Right Rate, Timing, Source and Placement: More Bang for the Pasture Fertilizer Buck

As we write this paper for the conference, fall fertilizer prices continue to increase, albeit at a slower pace than earlier this fall for most materials. The latest DTN retail price survey https://www.dtnpf.com/agriculture/web/ag/crops/article/2021/10/06/fertilizer‐price‐gains-losing‐steam has urea (46‐0‐0) at $620/ton, DAP (18‐46‐0) at$722/ton and potash (0‐ 0‐60) at $647/ton. This gives$0.675/lb N, $0.52/lb P2O5 (after the N value in DAP price was accounted for), and$0.54/lb K2O. Compared to this time last year, urea, DAP and muriate of potash are 71, 64 and 92% higher, respectively. Other important materials used in Kentucky are also higher: ammonium polyphosphate (APP, 10‐34‐0); UAN (32‐0‐0); and anhydrous (82‐0‐0) are 40, 78 and 84% more expensive, respectively

Managing Risk in Grazing Operations

Risk is an inherent part of agricultural production systems. Crane and coworkers (2013) identified five primary areas of risk in grazing operations: 1) MARKETING risk, 2) PRODUCTION risk, 3) LEGAL risk, 4) HUMAN risk, and FINANCIAL risk. These types of risk are described in the accompanying publication entitled “Controlling Risk in Grazing-Based Production Systems” by J. Parsons. This article will discuss the risk associated with “production” in grazing systems, focusing specifically on managing drought in grass based production operations

It Takes More Than Calcium to Neutralize Soil Acidity

Proper pH management is the foundation to a good soil fertility program. Soil pH influences nutrient availability and root growth and function. Just because an agricultural product contains calcium does not mean that it will change soil pH. The effectiveness of three calcium products in raising soil pH was compared to an untreated check in acid soils. A field trial was conducted at 16 locations across Kentucky and a laboratory incubation study was conducted at the University of Kentucky Research and Education Center. The same application rates were used for the three products, whether in field trials or laboratory incubations. The rates were 46.8 L ha-1 for the liquid calcium and 4.5 Mg ha-1 for the pelletized and ag limes. The field studies exhibited higher soil pH at 3-month and 12-month sample dates with ag lime and pelletized lime treatments than with the check and liquid calcium treatments. The lab study exhibited higher soil pH values at each sample date (1, 3, 6 and 12 month) with ag lime and pelletized lime than with check and liquid calcium. The soil pH was not improved with the addition of liquid calcium (chloride) and results of this study are supported by the chemical foundations of soil acidity neutralization reactions - calcium chloride does not neutralize acidity and calcium carbonates do

Searching for Faint Planetary Nebulae Using the Digital Sky Survey

Recent Halpha surveys such as SHS and IPHAS have improved the completeness of the Galactic planetary nebula (PN) census. We now know of ~3,000 PNe in the Galaxy, but this is far short of most estimates, typically ~25,000 or more for the total population. The size of the Galactic PN population is required to derive an accurate estimate of the chemical enrichment rates of nitrogen, carbon, and helium. In addition, a high PN count (~20,000) is strong evidence that most 1-8 Msun main sequence stars will go through a PN phase, while a low count (<10,000) argues that special conditions (e.g., a close binary interaction) are required to form a PN. We describe a technique for finding hundreds more PNe using the existing data collections of the digital sky surveys, thereby improving the census of Galactic PNe.Comment: 11 pages, 7 figures, accepted for publication in the Publications of the Astronomical Society of Australia (PASA), full resolution paper available at http://www.wiyn.org/jacoby_pasa.pd

Assessing the Nutrient Status of Alfalfa Stands in Kentucky

Alfalfa (Medicago sativa L.) is a perennial forage legume and is sometimes referred to as the “Queen of Forages” due to its high nutritional value. Alfalfa is commonly produced as hay for use in the dairy and equine industries. Alfalfa yield increased exponentially from the 1950s to the1980s due to new breeding and management innovations. However, during the 1980s yields plateaued at around 7.5 Mg/ha and remain there today. The overarching goal of this study was to determine the role of soil fertility in the observed yield plateau. Fifty alfalfa stands in Kentucky were sampled to gather information about their macro and micronutrient status. Samples were taken, when the stand reached the late bud to early flower stage of maturity, from a 6 x 6 m2 area that was representative of the entire stand. Soil samples were collected to 10 and 15 cm depths and were sent to the University of Kentucky soil testing lab for analysis. The top 15 cm of 30 stems were dried, ground, and sent to Kansas State University for tissue analysis. In 2022, soil and tissue data from the alfalfa stands sampled indicated that potassium, sulfur, and magnesium were the nutrients most commonly reported to be below established sufficiency ranges. In addition, pH was low in just under half of the sampled stands. Tissue analysis indicated that soil testing overestimated potassium deficiencies in alfalfa stands in Kentucky. Even so, potassium levels were below the sufficiency range in nearly one-fourth of the alfalfa stands sampled

Attacking the Yield Plateau: Assessing the Nutrient Status of Kentucky Alfalfa Stands

Soil and tissue analyses indicated that alfalfa yields may be limited in some cases by soil fertility. Soil pH was below the optimal range in more than 40% of the fields sampled. This may result in decreased nitrogen fixation and nutrient availability. Potassium was reported low in approximately one‐quarter of the sampled stands according to tissue analysis. This was not unexpected since hay production removes large quantities of potash. Sulfur and magnesium were reported low in 13 and 23 percent of stands, respectively. More work is needed to better understand if these two 2023 Kentucky Alfalfa and Stored Forage Conference Proceedings Page Number 76 nutrients are truly limiting alfalfa yield in Kentucky

Visualizing electrostatic gating effects in two-dimensional heterostructures

The ability to directly observe electronic band structure in modern nanoscale field-effect devices could transform understanding of their physics and function. One could, for example, visualize local changes in the electrical and chemical potentials as a gate voltage is applied. One could also study intriguing physical phenomena such as electrically induced topological transitions and many-body spectral reconstructions. Here we show that submicron angle-resolved photoemission (micro-ARPES) applied to two-dimensional (2D) van der Waals heterostructures affords this ability. In graphene devices, we observe a shift of the chemical potential by 0.6 eV across the Dirac point as a gate voltage is applied. In several 2D semiconductors we see the conduction band edge appear as electrons accumulate, establishing its energy and momentum, and observe significant band-gap renormalization at low densities. We also show that micro-ARPES and optical spectroscopy can be applied to a single device, allowing rigorous study of the relationship between gate-controlled electronic and excitonic properties.Comment: Original manuscript with 9 pages with 4 figures in main text, 5 pages with 4 figures in supplement. Substantially edited manuscript accepted at Natur

Yearling Beef Cattle Grazing Diverse Summer Annual Swards

Utilizing summer annuals is often regarded as “a breakeven proposition at best” due to high establishment costs. This study investigated using botanical diversity to increase forage yield or animal performance to improve the economic feasibility of grazing summer annual forages in western Kentucky, USA. Sorghum-sudangrass (Sorghum bicolor x S. bicolor spp. drummondii)-based treatments included a monoculture, a three-species mixture (two grasses, one legume), and a 12-species mixture (five grasses, four legumes, two brassicas, and one forb). Angus-cross yearling beef calves (329, 366, and 297 kg in 2017, 2018, and 2019, respectively) grazed summer annuals in 2017-2019 for an average of 40 days each year without supplementation. Pastures were stocked when forage was approximately 1 m tall and calves were removed when forage was 2-2.5 m tall (seedheads present). In all years, forage dry matter yield was not different between treatments (p \u3e 0.85) and both mixtures were dominated by sorghum-sudangrass. In 2017 (p \u3c 0.03) and 2019 (p \u3c 0.03), calves grazing the 12-species mixture had lower average daily gains (ADG) than the monoculture and 3-species mixture, while there was no difference in 2018 (p \u3e 0.3). Average daily gains were suboptimal for stocker calves in all years (0.75, 0.01, 0.54 kg day-1 in 2017, 2018, and 2019). The extremely low ADG in 2018 was likely a result of stocking pastures late in the season when grasses were at physiological maturity. Additional species increased seed cost but did not contribute significantly to forage production and did not result in increased animal production. Unless greater forage yield or livestock gains are attained, planting mixtures may not provide any economic benefit. However, adjusting seeding rates to favor less dominant species may provide a more accurate representation of species diversity manipulation effects on forage and livestock production