Seminars

Crop and Soil Sciences Seminars - Spring 2021

Teaching the Undergraduate IPM Course: A Mile Wide and Occasionally a Mile Deep

Dr. David Jordan
Reynolds Professor and Extension Specialist
Department of Crop and Soil Sciences

Summary:
The undergraduate course Integrated Pest Management (CS 415) is required for several undergraduate curricula in CALS. Major elements of the course include: IPM from an historical perspective; general overviews of entomology, plant pathology, nematology and weed science; calculations of economic thresholds for insects; calculation of the AUDPC used in plant pathology; challenges with economic thresholds for weeds; contrasts of organic and conventional production; cover crops as a tool for pest management; elements of boll weevil, screwworm, and witchweed (Striga) eradication programs; pollinators; evolved resistance of pests; pesticide stewardship; ramifications of climate change on pests and their management; statistics and pest management recommendations; and risk management tools for pests. Elements of pest management in multiple settings include: major agronomic crops (corn, cotton, grain sorghum, peanut, soybean, and tobacco); vegetable and fruit crops (blueberry, cucumbers, strawberry, sweet corn, sweetpotato, and tomato); contrasts of pest management in pastures and forages, turfgrass, and small grains; pest management in aquatic, urban, greenhouse and nursery settings; pests of stored products; and pest management in resource-limited countries with a focus on interactions of agriculture and human health. In addition to exams and daily quizzes, each student is assigned a unique setting and asked to prepare a one-page fact sheet on the distribution, biology and economic impact of a pest of their choice. Approaches to managing the pest using PAMS (Prevention, Avoidance, Monitoring, and Suppression) as outlined by the Southern Region IPM Center is required. A second component of the assignment is development of a risk index for the pest and setting. A textbook is not required for the course. However, in addition to PowerPoint presentations, students receive CAST and peer-reviewed articles throughout the semester and pest management guides and manuals. Students consider environmental, financial, and social ramifications of pest management and unexpected consequences that may occur.

April 28, 2021


 

Field and Laboratory Evaluations of NCDA Lime Recommendations

Mr. Joseph Wilson
Master of Soil Science Student
Department of Crop and Soil Sciences

Committee: David Hardy (co-advisor), John Havlin (co-advisor), Carl Crozier, and David Jordan
Moderator: Chandler Fulmer, MS Student in Soil Science

Over the last four years, the NCDA&CS Soil Testing Laboratory changed its soil:water pH (pHW) method to soil:0.01 M CaCl2 solution (pHS) and is reporting an adjusted water pH (pHadjW) by increasing pHS by 0.6 units. Also, a modified Mehlich soil buffer pH (BpH) method replaced the original Mehlich buffer to measure exchangeable acidity (Ac). Currently, lime requirement (LR) is calculated as: lime (t/ac) = 𝐮𝑐 × [(𝑡𝑎𝑟𝑔𝑒𝑡 đ‘đ» − đ‘đ»!”#$)⁄(6.6 − đ‘đ»!”#$)]. Due to these significant changes, field and laboratory studies were conducted to evaluate the current LR method’s ability to achieve target pH on North Carolina soils. Comparisons prior to change and substituting pHS for pHadjW were made. The University of Georgia LR method was also evaluated. Four, two-year field studies were established with eight treatments: four multiples of the NCDA LR (0X, 1X, 2X, 4X) in two tillage systems (till, no-till). Incorporated treatments were rototilled twice to 10 cm. Soil samples were collected at three depths (0-10 cm, 10-20 cm, 20-30 cm) every four months in the first year and every six months the second year. Eleven soils varying in texture and organic matter were collected for a six-month lime incubation including five multiples of the NCDA LR (0X, 0.5X, 1X, 1.5X, 2X). Soils were sampled every month. Soil from each of the four field sites was included in the incubation study for laboratory to field comparisons. All soil samples were analyzed for pHW, pHS, and BpH. Incubation and field results indicate that NCDA LRs were more accurate than the previous method, but under-recommend lime by an average factor of two for incorporated lime in finer textured soils. Field results further show NCDA LRs require an average multiplier of three to reach target pH in no-till systems.

Further research involving a larger population of soils is warranted.

April 14, 2021


 

Status of North Carolina Soil Fertility and Soil Health

Mr. Chandler Fulmer
Master of Soil Science Student
Department of Crop and Soil Sciences

Co-authors: L. Gatiboni (advisor), D. Osmond, A. Johnson, S. Kulesza and H. Mitasova

Moderator: Joseph Burns, MS Student in Soil Science

Understanding how soil health and fertility metrics change across the varied landscape of North Carolina is an essential step to evaluate our current management practices and serve as a guide for selecting best management practices in the state. The goal of this project is to provide unbiased background data, by gathering a representative sample of soil, that can serve as a baseline to further research in this field for North Carolina. 236 fields in normal agricultural production were randomly selected with an ArcGIS WebMap to be sampled and surveyed by utilizing North Carolina extension offices in 83 counties. The numbers of fields selected per county was weighted on the proportion of field crop acres in that county relative to the total in the state. Total nitrogen (TN), soil organic carbon (SOC), autoclave citrate extractable (ACE) protein, textural analysis, permanganate oxidizable carbon (POXC), and a North Carolina Department of Agriculture & Consumer Services soil fertility parameters suite will be measured in laboratory analysis. These data, paired with survey information including soil mapping unit, crop history, tillage system, and fertilizer information will provide a characteristic foundation for further soil health and fertility research in the state.

April 7, 2021


 

Agroecological Pursuits in Soil Management: The First Half of the Last Half

Dr. Alan Franzluebbers,
USDA Professor, Dept of Crop and Soil Sciences

Summary:
The balance between agricultural production and environmental quality has never been more important. While food production goals appear daunting in the not-too-distant future, ongoing threats to environmental quality from business-as-usual approaches will only make our tasks toward sustainability more difficult to achieve. Healthy soil that fully expresses its functions must be fostered for human society to enjoy ecological balance now and into the future. This seminar will review research conducted in the Soil Ecology and Management Lab since its development in 2012.

March 31, 2021


 

Going Underground: Unearthing the Role of the Soil Microbiome in a Warmer, Fertilized World

Dr. Serita Frey,
Professor of Soil Microbial Ecology, University of New Hampshire
The 2nd Willie Woltz Lecture for 2020-21.

Abstract:
There are an estimated nonillion (1030) microbes on the planet and these organisms play a critical role in planetary health, including the composition of the Earth’s atmosphere. This presentation will take you belowground to explore the microorganisms beneath our feet, the role they play in the Earth’s carbon cycle, and how global change, particularly soil warming and nitrogen enrichment, is altering the soil microbiome.

Biography:
Dr. Serita Frey is a Professor in the Department of Natural Resources and the Environment at the University of New Hampshire. Her lab’s research focuses on how human activities are impacting terrestrial ecosystems and the composition and diversity of soil microbial communities involved with the carbon and nitrogen cycles

Wednesday March 24, 2021


 

Using GIS to Evaluate Coastal Septic System Vulnerability in North Carolina

Ms. Sarah Jordan
Master of Soil Science Student
Department of Crop and Soil Sciences

Co-authors: M.C. Ricker (advisor), E. Severson, R. Austin
Moderator: Joseph Wilson, MS Student in Soil Science

Coastal climate change is predicted to cause increased flooding, salinization of soils, and rising ground water tables. The ability of septic systems to treat waste and protect water quality will be adversely affected. Many coastal residents do not have access to public sewer lines and therefore rely solely on septic systems. In North Carolina, we analyzed geospatial data from Bertie, Brunswick, Camden, Chowan, Currituck, Pasquotank, and Perquimans counties. Our research has located 30,361 coastal septic systems that are likely at risk of flooding because of sea level rise over the next century. Using SSURGO soil polygons in GIS, we have mapped soil series and joined the data to the location of existing septic systems. We have found that 47% of existing systems are located in soils that have seasonal high water tables located less than 100 cm from the soil surface and 27% of systems are located in soils that have seasonal high water tables located less than 30 cm from the soil surface. NOAA sea level rise (SLR) projections of 1 foot by 2050 and 3 feet by 2100 were used to predict which systems will be most adversely affected. These data will be used to quantify the number of systems and soil types that will be impacted by coastal climate change over the next century.

Wednesday, March 3


 

Investigating Autonomous and Emerging Technologies for Incorporation into Aquatic Plant Management

Dr. Rob Richardson
Professor of Aquatic and Non-Cropland Weed Science

Department of Crop and Soil Sciences
Moderator: Joseph Burns, MS student in Soil Science

Summary
Effective management of invasive aquatic plants requires knowledge of the distribution of those plants as well as any desirable plant species. However, vegetation surveys are typically labor intensive as submersed plants are difficult to detect via aerial sensing techniques. Research was conducted to evaluate new and emerging technologies to improve the efficiency of vegetation surveys and overall management programs. Results indicated that hydroacoustic (sonar) signature was correlated with hydrilla biomass,
hydroacoustic sensing can detect filamentous cyanobacteria, machine learning can be used to identify species from hydroacoustic signature, and that hydroacoustic sensing can be integrated with autonomous spraying technology

February 24, 2021


 

Dr. Rich Cooper
Professor of Turfgrass Science, Department of Crop and Soil Sciences

Moderator: Mr. Joseph Wilson, Master of Science in Soil Sciences Student

ABSTRACT
Time waits for no one. So, it is not unexpected that the occasion of my fifth quinquennial Post Tenure Review (PTR) is at hand. Revised PTR guidelines afford faculty the opportunity to present a Departmental Seminar summarizing their efforts. Thus, I will use this occasion to share my efforts during the last five years to fashion exciting research initiatives in Turfgrass Science and to engage information technologies in an effort to push back the boundaries of ignorance (my own included). I look forward to the opportunity.

February 10, 2021


 

Phosphorus Mobility with a Fertilizer Enhancer and Soil Saturated Hydraulic Conductivity

Dr. Aziz Amoozegar

Professor of Environmental Soil Physics, Department of Crop and Soil Sciences

Moderator: Ms. Sarah Jordan, Master of Soil Science Student

ABSTRACT

Phosphorus (P) is an essential element for all forms of life.  In addition to being essential for life, in soil, water is the medium in which nutrients become available for plant uptake as well as being transported to groundwater and surface water resources.  Two studies will be presented in this seminar. (1) Mobility of P through a clayey soil with and without AVAIL, a commercial fertilizer enhancer, was investigated using an innovative horizontal soil column under capillary flow system. (2) Four mathematical models for determining soil saturated hydraulic conductivity (Ksat) of the vadose zone were evaluated.  In two experimental runs, air dried soil material, < 0.25-mm and adjusted to pH 6, was packed in three side-by-side, 1.4 cm wide and 0.6 cm deep tracks.  The tracks were connected to a sand box and water was imbibed into the soil via capillarity.  While water was moving through the track, 5 ΌL of a solution containing 400 mmol/L P or P + AVAIL was applied at one point to each track.  At the termination of water application, each track was sectioned and air-dried.  Distribution of P at the surface of one sample from each track was analyzed using micro-X-ray fluorescence imaging at synchrotron facilities at Stanford University and Brookhaven National Lab.  In the constant head well permeameter method, the rate of water flow rate from a cylindrical hole under a constant depth of water is used to calculate Ksat using a model. Since water flow from a cylindrical hole is three-dimensional, under an idealized condition, a saturated bulb of limited size is developed when steady-state is achieved.  The surface area and volume of the idealized saturated bulb determined by four different models were compared.  The results show that the Glover model, which is based only on saturated water flow around the hole, is superior to the three other models that consider both saturated and unsaturated water flow.

Wednesday, February 3