Location: National Peanut Research Laboratory
2024 Annual Report
Objectives
1. Develop and evaluate agronomic strategies to minimize aflatoxin in peanut cropping systems and mitigate the effects of late-season drought.
Sub-objective 1a: Assess seed coatings with associated non-toxigenic A. flavus that have been known to reduce aflatoxin.
Sub-objective 1b: Evaluate biological (soil) amendments as food source for fungi to minimize aflatoxin contamination in peanut.
Sub-objective 1c: Use mechanical and chemical techniques that may reduce soil moisture loss and measure the response in plant transpiration.
Sub-objective 1d: Evaluate peanut response to late season rainfall after digging and prior to harvest with respect to peanut yield, grade, and quality.
2. Enhance agronomic decision support systems and economic feasibility models that support a wide variety of end users, including small- and medium-scale producers, in selecting system management options to improve profitability and environmental stewardship of peanut-based cropping systems.
Approach
The United States peanut industry produces high quality peanut and generates approximately $4.4 billion annually in economic activity. Regrettably, some peanuts may be contaminated with mycotoxins during late season drought especially in dryland produced peanut. A decade ago, losses due to aflatoxin contamination were approximately $25 Million/year; in 2017-2018 they averaged $56 Million/year, and in 2019 they reached $117 Million following warmer and dryer conditions. It has been shown that Aflatoxin contamination can be minimized by irrigation or by applying a competitive, non-toxigenic fungi source applied 60 to 80 days after planting. Unfortunately, some land areas are not economical feasible to install any type of irrigation system to minimize aflatoxin and remain in dryland peanut production. However, with new technology, it is possible to apply the bio-competitive fungi to the peanut seed at planting instead of later in the growing season, thereby, reducing time, energy, and application costs. Therefore, the project objects are to 1) Develop and evaluate agronomic strategies to minimize aflatoxin in peanut cropping systems and mitigate the effects of late-season drought and 2) Enhance agronomic decision support systems and economic feasibility models that support a wide variety of end users, including small- and medium-scale producers, in selecting system management options to improve profitability and environmental stewardship of peanut-based cropping systems. The focus will assess various agronomic strategies to minimize aflatoxin contamination in peanut and the economic impact of these strategies. These techniques may include: 1) the assessment of possible seed coatings with associated non-toxigenic Aspergillus. Flavus, 2) the application of biological (soil) amendments as food source for fungi, 3) reduce plant transpiration using mechanical or chemical means that curtails soil moisture loss (reduce drought effects), 4) document peanut response to late season rainfall after digging and prior to harvest, and 5) determine economic feasibility of these practices on grower income coupled with economic impact analysis for the entire US peanut industry. Results will improve knowledge on peanut sustainability with respect to changes in climate during and at the end of the growing season and provide an electronic platform quantifying economic and sustainable impacts. End users include farmers, crop consultants, university extension personnel, bankers/lenders, peanut brokers, peanut buyers, storage facility managers, policy makers, and others associated in the peanut industry.
Progress Report
3. Progress Report: Objective 1A: [Assess seed coatings with associated non-toxigenic A. flavus that have been known to reduce aflatoxin]. This project is still ongoing. Yield, grade, and segregation data of peanut have been collected. Soil and peanut kernel aflatoxin have been completed and associated with yield data in large database.
Objective 1B. [Evaluate biological (soil) amendments as food source for fungi to minimize aflatoxin contamination in peanut.] This project is still ongoing with yield, kernel characteristics, and aflatoxin data being collected, organized, and waiting for further data for analysis.
Objective 1C. [Use mechanical and chemical techniques that may reduce soil moisture loss and measure the response in plant transpiration.] This project has been completed in the field. Collected data has been organized, analyzed, and in the process of being written for publication.
Objective 1D [Evaluate peanut response to late season rainfall after digging and prior to harvest with respect to peanut yield, grade, and quality.] This project has been completed. Collected data has been organized, analyzed, and in the process of being written for publication.
Objective 2. [Enhance agronomic decision support systems and economic feasibility models that support a wide variety of end users, including small- and medium-scale producers, in selecting system management options to improve profitability and environmental stewardship of peanut-based cropping systems.] This project is ongoing. As research data are collected and analyzed, this decision support system part of the objective will be updated.
Accomplishments
1. Unexpected Benefits: Herbicide Diflufenzopyr’s Neutral Impact on Transpiration and Enhanced Plant Performance in Arachis hypogaea. ARS researchers at Dawson, Georgia believe that while herbicides are commonly used in agriculture to induce negative effects on unwanted herbaceous plants, many studies have found that application of sublethal doses of herbicides can enhance plant growth and induce varying physiological responses in a process called herbicide hormesis. Responses may include but are not limited to stimulation of shoot elongation, increase in aboveground biomass, altered protein content, and changes in photosynthetic habit. In peanut (Arachis hypogaea), an application of the herbicide diflufenzopyr resulted in late season flower termination, inducing short-term determinate plant response resulting in less immature pods at harvest. Application of diflufenzopyr did not cause dieback or permanent discoloration of leaves but did induce a temporary response of leaf rolling for about 4-5 days. Leaf rolling is a hydronastic mechanism that reduces light interception, transpiration, and leaf dehydration, playing a similar role as osmotic adjustment in maintaining internal plant water status and preventing water loss. Therefore, finding a sub lethal dose of diflufenzopyr that acts as a stimulant to this hydronastic mechanism or illicit a temporary change in plant habit, could potentially result in a beneficial recovery in terms of plant water status, soil water status, and biomass allocation patterns. We found that in irrigated plots, application of diflufenzopyr resulted in enhanced physiological functioning that maintained soil moisture, whereas in dryland plots the same application caused an inhibitory response and rapid decline of soil moisture. Application of this herbicide did not result in a straightforward strategy to limit plant transpiration and control soil moisture.
2. Peanut yield and grade response to multiple simulated rainfall events following inverting.. ARS researchers at Dawson, Georgia believe during peanut (Arachis hypogaea) harvest, climatic conditions may suddenly change from a drought scenario to a high rainfall scenario. During this time of intense rainfall situations, pods must be left in windrows to dry down for days and possibly weeks before pod harvest. In recent years there has been increasing frequency and intensity of rainfall events that have occurred during the harvest of peanut, especially with fluctuating hurricane seasons. Peanut pods are exposed to these variable climatic elements longer than normal. It’s been proposed by growers and storage managers that these weather patterns can create unhealthy conditions pertaining to peanut yield and quality. In this three-year study, we dug mature peanuts and left them in the field (an extra four weeks), exposed them to variable rates and amount of simulated rainfall (over150 mm simulated and natural rainfall) and documented peanut yield, quality characteristics, and aflatoxin values. Across all three years we found a negative relationship with increasing simulated rainfall and decreasing pod yield, and proportion of LSK and splits. However, in 2022 and 2023 where the length of time the peanuts were left in the field increased, and total simulated rainfall applied increased, we saw a subsequent strength in significance related to our measured variables. This suggests that shorter and lesser depths(?) of precipitation may have only slight negative effect on yield and quality metrics in peanut both increased precipitation and time may dramatically affect these variables, and ultimately reduce grower profits.
Review Publications
Dang, P.M., Patel, J., Sorensen, R.B., Lamb, M.C., Chen, C. 2024. Genome-wide association analysis identified quantitative trait loci (QTLs) underlying drought-related traits in cultivated peanut (Arachis hypogaea L.). Genes. 15(7):868. https://doi.org/10.3390/genes15070868.
Sorensen, R.B., Bucior, E.R., Lamb, M.C. 2024. Scheduling irrigation events in corn using three soil water potential strategies. Crop, Forage & Turfgrass Management. 10(2). Article e20288. https://doi.org/10.1002/cft2.20288.
Sorensen, R.B., Lamb, M.C., Butts, C.L. 2022. Cotton yield and quality response to row pattern, seeding rate. Journal of Cotton Science. 26:66–75. https://doi.org/10.56454/QLIP5101.
Sorensen, R.B., Lamb, M.C., Butts, C.L. 2022. Corn, cotton, and peanut response to row spacing, seeding rate, and irrigation system. Journal of Crop Improvement. (37)3:323-340. https://doi.org/10.1080/15427528.2022.2093809.
Sorensen, R.B., Lamb, M.C., Butts, C.L. 2022. Corn yield response to irrigation level, crop rotation, and irrigation system. Journal of Crop Improvement. 36(5):701-716. https://doi.org/10.1080/15427528.2021.2005212.
Sorensen, R.B., Lamb, M.C., Butts, C.L. 2021. Corn yield as affected by row pattern, plant density, and irrigation system. Journal of Crop Improvement. https://doi.org/10.1080/15427528.2021.1980754.
Lamb, M.C., Sorensen, R.B., Butts, C.L. 2020. Agronomic and Economic Effects of Irrigation and Rotation in Peanut-based Cropping Systems. Peanut Science. 47(3): 173–179. https://doi.org/10.3146/PS20-10.1.