A study was initiated at Bracy's Nursery, Amite, La., in Apr. 1997 to evaluate the influence of seven controlled-release fertilizer sources and three top-dressed application rates in production of 4-gal (15.7-L) containers of `LaFeliciana' peach and swamp red maple. The fertilizers tested were Osmocote Plus 15-9-11, Osmocote Plus 16-8-12, Woodace 20-5-10, Woodace 20-4-11, Customblen 24-4-6, Nutricote (Type 270) 17-7-8, and Nutricote (Type 360) 17-6-8. Application rates were 1.75, 2.25, and 2.75 lb N per cubic yard. The experiment was completely randomized within blocks (species) and each treatment was replicated five times. A control treatment was also included. For `LaFeliciana' peach, Nutricote and Osmocote yielded the superior results when shoot height and visual quality ratings were determined in October (6 months after initiation). Increases in application rate did not significantly increase shoot height or visual quality ratings in most cases. For swamp red maple, shoot height was not affected by fertilizer source or application rate. Caliper ranged from 19.2 to 23.0 mm but was only slightly influenced by fertilizer source and application rate. Visual quality ratings were significantly higher for Osmocote Plus 16-8-12 when compared to some of the other fertilizer sources.
A small inexpensive (less than $1000) container yard, measuring 10 × 10 ft square, with an automatic irrigation system was designed for schools participating in the Louisiana State University Coastal Roots Program: A School Seedling Nursery Program for Habitat Restoration. Students helped install the container yard on their school site and oversee native plant production through the course of the school year. Teachers and other school staff checked the nursery during summer months to ensure that the irrigation system was working properly and the plants were healthy. Students grew ≈1000 restoration seedlings per year in their container yard. Each year they transplanted their seedlings and grass plugs on trips to habitat restoration sites across Louisiana's coastal zone. Since the inception of the program in 2000, the students using this container yard design have produced nearly 24,500 trees and shrubs and over 8000 grass plugs.
Leachates were collected at 3-month intervals over 12 months to determine the influence of bark, controlled-release fertilizer, and dolomitic lime sources and dolomitic lime application rates on pH of nursery media. The randomized complete-block design was arranged as a factorial and included three bark sources (pinebark, hardwood, and pinebark + hardwood), two fertilizer sources (Nutricote 17-7-8 and SierraBlen 18-7-10), and two dolomitic lime sources (microencapsulated granular and pulverized). Dolomitic lime application rates were 0, 5, 10, and 15 pounds per cubic yard. Leachate pH was influenced over the one-year evaluation period by fertilizer source, bark source, and application rate of dolomitic lime. Dolomitic lime source was not a significant factor in adjustment of leachate pH. Pinebark medium had lower leachate pHs than hardwood medium and the medium containing hardwood and pinebark. Dolomitic lime influenced leachate pH of pinebark medium more than the other bark sources. SierraBlen was more acid-forming than Nutricote.
Four warm-season grass species [common carpetgrass (Axonopus affinis Chase), common bermudagrass (Cynodon dactylon [L.] Pers.), St. Augustinegrass (Stenophrum secondatum Walt. Kuntze.), and zoysiagrass (Zoysia japonica Steud.)] were established in containers filled with an Olivia silt loam soil for 12 weeks. Grasses were maintained weekly at 5 cm prior to the start of the experiment. Water stress treatments consisted of a control (field capacity), waterlogged, and flooded treatments. Waterlogging and flood treatments were imposed for a period of 90 days. The effects of water stress was dependent on grass species. Bermudagrass vegetative growth and turf quality were significantly reduced when flooded. Carpetgrass, St. Augustingrass, and zoysiagrass quality and vegetative growth were also reduced by flooding. St. Augustinegrass and zoysiagrass root dry weight was significantly decreased. Zoysiagrass plants did not survive 90 days of flooding. Leaf tissue analysis for common carpetgrass, common bermudagrass, St. Augustinegrass, and zoysiagrass indicated that plants subjected to waterlogging and flooding had significantly elevated Zn concentrations.
A study was initiated to determine the effects of fall fertilization, specifically N application rate and additions of supplemental K on the production of woody ornamental shrub species. The influence of two slow-release sources of K (4- and 8-month) in the form of K2SO4, three K application rates (0, 1, 2 lb/yd3), and four incorporated application rates of N (0, 1, 2, and 3 lb/yd3) from Osmocote Plus+ 15-9-11 were evaluated on the growth of `Fisher Pink' Indian azalea, glossy abelia, and `Tuscarora' crape myrtle. Growth of `Fisher Pink' azalea, as determined by shoot height and shoot width, increased as N rate increased from 1 to 3 lb/yd3 when compared to the control. The resulting growth index improved at the 2 and 3 lb/yd3 N rate when compared to the 0 and 1 lb/yd3 N rates. Height and width of glossy abelia at the 1 lb N rate with or without supplemental K applications increased when compared to some glossy abelia at the 3 lb N rate (primarily those with supplemental K). Glossy abelia at the 2 lb/yd3 N rate with 2 lb/yd3 N from 4-month 0-0-46 had significantly greater shoot dry weight when compared to the 3 lb/yd3 N rate with 2 lb/yd3 N from 8-month 0-0-46. The 1 to 3 lb/yd3 N application rate had more of a response on growth index, visual quality, and visual color on `Tuscarora' crape myrtle as compared to the 0 lb/yd3 N rate. In this study, the potential influence of supplemental K applications on plant growth was mostly evident for glossy abelia at the 2 lb/yd3 N rate and was not evident on azalea or crape myrtle.
Priming or presoaking seed of common carpetgrass (Axonopus affinis Chase) and centipedegrass [Eremochloa ophiuroides Munro. (Kunz)] increased germination percentage and decreased mean time of germination (MTG) at 20, 25, and 30 °C. The effect of presoaking and priming was dependent on grass species and temperature. The optimum seed germination temperature for both of these warm-season species was 30 °C. Maximum effect on common carpetgrass or centipedegrass seeds was achieved by priming in 2% KNO3; higher concentrations did not improve germination percentage or MTG, and 4% was in some cases detrimental. Germination was higher and MTG lower at 20 and 30 °C than at 15 °C. Presoaking common carpetgrass and centipedegrass seeds was the most efficient seed enhancement treatment for germination at 30 °C.
Science is a challenging subject to teach at the middle school level. The state of Louisiana requires public school teachers to plan their curriculum around Grade-Level Expectations or state mandated educational benchmarks. A program titled Horticulture in a Can has been designed to teach horticulture lessons to middle school students while targeting the state regulated grade-level expectations. All lessons use a hands-on approach as it has been proven more effective than traditional classroom teaching. Horticulture in a Can was developed by a cooperative effort between the Louisiana Sea Grant College Program and the LSU AgCenter's Department of Horticulture within the Coastal Roots Nursery Program. Eight lesson plans have been created to meet twenty-six Grade-Level Expectations for 463 students in 4 schools. Pre- and PostHorticulture tests were given to each class in addition to pre- and postChildren's Attitude Towards the Environment Scale (CATES). All tests were given to both treatment and control classes within each school. The evaluations tested both short and long-term memory on material contained in the lesson plans. The data was analyzed by school, treatment, sex, and grade-level.
Bifenthrin and fipronil are important pesticides used in the nursery industry for the control of imported fire ants. Our research measured the influence of irrigation frequency and time on the degradation of bifenthrin and fipronil in pine bark nursery medium. Pine bark media leachates were collected over a 180-d period. Levels of bifenthrin, fipronil, and metabolites of fipronil (MB 46513, MB 45950, MB 46136) were measured using gas chromatography and mass spectrophotometery. Bifenthrin leachate concentrations decreased from 60 ppb on day 1 to ≈1 ppb after 120 d. Fipronil leachate concentrations decreased from 40 ppb on day one to a low of 15 ppb after 120 d. In contrast, metabolites MB 45950 and MB 46136 gradually increased over the 180-d period. Metabolite MB 46513 was not detected during the experiment. Pine bark medium leachate concentrations of bifenthrin and fipronil were greater than previously reported levels in pure water. We theorize that organic compounds present in pine bark may have increased the solubility of these chemicals.
Lantana camara `New Gold', `Irene', and `Patriot Dove Wings' were planted in five pine bark-based media containing 0%, 12.5%, 25%, 37.5%, and 50% crumb rubber. Each medium was amended with 7.14 kg·m-3 dolomite lime, 0.892 kg·m-3 of Micromax, and 4.76 kg·m-3 of 17-6-12 Nutricote fertilizer. Height and visual quality ratings were taken at 4 and 8 weeks. Dry weights were taken when the experiment was terminated. There were no significant differences in height, visual quality, and dry weight of `New Gold' lantana for all crumb rubber rates. `Irene' grew taller and had higher visual quality rating in the 4th week with 12.5% and 25% crumb rubber. This trend continued in the 8th week with taller plants grown in 25% crumb rubber. However, there were no differences in plant quality. Dry weight of plants grown in 37.5% and 50% crumb rubber was reduced when compared to the control. There were no differences in growth or quality of `Patriot Dove Wings' at week four. At week eight a reduction in both height and visual quality occurred with 37.5% and 50% crumb rubber. Plant dry weights were also significantly reduced at >37.5% crumb rubber.