Environmental restoration of streams and wetlands in North Carolina is creating a growing demand for commercially available native plant material. Recent changes in the tobacco industry have resulted in decreased production leaving some tobacco greenhouses, once utilized for a few months, empty year-round. Identifying alternative crops that can be grown in tobacco greenhouses will provide valuable income to economically distressed tobacco growers. The floatation system (sub-irrigation) employed in the production of tobacco transplants in greenhouses is similar to that utilized by some native plant nurseries to produce wetland and riparian species. Local production of this plant material can enhance restoration project goals by increasing utilization of regional germplasm in this industry and reducing the risk of importing exotic pests with material shipped from out-of-state. To research these possibilities, we constructed a demonstration tobacco greenhouse with multiple float beds. Three commercially available media, including a tobacco seedling mixture, were tested. No differences were observed among the plants grown in different media. After one growing season, we have identified close to 20 species, woody and herbaceous, that can be successfully grown in a traditional tobacco greenhouse with minimal input or alternation to the structure or normal production practices. Additional research is needed, however, to address optimal production criteria.
Andrew C. Bell and Mary M. Peet*
M.K. Schon, M. Peggy Compton, E. Bell and I. Burns
Experiments were conducted to determine the effect of varying solution N concentrations on fruit yield and NO3-N concentration in leachate from rockwool-grown `Midal' peppers (Capsicum annuum L.) in Florida. Treatment 1 plants received a series of nutrient solutions containing N at 60, 90, and 120 mg·liter–1 (60–90–120 mg·liter–1) during their growth cycle. Plants in treatments 2 and 3 were grown with N at 120 or 175 mg·liter–1, respectively, throughout their entire growth cycle. Two trials were conducted; trial 1 from 17 Nov. 1991 to 1 July 1992, and trial 2 from 31 July 1992 to 23 Feb. 1993. In both trials, total marketable fruit weight was significantly (P ≤ 0.05) higher (16% to 67%) for plants grown with N at 175 than with 60–90–120 mg·liter–1. In trial 2, plants receiving N at 175 mg·liter–1 produced significantly more fruit (8%) and 14% higher total fruit weight than plants receiving N at 120 mg·liter–1. The trend toward higher yield with N at 175 rather than 120 mg·liter–1 also occurred during trial 1, but differences were not significant. Nitrogen concentration did not significantly affect the percentage of total fruit having blossom-end rot in either trial (41% in trial 1; 13% in trial 2). Nitrogen at 175 mg·liter–1 resulted in 10% to 40% increases in total nutrient solution use and 2.5- to 3.5-fold increases in leachate NO3-N concentration compared to N at 120 mg·liter–1.
M.J. Haar, S.A. Fennimore, M.E. McGiffen, W.T. Lanini and C.E. Bell
In an effort to identify new herbicides for vegetables crops, broccoli (Brassica oleracea) cantaloupe (Cucumis melo), carrot (Daucus carota), head lettuce (Lactuca sativa), bulb onion (Allium cepa), spinach (Spinacia oleracea) and processing tomato (Lycopersicon esculentum) were evaluated in the field for tolerance to eight herbicides. The following herbicides and rates, expressed in a.i. lb/acre, were applied preemergence: carfentrazone, 0.05, 0.1, 0.15 and 0.2; flufenacet, 0.525; flumioxazin, 0.063, 0.125 and 0.25; halosulfuron, 0.032 and 0.047; isoxaben, 0.25 and 0.50; rimsulfuron, 0.016 and 0.031; SAN 582, 0.94 and 1.20 and sulfentrazone, 0.15 and 0.25 (1.000 lb/acre = 1.1208 kg·ha-1). Tolerance was evaluated by measuring crop stand, injury and biomass. Several leads for new vegetable herbicides were identified. Lettuce demonstrated tolerance to carfentrazone at 0.05 and 0.10 lb/acre. Cantaloupe and processing tomato were tolerant of halosulfuron at 0.032 and 0.047 lb/acre. Broccoli, cantaloupe and processing tomato were tolerant of SAN 582 at 0.94 lb/acre. Broccoli and carrot were tolerant of sulfentrazone at 0.15 lb/acre.
G.E. Bell, B.M. Howell, G.V. Johnson, W.R. Raun, J.B. Solie and M.L. Stone
Differences in soil microenvironment affect the availability of N in small areas of large turfgrass stands. Optical sensing may provide a method for assessing plant N needs among these small areas and could help improve turfgrass uniformity. The purpose of this study was to determine if optical sensing was useful for measuring turfgrass responses stimulated by N fertilization. Areas of `U3' bermudagrass [Cynodon dactylon (L.) Pers.], `Midfield' bermudagrass [C. dactylon (L.) Pers. × C. transvaalensis Burtt-Davy], and `SR1020' creeping bentgrass (Agrostis palustris Huds.) were divided into randomized complete blocks and fertilized with different N rates. A spectrometer was used to measure energy reflected from the turfgrass within the experimental units at 350 to1100 nm wavelengths. This spectral information was used to calculate normalized difference vegetation index (NDVI) and green normalized difference vegetation index (GNDVI). These spectral indices were regressed with tissue N and chlorophyll content determined from turfgrass clippings collected immediately following optical sensing. The coefficients of determination for NDVI and GNDVI regressed with tissue N averaged r 2 = 0.76 and r2 = 0.81, respectively. The coefficients of determination for NDVI and GNDVI regressed with chlorophyll averaged r 2 = 0.70 and r 2 = 0.75, respectively. Optical sensing was equally effective for estimating turfgrass responses to N fertilization as more commonly used evaluations such as shoot growth rate (SGR regressed with tissue N; r 2 = 0.81) and visual color evaluation (color regressed with chlorophyll; r 2 = 0.64).
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.