Cover crop adoption is increasing among growers with the occurrence of herbicide-resistant weed species. A field study conducted at three sites from autumn 2021 through the crop harvest in 2022 in Alabama aimed to evaluate the combined effect of cover crop residue and herbicides for weed control and improved cotton lint yield. The experiment was conducted in split-plot design with main plots consisting of six cover crop treatments: cereal rye, crimson clover, oat, radish, cover crop mixture, and winter fallow. The subplots included four herbicide treatments: (i) preemergence, pendimethalin + fomesafen, (ii) postemergence, dicamba + glyphosate + S-metolachlor, (iii) preemergence followed by postemergence, and (iv) nontreated (NT) check. Cover crops, excluding radish, exhibited greater weed biomass reduction than winter fallow with corresponding herbicide treatments of either preemergence, postemergence, or preemergence + postemergence as compared to control (winter fallow and NT check). Considering preemergence + postemergence treatment, cereal rye, crimson clover, oat, and cover crop mixture provided >95% weed biomass reduction as compared to control. Looking at the overall effect of cover crop, cereal rye outperformed and showed greater weed biomass reduction than radish relative to control. Preemergence + postemergence herbicide treatment resulted in greater lint yield than other treatments. Cotton in cereal rye plots had a greater lint yield than in winter fallow at one out of three locations. In conclusion, integrating herbicides and incorporating high-residue cover crops such as cereal rye is an effective weed management strategy to control troublesome weeds.

In mid-southern, southeastern, and northeastern U.S. soybean production regions, the evolution of herbicide-resistant weeds has become a significant management challenge for growers. The rising herbicide costs for managing herbicide-resistant weeds are also a growing concern, leading to the utilization of cover crops as an integrated weed management strategy for addressing these challenges. Field experiments were conducted at two locations in Alabama in 2022 to evaluate winter cereal cover crops, including a mixture and herbicide system integration in soybean. Treatments included five cover crops: oats, cereal rye, crimson clover, radish, and a cover crop mixture. Cover crops were evaluated for their weed-suppressive characteristics compared to a winter fallow treatment. Additionally, four herbicide treatments were applied: a preemergence (PRE) herbicide, a postemergence (POST) herbicide, PRE plus POST herbicides, and a nontreated (NT) check. The PRE herbicide was S-metolachlor; the POST treatment contained a mixture of dicamba and glyphosate. The PRE plus POST system contained the PRE application followed by POST application. Results show that cereal rye and the cover crop mixture provided weed biomass reduction compared to all cover crop treatments across both locations. Furthermore, we observed greater soybean yield following the cereal rye cover crop than following the winter fallow treatment at one location. POST and PRE plus POST herbicide treatment resulted in greater weed biomass reduction and improved soybean yield than the PRE herbicide treatment alone and the NT check at both locations.

A Palmer amaranth biotype (CT-Res) with resistance to glyphosate was recently confirmed in a pumpkin field in Connecticut. However, the underlying mechanisms conferring glyphosate resistance in this biotype is not known. The main objectives of this research were 1) to determine the effect of plant height (10, 20, and 30 cm) on glyphosate resistance levels in CT-Res Palmer amaranth biotype, and 2) to investigate whether the target site–based mechanisms confer glyphosate resistance. To achieve these objectives, progeny seeds of the CT-Res biotype after two generations of recurrent selection with glyphosate (6,720 g ae ha−1) were used. Similarly, known glyphosate-susceptible Palmer amaranth biotypes from Kansas (KS-Sus) and Alabama (AL-Sus) were included. Results from greenhouse dose-response studies revealed that CT-Res Palmer amaranth biotype had 69-, 64-, and 54-fold resistance to glyphosate as compared with the KS-Sus biotype when treated at heights of 10, 20, and 30 cm, respectively. Sequence analysis of the EPSPS gene revealed no point mutations at the Pro106 and Thr102 residues in the CT-Res Palmer amaranth biotype. Quantitative polymerase chain reaction analysis revealed that the CT-Res biotype had 33 to 111 relative copies of the EPSPS gene compared with the AL-Sus biotype. All these results suggest that the EPSPS gene amplification endows a high level of glyphosate resistance in the GR Palmer amaranth biotype from Connecticut. Because of the lack of control with glyphosate, growers should adopt the use of effective alternative preemergence and postemergence herbicides in conjunction with other cultural and mechanical tactics to mitigate the further spread of GR Palmer amaranth in Connecticut.

The U.S. Department of Agriculture–Agricultural Research Service (USDA-ARS) has been a leader in weed science research covering topics ranging from the development and use of integrated weed management (IWM) tactics to basic mechanistic studies, including biotic resistance of desirable plant communities and herbicide resistance. ARS weed scientists have worked in agricultural and natural ecosystems, including agronomic and horticultural crops, pastures, forests, wild lands, aquatic habitats, wetlands, and riparian areas. Through strong partnerships with academia, state agencies, private industry, and numerous federal programs, ARS weed scientists have made contributions to discoveries in the newest fields of robotics and genetics, as well as the traditional and fundamental subjects of weed–crop competition and physiology and integration of weed control tactics and practices. Weed science at ARS is often overshadowed by other research topics; thus, few are aware of the long history of ARS weed science and its important contributions. This review is the result of a symposium held at the Weed Science Society of America’s 62nd Annual Meeting in 2022 that included 10 separate presentations in a virtual Weed Science Webinar Series. The overarching themes of management tactics (IWM, biological control, and automation), basic mechanisms (competition, invasive plant genetics, and herbicide resistance), and ecosystem impacts (invasive plant spread, climate change, conservation, and restoration) represent core ARS weed science research that is dynamic and efficacious and has been a significant component of the agency’s national and international efforts. This review highlights current studies and future directions that exemplify the science and collaborative relationships both within and outside ARS. Given the constraints of weeds and invasive plants on all aspects of food, feed, and fiber systems, there is an acknowledged need to face new challenges, including agriculture and natural resources sustainability, economic resilience and reliability, and societal health and well-being.

Soybean is the world’s most widely grown leguminous crop and is an important source of oil and protein for food and feed in addition to other industrial uses. However, herbicide-resistant and troublesome weed control challenges limit yield potential and threaten conservation tillage (CT) systems. Cover crops have been widely adopted as an integrated pest management component in CT systems to suppress weeds and maintain soybean yield potential. A 3-yr field experiment was conducted to estimate the influence of a cereal rye cover crop following CT on the critical period for weed control (CPWC) in soybean. The experiment was implemented in a split-plot design in which main plots as CT following cover crop (CT + CC), CT following winter fallow (CT + WF), and conventional tillage (CVT), and subplots were multiple durations of weed-free and weed interference. Results showed that the estimated CPWC of CT + CC and CT + WF treatments was 0 wk and >7 wk, respectively, in 2018. In 2019, the estimated CPWC was 0 wk, 5.0 wk, and 1.3 wk under CT + CC, CT + WF, and CVT treatments, respectively. In 2020, the estimated CPWC was 3.5 wk, >6.2 wk, and 0 wk under CT + CC, CT + WF, and CVT treatments, respectively. The presence of a cover crop delayed the CTWR and caused an early beginning of the CWFP compared with CT + WF treatment, and hence shortened the CPWC in 2018 and 2019. In conclusion, the CT + WF system did not reduce the weed competition and subsequent yield loss in soybean compared to the CT + CC system.

Field studies were conducted in Alabama in 2016 and 2017 to determine the effect of postemergence applications of glufosinate alone and glufosinate applied with S-metolachlor, using two different nozzle types, on LibertyLink®, XtendFlex®, and WideStrike® cotton growth and yield. Two applications of glufosinate at 0.6 kg ha−1, and glufosinate with S-metolachlor at 1.39 kg ha−1 were applied to each cotton cultivar at the four-leaf and eight-leaf growth stages using a flatfan and Turbo TeeJet Induction® nozzle. Visual estimates of cotton injury were evaluated after each application, as well as yield. No differences in yield within each cotton cultivar were observed for either year. Visible injury was higher for WideStrike cotton than LibertyLink or XtendFlex cultivars. On average, glufosinate applied with S-metolachlor resulted in greater injury than glufosinate applied alone. In LibertyLink cotton, applications made with TTI nozzles resulted in greater injury than flatfan nozzles. However, cotton injury was transient and did not affect cotton yields. These data indicate that applications of glufosinate and glufosinate applied with S-metolachlor, at 0.6 kg ha−1 and 1.39 kg ha−1, respectively, with either a flatfan or TTI nozzle, can have no detrimental effect on cotton growth or yield.

A goosegrass [Eleusine indica (L.) Gaertn.] population uncontrolled by paraquat (R) in a vegetable production field in St. Clair County, AL, was collected in summer 2019. Research was conducted to assess the level of resistance of the suspected resistant population compared with three populations with no suspected paraquat resistance (S1, S2, and S3). Visual injury at all rating dates and biomass reduction at 28 d after treatment (DAT) of S populations occurred exponentially to increasing paraquat rates. S biotypes were injured more than R at 3 DAT, with biomass recovery at 28 DAT only occurring at rates <0.28 kg ha−1. Plant death or biomass reduction did not occur for any rate at any date for R. Paraquat rates that induced 50% or 90% injury or reduced biomass 50% or 90% compared with the non-treated (I50 or I90, respectively) ranged from 10 to 124 times higher I50 for R compared with S and 54 to 116 times higher I90 for R compared with S biotypes. These data confirm a paraquat-resistant E. indica biotype in Alabama, providing additional germplasm for study of resistance to photosystem I electron-diverting (PSI-ED) resistance mechanisms.

Conservation tillage adoption continues to be threatened by glyphosate and acetolactate synthase–resistant Palmer amaranth and other troublesome weeds. Field experiments were conducted from autumn 2010 through crop harvest in 2013 at two locations in Alabama to evaluate the effect of integrated management practices on weed control and seed cotton yield in glyphosate-resistant cotton. The effects of a cereal rye cover crop using high- or low-biomass residue, followed by wide or narrow within-row strip tillage and three PRE herbicide regimens were evaluated. The three PRE regimens were (1) pendimethalin at 0.84 kg ae ha−1 plus fomesafen at 0.28 kg ai ha−1 applied broadcast, (2) pendimethalin plus fomesafen applied banded on the row, or (3) no PRE. Each PRE treatment was followed by (fb) glyphosate (1.12 kg ae ha−1) applied POST fb layby applications of diuron (1.12 kg ai ha−1) plus monosodium methanearsonate (2.24 kg ai ha−1). Low-residue plots ranged in biomass from 85 to 464 kg ha−1, and high-biomass residue plots ranged from 3,119 to 6,929 kg ha−1. In most comparisons, surface disturbance width, residue amount, and soil-applied herbicide placement did not influence within-row weed control; however, broadcast PRE resulted in increased carpetweed, large crabgrass, Palmer amaranth, tall morning-glory, and yellow nutsedge weed control in row middles compared with plots receiving banded PRE. In addition, high-residue plots had increased carpetweed, common purslane, large crabgrass, Palmer amaranth, sicklepod, and tall morning-glory weed control between rows. Use of banded PRE herbicides resulted in equivalent yield and revenue in four of six comparisons compared with those with broadcast PRE herbicide application; however, this would likely result in many between-row weed escapes. Thus, conservation tillage cotton would benefit from broadcast soil-applied herbicide applications regardless of residue amount and tillage width when infested with Palmer amaranth and other troublesome weed species.

Palmer amaranth is the latest pigweed species documented in Connecticut; it was identified there in 2019. In a single-dose experiment, the Connecticut Palmer amaranth biotype survived the field-use rates of glyphosate (840 g ae ha−1) and imazaquin (137 g ai ha−1) herbicides applied separately. Additional experiments were conducted to (1) determine the level of resistance to glyphosate and acetolactate synthase (ALS) inhibitors in the Connecticut-resistant (CT-Res) biotype using whole-plant dose-response bioassays, and (2) evaluate the response of the CT-Res biotype to POST herbicides commonly used in Connecticut cropping systems. Based on the effective dose required for 90% control (ED90), the CT-Res biotype was 10-fold resistant to glyphosate when compared with the Kansas-susceptible (KS-Sus) biotype. Furthermore, the CT-Res biotype was highly resistant to ALS-inhibitor herbicides; only 18% control was achieved with 2,196 g ai ha−1 imazaquin. The CT-Res biotype was also cross-resistant to other ALS-inhibitor herbicides, including chlorimuron-ethyl (13.1 g ai ha−1), halosulfuron-methyl (70 g ai ha−1), and sulfometuron-methyl (392 g ai ha−1). The CT-Res Palmer amaranth was controlled 75% to 100% at 21 d after treatment (DAT) with POST applications of 2,4-D (386 g ae ha−1), carfentrazone-ethyl (34 g ai ha−1), clopyralid (280 g ae ha−1), dicamba (280 g ae ha−1), glufosinate (595 g ai ha−1), lactofen (220 g ai ha−1), oxyfluorfen (1,121g ai ha−1), and mesotrione (105 g ai ha−1) herbicides. Atrazine (2,240 g ai ha−1) controlled the CT-Res biotype only 52%, suggesting the biotype is resistant to this herbicide as well. Here we report the first case of Palmer amaranth from Connecticut with multiple resistance to glyphosate and ALS inhibitors. Growers should proactively use all available weed control tactics, including the use of effective PRE and alternative POST herbicides (tested in this study), for effective control of the CT-Res biotype.

We describe an ultra-wide-bandwidth, low-frequency receiver recently installed on the Parkes radio telescope. The receiver system provides continuous frequency coverage from 704 to 4032 MHz. For much of the band ( ${\sim}60\%$ ), the system temperature is approximately 22 K and the receiver system remains in a linear regime even in the presence of strong mobile phone transmissions. We discuss the scientific and technical aspects of the new receiver, including its astronomical objectives, as well as the feed, receiver, digitiser, and signal processor design. We describe the pipeline routines that form the archive-ready data products and how those data files can be accessed from the archives. The system performance is quantified, including the system noise and linearity, beam shape, antenna efficiency, polarisation calibration, and timing stability.

Cover crops can provide many benefits to peanut and cotton crops planted in rotation including suppressing weeds, conserving soil moisture after termination, increasing soil organic matter, and reducing soil erosion. However, herbicide carryover can affect cover crop establishment. The objective of this study was to investigate the responses of 6 cover crops (daikon radish, cereal rye, oat, crimson clover, winter wheat, and common vetch) to 12 soil residual herbicides. A multiyear (2016–2018), multilocation study was conducted in Macon and Henry counties, Alabama. Herbicide treatments included S-metolachlor, acetochlor, pyroxasulfone, diclosulam, imazapic, chlorimuron-ethyl, bentazon plus acifluorfen, pyrithiobac-sodium, trifloxysulfuron-sodium, diuron, prometryn, and flumioxazin, each applied at 10% of the full-labeled rate. At 42 to 52 and 145 to 149 d after planting (DAP), cover crop plant heights and stand counts were evaluated, as was biomass at 145 to 149 DAP. Treatments varied from year to year but not locations. In 2016, significant stand reductions (P ≤ 0.10) of 36% to 43% in rye and 44% to 75% in wheat were observed at 48 to 52 DAP for S-metolachlor, acetochlor, pyroxasulfone, imazapic, and bentazon plus acifluorfen compared with nontreated plants. Vetch had stand reductions ranging from 14% to 80% for all treatments 50 DAP except for plants treated with prometryn. S-metolachlor, pyroxasulfone, and acetochlor reduced stands of rye, wheat, and vetch more than any other herbicides. In 2017, at 147 to 149 DAP, clover stands were reduced by 29% with diclosulam and by 38% with trifloxysulfuron-sodium. Similarly, radish stands were reduced by 64% with diclosulam treatment. No significant biomass reductions were observed for any cover crop species either year. Oat showed the most tolerance with no treatments reducing any growth parameters either year. Although initial injury and stunting may occur, biomass at termination of cover crops were not affected by herbicide residues evaluated in this study.

OBJECTIVES/SPECIFIC AIMS: 1.Identify barriers to pursuing research for physician trainees 2.Develop a sustainable pipeline of physician-scientists at Duke 3.Coordinate physician-scientist development programs across the School of Medicine under one central Office 4.Provide infrastructure and resources for all physician-scientists 5.Increase the number of MDs and MD/PhDs who pursue, succeed, and are retained in research METHODS/STUDY POPULATION: To establish a baseline understanding of the needs and concerns of physician-scientist trainees at Duke, we conducted focus groups using a standardized interview guide and thematic analysis. Findings from these focus groups were used to develop a framework for support, leading to the creation of the Office of Physician-Scientist Development (OPSD) housed centrally within the Duke School of Medicine. The OPSD integrates programs and resources for multiple populations including medical students, residents, fellows, junior faculty, and faculty mentors. Pipeline programs will also be developed to enhance research engagement in targeted student populations prior to medical school. RESULTS/ANTICIPATED RESULTS: A total of 45 students and faculty participated in the focus groups and structured interviews (1st year medical student, n=11; 4th year medical students, n=11; residents/fellows, n=13; junior faculty, n=11). While participants raised a number of specific issues, one key message emerged: non-PhD MDs in basic research felt they lacked opportunities for directed training. Moreover, they felt the need to teach themselves many critical skills through trial and error. This has led to perceptions that they cannot compete effectively with PhDs and MD-PhD scientists for research funding and positions. Consensus recommendations included: better guidance in choosing mentors, labs, and projects; central resource for information relevant to physician scientists; training specifically tailored to physician scientists conducting laboratory-based research; improved infrastructure and well-defined training pathways; and assistance with grant preparation. To-date, over 90 students, residents, and fellows have been identified who identify as laboratory-based physician scientists. Additional efforts are underway to identify and characterize the broader range of physician-scientist students and trainees at Duke. DISCUSSION/SIGNIFICANCE OF IMPACT: Our planning study revealed specific steps forward toward developing a robust community of physician-scientists at Duke. As a first step, the Dean of the School of Medicine has appointed an Associate Dean of Physician-Scientist Development to oversee a new Office of Physician-Scientist Development (OPSD) being launched in December of 2018. The OPSD will offer four primary programs. 1) A concierge mentoring program will assist new trainees in identifying research areas of interest and mentors. Trainees will receive periodic contact to provide additional support as needed and promote success. 2) A physician-scientist training program is being created to provide training specific to laboratory research skills as well as career and professional development training to complement existing clinical and translational research programs. 3) Integrated training pathways will provide additional mentored research training for those pursuing research careers. Pathways will capitalize on existing resources from R38 programs, while pursuing additional R38 and R25 support. 4) An MD-Scientist funding program has been developed to provide additional research funding and protected time for students pursuing a second research year. Through the support and programming offered by the OPSD, we anticipate decreased perceptions of barriers to pursuing a physician-scientist career and increased satisfaction with training opportunities. Over time, we expect such support to increase the number of MD students pursuing research as a career and the number of residents, fellows, and MD junior faculty remaining in research careers.

Cover crops are being increasingly recommended as an integrated approach to controlling glyphosate-resistant Palmer amaranth and other troublesome weeds. Thus, a field experiment was conducted in 2010 through 2012 to evaluate the critical period for weed control (CPWC) in cotton as affected by a cereal rye cover crop and tillage. The management systems evaluated included conventional tillage following winter fallow, conservation tillage (CT) following winter fallow, and CT following a cereal rye cover crop managed for maximum biomass. Throughout most of the growing season, weed biomass in cereal rye cover crop plots was less than the CT winter-fallow system in both years and less than both CT winter fallow and conventional tillage in 2012. The CPWC was shortest in 2010 following conventional tillage; however, in 2012, production system influences on CPWC were less. The presence of the rye cover crop delayed the critical timing for weed removal (CTWR) approximately 8 d compared with fallow treatment both years, while conventional tillage delayed CTWR about 2 wk compared with winter fallow. Relative yield losses in both years did not reach the 5% threshold limit until about 2 wk after planting (WAP) for CT following winter fallow, 3 WAP for CT following a cover crop, and 3.5 WAP following conventional tillage. Thus, CT following winter fallow should be avoided to minimize cotton yield loss.

Breakthrough Listen is a 10-yr initiative to search for signatures of technologies created by extraterrestrial civilisations at radio and optical wavelengths. Here, we detail the digital data recording system deployed for Breakthrough Listen observations at the 64-m aperture CSIRO Parkes Telescope in New South Wales, Australia. The recording system currently implements two modes: a dual-polarisation, 1.125-GHz bandwidth mode for single-beam observations, and a 26-input, 308-MHz bandwidth mode for the 21-cm multibeam receiver. The system is also designed to support a 3-GHz single-beam mode for the forthcoming Parkes ultra-wideband feed. In this paper, we present details of the system architecture, provide an overview of hardware and software, and present initial performance results.

A 3-yr watermelon experiment was established in fall 2013 to evaluate cover crop, polyethylene mulch, tillage, and herbicide application components for weed control, yield, and profitability. Conservation tillage, either with a cereal rye cover crop alone or integrated with polyethylene mulch, was compared to the standard industry practice of conventional tillage with bedded polyethylene mulch. The study also used a non-bedded conventional tillage system without polyethylene to determine polyethylene and cover crop residue effects. Within each of the four systems, herbicide treatments comprised halosulfuron applied (1) at 26.3 g ai ha–1 PRE, (2) at 26.3 g ai ha–1 POST, or (3) sequentially at 26.3 g ai ha–1 PRE and POST. Each system also had a nontreated control. In addition, clethodim was applied in all plots twice POST at 140 g ai ha–1, except for nontreated in each system. In 2014, polyethylene or cereal rye cover crop effectively controlled tall morningglory, coffee senna, and carpetweed early season in nontreated plots, whereas the integration of the two was effective at controlling common purslane. Tall morningglory and purslane control was insufficient late season regardless of production system and herbicide application. In 2015, polyethylene effectively controlled cutleaf eveningprimrose, sicklepod, and arrowleaf sida early season in nontreated plots. Yellow nutsedge control was insufficient late season regardless of production system and herbicide application. Utilizing sequential halosulfuron applications did not increase weed control over PRE or POST alone in all years. Polyethylene use resulted in yields higher than systems without in all years. Across all 3 yr, net returns were highest for polyethylene mulch systems. The results of this experiment underscore the need for more progress in developing integrated conservation systems for watermelon production. Effective herbicides, low-disturbance cultivation, and/or hand weeding are most likely the key to success in conservation specialty crop systems.

We report the single-crystal average structure of cyanotrichite, Cu4Al2[SO4](OH)12(H2O)2, from the Maid of Sunshine mine, Arizona, USA. Cyanotrichite crystallizes in space group C2/m, with the unit-cell parameters a = 12.625(3), b = 2.8950(6), c = 10.153(2) Å and β = 92.17(3)o. All non-hydrogen atoms were located and refined to R1 = 0.0394 for all 584 observed reflections [Fo > 4σFo] and 0.0424 for all 622 unique reflections. The cyanotrichite structure consists of a principal building unit of a three-wide [Cu2Al(OH)6] ribbon of edge-sharing Cu and Al polyhedra || b, similar to that found for camerolaite. The ribbons lie in layers || (001) and between these layers, while SO4 tetrahedra and H2O molecules form rods running || b. A hydrogen-bonding scheme is also proposed.

A sample of cyanotrichite from the Cap Garonne mine, Le Pradet, France, showed a 4b superstructure with the following unit cell: space group P2/m, a = 12.611(2) Å, b = 11.584(16) = 4 × 2.896(4) Å, c = 10.190(1) Å and β = 92.29(6)o. The supercell could not be refined in detail, but nevertheless imposes constraints on the local structure in that while the space-group symmetry prevents full order of SO4 and H2O in the 4b supercell, it requires that the sequence of species along any given rod is [-SO4-SO4-(H2O)2-(H2O)2-] rather than [-SO4-(H2O)2-SO4-(H2O)2-].