Retention of Freshman Agricultural Engineering Students Through an Experiential Lab Course

Retention of freshman agricultural engineering (AE) students has been a struggle at Iowa State University (ISU) in past years. This has been attributed to the lack of interaction of the freshmen students with faculty, upperclassmen in AE, and meaningful exposure to the field of AE during their first two semesters. A laboratory-based, team orientated, and hands-on course was developed to help address this problem. Students took this course during their second semester at ISU. Using a pre- and post- semester questionnaire assessment tool, the success of the course was evaluated. Results showed that the students attitude toward the department improved significantly during the semester, that meaningful relationships with faculty and upperclassman in the department increased, and that they were still confident in the major they had chosen. Mentoring by upperclassmen was also found to be a very positive experience for the freshmen. The mentors also found the experience very valuable. An additional benefit was that students became more comfortable in writing technical lab reports. Faculty support was found to be excellent

Band Injection of Herbicides for Reducing Environmental Losses

Herbicides can be an important component for weed control in profitable crop production when selected and used properly. When herbicides are incorrectly applied, however, losses to the atmosphere, surface water, and ground water can be the result. Banding as opposed to broadcast application can reduce herbicide input, but losses of herbicides to the atmosphere during spray application can still be substantial, particularly on windy days (Tremwel, 1985). In addition, herbicide applied directly to crop residue is subject to greater volatilization losses (Burt, 1974; 1987). Crop residue with conservation tillage reduces water and sediment losses, and thus can be an effective tool for reducing herbicide runoff losses, although herbicides surface-applied to crop residue may be subject to greater volatilization and runoff losses (Baker et al., 1982; Baker and Johnson, 1979; Kenimer et al., 1987; Laflen et al., 1978)

Efficient herbicide application to reduce environmental losses

Media reports of atrazine in rainwater and surface and groundwater resources have prompted a concerned public, which includes farmers, to find more efficient, environmentally sound ways to apply pesticides and fertilizer

Buffer strips for controlling herbicide losses

Buffer strips are considered effective for reducing runoff of sediment and agricultural chemicals from cropland. In fact, buffer strips, or vegetative filter strips, have been suggested as a Best Management Practice to reduce nonpoint source pollution from cropland. This pollution can be great, especially if rainfall occurs shortly after a chemical has been applied

Subsurface Application of Herbicides

Traditional methods of preplant herbicide application often involve a broadcast spray followed by one or more incorporation passes. Incorporation reduces the amount of crop residue on the soil surface, which can lead to increased soil loss through wind and water erosion. Incorporation also distributes the herbicide more evenly throughout the soil profile, reducing chemical concentrations in the surface mixing zone. Chemicals located within the 1-2 em mixing zone contribute to herbicide losses with surface runoff (Mickelson et al., 1983; Baker et al., 1979). Conservation tillage, as defined by leaving a minimum of 30% of the soil surface covered by crop residue after planting, allows for incorporation of herbicides while still leaving adequate residue on the surface to reduce erosion losses. Although incorporation has been shown to be extremely effective in reducing surface runoff losses of herbicides, it also is the major contributor to reduced residue cover. No-till, the extreme end of conservation tillage, uses no tillage and maximized residue cover for maximum erosion control. Unfortunately, due to surface application of herbicides, no-till often prevents the use of the more volatile and moderately adsorbed herbicides. In some cases, no-till can increase herbicide concentration and losses with runoff water when compared to conventional tillage (Mickelson et al., 1995)

Measuring the Success of Learning Communities

In 1998, our department turned to the pedagogical innovation termed “learning communities” in an effort to enhance student retention and to bring coherence and meaning to our first-year student curriculum. We have found that our learning community has provided an opportunity for agricultural engineering students to become involved in the Agricultural and Biosystems Engineering (ABE) department from the moment they arrive on campus. Not only has the learning community helped us to increase our first-year, first time student retention in the major of Agricultural Engineering (AE) from 63.6% in 1997 to 79.0% in 2003 in the department (ABE) from 78.8% in 1997 to 89.5% in 2003, it has helped us to address many of our program objectives including students’ abilities to function on multi-disciplinary teams, communicate effectively, and have knowledge of important contemporary issues. Results of our assessment efforts, which encompass both quantitative and qualitative strategies, suggest that students are overwhelmingly satisfied with the program, are involved in our department, and are successful in their academic progress toward their engineering or technology degree

Subsurface Herbicide Application with the Modified John Deere Mulch Master

Subsurface versus surface application can reduce herbicide losses from surface runoff, volatilization, photodegradation, and wind-induced drift. Because distribution in the soil plays an important role in herbicide fate and transport, this study was conducted to analyze the effect of various application methods on herbicide losses with surface runoff. Twelve rainfall simulation plots (three replications of four herbicide application treatments) were established in 1995. Losses of atrazine, metolachlor, and cyanazine with surface runoff were measured for the four different treatments: broadcast spray without incorporation with no-till (NT), broadcast spray with disk incorporation (SD), broadcast spray with Mulch Master incorporation (MR), and subsurface application with incorporation using a modified Mulch Master (MB). For the modified Mulch Master, sprayer nozzles were added to the trailing edges of 61-cm wide Mulch Master sweeps, which were run at a depth of 6 cm. Following herbicide application, rainfall was simulated at 6.35 cm h -1 for 1.5 h on the 3.1 m × 10.7 m plots. Runoff volumes and soil losses were greatest for NT (3.36 cm and 632 kg ha -1 ), followed by MR and MB, with SD showing the lowest total runoff and sediment losses (0.34 cm and 217 kg ha -1 ). Herbicide losses and concentrations were significantly greater (P = 0.10) for NT than for the other three treatments. On the NT plots, runoff began quickly and only occurred on two of the four inter-row areas that had traffic tracks. Herbicide losses decreased in the order of NT, MR, SD, and MB. In addition, MR and MB retained more surface crop residue than SD

Effectiveness of Vegetated Buffer Strips in Reducing Pesticide Transport in S imulated Runoff

Several processes take place within vegetated buffer strips that affect their performance. To better understand these processes, a runoff study was conducted to evaluate vegetated buffer strips performance in reducing atrazine, metolachlor, and chlorpyrifos transport as affected by the drainage area to buffer strip area ratio. The simulated runoff water mixed with pesticide–treated soil was distributed onto six vegetated buffer strips, each 1.52 m wide . 20.12 m long, located downslope of the inflow distribution tank in a well established vegetated grassed waterway. These strips provided for three replications of two inflow rates designated as “drainage area/buffer strip area ratio treatments” of 15:1 and 30:1. Infiltration for the 15:1 treatment averaged 38.8% of the inflow volume, whereas it averaged 30.4% for the 30:1 treatment. Sediment retention efficiencies averaged 90.1% and 86.8% for the 15:1 and 30:1 treatments, respectively. Concentrations of atrazine and metolachlor associated with sediment outflows from the strips were larger than their respective inflow concentrations, while the results were opposite for chlorpyrifos. Concentrations in runoff water for both atrazine and metolachlor in outflow from the strips were smaller than the inflow concentrations; again, the results were opposite for chlorpyrifos. The 15:1 treatment retained an average of 52.5% of the total input of atrazine, 54.4% of metolachlor, and 83.1% of chlorpyrifos. Corresponding numbers for the 30:1 treatment were 46.8% for atrazine, 48.1% for metolachlor, and 76.9% for chlorpyrifos. Analysis of variance using the randomized block design showed that differences of percent retention of pesticide between treatments were not significant for any of the three pesticides at the 10% significance level. A lack of significant difference indicates either a need for more than three replications and/or larger area ratio treatments to be studied. The results of this study indicate that a 30:1 area ratio buffer strip could perform equally as well as a 15:1 area ratio buffer strip. Thus, less land would be required under buffer strips to get the desired results

Holistic Student Professional Development and Assessment: A Backward Design Approach

The paper, "Holistic Student Professional Development and Assessment: A Backward Design Approach (Baughman, Brumm and Mickelson), JTMAE 31/1, April–June 2014" is a copyrighted publication of ATMAE. This paper has been republished with the authorization of ATMAE, and may be accessed directly from the JTMAE website at http://c.ymcdn.com/sites/www.atmae.org/resource/resmgr/articles/baughmanbrummmickelson_vol31.pdf.</p

Longitudinal Study of Learning Communities in Agricultural and Biosystems Engineering

In 1998, the Agricultural Engineering programme at Iowa State University turned to the pedagogical innovation termed `learning communities\u27 in an effort to enhance student retention and to bring coherence and meaning to our first-year student curriculum. Not only has the learning community helped us to increase our first-year, first time student retention in the major of Agricultural Engineering (AE), it has helped us to address many of our AE programme objectives including students\u27 abilities to function on multi-disciplinary teams, communicate effectively and have knowledge of important contemporary issues. Results of the AE learning community assessment efforts suggest that students are overwhelmingly satisfied with the programme