spectroscopy (NIRS). In order to translate the results and relate them to a field setting, the use of remote sensing methods for estimating impact was also assessed by using NDVI values ten days into its re-growth following each destructive harvest. After the 6th cutting of the year, a penetrometer was used to determine penetration resistance at depth of the soil at a water content near field capacity. At the end of the sixth harvest, the soil was taken out of the tube, washed away from the roots, and the crown and roots were examined. The length and total length and mass per plant was measured and the number of cracks and damage to the crown was counted. The top 8 cm of the crown and root was then separated, washed and weighed. Objective 2: The 2020 field season at the University of Wisconsin-Madison was successful even with the effects of the COVID-19 pandemic. Yield, compaction measurements, forage quality measurements, and Uncrewed Aerial Vehicle remote sensing data were all collected in the alfalfa plots established in early 2019. Data analysis is ongoing, but preliminary results show that compaction treatments applied at different timings are reducing yield by approximately 0.4 ton/ac. Statistical differences observed in forage quality did not correlate well to the applied wheel traffic treatments. Soil compaction differences were observed, and the main area affected was at depths of 4 in to 9 in below the soil surface. Wheel traffic treatments at high traffic and late timing (3-pass hay and 5-pass hay treatments) showed the highest amount of compaction. Another interesting result from this study showed substantial soil relaxation over the dormant winter period where most of the imposed compaction in 2019 was relieved in the spring of 2020. Remote sensing data shows damage to the plants increased as the amount of wheel traffic increased when measuring 10 days post-harvest. These results show promise that remote sensing data can identify and quantify wheel traffic damage in alfalfa fields. Objective 3: In 2020, data were collected on all machines associated with alfalfa harvest on a cooperating dairy farm. Global Navigation Satellite Navigation System data collection units were installed in April 2020 and data were downloaded and collected throughout the growing season. Analysis has shown that an average of 49% of the area of fields included in this study interacted with machinery tires. This result is staggering since our yield data has shown that approximately 0.4 ton/ac of yield loss occurs when the plants interact with tires. Objective 4: The data collected in Objectives 1 - 3 will be used to develop a model for identifying wheel traffic damage in alfalfa and estimating yield loss. Objective 5: Several extension activities were completed and data were presented at an international conference.
Publications
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2020
Citation:
Anderson, R., N. Gaur, D. W. Hancock, P. J. Williams, B. D. Luck, F. J. Arriaga, J. D. Hale, and J. L. Drewry. 2020. Assessing impact of agricultural machinery traffic on alfalfa fields on crop yields: A greenhouse study. 2020 ASA-CSSA-SSSA International Annual Meeting (Virtual). https://scisoc.confex.com/scisoc/2020am/prelim.cgi/Paper/128129
- Type:
Other
Status:
Published
Year Published:
2020
Citation:
Williams, P. J., B. D. Luck, F. J. Arriaga, D. W. Hancock, and J. L. Drewry. 2020. How much ground pressure am I applying with my different tire and vehicle configurations? University of Wisconsin Division of Extension Publication #A4181. https://cdn.shopify.com/s/files/1/0145/8808/4272/files/A4181.pdf
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Progress 09/01/18 to 08/31/19
Outputs
Target Audience:The target audience for this research project is farmers that grow alfalfa for hay production or silage production. Opportunities for reaching this target audience have been limited due to this being our first field season. However, a limited number of Midwest Forage Association regional meetings were attended by Dr. Luck where an overview of the project and its goals were presented. Dr. Hancock also presented preliminary/observational results at a limited number of forage meetings in Georgia. Upon the conclusion of the initial field season, we envision a peer-reviewed extension publication will be produced and several regional meetings will be attended to disseminate results from this effort. Changes/Problems:The only problems were the lack of availability of a plot harvester for the research conducted at the University of Wisconsin-Madison and the inability to define a graduate research assistant at the University of Georgia. Both of these challenges have been remedied and work is moving forward smoothly. What opportunities for training and professional development has the project provided?
Nothing Reported
How have the results been disseminated to communities of interest?Since the inception of this project there has been little information regarding the research disseminated to our communities of interest. Dr. Luck provided a brief overview of the project to a few Midwest Forage Association Grower Meetings in early 2019 and Dr. Hancock did the same with interested grower groups in Georgia. What do you plan to do during the next reporting period to accomplish the goals?Continuation of this project in year two will involve data processing from the field work efforts in year one, initially. This includes spatial assessment of the machinery movement on the cooperating dairy farm, analysis of the Unmanned Aerial Vehicle based remote sensing data, and plot yield and quality data assessment. In the first quarter of year two, the greenhouse study will commence to assess the impact of wheel traffic on alfalfa yield and quality. The plot work, machinery movement, and remote sensing assessment will all be continued in year two. Replication of the greenhouse work will be completed as well in year two.
Impacts
What was accomplished under these goals?
In late 2018, at the inception of the project, the research team scheduled monthly meetings to discuss project goals, time-lines, and plans for the upcoming field season. In January, 2019, a graduate research assistant was hired at the University of Wisconsin-Madison in the Biological Systems Engineering Department to focus on the research goals of this project. The University of Georgia intended to hire a graduate assistant, starting in May, 2019, but was unsuccessful in the search. They have since hired a graduate assistant starting in Fall, 2019 to complete the research goals of this project. Accomplishments for Objective 1: In the fall of 2018, a field was identified as a candidate for new alfalfa seeding in 2019. Three tillage treatments were identified for this study: 1) no-till seeding, 2) spring tillage before seeding, and 3) fall and spring tillage before seeding. The plot areas were surveyed and defined using Real-Time Kinematic Global Satellite Navigation System equipment, which has an accuracy of less-than one inch. Fall deep tillage was applied to one third of the plot area in October, 2018. During the spring of 2019, the research assistant housed at the University of Wisconsin-Madison focused on design and construction of the alfalfa compaction machine that will be used for the greenhouse study at the University of Georgia. This machine consisted of a frame capable of accommodating 6-inch PVC tubes in which the alfalfa plants will be grown, a pneumatic cylinder capable of providing down-force on the alfalfa plants simulating wheel traffic, and a control system to automate this process and ensure its repeatability. The mechanical construction of this system was completed by April, 2019. From there, the control system was designed and assembled and the code was written for implementation. Since the University of Georgia wasn't able to employ their research assistant by May, 2019, work on the compaction machine was paused in order to focus on the fast approaching field season. In May, 2019, spring tillage was applied to two-thirds of the plot areas and new alfalfa was seeded across the entire field. A second location was identified that had established alfalfa and was marked out for the same treatments and replications that the other newly seeded plots were receiving. Seven different treatments with different compaction inputs and timings were implemented in the four plot locations along with three replications of each treatment. The new seeding plots were allowed to grow 60 days past seeding prior to the first harvest. The established alfalfa plots were harvested 30 days after they emerged from dormancy. For harvest one and two in 2019, a plot harvester was not available. We used a swather to mow the alfalfa, keeping track of where the wheel tracks were so that a known amount of compaction/wheel traffic was applied post harvest. The mowed alfalfa was collected by hand in a bucket and was then weighed for yield determination. Four, 500 gram samples were collected after the weight was determined for moisture content determination and forage quality assessment. These samples were immediately taken to an oven and dried for quality analysis per the American Society of Agricultural and Biological Engineers Standards. Once the samples had dried for 72 hours, they were removed from the oven and weighed for moisture content determination. The samples were then ground into smaller particle lengths using a food processor and immediately frozen until quality analysis can be performed. This analysis will happen in quarter 4 of 2019. Harvest three in 2019 was conducted with a flail type plot harvester. This machine simplified the harvest process and made for a more efficient harvest. Care was taken when sampling the harvested material to randomize sample collection. The drying and grinding process was conducted with the same methods as described above. Accomplishments for Objective 2 and Objective 3: A commercial Unmanned Aerial Vehicle (DJI Matrice 100) was used to collect remote sensing data over three production alfalfa fields on a cooperating farm near Madison, Wisconsin. This unmanned aerial vehicle is equipped with a visible light camera, a multi-spectral remote sensing camera (MicaSense Red Edge), and a thermal imaging camera (Zenmuse XT). The cooperating farm has two self-propelled forage harvesters, two self-propelled swathers, two pull-type 30 ft. mergers, and a mixed fleet of twelve material transport vehicles. These machines are instrumented with Wide Area Augmentation System corrected Global Satellite Navigation System receivers that log the location and speed of the vehicle at a frequency of 1 Hz. At each alfalfa harvest (one, two, and three during this reporting period) the machinery data was logged and two Unmanned Aerial Vehicle flights were conducted. One data collection flight over the alfalfa was performed prior to harvest and a second flight was conducted approximately 10 days post harvest once some re-growth had occurred. Each flight over these production alfalfa field produced >500 images of each field. These images will be stitched into a high-resolution orthomosaic image and then overlayed with the machinery traffic patterns (taking the footprint of each machine into account) to determine if there is correlation between reduced multi-spectral sensor responses and wheel traffic locations. This data was collected for all three cuttings to date in 2019 and will be collected during the fourth cutting of the season. Accomplishments for Objective 4: None to date. Accomplishments for Objective 5: As we are just wrapping up our first field season and beginning to work through the data processing and since our University of Georgia collaborators are just starting their research assistant, we have not had the opportunity to present results from this work to date.
Publications
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