8 pages, via Online journal, The use of tomato (Solanum lycopersicum) grafting is gaining traction across the United States, but small-scale growers face the challenge of creating optimum postgrafting healing conditions. The practice of blocking light for a period of 2 to 4 days while maintaining high humidity is commonly recommended for healing grafted tomato transplants; however, research is exploring alternatives to this practice. The present study investigated a low-input healing method for grafted tomato transplants with a specific focus on light and the use of propagation heat mats to regulate substrate and healing chamber air temperatures during the 7-day healing process. We hypothesized that 4 days of light exclusion and the use of propagation heat mats would improve grafted tomato transplant survival and growth. ‘Cherokee Purple’ was used as the scion and ‘RST-04-106-T’ was used as the rootstock. The whole plot factor was heat [propagation mats set at 80 °F (heat) or no propagation mat (no heat)] and the subplot factor was light exclusion (0, 4, or 6 days of dark). The highest survival rate among treatments was 97% in 0 days of dark with no heat treatment; survival decreased to 84% in 4 and 6 days of dark with no heat treatments. The plant survival rate was 96% with 0 days of dark and heat treatment; however, the survival rates were 63% and 45% for the 4- and 6-day dark treatments, respectively. The scion stem diameter was largest for transplants grown in 0 days of dark, but there was no difference in stem diameter due to heat treatments. There were no differences among scion or rootstock biomasses due to heat or light treatments. These results demonstrate that propagation mats set at 80 °F to regulate the substrate temperature were detrimental to grafted transplant survival under extended periods of light exclusion. However, this finding creates the basis to explore lower levels of substrate temperature modification. Our work also indicates that light exclusion may not be necessary for healing grafted tomato plants regardless of root-zone temperature treatments. Future work should examine the interactions of various substrate and air temperatures under full light conditions and their effects on grafted tomato transplant survival and growth. This work contributes to the ongoing research of how to optimize low-input healing methods that may be readily adopted by small-scale tomato growers.
7 pages, via Online journal, Hair fescue (Festuca filiformis) is a tuft-forming perennial grass that reduces yields in lowbush blueberry (Vaccinium angustifolium) fields. Nonbearing year foramsulfuron applications suppress hair fescue, but there is interest in increasing suppression through foramsulfuron use in conjunction with fall-applied herbicides. The objective of this research was to determine the main and interactive effects of fall-bearing year herbicide applications and spring-nonbearing year foramsulfuron applications on hair fescue. The experiment was a 5 × 2 factorial arrangement of fall-bearing year herbicide (none, terbacil, pronamide, glufosinate, dichlobenil) and spring-nonbearing year foramsulfuron application (0, 35 g·ha−1) arranged in a randomized complete block design at lowbush blueberry fields in Portapique and Stewiacke, Nova Scotia, Canada. Spring-nonbearing year foramsulfuron applications did not reduce total tuft density or consistently reduce flowering tuft density, flowering tuft inflorescence number, or flowering tuft seed production. Fall-bearing year pronamide applications reduced hair fescue density for the 2-year production cycle, although additional bearing year density reductions occurred when pronamide was followed by spring-nonbearing year foramsulfuron applications at Stewiacke. Fall-bearing year dichlobenil applications reduced total and flowering tuft density at each site, although reductions in flowering tuft inflorescence number and seed production were most consistent when followed by spring-nonbearing year foramsulfuron applications at Stewiacke. Suppression extended into the bearing year at each site, and dichlobenil should be examined further for hair fescue control. Fall-bearing year glufosinate applications reduced hair fescue total tuft density at each site and flowering tuft density and flowering tuft seed production at Stewiacke. Fall-bearing year glufosinate applications followed by spring-nonbearing year foramsulfuron applications also reduced nonbearing year flowering tuft inflorescence number and bearing year hair fescue seedling density at Stewiacke, indicating that this treatment may reduce hair fescue seedling recruitment at some sites. Fall-bearing year terbacil applications did not suppress hair fescue and are not recommended for hair fescue management in lowbush blueberry.
12 pages, via Online journal, Corn (Zea mays) grown in the southern Piedmont requires 200 to 280 kg nitrogen (N) ha−1 annually and requires up to 0.87 cm of water per day, making groundwater systems susceptible to nitrate (NO3−) leaching. A perennial white clover (Trifolium repens L.) living mulch (LM) system may reduce NO3-N leaching by using legume N to replace mineral N, though little information is available on such a system in the southern Piedmont. Therefore, a HYDRUS-1D model was used to simulate water and NO3-N flux in three cover crop systems. Cereal rye (Secale cereal L.) (CR), crimson clover (Trifolium incarnatum L.) (CC), and a white clover LM were fertilized with 280, 168, and 56 kg N ha−1. The HYDRUS-1D model was calibrated and validated with observed water contents and NO3-N data that were collected over two years. Water and NO3-N flux models were created for each treatment and evaluated using coefficient of determination, percentage bias, and index of agreement, and showed good agreement to observed data. Nitrate leaching below 1 m in 2015/2016 was 23.5, 12.7, and 21.4 kg ha−1 for the CC, LM, and CR treatments, respectively, but was less than 1 kg ha−1 for all treatments in 2016/2017 due to prolonged drought. Differences in leached NO3-N among treatments were attributed to variation in mineral N application rate and NO3-N uptake by cover crops. Overall, results suggest that the use of a perennial LM system may reduce NO3-N leaching when compared to annual CC and CR cover crop systems.
20 pages., Via online journal., Agricultural technology continues to evolve to meet the demands of a growing world, but previous advancements in agricultural technology have been met with resistance. Improved science communication efforts can assist in bridging the gap between expert and lay opinion to improve reception of scientific information. Using the framework of the heuristic model of persuasion, the purpose of this study was to examine the impact of emphasizing elements of source credibility – trustworthiness and expertise – and the gender of the source on perceptions of source credibility. A sample of 122 undergraduate students were exposed to one of the four possible developed message treatments. Data collection took place in a laboratory setting using an online instrument that had a randomly-assigned stimulus research design. The results indicated the treatment conditions had higher mean scores for source credibility than the control. Further inferential analysis, however, showed the differences to be non-significant. One significant finding showed the gender of the source can influence perceptions of credibility. This suggests merit in using female sources when presenting scientific information to the Millennial population. While choosing credible sources to present information is important, more research is needed regarding the effect of emphasizing various credibility components and the role of source gender on perceptions of source credibility.
18 pages, Recent studies cast doubt on the ability of abstract experiments to predict decision-making in the field. Thus, scholars have argued for more ‘realism’ by introducing context to field experiments. Yet, such realism may work against the induced values of monetary incentives in economic experiments. It is an open question whether contextual framing works best with or without inducing values, through methods such as the use of monetary incentives. Using a sample of 146 German farmers, we compare experimentally the predictive power of a framed lottery in an agricultural context vs. using an abstract version. For one half of the sample, lotteries are incentivised; for the other half, they are hypothetical. Although risk preferences differ between treatments, all four lottery tasks correlate poorly with farmers’ real-world use of risk management instruments such as harvest or hail insurance. Subjects who start with an agricultural framing are willing to take significantly greater risks in the lotteries. More generally, our findings cast doubt on the ability of lottery tasks to predict risk-taking in the field.
16 pages, via online journal article, This meta-analytic study reviewed experimental studies that examined the effects of message framing on public engagement with climate change. We included 10 studies that used self-reported measures of climate-related attitudes and behaviors, with 26 comparison pairs. The results suggested that message framing generally has a positive effect on individuals’ engagement with climate change and its two sub-categories – behavioral intentions and support for climate policy. More specifically, we found message frames that emphasize the environmental, economic, and moral dimensions of climate change have a small-to-medium size impact on individuals’ engagement with climate change. In contrast, message frames around public health implications or geographical identity barely influence individuals’ engagement with this issue. We discussed the implications on strategic communications of climate change.
4 pages., Via journal article., Learning by doing plays a critical role in a learner’s conceptual understanding. By actively engaging with a concept, students gain experience and develop an enduring understanding of the concept. The concept of pollen viability is a critical component in the field of plant breeding and can be used to explain various aspects of pollen quality. An inquiry activity was designed to expose undergraduate students in a horticulture course to the concept of pollen viability and its application. The entire class was tasked with collaborating to identify an in vitro germination medium optimized to germinate plumeria (Plumeria rubra) pollen. To determine optimum sucrose and pH concentrations of the medium, student groups were assigned treatments of pollen from two plumeria cultivars that were germinated in Brewbaker and Kwack media of differing sucrose and pH concentrations. Students calculated the percentage of germinated pollen and assessed pollen tube integrity and used these variables as evidence of an optimized medium. Although undergraduates were engaged in authentic research practices during the inquiry activity, lack of time and resources impeded completion of the activity. However, students were exposed to methods and instrumentation directly related to evaluating pollen viability. Moreover, they were exposed to the basic practice of pollen quality assessment that they can use to carry out investigations on pollen fertility. In addition, insight was gained to improve the inquiry activity in the future. Now, well-informed modifications to the inquiry activity can be made to pilot this activity in a formal horticulture laboratory section.
