Fertilizer Nitrogen Uptake Efficiency in Soft Red Winter Wheat and the Ability of N-STaR to Detect Alkaline Hydrolyzable Nitrogen in Crop Residues

Soil testing methods such as the Illinois Soil Nitrogen Test (ISNT) and Direct Steam Distillation (DSD) have been developed which measure alkaline hydrolyzable-N (AH-N) as a means of estimating potentially mineralizable-N. Crop residues play an important role in N cycling. However, the ability of the ISNT and DSD methods to determine AH-N within crop residues is unknown. Therefore, the first objective of this study was to determine the ability of the ISNT and DSD to quantify potentially mineralizable-N within five different crop residues common to Arkansas. Corn (Zea mays L.), soybean (Glycine max, L.), wheat, rice (Oryza sativa, L.), and grain sorghum (Sorghum bicolor, L.) residues were labeled with 15N using 10 atom% 15N labeled-urea. A 0.2 g subsample of residue was subjected to both the DSD and ISNT. Hydrolyzed-N was captured and analyzed for atom % 15N to compare fertilizer atom % 15N to that of the original residue. Total N was quantified to establish percent recovery. Analysis of variance for percent N recovery showed a significant residue by method interaction (p\u3c0.0001) indicating that the two methods recovered varying amounts of N based on the type of residue. Atom % 15N recovered from the soybean residue as AH-N was significantly lower than what was quantified in the plant tissue. Conversely, atom % 15N recovered from the rice residue as AH-N was significantly greater than that which was quantified in the original plant tissue. Comparison of atom % 15N in the residue and recovered AH-N suggested that certain crop species partition fertilizer N differently. The final objective of this study was to determine the influence of N rate and application time on fertilizer N uptake efficiency (FNUE) for winter wheat on a poorly-drained silt loam soil. Six different fertilizer N-rates were applied by hand ranging from 0 to 225 kg N ha-1 at three different times: Early-single, Late-single, and Split applications in 1.5 x 1.74 m microplots using 2.65 atom% 15N-labeled urea. There was a significant application time by rate interaction (p\u3c0.0408). The greatest FNUE was achieved with the Early-single and Split applications at the 90 kg N ha-1 rate, and were 80.1% and 83.1%, respectively. The minimum yield-maximizing, N-rate was determined to be 135 kg N ha-1 applied as an Early-single or Split application. The Late-single application across all N-rates resulted in lower FNUE and yield. Soil N uptake was not significantly different for any of the treatments that received fertilizer regardless of N rate or timing of application, but were significantly higher than soil N uptake where no fertilizer was applied. Total N uptake by the wheat was directly related to fertilizer N uptake with the Early-single and Split application tending to have higher TN uptake than the Late-single application. Results of both the TN uptake and FNUE support the yield data obtained in these trials and indicate that current N rate recommendations for wheat produced in the delta region of Arkansas optimize fertilizer N inputs while maintaining high yields. These results highlight the importance of proper rate and application time for maximizing FNUE and yield in winter wheat production

Evaluating Consumer Sensory and Composition Attributes of Arkansas-Grown Fresh-Market Blackberries

Blackberries are grown worldwide for commercial fresh markets. Three Arkansas-grown fresh-market blackberry genotypes (‘Natchez’, ‘Ouachita’, and A-2418) were evaluated for consumer sensory and compositional attributes at the University of Arkansas Food Science Department, Fayetteville. The compositional attributes of the blackberries were within an acceptable range for commercial markets (soluble solids=8.20-11.90%, pH=2.79-3.18, titratable acidity=1.09-1.32%). In terms of soluble solids to titratable acidity ratio, ‘Ouachita’ (10.92) had the highest ratio, followed by ‘Natchez’ (8.93) and A-2418 (6.25). A consumer sensory panel (n=80) evaluated fresh-market blackberry attributes using a 9-point hedonic scale for overall impression, overall flavor, sweetness, and sourness and a 5-point Just-about-Right (JAR) scale for sweetness and sourness. The participants also ranked the blackberries in order of overall liking from most to least liked. For overall impression, overall flavor, and sweetness, ‘Natchez’ scored higher than ‘Ouachita’ and A-2418, but the panelists did not detect differences in sourness. In terms of JAR for sweetness, 64% of consumers scored ‘Natchez’ JAR, followed by ‘Ouachita’ (39%) and A-2418 (34%). Whereas, 42% percent found A-2418 “Too Sour”, followed by ‘Ouachita (33%) and ‘Natchez’ (25%). In terms of ranking the blackberries, ‘Natchez’ was the most liked blackberry followed by ‘Ouachita’ and A-2418. When looking only at blackberries ranked first, 53% of consumers ranked ‘Natchez’ as their most liked berry, compared to A-2418 (26%) and ‘Ouachita’ (21%). The results from this research suggested that fresh-market blackberries with medium-level sweetness to sourness ratios were preferred though more consumers than expected preferred the blackberries with the more extreme ratios

Depressive Symptom Severity as a Predictor of Attendance in the HOME Behavioral Weight Loss Trial

Objective We examined whether total depressive symptoms and symptom clusters predicted behavioral weight loss attendance among economically disadvantaged adults in a randomized controlled trial. Methods 150 adults with obesity were randomized to 12 months of in-person, video conference, or enhanced usual care weight loss groups. We categorized percent session attendance in the intervention arms into three levels: no attendance, poorer attendance, and better attendance. Results Higher baseline Patient Health Questionnaire-8 (PHQ-8) score was associated with a greater odds of being in the poorer versus better attendance group (OR = 1.94, 95% CI: 1.02–3.69, p = .04). A similar relationship between PHQ-8 score and odds of being in the no attendance versus better attendance group was observed but was not statistically significant (OR = 1.63, 95% CI: 0.94–2.81, p = .08). Both cognitive/affective and somatic clusters contributed to the depressive symptoms-attendance relationships. Conclusion Greater depressive symptoms at the start of a behavioral weight loss program may predict poorer subsequent session attendance. Screening for and addressing depression may improve intervention uptake

Republicanism and Markets

The republican tradition has long been ambivalent about markets and commercial society more generally: from the contrasting positions of Rousseau and Smith in the eighteenth century to recent neorepublican debates about capitalism, republicans have staked out diverse positions on fundamental issues of political economy. Rather than offering a systematic historical survey of these discussions, this chapter will instead focus on the leading neo-republican theory—that of Philip Pettit—and consider its implications for market society. As I will argue, Pettit’s theory is even friendlier to markets than most have believed: far from condemning commercial society, his theory recognizes that competitive markets and their institutional preconditions are an alternative means to limit arbitrary power across the domestic, economic, and even political spheres. While most republican theorists have focused on political means to limit such power—including both constitutional means (e.g., separation of powers, judicial review, the rule of law, federalism) and participatory ones (democratic elections and oversight)—I will examine here an economic model of republicanism that can complement, substitute for, and at times displace the standard political model. Whether we look at spousal markets, labor markets, or residential markets within federal systems, state policies that heighten competition among their participants and resource exit from abusive relationships within them can advance freedom as non-domination as effectively or even more effectively than social-democratic approaches that have recently gained enthusiasts among republicans. These conclusions suggest that democracy, be it social or political, is just one means among others for restraining arbitrary power and is consequently less central to (certain versions of) republicanism than we may have expected. So long as they counteract domination, economic inroads into notionally democratic territory are no more worrisome than constitutional ones

Cascading Failures in Production Networks *

Abstract I show how the extensive margin of firm entry and exit can greatly amplify idiosyncratic shocks in an economy with a production network. I show that input-output models with entry and exit behave very differently to models without this margin. In particular, in such models, sales provide a very poor measure of the systemic importance of firms or industries. I derive a new notion of systemic influence called exit centrality that captures how exits in one industry will affect equilibrium output. I show that exit centrality need not be monotonically related to an industry's sales, size, or prices. Unlike the relevant notions of centrality in standard input-output models, exit centrality depends on the industry's role as both a supplier and as a consumer of inputs. Furthermore, I show that granularities in systemically important industries can cause one failure to snowball into a large-scale avalanche of failures. In this sense, shocks can be amplified as they travel through the network, whereas in standard input-output models they cannot

Cascading Failures in Production Networks *

Abstract I show how the extensive margin of firm entry and exit can greatly amplify idiosyncratic shocks in an economy with a production network. I show that canonical input-output models, which lack the extensive margin of firm entry and exit, have some crucial limitations. In these models, the systemic importance of a firm does not respond to productivity shocks, depends only on the firm's role as a supplier, and is equal to or well-approximated by the firm's size. This means that for every canonical input-output model, there exists a non-interconnected model that has the same aggregate response to productivity shocks. I show that when we allow for entry and exit, the systemic importance of a firm responds endogenously to productivity shocks, depends on a firm's role not just as a supplier but also as a consumer, and a firm's systemic influence is no longer well-approximated by its size. Furthermore, I show that nondivisibilities in systemically important industries can cause one failure to snowball into a large-scale avalanche of failures. In this sense, shocks can be amplified as they travel through the network, whereas in canonical input-output models they cannot