Triploid watermelon (Citrullus lanatus Thunb.) was grown on the same plots in 1990 and 1991 and fertilized with either poultry litter or commercial fertilizer. Additional treatments included bare soil or plots mulched with black polyethylene, and plots with or without spunbonded fabric row covers over both bare soil and mulch. Watermelon yields were unaffected by fertilizer source in 1990 but were significantly higher for poultry litter than for commercial fertilizer treatment in 1991. Polyethylene mulch significantly increased postharvest soil NO3 and leaf N concentrations in 1990 and increased yield and yield components in both years. There were no beneficial effects of row covers on yield in either year, presumably because no early-season freezes occurred.
J.T. Baker, D.R. Earhart, M.L. Baker, F.J. Dainello and V.A. Haby
J.T. Baker, D.R. Earhart, M.L. Baker, F.J. Dainello and V.A. Haby
Triploid watermelon (Citrullus lanatus Thunb.) was grown on the same plots in 1990 and 1991 and fertilized with either poultry litter or commercial fertilizer. Additional treatments included bare soil or plots mulched with black polyethylene, and plots with or without spun-bonded fabric row covers over both bare soil and mulch. Watermelon yields were unaffected by fertilizer source in 1990 butwere significantly higher for poultry litter than for commercial fertilizer treatment in 1991. Polyethylene mulch significantly increased postharvest soil NO3 and leaf N concentrations in 1990 and increased yield and yield components in both years. There were no beneficial effects of row covers on yield in either year, presumably because no early-season freezes occurred.
D. R. Earhart, F. J. Dainello and M. L. Baker
Response of triploid watermelon [Citrullus lanatus (Thunb.) cv. Tiffany] to fertilizer source (FS) [poultry litter (PL) vs. commercial fertilizer (CF)1, black plastic mulch (BPM), and spunbonded floating row cover (SFC) was evaluated in 1990 on an East Texas Fuquay-Darco sandy loam soil. Plant growth and percent soluble solids were equated by FS. Vine fresh weight, number and total melon weight per plot, average melon weight, and percent soluble solids were increased 27%, 29%, 45%, 24%, and 17%, respectively, by BPM when compared to no mulch treatment. BPM + SFC treatment decreased vine fresh weight but increased total melon number which in turn increased plot weight. PL increased plant P, K, and Mg 16%, 12%, and 24%, respectively, when compared to CF. Plant Ca was increased 21% by CF. Plant N, P, Ca, and Mg were increased 18%, 16%, 22%, and 15% by the use of BPM. A reduction in plant N was found when SFC was used alone and with treatments lacking BPM or BPM + SFC. Mean soil temperature was increased on the average 2°C at 10 cm depth by BPM when compared to all other treatments. Mean 24 hr air temperature 2 cm above BP and bare ground under SFC was increased 5°C above ambient.
D. R. Earhart, M. L. Baker and F. J. Dainello
In a field experiment, fertilizer source (poultry litter vs. commercial), plastic mulch, row cover, and fertilizer rate (residual from 1990 study vs. additional) were applied in factorial combinations to determine the effect on vegetative growth and production of triploid watermelons. Litter (3.12 % total N) was re-applied at the rate of 13.2 Mt·ha-1 along with commercial fertilizer (6N-10.5P-20K) at 1.1 Mt·ha-1. Plastic mulch showed the greatest influence on vegetative growth and production variables by increasing vine length 26.1 cm, leaf area 61.8 cm2, yield 4207 kg·ha-1, melon number 741 ·ha-1, and average melon weight 0.8 kg, over unmulched plots. Plastic mulch with or without row cover increased melon number significantly when compared to plots without mulch or row covers. Poultry litter increased vine length, yield, and average melon weight 15.4 cm, 1971 kg·ha-1, and 0.5 kg, respectively, when compared to commercial fertilizer. Poultry litter in combination with row cover increased yield by 3864 kg ·ha-1 over commercial fertilizer with row cover, and approximately 2567 kg·ha-1 over poultry litter and commercial fertilizer without row cover. Additional fertilizer increased average melon weight 1.3 kg.
S.-S.T. Hua, J.L. Baker and M. Flores-Espiritu
California is the major state for producing almonds, pistachios, and walnuts, with a total market value of $1.6 billion. Both domestic and export markets of these nuts presently allow a maximum level of aflatoxin B1 contamination in the edible nuts to be 20 ppb. Even very low degrees of infection of the nuts by A. flavus can result in aflatoxin levels above the mandatory standards. Biological control to reduce the population of and to inhibit the biosynthesis of A. flavus in orchards may be useful to decrease infection and thus aflatoxin content in the edible nuts. Certain saprophytic yeasts were shown to effectively compete with postharvest fungal pathogens such as Penicillium expansum and Botrytis cinerea. The potential of saprophytic yeasts to reduce aflatoxin contamination in tree nuts has not been hitherto extensively explored. A safe visual bioassay for screening yeasts antagonistic to A. flavus has been developed. The nor mutant of A. flavus has a defective norsolorinic acid reductase and blocks the aflatoxin biosynthetic pathway, resulting in the accumulation of norsolorinic acid, a bright red-orange pigment. We used the nor mutant in the assay to screen yeasts strains for their ability to inhibit aflatoxin production by visually scoring the accumulation of this pigment as well as the growth and sporulation of the fungus. Yeast strains that reduced the red-orange pigment accumulation in the nor mutant were identified and shown to inhibit aflatoxin biosynthesis of several toxigenic strains of A. flavus.
M. Haque, M. Baker, C. Roper, C. Carver Wallace, M. Whitmire, S. Zabel, J. Arnold, L. Petty, A. Dabbs, B. Jordan, R. Keydoszius and L. Wagner
The term Ethnobotany describes the study of people's relationships to plants as foods, fibers, medicines, dyes, and tools throughout the ages. Using the student active technique of experiential learning, undergraduate students enrolled in landscape design and implementation classes at Clemson University planned and installed an Ethnobotany garden in partnership with the South Carolina Botanical Garden (SCBG) staff, volunteers, and Sprouting Wings children. Sprouting Wings is an after-school gardening and nature exploration program for under-served elementary school students. College students and faculty working on this service-learning project contributed over 1,000 hours to their community while learning more about both the art and the science of landscape design and implementation. Students enrolled in the landscape Implementation class were surveyed to evaluate their perceptions on a variety of possible learning outcomes for this class. Students indicated that their service learning experience with the Ethnobotany project allowed them to acquire and practice new skills, broadened their understanding of the surrounding community, increased their ability to work in real world situations, introduced new career possibilities, gave students a better understanding of their course work, increased their ability to work on a team, increased their knowledge of environmental sustainability, and allowed them to discover or develop leadership capabilities. In a survey question regarding preference for service learning rather than traditional classes, the majority of students prefer the service learning pedagogy. In addition, most students reported a high degree of initiative for this project in their reflections.
L. Brandenberger, M. Baker, D. Bender, F. Dainello, R. Earhart, J. Parsons, R. Roberts, N. Roe, L. Stein, M. Valdez, K. White and R. Wiedenfeld
During the past several years, watermelon trials have been performed in the state, but not as a coordinated effort. Extensive planning in 1997 led to the establishment of a statewide watermelon trial during the 1998 growing season. The trial was performed in five major production areas of the state including: The Winter Garden (Carrizo Springs); South Plains (Lubbock); East Texas (Overton); Cross Timbers (Stephenville); and the Lower Rio Grande Valley (Weslaco). Twenty seedless and 25 seeded hybrids were evaluated at each location. Drip irrigation with black plastic mulch on free-standing soil beds was used to grow entries in each area trial and yield data was recorded in a similar manner for each site. Results were reported in a statewide extension newsletter. Future plans include a continuation of the trial in the hope that multiple-year data will provide a basis for valid variety recommendations for watermelon producers in all areas of the state.