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One of the largest challenges in teaching introductory soil science is explaining the dynamics of soil infiltration. To aid students in understanding the concept and to further engage them in active learning in the soils laboratory course, we developed an exercise using Decagon Mini-Disk Infiltrometers with a tension head (h[subscript o]) of 2 cm. Groups of up to four students measured cumulative infiltration for up to 5 minutes and plotted their results vs. time (t). Curves for each group were plotted using SigmaPlot through a computer-projection system so that students could observe infiltration differences between different soils. With the help of their lab instructors, regression analyses were completed to obtain curve-fitting parameters needed to calculate hydraulic conductivity (K). Upon completion of data analyses, the students worked cooperatively to answer several questions concerning infiltration physics. Based on student comments, we believe that we successfully engaged the students and increased their exposure and understanding of infiltration dynamics. (Contains 3 tables and 6 figures.)

Research on elders’ acceptance of virtual technologies is much needed. Here we studied the user experience of elders (N = 10, mean age = 88.2 years) during virtual biking, an exergame where participants pedal on a cycle ergometer and wear a Head-Mounted Display that provides them an immersive experience of a bike ride. We tested the effects of augmented gaze on user experience. Augmented gaze is a condition in which horizontal head turns yield amplified visual shifts, which is assumed to facilitate visual exploration. User experience was measured by asking participants to rate satisfaction, motivation, sense of presence and sense of safety. We found a very good acceptance of virtual biking and no signs of negative effects of augmented gaze. These preliminary observations suggest that augmented gaze may be a viable optimization of elders’ experience with certain virtual reality applications.

Private and public irrigation development projects were fundamental to bringing irrigation to arid regions of the western U.S. The Twin Falls Canal Company in southern Idaho provides a case study of private and public irrigation development because the project was developed by private investors under the Carey Act and receives a portion of its irrigation water supply from U.S. Bureau of Reclamation reservoirs. The project survived initial financial struggles and waterlogged soil to focus on sustaining crop production by reducing chronic furrow irrigation erosion and nutrient losses in irrigation return flow. Average sediment loss from the project was 460 kg ha-1 in 1970. A cooperative effort by the canal company, state and federal agencies, and farmers improved water quality by installing sediment ponds on fields, applying polyacrylamide with furrow irrigation, converting from furrow to sprinkler irrigation, and constructing water quality ponds on irrigation return flow streams. From 2006 to 2018, more sediment and total phosphorus flowed into the watershed than returned to the Snake River, and the project removed 13,000 Mg of sediment and 30 Mg of total phosphorus from the Snake River each year. However, nitrate-N from subsurface drainage was lost at 10 kg ha-1 each year, or 800 Mg year-1, for the entire watershed. While sediment and phosphorus concentrations in irrigation return flow have decreased, these concentrations were still greater than the irrigation water, indicating that more can be done to reduce the project's influence on water quality in the Snake River. [ABSTRACT FROM AUTHOR]

Organic farmers use natural inputs and ecological principles to produce crops in ways that protect soil, the environment, and human health. The objectives of this study were to determine (i) how organic farming with composted manure application affects soil properties under soybean and (ii) how soil C and N transformations in this system are related to soil microbial community structure, soil nutrient and heavy metal content, and soybean yield and quality. The results showed that three years of organic farming promoted soil aggregation and significantly increased aggregate associated C and N concentrations by 11.7 to 24.1% and 9.4 to 17.0%, respectively. Microbial biomass and species diversity (i.e., Shannon, Simpson, and Pielou indexes) were significantly greater in the organic farming than in the conventional farming. Organic farming also increased soil respiration by 56%, nitrification by 51%, and dentrification by 75%. Soybean yield was 13.7% in the organic farming than in conventional farming. Organic farming increased soil Cu and Ni; however, their concentrations were still less than the allowable limits for organic production. Redundancy analysis indicated that the increases in soil nutrient content, heavy metal content, and soybean yield in the organic farming were closely linked with C and N concentrations in the <0.25-mm size fraction. In summary, organic farming with composted manure application improved soil properties and altered the structure and function of the microbial community. The <0.25-mm aggregate fraction had a major influence on microbially mediated C and N transformations and soybean yield. [ABSTRACT FROM AUTHOR]