Innovative didactive strategies such as online learning and flipped classroom can improve student performance while maximizing university resources and personnel. Assessing how students perceive courses designed using these strategies, as well as perform within them, is becoming increasingly important. An introductory soil science course at a 4-year land-grant university was taught (1) face-to-face (FTF, n = 110) with one 50-minute lecture per week and a 2-hour lab twice per week, using (2) flipped classroom (FC, n = 31) design in which most instruction occurred online with a 2-hour lab once per week, and (3) fully and asynchronously online (OL, n = 23). Students completed an end of the semester survey designed to assess perceptions of course utility, the utility of course components, and engagement level in the course. Proportional odds regression models and log odds ratios were used to assess how student perceptions of and performance in this course were influenced by teaching method or student class standing. Class standing had the strongest influence on responses to perception and engagement questions, while teaching method minimally influenced responses to perception and engagement questions. Furthermore, students with the largest odds of expressing potentially less positive perceptions -in this case sophomores -also had the largest odds of performing poorly in the course. These results suggest that FC and OL are viable options which can extend university resources, impact, and accessibility, and that student perceptions of college courses, which in this study varied by class standing, can influence their performance.

HighlightsComparison of PC system and PWM system in-field performance indicated that the PWM system made sensor-based N applications more accurately than the PC system.The turndown ratio calculated from the aggregate application instances was 6.2:1.For both the PWM system and the PC system, applications were made more accurately when 28% UAN was applied rather than 32% UAN. Abstract. Sensor-based nitrogen (N) applications have shown promise for improving N use efficiency, but present significant challenges for application rate control due to highly variable and frequently changing target rates. If applications are to be made precisely, equipment systems used for sensor-based N applications must be designed to meet system demands. Pulse-width modulation (PWM) equipped systems have emerged as a technological advancement over traditional pressure-controlled (PC) systems for improving variable rate N application accuracy. Little research, however, has been done to assess the performance of PWM systems during sensor-based N applications in-field. This work analyzed as-applied data collected from in-field sensor-based N applications with pressure-controlled (PC) and PWM systems in Nebraska between 2015 and 2017 to quantify system requirements, assess system performance, and determine performance impacting operational variables. It was found that systems should be capable of 1-s rate changes of ±71.1 L ha-1 (7.6 gpa), 1-s flow rate changes of ±11.4 L min-1 (3 gpm), and turndown ratios of at least 6:1. PWM systems achieved application rates within 10% of the target rate 10% more often than PC systems, and showed less variability in application error. However, PWM systems still demonstrated significant application errors with an observed RMSE of 44.9 L ha-1 (4.8 gpa). Speed change magnitude was found to be most associated with increases in percent application error. These findings substantiate that PWM systems effectively improve sensor-based N application accuracy versus traditional PC systems. However, collaborative efforts toward greater cohesion between sensor-based application expectations and application equipment capabilities are necessary for maximizing the effectiveness of sensor-based N applications. Keywords: Precision agriculture, Rate controllers, Site-specific crop management, Sprayer, Turndown ratio.

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