Asimina triloba (L.) Dunal is an underused tree species with demonstrated potential as a new fruit crop and landscape ornamental plant. Best management practices for A. triloba are not adequately defined, particularly for field establishment in high-Na conditions characteristic of numerous southern U.S. production areas. We evaluated the growth and net macroelement uptake of field-grown A. triloba seedlings on soil amended with a single addition of gypsum at 0, 7.5, or 15.0 t·ha-1 and later receiving a regular supply of Na-affected but nonsaline irrigation water [sodium adsorption ratio (SAR) of 15.5 and electrical conductivity (EC) at 0.4 dS·m-1]. Over two growing seasons, the soil saturation extract Ca concentration increased while the soil saturation extract SAR decreased with increasing gypsum rate. Amending the soil with gypsum increased total lateral branch extension per tree by 60% to 73% and trunk cross-sectional area (TCSA) per tree by 68% to 87% above a non-gypsum-amended control treatment. Total dry matter accumulation and the net uptake of N, P, and K per tree were over 100% greater following gypsum application as compared to controls. The growth and mineral uptake-enhancing effects of gypsum were likely related to functions of Ca at the root level and on soil physical properties that should be considered in establishing young A. triloba trees with irrigation water containing high sodicity but relatively low total salinity.
G.A. Picchioni, C.J. Graham, and A.L. Ulery
Glenn D. Israel, Janice O. Easton, and Gary W. Knox
The Florida Cooperative Extension Service (FCES) teaches residents the importance of proper landscaping practices. FCES offers several educational programs that teach residents how to integrate energy and water conservation, pest management, and waste recycling practices into their home landscapes. In 1997, extension staff and volunteers planned and conducted environmental landscape management (ELM) programs resulting in >800,000 customer contacts. A survey was conducted to measure the adoption of recommended best management practices by program participants and nonparticipants. Results show that, of 39 practices examined, Master Gardener trainees increased the number of practices used by an average of 7.3, while educational seminar and publications-only participants increased by an average of 4.5 and 2.8 practices, respectively. Nonparticipants showed essentially no change. When practices are examined one at a time, the Master Gardeners made statistically significant increases in 28 of the 39 recommended practices. Educational seminar and publications-only participants made similar gains in 31 and 6 practices, respectively, and the nonparticipant comparison group made significant increases in 2 practices and decreases in 8. The results suggest that the publications-only strategy for delivering information to homeowners is less effective than strategies combining educational seminars or intensive training with relevant publications.
Sloane M. Scheiber* and Richard C. Beeson Jr.
Petunia `Midnight' were grown in drainage lysimeters in an open-sided clear polyethylene covered shelter to evaluate growth responses in response to alternative irrigation strategies. Three irrigation methods were evaluated: tensiometer-controlled automatic irrigation system, regularly scheduled irrigation utilizing an automated controller, and human perception of plant irrigation need. Drainage lysimeters (250 L) were backfilled with native sand field soil to simulate landscape conditions and managed with Best Management Practices. Following establishment, lysimeters irrigated by an automated controller were irrigated 1.3 cm daily. Tensiometer-controlled lysimeters were irrigated when plant available water (2.5 kPa to 1.5 MPa) had declined to 70% or less, and were irrigated back to field capacity. Canopy growth indices and leaf gas exchange measurements were evaluated relative to irrigation strategies. Actual evapotranspiration was calculated for each replication. Daily irrigation resulted in significantly higher assimilation rates, transpiration rates, and final shoot dry weights than the other treatments tested. Assimilation rates and transpiration rates were significantly higher for tensiometer-controlled irrigation than the human judged treatment, but no differences were found in final shoot dry mass.
The Department of Horticultural Sciences at North Carolina State University began offering landscape horticulture students a construction studio in 2002. This unique studio engages students in experiential learning (hands-on) and service learning (client-based) projects while simultaneously applying knowledge they have gained during their university education. Three years later, the Landscape Construction Studio is a model course that pushes students to design creatively, while providing a practical foundation in how ideas transition from paper to reality. Projects embody several learning objectives, including fostering exploration and discovery while raising students' awareness of strengths and limitations of traditional and nontraditional construction materials. In addition, the studio enables the elimination of students' tendency to compartmentalize course work, and encourages students to broaden their understanding and appreciation of the world around them. A typical semester incorporates several smaller projects that introduce students to a variety of materials and lessons in construction methodologies. Projects increase in size and complexity over the course of the semester, leading to a comprehensive landscape design and installation project in which students experience the entire design process. Through this final project, students see how information gained from other horticultural and general classes are applied in landscape design. This presentation will discuss the importance of incorporating experiential learning components to horticultural courses, and the pros and cons of service learning projects. Presentation of best management practices will stimulate discussion among the audience.
S. Varlamoff, W.J. Florkowski, J.L. Jordan, J. Latimer, and K. Braman
A survey of Georgia homeowners provided insights about their use of fertilizers and pesticides. Knowledge of current homeowner practices is needed to develop a best management practices manual to be used by Master Gardeners to train the general public through the existing outreach programs. The objective of the training program is to reduce nutrient runoff and garden chemicals and improve the quality of surface water in urban water-sheds. Results showed three of four homeowners did their own landscaping and, therefore, fully controlled the amount of applied chemicals and the area of application. Fertilizers were primarily applied to lawns, but a high percentage of homeowners also applied them to trees, shrubs, and flowers. Insecticides were applied by a larger percentage of homeowners than herbicides. Control of fire ants (Solenopsis invicta) was likely the reason behind the frequent use of insecticides. The desire for a weed free lawn was the plausible motivation behind the use of herbicides, which were used mostly on lawns. Fungicide use was infrequently reported by Georgia homeowners. The pattern of fertilizer and pesticide use suggests that the developed manual should emphasize techniques and cultural practices, which could lower the dependence on chemicals, while ultimately assuring the desired appearance of turf and ornamental plants.
Sloane M. Scheiber, Richard C. Beeson Jr., and Sudeep Vyapari
Root ball slicing is often recommended for root-bound woody ornamentals to promote new root development during establishment in the landscape. It is a common practice among gardeners, but not necessarily landscapers, to disrupt root-bound annuals during transplant. However, little if any evidence exists for such practices. Therefore, this study evaluated the effect of root ball condition of annual bedding plants on landscape establishment and growth. Begoniasemperflorens were transplanted from 0.72-L (#1) containers into field plots in an open-sided clear polyethylene covered shelter and managed with Best Management Practices. Three root ball conditions were evaluated: non root-bound (6-week-old plants), root-bound (10-week-old plants), and root-bound with the bottom 1 cm of the root ball removed. Shoot and root dry masses and growth indices were collected weekly for 12 weeks and evaluated relative to root ball condition by linear regression analysis. Nonroot-bound plants had significantly greater biomass, growth indices, height, and root dry weights than the other treatments tested. No significant differences were found between root-bound and manipulated root-bound plants for any parameter examined. The data indicate that the practice of disrupting root-bound plants has no benefit on establishment or growth of annual bedding plants in the landscape.
Donald J. Merhaut and Julie P. Newman
Lilies are produced throughout the year in coastal areas of California.
Cultural practices involve daily applications of water and fertilizer, using both controlled release fertilizers (CRF) and liquid fertilizers (LF). However, many production facilities are in proximity to coastal wetlands and are therefore at greater risk of causing nitrogen pollution via runoff and leaching. Due to federal and state regulations, nurseries must present a plan of best management practices (BMPs) to mitigate nutrient runoff and leaching and begin implementing these practices in the next 2 years. In the following studies, we determined the potential for nitrate leaching from four different types of substrates (coir, coir: peat, peat, and native soil). There were four replications of each treatment, with a replication consisting of one crate planted with 25 bulbs. Two cultivars were used in two separate experiments, `Star Fighter' and `Casa Blanca'. Nitrate leaching was determined by placing an ion-exchange resin bag under each crate at the beginning of the study. After plant harvest (14–16 weeks), resin bags were collected and analyzed for nitrate content. Plant tissues were dried and ground and analyzed for nitrogen content. Based on the results of these studies, it appears that the use of coir, peat, and soil may not influence plant growth significantly. Substrate type may mitigate the amount of nitrate leaching through the media. However, the cultivar type may also influence the degree of nitrate mitigation, since leaching results varied between the two cultivars.
Scott A. Harrison
A paucity of data exists on the water quality impacts of fertilizer nutrients used for turfgrass management. The primary macronutrients N and P have been shown to cause the eutrophication of surface water bodies, and excessive nitrate (NO- 3) concentrations in drinking water have been linked to methemoglobinemia in infants. Several studies have indicated that runoff quantities from high-quality turf areas are minimal; therefore, nutrient transport by this mechanism should not be a major concern. The leachability of N is favored by the presence of soluble forms in permeable soils receiving rainfall or irrigation in excess of field capacity. Most of the factors contributing to this condition are manageable. However, a wide range of turfgrass types, uses, and management expertise make it difficult to generalize the overall impact of turfgrass fertilization on water resources. While research has demonstrated the ability to minimize nutrient loading, characterization of nonresearch sites is critical to gain a legitimate understanding of environmental impacts. Once developed, best management practices can be effective only if understood and adopted by applicators.
J.P. Mueller, M. E. Barbercheck, M. Bell, C. Brownie, N.G. Creamer, A. Hitt, S. Hu, L. King, H.M. Linker, F.J. Louws, S. Marlow, M. Marra, C.W. Raczkowski, D.J. Susko, and M.G. Wagger
The Center for Environmental Farming Systems (CEFS) is dedicated to farming systems that are environmentally, economically, and socially sustainable. Established in 1994 at the North Carolina Department of Agriculture and Consumer Services (NCDACS) Cherry Farm near Goldsboro, N.C.; CEFS operations extend over a land area of about 800 ha (2000 acres) [400 ha (1000 acres) cleared]. This unique center is a partnership among North Carolina State University (NCSU), North Carolina Agriculture and Technical State University (NCATSU), NCDACS, nongovernmental organizations (NGOs), other state and federal agencies, farmers and citizens. Long-term approaches that integrate the broad range of factors involved in agricultural systems are the focus of the Farming Systems Research Unit. The goal is to provide the empirical framework to address landscape-scale issues that impact long-run sustainability of North Carolina's agriculture. To this end, data collection and analyses include soil parameters (biological, chemical, physical), pests and predators (weeds, insects and disease), crop factors (growth, yield, and quality), economic factors, and energy issues. Five systems are being compared: a successional ecosystem, a plantation forestry-woodlot, an integrated crop-animal production system, an organic production system, and a cash-grain [best management practice (BMP)] cropping system. An interdisciplinary team of scientistsfrom the College of Agriculture and Life Sciences at NCSU and NCATSU, along with individuals from the NCDACS, NGO representatives, and farmers are collaborating in this endeavor. Experimental design and protocol are discussed, in addition to challenges and opportunities in designing and implementing long-term farming systems trials.
Monica Ozores-Hampton, Eric Simonne, Eugene McAvoy, Phil Stansly, Sanjay Shukla, Pam Roberts, Fritz Roka, and Tom Obreza
About 10,000 ha of staked tomato are grown each year in the winter–spring season in southwest Florida. Tomatoes are produced with transplants, raised beds, polyethylene mulch, drip or seepage irrigation, and intensive fertilization. With the development of nutrient best management practices (BMPs) for vegetable crops and increased competition among water users, N recommendations must ensure economical yields, but still minimize the environmental impact of tomato production. The current University of Florida–IFAS (UF–IFAS) N fertilization rate of 224 kg·ha-1 (with supplemental fertilizer applications under specified conditions) may require adjustment based on soil type and irrigation system. Because growers should be involved in the development and implementation of BMPs, this project established partnerships with southwest Florida tomato growers. Studies evaluated the effects of N application rates on yield, plant growth, petiole N sap, pests, and diseases. Nine on-farm trials were conducted during the dry winter 2004–05 season. Treatments consisted of N fertilizer rates ranging from 224 to 448 kg·ha-1, with each trial including at least the UF–IFAS rate and the traditional rate. Although total yields were comparable among N rates, there were differences in size category. Nitrogen rates had little effect on tomato biomass 30 and 60 days after transplanting. Changes in petiole sap NO3-N and K concentrations were different between seepage and drip irrigation, but usually above the sufficiency threshold. It is important to consider the type of irrigation when managing tomato and determining optimum N fertilizer rates.