Roots in Research CMREC - Upper Marlboro Facility - Yield Year 2024
Updated: June 11, 2025
One of the most intriguing aspects of agriculture, and by extension agricultural research, is that no two years are the same. This dynamic allows for learning, growing, and improving. Unfortunately, it can also lend itself to struggle and disappointment. We had a little more of the latter than I would have cared for. The heat and drought made this past growing season one of the more challenging of my career. Throughout most of the Summer it felt like an endless struggle to keep crops alive from one sporadic rain event to the next. The silver lining to the less-than-ideal growing conditions we dealt with is we were able to conduct research to better prepare ourselves, and the Maryland farming community, the next time this happens.
In this year’s newsletter, you can read about the work that Dr. Hemendra Kumar is doing to develop irrigation strategies to best suit our region. His work with soil moisture sensors and irrigation scheduling is not only timely but also relevant no matter what type of growing conditions we face. You can also read about alternative methods for weed management in vegetable crops. This work is being conducted by Dr. Cerruti Hooks, Dr. Dwayne Joseph, Dr. Kurt Vollmer, and Dr. Alan Leslie. Their methodologies include water conserving techniques such as high residue systems and strip tillage.
In these very pages, Dr. Shirley Micallef and her Ph.D. candidate, Claire Hudson, are looking at the effects of drought stress on kale and lettuce crops. Just one more example of timely research being conducted by UMD Faculty.
While the past growing season was challenging, our Staff and Faculty continued to achieve. They proved once again that necessity is the mother of invention and adversity is the catalyst for great research.
Donald Murphy, Facility Manager
To view this newsletter electronically, scan the QR code!
In fact, we have had them installed at each MAES station, except Salisbury and Beltsville. Gone are the days of manually checking the weather!
Weather data for Upper Marlboro is displayed on our website. The information can be displayed by month or by the year in printable format. To compare weather data averages by the month or year, check out our website! If your research requires this data in a different format, please contact Elizabeth McGarry and she will help to get the information you are requesting.
SECU Joins UMD Athletes to Spread Kindness at Terp Farm
SECU Employees and UMD Athletes Harvesting Sweet Potatoes
On a sunny day in October, 16 employees at SECU, the official banking partner of the Maryland Terps, met UMD athletes at Terp Farm. Their goal: Spread kindness by harvesting sweet potatoes.
October is Kindness Month in Maryland, a movement that SECU began four years ago to spread kindness in our Maryland communities. SECU designates one day in October as their Day of Kindness, where employees volunteer at local organizations doing everything from packing food bags for the hungry to taking shelter pets for a walk.
They also harvest sweet potatoes.
At the end of SECU’s Day of Kindness, the group at Terp Farm harvested 2,000 pounds of sweet potatoes.
To learn more about SECU's Kindness Campaign or get involved next year, go to secukindness.org or email annie.weinschenk@secumd.com
Pilots on the Ground: UMD Researchers Take a Bird’s Eye View Into the Future of Agriculture
By Haley R Moore, Communications Specialist
Like many industries, technology is changing agriculture in America. Precision agriculture uses new tech to observe and measure farm field data, and one of the most useful tools is proving to be drones. Researchers at the University of Maryland in the College of Agriculture and Natural Resources and University of Maryland Extension (UME) are using drones to help farmers and growers enhance their integrated pest management plans (IPM), learn about programming, and gather aerial data on crops and wildlife.
Prepare for takeoff – Part 107
To start building out a future workforce of agriculture professionals equipped with this technology, Tom Mazzone, a lecturer for IAA at UMD, teaches a GPS and Drone Applications course. Students learn to fly drones and prepare for a Federal Aviation Administration (FAA) test called Part 107, which is required for those who want to fly drones for commercial purposes.
Mazzone said that growers also need guided education for taking the test and to understand the software that comes along with being a drone pilot.
“If you don’t have basic programming knowledge, you are going to be lost, and a lot of farmers are going to need an instruction manual or an all-in-one solution for using drone technology,” Mazzone said.
Putting drones to work in research projects
Because College Park falls under the FAA no fly-zone, researchers utilize the Maryland Agricultural Experiment Station (MAES) Research and Education Centers (RECs) for flights. Mazzone takes his class to the Central Maryland REC (CMREC) Clarksville facility where the drone program was born from the ideas of the late Stanton Gill, a visionary in Extension programming. “Drones have so many applications and possibilities for the commercial horticulture industry in Maryland,” said Gill. “We’re trying to move the industry forward with this technology.”
Aerial Research
Scientists at the RECs are putting drones to work in their research projects to carry out activities like inventory management and assessing water stress in crops.
Andrew Ristvey, Extension specialist in commercial horticulture, helps nurseries and Maryland growers utilize drones as part of their operations.
To measure water stress in a plant using drones, a pilot must select the sensor best suited for their needs. For example, multi-spectral cameras take images with four different wavelengths: red, green, infrared and near infrared. This type of sensor can be used to measure normalized difference vegetation index (NDVI)—a visual indicator for plant health.
Ristvey also utilizes thermal imaging to help with data collection. A thermal imagery drone determines the water stress by looking at transpiration levels on leaves.
“So, a leaf would appear cool if the plant is healthy and transpiring water. But if it’s not transpiring water, which means it is in water stress, the leaf gets hot,” said Ristvey. “And, you can clearly see that using thermal imaging.” Read more>>
Harvesting Pumpkins at the Upper Marlboro Terp Farm
Lindsay Barranco, Experiential Learning Coordinator, University of Maryland Institute of Applied Agriculture
Students harvest white ‘snowball’ pumpkins at the UMD Terp Farm and Upper Marlboro Research Center (Photo by Lindsay Barranco)
On October 2, 2024, University of Maryland students in INAG123 People, Profit and Planet: Sustainable Food Systems, traveled to the Central Maryland Research and Education Center, Upper Marlboro Facility.
This is a popular course with many students from a number of wide-ranging undergraduate programs and includes Institute of Applied Agriculture (IAA) students who are enrolled in the 2-year certificate program in Applied Agriculture.
The tour began with facility manager, Donny Murphy, who spoke about many of the agricultural implements used at the Terp Farm for the cultivation and harvesting of crops, about the overall layout of the farm, and the farm’s support of university research projects.
Following Donny’s talk, the students took a hayride down to the pumpkin fields where Donny, Terp Farm Manager Guy Kilpatric and Agricultural Technician Lead, Michael Perise showed the group the pumpkin fields where white ‘snowball’ pumpkins were being grown for sale and for eventual use at the College Park campus for an end-of-the-month Halloween event. Aside from decorative uses, white pumpkins, like their orange counterparts, are used in culinary dishes like soups and pies. Students harvested the pumpkins and carefully set them into large cardboard bins so that they could be shipped to their destinations.
Students learn about vegetable and basil production from Terp Farm Manager, Guy Kilpatrick (Photo by Lindsay Barranco)
For the final part of the visit, the students toured the area of the farm where several hoop houses are used for growing vegetables and basil plants for use by the UMD Dining Facilities.
Thank you to Upper Marlboro Facility Manager Donny Murphy, Terp Farm Manager Guy Kilpatric, and Upper Marlboro Agricultural Technician Lead, Michael Perise for the time they spent teaching students about harvesting, equipment and crop production.
An Educational Experience Through the Advancing Careers in Agriculture and STEM (ACAS) Internship Program
Kirsten Cowan, Extension Educator, 4-H Youth Development Calvert County Jenna Jones, Extension Educator, 4-H Youth Development Prince George’s County
This summer, ten teens from Prince George's and Calvert County embarked on an educational experience through the Advancing Careers in Agriculture and STEM (ACAS) Internship Program. Aimed at exposing youth to the diverse fields of agriculture and STEM, the program offered hands-on experiences, leadership training, and career exploration while equipping participants with valuable skills for their future.
STEM Students Engaged with Industry and Other Professionals
Throughout the program, participants engaged with industry professionals, visited farms, and explored non-traditional career paths within the Agricultural industry. As a result, 70% of participants reported a newfound familiarity with agricultural careers, compared to just 10% at the start.
Additionally, 100% of the teens felt more prepared for their future educational and career goals, with many citing improved leadership skills.
One of the internship days took place at the CMREC in Upper Marlboro, where youth had the opportunity to tour the impressive facility under the guidance of Facility Manager Donny Murphy. In addition to learning about the various crops planted at the facility, they were introduced to the numerous educational opportunities available to UMD students; including summer internships and research opportunities. A fun fact the teens learned was the significant quantity of tomatoes grown at the Upper Marlboro location for campus dining halls sp;(approx. 10,000 lbs per year). As part of this experience, the teens participated in hands-on activity: learning how to clean and sort tomatoes. From& those ready for immediate shipment to the dining halls to those that needed more time to ripen in the sun. "This internship opened my eyes to so many new possibilities," shared one participant. "I never realized the variety of careers in agriculture, and now I feel more confident about pursuing one."
With plans to expand into a full apprenticeship in the future, the ACAS Internship Program is not only addressing the workforce development needs in agriculture but also helping to create equitable and accessible opportunities for young people. The program aims to empower the next generation of leaders and professionals who will shape the future of the agricultural industry.
For more information on how to get involved or support the ACAS program, please contact your local 4-H office.
Crops Research Twilight Barbecue & Ice Cream Social
CMREC Upper Marlboro Farm August 7, 2024, 4 - 9pm
Puneet Srivastiva, Alan Leslie, and Dean Craig Beyrouty
University of Maryland educators and specialists share with you their field crop, vegetable and fruit research plots. The traditional Bayside Bull pit beef dinner was served, followed by homemade ice cream prior to the evening tours.
Our 2025 Twilight Tour is scheduled for Tuesday, August 5th. Please contact the Anne Arundel County Extension office at 301-226-7471 for more information or to register.
Combining Biosolarization, Cover Cropping, and Strip Tillage for Weed Management in Vegetables
Dwayne Joseph - University of Maryland Extension Educator, Kent County Alan Leslie – Center Director WMREC, CMREC, LESREC, University of Maryland Kurt Vollmer - University of Maryland Extension Specialist, Weed Management Cerruti Hooks - Professor Department of Entomology, University of Maryland
Vegetable farmers face challenges due to the limited availability of herbicides registered for vegetable production compared to row crops. Furthermore, existing herbicides often fail to provide full-season weed control and may pose risks of crop injury if not applied correctly. Weed management issues are even more pronounced in organic systems, where reliance on manual and mechanical control is both time consuming and labor intensive. To address these challenges, we evaluated an integrated weed management (IWM) approach that combines biosolarization, strip tillage, and living mulch.
Biosolarization, a technique similar to solarization, involves incorporating organic amendments into moist soil before covering it with clear plastic for passive solar heating. As the material decomposes, it releases biotoxic compounds that suppress weeds and soilborne pests. Following the 14-day biosolarization process, the transparent plastic is removed, and the soil is aerated for seven days before transplanting the cash crop. Biosolarization is compatible with organic systems and shows promise when combined with IWM practices such as conservation tillage and cover cropping. This study focused on evaluating a holistic weed management system that integrates within-row techniques such as biosolarization, solarization, and strip tillage, along with between-row strategies like red clover living mulch. We hypothesized that this IWM system would suppress weeds, improve crop yield, and enhance soil health.
Methods
Treatments were organized in a randomized complete block split-plot design and were replicated four times. The whole plo treatments included summer squash and okra grown under the following conditions:
1) in living mulch with no-till (LM-NT), 2) in living mulch and strip tilled (LM-ST), 3) grown in solarized soil (SOL), or 4) in living mulch and grown in biosolarized soil (BIOSOL).
Fall plot preparation – In early fall, red clove + cereal rye mixture was planted in BIOSOL, SOL and LM- ST treatment plots at a 6-inch row spacing. In LM-NT plots, the red clover and cereal rye was seeded in separate, alternating rows. Two rows of red clover were planted at each border and internal rows were alternated between six rows of cereal rye and four rows of red clover. Read more>>
Integrating Real-Time Sensing for Smart Irrigation Strategies
Hemendra Kumar, PhD - Precision Ag Specialist - Precision Agriculture Lab Central Maryland Research and Education Center - University of Maryland Ajay Sengar, Graduate Student - Precision Agriculture Lab
Introduction
More than 40 % of the earth’s population is already experiencing water scarcity problems, and approximately 70 % of available freshwater withdrawal is for meeting irrigation needs in agricultural production to meet food demands. Furthermore, the growing population and ongoing development in the Mid-Atlantic region have significantly increased the demand for freshwater, especially irrigation water requirements, due to recent climatic shifts, including irregular rainfall patterns and rising temperatures during the growing season, which are creating challenges for water availability. With more intermittent rainfall and higher evaporation rates, the risk of short-term droughts during the summer is becoming more prevalent (Boesch, 2008 and Paul et al., 2020). This study emphasizes the importance of efficient water management strategies to mitigate these challenges. By integrating precision irrigation techniques, this study aims to optimize the irrigation schedules and develop the irrigation prescriptions. Any improvements in the current irrigation practices in the Mid-Atlantic can help conserve limited water resources and promote sustainable agriculture. The sensor-based irrigation method has received a lot of attention since this approach provides real-time soil water status (Kumar et al., 2021). In sensor-based irrigation, soil water dynamics in the soil profiles can be explained using knowledge of the soil hydraulic properties (Kumar et al., 2022, 2023).
Study area
The study was conducted at the Central Maryland Research and Education Center of the University of Maryland. The corn was planted on June 1, 2024 with a row spacing of 20 inches. Three irrigation treatments and one rainfed scenario (NI) were tested in the field conditions. Each treatment plot was 43 ft long and 43 ft wide. The sensors were installed on June 18 in the field at 6-, 12-, and 24-inches depths. These sensors in each scenario were used to schedule the irrigation at different irrigation thresholds. We estimated the soil hydraulic properties for the study site using the artificial neural network to understand the soil and water engineering for irrigation scheduling. The following were the properties of the soil in this study:
Figure 1. Three different irrigation and one no irrigation (NI) scenarios in the field.Figure 2. Installed sensor in the field (a), irrigated corn (b), and non- irrigated corn (c). Soil Type: Sandy Loam Soil hydraulic properties (SHP):Soil Field Capacity: 10 kPa (kilo Pascal) Permanent wilting Point: 1500 kPaFigure 3. Left: Soil Water Retention curve. Right: Hydraulic Conductivity Curve. h is soil water tension reading from sensors in kPa. pF is a logarithmic function of absolute matric potential in cm (pF=log10 (|h|), where h is the matric potential.
Rainfall variability during the growing season
Based on the 30-year normal precipitation records during the growing season, the 2024 growing season received a total rainfall of 21.3 inches, which is less than the 30-year normal precipitation of 29.68 inches (Figure 4). The precipitation pattern varied throughout the growing season. While the precipitation in the 2024 growing season for all the months received deficit rainfall compared to 30-year normal rainfall, however, August 2024 received excess rainfall compared to 30 years normal rainfall. The total monthly rainfall varies from 0.24 inches to 6.6 inches. Read more>>
University of Maryland Extension hosts monthly Wednesday Water Webinars on various water quality related topics. Join Andy as he dives into water topics that affect us all. These webinars take place via Zoom from 12 - 12:40 PM, allowing time for Q & A at the end. Click on the title below to register, or check out our website for past recordings and more!
6/18/25 - Advantages of Upgrading your Septic System- Is your septic system old and in need of replacement? Join this webinar to learn more about how advanced treatment units (ATU) can provide benefits to the environment and public health. Also, learn about Maryland’s Bay Restoration Fund grant program to help replace septic tanks with advanced treatment units or best available technology (BAT). The increased treatment and nitrogen reduction and operation of these systems greatly reduces the risks to groundwater and helps to extend the lifespan of a drainfield.
7/16/25 - The Latest on PFAS and How to Protect You and Your Family - PFAS is a huge global pollution issue that will be with for many decades or longer. These ‘forever chemicals’ are also everywhere and are causing human health issues and impacting our environment. There are dozens of research studies ongoing to help us know more about the risks of PFAS and also how to reduce our exposure. Tune into this webinar to hear the latest on this contaminant and what you can do.
8/20/25 - Common Issues with Ponds and Management Tips- Ponds of any size and type are dynamic aquatic ecosystems. Warmer water temperatures may create additional concern for ponds and water quality. Excessive aquatic plant growth, and low oxygen are a few examples. This webinar will present basic pond management principles and practices to keep ponds healthy.
9/17/25 - Exposure to Microplastics and Reducing Risks- Plastics have been around for decades and as they break down into small particles, micro and nano plastics pollution is everywhere. This includes air, rain, surface and groundwater, animals, plants, some of the foods we eat, and even in human body tissue. Tune into this& webinar to learn more about how we can reduce our exposure while being better stewards of our environment.
10/15/25 - New to a Septic System – What You Should Know to ProtectYour System- If you have just bought or moved into a home that has a septic system, there are important things you need to know to help keep the system functioning properly and as long as possible. This webinar will discuss the basic system types and the recommended maintenance practices to follow.
11/29/25 - On a Well? Basics Tips to Ensure Good Water Quality-Wells are a significant source of drinking water for Americans. Well water is not regulated as are public water supplies, and therefore the well owner is responsible to test, if necessary, treat the water. This webinar will cover basic well design and types, wellhead protection measures, how to test your well and review basic water filtration.
12/17/25 - Salinization of our Waters – What Can We Do- The use of deicing salts and rising sea level is increasingly making our surface and ground water more saline. This issue has major implications on aquatic ecosystems and the numerous species that depend on them. In addition, increasing salinity can increase corrosion with subsequent infrastruc ture damage and releasing toxic metals in our drinking water.This webinar will discuss the impact of this issue, ways to reduce impacts and protect drinking water quality.
Andrew Lazur, Ph.D. State Extension Specialist - Water Quality University of Maryland Extension lazur@umd.edu.
Terp Farm Increases Sweet Potato Yield and Deepens Community Bonds
Guy Kilpatric, Terp Farm Manager
For a few years now, we've been working to boost our sweet potato production at Terp Farm. In 2024, we made some important accomplishments, like selecting a better variety to grow, making improvements to how we harvest and store, developing a new marketing outlet, and getting more of the community involved. Sweet potatoes grow really well in the Southern Maryland region, and the hard part always winds up being how to harvest and where to put it when it comes to big volume. The 2024 yield ended up with about 12,000 pounds of sweet potatoes from just a third of an acre.
UMF Ag. Technician, Nathan Hepp, with the sweetpotato plow he built
New Harvesting Tool
One key to our success is a new tool for harvesting sweet potatoes. Nathan Hepp, CMREC-UM Agricultural Technician, built a tractor attachment that flips the sweet potato beds. This tool makes harvesting a lot easier and keeps the potatoes from getting damaged, so more of them stay in good shape for storage. Flipping the beds means we can get to the potatoes quicker, cutting down on the work and time it usually takes.
Root Cellar Construction
Storing our harvest right is key to making it successful. We took an old pump room from the days when the farm’s irrigation ran on a well and turned it into a climate-controlled root cellar. It’s built into a hill-side and was pretty un-down, but now it can hold about 15,000 lbs of sweet potatoes. This setup keeps our potatoes fresh longer, cuts down on spoilage, and lets us time the market better to reduce waste.
Variety Selection
Picking the right sweet potato variety is important for how much we grow and how long we can store them. This year, we switched from Beauregard to Covington (propagated by Jones Family Farms, NC). Covington has better disease resistance and lasts longer in storage. It’s also a high quality eating variety with a slightly darker orange skin and a more uniform shape, which pleases the Chefs that use our product.
Top: Before and After root cellar construction; Bottom: Root cellar filled with about 12,000 lbs of sweet potatoesLeft: Jones Family Farms website homepage; Right: Covington sweet potato
Volunteer Support
This season's sweet potato harvest was a real community effort, thanks to volunteers. Folks from Terps For Change, Alpha Phi Omega, Epsilon Eta, and employees from SECU pitched in over two weekends in late September. Their hard work helped us get the potatoes in on time and showed what community spirit is all about. Having their support cut down on our labor costs and gave participants a great experience on the farm.
SECU employees harvesting sweet potatoes during their “Day of Kindness”
Partnership with Food and Friends
With growing more sweet potatoes, we've teamed up with a community-based organization called Food and Friends in Washington, DC. This partnership lets us sell our sweet potatoes for the organization to use in their medically-tailored grocery distribution and meal services. It's a good market for us and helps get healthy food to folks who need it.
Developing Integrated Weed Management Approaches for CBD Hemp Production
Dwayne Joseph, University of Maryland Extension Educator, Kent County Simon Zebelo Professor, Department of Natural Sciences, University of Maryland Eastern Shore Kurt Vollmer, University of Maryland Extension Specialist, Weed Management Alan Leslie, Center Director WMREC, CMREC, LESREC, University of Maryland Cerruti Hooks, Professor, Department of Entomology, University of Maryland
As hemp production gains momentum in the U.S., growers face significant challenges with weed control, particularly due to the lack of herbicide options. Currently, only one conventional herbicide is approved for use in hemp, and research in this area remains limited following the crop’s relatively recent removal from the controlled substances list. Weeds, especially aggressive broadleaf species like Palmer amaranth, marestail, and common ragweed, pose a major threat to hemp yields and farm profitability.
This issue was highlighted in a pilot program led by the University of Maryland Eastern Shore, where participating growing experienced serious weed pressure and increased labor costs due to hand weeding. The economic impact underscores the urgent need for effective, low-cost weed management solutions.
Integrated weed management (IWM) offers a promising path forward. Cover cropping, in particular, has shown promise in vegetable production systems for reducing weed pressure and improving soil health, making it a good strategy to explore in hemp. When combined with conservation tillage, cover cropping may serve as a practical and sustainable tool for weed management in both conservation tillage (“bareground”) and plasticulture-grown hemp systems. This study seeks to evaluate the effectiveness of these integrated tactics on weed control and floral hemp yield on hemp grown in a plasticulture system and a conservation tillage system.
Methods
This project consisted of two individual field studies. The first study focused on conservation tillage systems, while the second examined a plasticulture-based system.
Study 1 – Conservation Tillage System
The study was laid out in a randomized complete block design with four replications. Individual plots measured 26 ft × 42 ft. In early fall, three different treatments were established: conventional tillage (CT), no-till (NT), and a living mulch (LM) treatment. Cover crops, including crimson clover, forage radish, and cereal rye were planted in CT and NT plots at seeding rates of 3 lbs/ac, 3.5 lbs/ac, and 56 lbs/ac, respectively. In LM plots, a red clover + rye combination was drilled in alternating rows (ten rows red clover and three rows rye) at 6-inch spacing, with seeding rates of 8 lbs/ac for red clover and 67 lbs/ac for rye.
In spring, cover crops in CT plots were mowed, plowed, and disked under. Crimson clover senesced naturally, and forage radish winter-killed. Rye was terminated using a roller crimper in NT and LM plots. In LM plots, this also served to temporarily suppress red clover growth. Hemp was transplanted into all plots in mid-June at a 6 ft spacing, with plants placed in the center of the rye residue in LM plots.
Study 2 – Plasticulture System
This study was arranged in a randomized complete block design with four replications. Individual plots measured 30 ft × 36 ft. Three treatments were evaluated: bareground (BG), premium clover mix (CM), and Teff + red clover (Teff-RC). In early fall, a cover crop mixture consisting of four clover cultivars: 44% yellow blossom sweet clover, 33% red clover, and 23% ladino white clover, was drilled into BG and CM plots at a seeding rate of 12 lbs/acre, using a 6-inch row spacing. In Teff-RC plots, cereal rye was seeded as the winter cover.
In early spring, BG plots were mowed and disked to incorporate cover crops, followed by the installation of 3-foot-wide black plastic mulch using a plastic mulch bed layer. In Teff-RC plots, the entire plot was mowed to terminate the rye, and then black plastic mulch was laid in planting rows. Following mulch installation, Teff and red clover were seeded into the inter-row spaces at rates of 15 lbs/acre each, using 6-inch row spacing to establish a living mulch. In CM plots, 40-inch-wide strips were rotovated in the intra-row areas, where black plastic mulch and drip irrigation lines were laid. The clover mixture in PCM plots was left undisturbed in the inter-row areas to serve as a living ground cover throughout the growing season.
Data sampling
Weeds – Weed density and visual percent cover measurements were collected at 1, 2, 3, and 5 weeks after planting (WAP). In the conservation tillage study, 100 square-inch quadrats were randomly placed in each plot within two inter-row and two intra-row areas to capture weed density in both areas. In the plasticulture study, quadrats were placed only in the inter-row areas due to the presence of black plastic mulch covering the intra-row area. During each assessment, weeds were identified, counted, and visually rated for the percentage of ground covered by cover crop, weeds, and bare soil. Visual percent ground cover assessments ranged from 0% (no soil cover) to 100% (total soil cover).
Crop growth & yield – Hemp height and width were measured on six randomly selected plants per plot every 14 days after transplanting, continuing until the onset of flowering. Once flowering began, crop maturity was monitored by testing the total THC content of randomly selected plants within each treatment to ensure compliance with the 0.3% legal threshold. Plants were harvested when THC content approached the maximum allowable limit to optimize cannabinoid yield while maintaining regulatory compliance. Subsequently, four plants were randomly harvested from the center rows of each plot and weighed for fresh mass before being air-dried (Picture 2) to approximately 13% moisture content. After drying, each plant was re-weighed to determine dry mass, and colas were clipped from the branch terminals and weighed separately. Finally, representative samples from each plot were submitted to a laboratory for analysis of total CBD and THC concentrations.
Preliminary Results
Data on weed density, species counts, and hemp growth and yield from the 2024 trial year are still being analyzed; therefore, no official quantitative results are reported at this time. However, visual observations during the growing season offer some preliminary insights.
The plasticulture system incorporating living mulches appeared to provide more effective weed suppression than the conservation tillage system. Among the plasticulture treatments, CM plots consistently exhibited the lowest weed presence at all sampling times. The Teff-RC plots also maintained relatively low weed pressure, though slightly higher than the CM plots.
In the conservation tillage system, LM treatment demonstrated the most effective weed suppression and also supported the largest hemp plants in terms of size. In contrast, NT plots showed minimal weed control, particularly later in the season. These plots became heavily infested with grassy weeds, which coincided with stunted hemp growth. Plants in the NT plots remained small from transplanting through to the later sampling periods. While these observations suggest potential for IWM strategies in floral hemp production, particularly in systems utilizing plasticulture and living mulches, a more definitive assessment will be made following data analysis.
Picture 1. A) Teff-RC plot 9 weeks after transplant, and B) CM plot 9 weeks after transplant.Picture 2. Harvested hemp plants hung to dry in a barn prior tode-budding (removal of floral biomass from stalks).
Effect of Downforce and Irrigation Management on Corn
Hemendra Kumar, PhD, Precision Agriculture Specialist Central Maryland Research and Education Center, Upper Marlboro, University of Maryland
Donald L. Murphy, Facility Manager Central Maryland Research and Education Center, Upper Marlboro, University of Maryland
Introduction
Precision downforce management techniques in corn planting stand as indispensable elements within contemporary agricultural practices, profoundly influencing the success and productivity of this pivotal crop. The increase in vertical loads on the row units is usually done by a system known as downforce. Accurate management of downforce plays a critical role in ensuring optimal soil conditions during planting, which directly impacts the consistent and proper placement of seeds at the required depth in the soil. The significance lies in striking the right balance: excessive downforce can lead to the formation of compacted zones within the soil and lead to poor root development. Conversely, insufficient downforce can lead to inadequacies in planting depth, potentially compromising seed-to- soil contact essential for uniform germination and emergence. The implementation of advanced corn planting technologies for downforce management stands as a critical need for Maryland farmers aiming to enhance crop productivity and sustainability.
Irrigation plays a crucial role in improving crop yield by ensuring that crops receive adequate water at the peak growth stage. Proper irrigation helps maintain optimal soil moisture levels, promoting strong root development, efficient nutrient uptake, and improved photosynthesis, which collectively enhances plant health and yield potential. Crops under irrigation are better able to withstand environmental stresses such as heat and drought, leading to more uniform growth and higher productivity. In contrast, lack of irrigation or water scarcity can result in water stress, poor germination, stunted growth, and reduced nutrient availability, ultimately lowering crop yield. Severe water deficits during critical growth stages, such as flowering and grain filling, can significantly reduce yield quality and quantity. Therefore, managing irrigation effectively is essential to sustaining and maximizing crop production.
Objectives
The primary objective is to determine the effect of planter downforce and seeding rate with and with- out irrigation on crop yield potential. This initiative aims to empower farmers with innovative tools and data-driven insights that revolutionize planting techniques, fostering a more sustainable, efficient, and profitable agricultural sector in Maryland.
Materials and methods
The study was conducted at the Central Maryland Research and Education Center (CMREC) Upper Marlboro of the University of Maryland. The study design was developed with four different treatments as shown in Figure 1. The optimal planter downforce (OD) was 20 psi for our controlled treatment, 50% increased planter downforce (ID) was 30 psi, and 50% decreased planter downforce (DD) was 10 psi.
The standard seeding rate of 35 thousand was used in this study. The Increased seeding rate (ISR) of 39.5 thousand seeds with optimal downforce was the fourth treatment in this study. Each treatment was under irrigation and no irrigation scenarios (Figure 1). The corn was planted on 02 June 2024 and harvested on 18 October 2024. The row spacing for corn in this study was 20 inches, and each plot covered 0.03 acres.
Figure 1. Study design for downforce management with irrigation and not irrigation
Results
Effect of downforce and irrigation on emergence After the corn planting, the seed emergence counting was done until we found maximum emergence of the corn in the plots for each treatment. Multiple 26 feet long corn rows were selected randomly to count the plant emergence in each plot and extrapolated with the number of rows and length of the plots (Figure 2). On 10 June 2024, the OD, ID, DD, and ISR had 94%, 91%, 89%, and 94% of emergence, respectively. In terms of the number of plants, OD iD, and DD had 33,000, 32,000, and 31,000 emergences when planted at the rate of 35,000 seeds. However, ISR had the emergence of 37,000 when planted at the seed rate of 39,500. With the maximum emergence rate, the OD, ID, and DD had an emergence of 94% and ISR had an emergence of 96% under irrigation conditions. Read more>>
Impact of Pre-Harvest Water Stress on Enteric Pathogen Persistence on Baby Leaf Romaine Lettuce and Kale
Shirley Micallef, Professor, PSLA/CFS3 Claire Hudson, Ph.D. Candidate
Regulated water stress has a profound effect on plant phytochemical profiles and can induce several metabolites and plant specialized compounds to help the plant maintain osmoregulation and redox homeostasis. This study is investigating the impact of water-stress driven metabolome changes on the microbiota of baby-leaf Romaine lettuce and kale grown in high tunnels at CMREC-Upper Marlboro. Our approach is to describe the phyllosphere microbiome of Romaine lettuce and kale grown to the baby leaf stage, as well as evaluate the effects on naturally occurring commensal bacteria and foodborne pathogens introduced to the leafy greens under laboratory conditions.
Romaine lettuce 'Rouge d’Hiver' and kale 'Red Russian' were direct seeded in a high tunnel in the fall of 2024. Two irrigation treatments were set up in a randomized design based on regular watering (High) and water restriction (Low) and volumetric soil water content, (VWC) recorded continuously prior to harvesting at 26 days post-germination. On harvest ations with the foodborne pathogens Escherichia coli O157:H7, Salmonella Enteritidis and Listeria monocytogenes. Leaves were also collected for microbiome analysis and for phenolic and flavonoid profiling. The crops were also harvested for sensory evaluation by a trained panel in a collaboration wit USDA-ARS, Beltsville MD.
Results to data are showing that lower E. coli O157:H7 counts were retrieved from the surface of lab- inoculated lettuce leaves grown under low irrigation, while Listeria and Salmonella were unaffected. Under refrigerated storage, soil moisture was found to be a factor driving lower Salmonella counts on lettuce.
In kale, the foodborne pathogens tested were infiltrated into leaves. Overall, counts for Listeria, followed by E. coli O157:H7, then Salmonella. Pre-harvest soil moisture and post-harvest storage time were also identified as factors driving down Salmonella persistence but not E. coli O157:H7.
Only storage time affected Listeria counts. The initial results from this ongoing study are showing that foodborne pathogen association with leafy greens may be impacted by soil moisture levels that can be regulated during cultivation. Microbiome analysis and phytochemical profiling are ongoing.
The First Field Season of the TomatoLab at the University of Maryland, College Park!
Dr. Daniel Rodriguez-Leal, Assistant Professor, PSLA
The TomatoLab led by Dr. Daniel Rodriguez-Leal opened in August 2023 and its first season in summer 2024 was fundamental for establishing the foundational materials for the lab’s research. During the summer at the Terp Farm in Upper Marlboro, with the invaluable help of the Terp Farm team (big shoutout to Donald Murphy and the crew!) we grew close to 2,800 plants, covering 100 different cultivars. These included wild tomato species, mapping populations, vintage/heirloom cultivars, pre- breeding and off-patent breeding lines, tetraploid cultivars and genome edited lines. We evaluated close to 10 heirloom tomatoes for different fruit quality traits in collaboration with the Farcuh Lab (big shoutout to Grad Students Emily Johnson and Shipon Miah!) as part of our efforts to build data that will allow us to design genetic strategies using biotech approaches to improve heirloom tomatoes, without significantly changing their fruit quality. Besides our research work performed at the farm, we also produced and shared fruits from 15 different heirloom tomatoes grown in the Mid-Atlantic with the students and faculty from the Plant Science and Landscape Architecture Department. Finally, we participated in Service Day 2024 and hosted ~20 College Park Scholars that supported us in harvesting and seed extractions for these valuable varieties. Those harvested seeds have been used in our experiments and in our fall and winter cycles at the greenhouse facility in the University of Maryland.
