Time is an important element in hydrologic design. Most hydrologic models require a watershed characteristic that reflects the timing of runoff. The time parameter used in this study was lag time, defined as the time from the centroid of rainfall excess to the centroid of direct runoff. Lag times were evaluated from rainfall-runoff data in over 40,000 events in 116 small watersheds in the United States. The watersheds ranged from 0.243 to 3490 acres, with periods of rainfall-runoff records from 3 to 58 years. Rainfall-runoff event characteristics were used to determine a unique value of lag time for each storm. A tendency towards a constant value of lag time for the "bigger" storms was observed, "bigger" meaning higher values of either previous 48-hour rainfall, average effective rainfall intensity, average runoff intensity, or peak flow. The variable peak flow best showed this tendency; higher peak flow was associated with constant lag time in over 90% of the watersheds. Several hydrologic relationships involving lag time previously described in the literature were not verified in this study. Watershed characteristics were evaluated as "predictors" of lag time within a given watershed. The geomorphic variables used were area, length, width, slope, and storage coefficient (Curve Number). All variables were significant in explaining the variation of lag time by the regression analysis. The watersheds were divided into groups to try to explain the variation of lag time between watersheds. Management practices, geographical region, and the tendency toward constant value of lag time for the "bigger" storms had significant effects in the regression analyses, whereas land use and hydrologic behavior did not. When only the watersheds with the tendency described above were used, no groupings significantly improved the regression equations. Rainfall-runoff data should be used to compute lag time directly, especially for the bigger storms. If data are insufficient, regression predictions can be improved by grouping watersheds by regions and management practices. Width, slope and Snat are the best variables for prediction of lag time. The multiple linear regression model developed in this study had a higher coefficient of determination than other models in the literature.

The Alto Rio Lerma Irrigation District (ARLID), located in the state of Guanajuato in Mexico, is an agricultural area whose sustainability depends partially upon groundwater withdrawal for crop irrigation. Because of high pumping demands and current land-management practices, water levels in the regional groundwater aquifers have declined severely, resulting in aquifer overdraft. The potential adverse consequences of this overdraft cannot be overstated, as the long-term economic viability and environmental integrity of the region is threatened. In order to analyze this economic, environmental, and water use problems in this region, simulation of the agricultural system was performed and associated water use impacts quantified under different management scenarios. Linear programming identified the 12 optimal cropping patterns, and then multi-criteria decision-making methodologies were applied to rank and identify the best cropping pattern (satisficing solution). The GLEAMS model was used to simulate the amounts of water, nitrate, and pesticides in both runoff and percolation for each cropping pattern. In order to quantify the economic and environmental impacts of aquifer overdraft, two attributes were used; pumping costs and an aquifer exploitation coefficient. Three multiple criteria methods: Q-analysis, ELECTRE II, and the Range of Value Method, were evaluated and the latter method was selected to analyze the payoff matrix for the ARLID, where 12 alternatives, each with 13 attributes, were considered. The results show the best alternative for effectively balancing environmental with economic considerations was the farming practice, consisting of land leveling, growing vegetables such as red tomato, and controlled groundwater withdrawals to preserve aquifer sustainability. Low water availability does not necessarily reduce farmer's profits, if new water saving alternatives are applied, combined with more profitable crops. Given that ROV method only considers full compensation between objectives, this research contemplate an extension for the nonlinear case in order to assess the whole range of values of the objective function. The final findings suggest that the best methodology was to apply L1 in the lower levels and then L2 for the highest level in the hierarchy. In this manner, the partial compensation between objectives is considered and also the decrease in the uncertainty of alternatives selection.

<p> This project explores the significance of seed saving as an integral part of sustainable agriculture through the lens of social-ecological resilience. In order to take a deeper look at seed saving and its relationship to social-ecological resilience on a regional scale, this research examines the practices of three culturally distinct seed-saving organizations in northern New Mexico and southern Colorado&mdash;an indigenous pueblo organization, a multi-generational Hispanic family, and an Anglo family farm. Guided by Participatory Action Research methods, interviews were conducted and an exchange of knowledge and ideas among farm managers was encouraged. Interviews focused on understanding the farms reasons for saving seed, their seed saving projects, and their perspectives on their role within the larger regional seed system. Through qualitative data analysis and concept mapping, this research also works towards revealing existing contributions to the resiliency of the regional seed system as well as limitations and possible steps for the future. The findings range, from contributions to the diversity and ecological knowledge to the region's seed system through crop choice and growing practices, to the discussion of limitations such as the difficulty in sharing agricultural knowledge between generations. Future steps are then shared through the mention of seed swaps, seed libraries and ways to open up new pathways of communication between farmers and the community.</p>

Thesis (Ph.D.)--Indiana University, Dept. of Biology, 2005. / Source: Dissertation Abstracts International, Volume: 66-11, Section: B, page: 5775. Adviser: James D. Bever. Title from dissertation home page (viewed 10/10/2006).

Doctor of Philosophy / Department of Horticulture, Forestry, and Recreation Resources / Khatamian Houchang / This project investigated the physiological and biochemical responses of three grapevine genotypes to a deficit irrigation strategy termed partial rootzone drying (PRD). The principle objectives of the project were to (1) establish if the response to PRD is a unique vine physiological response; (2) to investigate the effect of PRD on berry maturation and composition; (3) effect of PRD on vine water-use efficiency; (4) investigate the hormonal signal involved in the PRD mechanism. In addition, the project investigated the adaptation of these three grapevine genotypes to Kansas climatic conditions. The irrigation project was conducted in both a greenhouse at Kansas State University, Manhattan, KS, and field conditions in an experimental vineyard at the John C. Pair Horticultural Research Center, Haysville, Kansas. The greenhouse study was replicated four times (6 months each run) and the field study ran from the 2005/2006 season through the 2006/2007 season. Application of PRD to vines resulted in a unique physiological response distinct from other established deficit irrigation procedures such as regulated deficit irrigation (RDI); however, the overall physiological responses of the vines were defined by the environmental conditions of the vineyard where the experiment occurred. Reduced water availability, low to medium vigor vines, restricted root development, and high evaporative demand were all factors in the vines response to PRD. Under these conditions, PRD did maintain the yield at deficit irrigation rates compared to fully irrigated vines, and was responsible for physiological changes in the vine that could have long-term implications for yield stability. The application of PRD resulted in an improvement in plant water status and maintenance of leaf function as measured by photosynthesis, stomatal conductance and leaf water potential throughout the season.

Abstract not available.

Master of Science / Department of Horticulture, Forestry, and Recreation Resources / Kimberly A. Williams / Despite extensive evidence that appropriate use of floral preservatives extends postharvest longevity of most fresh flowers, their use by traditional full-service florists has been observed to be highly variable. This research was developed to determine if knowledge about floral preservatives increases consumers’ perception of quality, purchase intention, and price of a floral arrangement. A survey was administered to 222 participants at two locations in Manhattan, Kansas during April 2010. Seventy-three percent of respondents fell within the age range of Gen Y. The survey instrument contained four levels of presentation of a floral arrangement that were associated with increasing knowledge about the use of a floral preservative on consumers’ perceptions about the quality and price of that arrangement. Results were analyzed via within-subjects ANOVA, Bonferroni post-hoc tests, t-tests, and regression analyses. Participants of the survey rated the quality of a floral arrangement higher from Level 2 (presence of floral preservative not explicit) to 3 (presence of floral preservative explicit) and Level 3 to 4 (after reading 191 word count message about floral preservative function and effectiveness). Their intent to purchase the floral arrangement generally increased with each level of presentation. Participants increased the price that they were willing to pay for the floral arrangement at each level of presentation, starting at $25.49 at Level 1 (no floral preservative use indicated) to $29.17 at Level 4. Participants were more knowledgeable about the benefits of floral preservatives and believed that floral preservatives increased the value of floral arrangements after reading a message describing their function and effectiveness more so than before reading the message. Younger participants were more willing to pay more for floral arrangements with floral preservatives than older participants. As consumers become more aware of the use of floral preservatives and more knowledgeable about how and why they are effective, they attribute higher quality to floral arrangements with preservatives, are willing to pay more for arrangements with preservatives, and their purchase intention frequency increases. Florists should consider providing a message about the function and effectiveness of floral preservatives to their customers, and then market their use of these materials.

Master of Science / Department of Horticulture, Forestry, and Recreation Resources / Dale J. Bremer / Radiometric methods may provide more objective and quantitative assessments of turf quality and density than visual ratings and may be useful in measuring green leaf area index (LAI), aboveground biomass, and chlorophyll concentration. This three-year study was conducted near Manhattan, KS to examine: 1) relationships between canopy reflectance and visual quality and density ratings in four cool-season grasses tall fescue (Festuca arundinacea Schreb.), Kentucky bluegrass (Poa pratensis L.) and two hybrid bluegrasses (HBG); 2) effects of species, mowing height, and irrigation deficit on relationships between visual quality and reflectance; 3) comparisons of visual quality with reflectance and digital images of individual plots; and 4) relationships of LAI, aboveground biomass, and chlorophyll concentration with canopy reflectance in the same four grasses and in perennial ryegrass (Lolium perenne), zoysiagrass (Zoysia japonica Stued.), and bermudagrass [Cynodon dactylon (L.) Pers.]. Reflectance was strongly correlated with visual ratings in the normalized difference vegetation index (NDVI, [935-661]/[935+661] nm, r = 0.88), the near infrared to red (NIR/R [935/661] nm, r = 0.83), Stress1 (706/760 nm, r= 0.84), and Stress2 (706/813 nm, r= 0.70) ratios and at wavelengths 613 (r= 0.74) and 661 nm (r = 0.80), but correlations varied among years at each wavelength and vegetation index. For density, highest correlations were in NDVI (r=0.86), R661 (r=-0.84), and Stress2 (r=-0.82). Regressions between reflectance and quality and density ratings indicated cultivar- and mowing height-specific models. Irrigation-deficit strongly affected reflectance in KBG and both HBG but not in TF, indicating greater sensitivity to drought of bluegrasses than TF. Digital images indicated strong correlations between percentage green cover and visual quality (r=0.89). However, wide ranges in visual quality were observed in plots with similar green cover or NDVI for reasons that are not apparent. Correlations of LAI, aboveground biomass, and chlorophyll concentration with reflectance were strong in some species at different wavelengths and ratios. Results indicated both potential and limitations in using spectral reflectance to estimate turfgrass canopy characteristics.

Master of Science / Department of Animal Sciences and Industry / David M. Grieger / Mares in estrus can exhibit erratic and fractious behavior that may adversely affect their ease of handling. Current treatments for suppression of estrus in the mare include an oral progestin, Regu-mate® (Hodgson et al., 2005), uterine insertion of a glass ball (Nie et al., 2003), fetal crushing through rectal palpation (Lefranc, 2004) and surgical sterilization (McCue, 2003). Although effective, all of these procedures are problematic for different reasons. Immunization against an endogenous hormone critical to fertility is an attractive alternative in suppressing estrus; especially if it is less intrusive and reversible. This strategy has been demonstrated by targeting gonadotropin-releasing hormone (GnRH) in gilts (Esbenshade and Britt, 1985), ewes (Clarke et al., 1978), mares (Garza et al., 1986), and heifers (Johnson et al., 1988). The antigen developed for this study was produced using the sequence of the bacterial protein, glutathione-S-transferase (GST) linked to three in-tandem repeats of the mammalian GnRH gene coding sequence (GST-GnRH3). Six reproductively sound mares, between the ages of 3 and 8 years, were used in this study. The anti-GnRH group (n=4) received 1 mg of GST-GnRH3 in 2ml of incomplete Freund’s adjuvant (IFA) as the primary injection. Four weeks later, mares received a single booster injection of 0.5mg of GST-GnRH3 in 1ml of IFA. The control mares (n=2) received similar doses of GST protein only, in identical injection volumes of IFA as the anti-GnRH group. The entire duration of the study ran for 22 weeks from early May through September. Ovaries were monitored three times weekly to track follicular growth and ovulation via transrectal ultrasonography. In addition, all mares were exposed to a stallion twice weekly and observed for estrous behavior. Weekly blood samples were collected to evaluate progesterone levels and serum binding of GnRH. The GST-GnRH3 antigen suppressed follicular activity in all treatment mares within 45 days following the second injection. Estrous behavior was suppressed in all but one mare in the anti-GnRH group. When exposed to the stallion, this mare displayed strong estrous behavior for seven weeks despite her lack of ovarian cyclicity. Follicular activity and estrous behavior remained normal in one of the control mares (avg. cycle length = 20 days). For the final 10 weeks of the study, however, the other control mare developed large follicles but failed to ovulate according to the ultrasound data. This mare did not display estrous behavior during this period, and her progesterone levels remained greater than 2 ng/ml for most of the final 10 weeks of the study. Approximately 2 weeks after the booster injection all anti-GnRH mares had progesterone levels of <1ng/ml. GnRH antibody binding peaked two weeks following booster immunization in all treated mares and remained undetectable in control mares throughout the study. The GST-GnRH3 treatment induced GnRH binding, suppressed follicular activity and reduced progesterone concentrations in all four mares. Although estrous behavior was abolished in 3 of the 4 treated mares, one did continue to demonstrate estrous behavior in the presence of a stallion. This dissociation of ovarian activity and estrous behavior was evident in our study with a limited number of animals, but the vaccine does show promise in reducing unwanted estrous behavior.

Through semi-structured interviews with Mexican climatologists and farmers and others in the agricultural sector in Tlaxcala, Mexico, this study explored how uncertainties posed by both variable climatic and changing political-economic conditions affect the vulnerability of small-scale maize producers. The objective of my research was to assess whether and how small-scale Tlaxcaltecan farmers could use long-lead forecasts to mitigate climatic uncertainty. The potential effectiveness of the climate forecasts was evaluated within the context of cultural, political, social and economic factors that influence the decision-making of smallholder farmers. This research determined that the vulnerability of small-scale producers in Tlaxcala is more a function of political-economic uncertainty than of physical circumstances. While farmers employ complex methods for anticipating climatic events based on religious beliefs and local knowledge, their ability to adapt is constrained by lack of resources. As a result, the success of the forecasts in mitigating small-farmer vulnerability will be limited.