Garlic (Allium sativum L.) has been cultivated in much of the world for millennia. Little scientific research, however, has focused on improving cultural conditions for production in the temperate regions of the northeastern United States, where garlic is gaining importance as a horticultural crop. To study the effectiveness of wheat straw (Triticum aestivum) mulch on garlic, experiments were conducted at the Cornell Univ. research facilities in East Ithaca, N.Y., during the 1993–94 (year 1) and 1994–95 (year 2) growing seasons and at the Homer C. Thompson Vegetable Research Farm, Freeville, N.Y., during the 1994–95 growing season. Two clones, one bolting and one nonbolting, were studied in year 1, and four varieties, three bolting and one non bolting, in year 2. All were fall-planted (mid-October), and mulch treatments were covered with wheat straw early in the following December. Control plots were not covered. The mulch either remained on the crop throughout the growing season or was removed early in the spring to expedite soil warming. This is the common practice among growers who use mulch only for winter protection. The presence of mulch during the winter increased the survival rate. Soil temperatures under the wheat straw were significantly lower during the summer than soil temperatures in unmulched plots, which could have contributed to the increase found in the yield and average bulb size of several of the cultivars. Maintaining the mulch through the entire growing season reduced weed pressure >30%. We found no significant increase in the amount of basal fungal infection. The results indicate that using straw mulch can improve garlic produced in the northeastern United States.
Angela M. O'Callaghan
George E. Boyhan, Julia W. Gaskin, Elizabeth L. Little, Esendugue G. Fonsah and Suzanne P. Stone
summer cover crop between spring broccoli and fall lettuce or cover crops in the spring and fall with summer tomato ( Solanum lycopersicum ) production. There is relatively little information on choosing a cover crop for these functions in vegetable
Ted S. Kornecki and Francisco J. Arriaga
Soil Sci. Soc. Amer. J. 57 506 512 Mansoer, Z.D. Reeves, W.R. Wood, C.W. 1997 Suitability of sunn hemp as an alternative late-summer legume cover crop Soil Sci. Soc. Amer. J. 61 246 253 Reeves, D.W. 1994 Cover crops and rotations 125 172 Hatfield J
B.V. Pennisi and P.A. Thomas
In an effort to expand and improve the agriculture curriculum, the Georgia Department of Education set standards for new greenhouses to be built at high schools. These modern greenhouses are to serve as teaching facilities for new horticulture classes. However, current teachers had little or no background or experience in teaching greenhouse or nursery management courses. In response to the GDE needs, a summer workshop “Managing Crop Production and Equipment in the School Greenhouse” was held at CAES Griffin Campus and at Pike County High School. Faculty from UGA departments presented topics such as water quality, irrigation and crop nutrition, cultural guidelines for major floricultural crops, IPM, pesticide safety, and marketing, business planning and fund raising. Included in the program were numerous hands-on activities designed to cover the essential practical skills needed for a greenhouse employee—proper handling and planting of plugs, watering, calculating fertilizer rates, fertilizer injector maintenance and calibration, soil pH and fertility monitoring, scouting and pest identification, and proper pesticide handling and spraying techniques. Twenty-two teachers from schools with horticulture curriculum attended the training. The workshop evaluations indicated high satisfaction with the material presented. Teachers pointed out that the practical skills had not only been very useful but also the manner in which they were presented would be easily applicable to students. The knowledge acquired will be incorporated into the fall and spring curriculum. Through the effort of the floriculture specialist, a high-quality educational program was delivered to Georgia High School teachers, which in turn translate into attracting student into joining the growing ornamental horticulture industry.
A.W. McKeown, J.W. Potter, M. Gartshore and P. Carson
Because of the need to find plants that suppress root lesion nematodes for use in rotation or cover-crops, 16 native sand-prairie species were evaluated for host status for 6 years. Plants were grown on a Fox sand soil at a local prairie plant nursery. Soil cores were taken in the spring, summer, and fall and assayed for plant parasitic nematodes. Five species supported very low numbers (less than 100/kg soil) of root lesion nematodes. Brown-eyed Susan (Rudbeckia hirta) had no detectable nematodes for the duration. Switchgrass (Panicum virgatum L.) and Indiangrass (Sorghastrum nutans L., Nash) samples produced detectable nematodes on only two sampling dates over the 6 years and were statistically not different from brown-eyed Susan. Butterfly weed (Asclepias tuberosa L.) also had very low detectable nematodes as did sand dropseed [Sporobolus cryptandrus (Torr.) Gray.]. New Jersey tea (Ceanothus americanus L.), little bluestem [Schizachyrium scoparium (Michx.) Nash], and big bluestem (Andropogon gerardi Vitman) were poor hosts with <200 nematodes/kg soil. Mountain mint (Pycnanthemum virginianum L), wild bergamont (Monarda fistulosa L), horsemint (Monarda punctata L), and dwarf blazing star (Liatris cylindracea L) all had root lesion populations over 3000/kg soil. Horsemint and wild bergamont plants died out, possibly as a result of nematode infestation. Root lesion nematodes have an extremely wide host range in current agronomic and horticultural crops, and weeds and are difficult to manage using nonchemical means. Indiangrass, switchgrass, big bluestem, and little bluestem have all been used agriculturally for pastures and consequently have potential as beneficial long-term rotation crops for nematode management and soil building.
Sidat Yaffa, Bharat P. Singh, Upendra M. Sainju and K.C. Reddy
Sustainable practices are needed in vegetable production to maintain yield and to reduce the potential for soil erosion and N leaching. We examined the effects of tillage [no-till (NT), chisel plowing (CP), and moldboard plowing (MP)], cover cropping [hairy vetch (Vicia villosa Roth) vs. winter weeds], N fertilization (0, 90, and 180 kg·ha-1 N), and date of sampling on tomato (Lycopersicon esculentum Mill.) yield, N uptake, and soil inorganic N in a Norfolk sandy loam in Fort Valley, Ga. for 2 years. Yield was greater with CP and MP than with NT in 1996 and was greater with 90 and 180 than with 0 kg·ha-1 N in 1996 and 1997. Similarly, aboveground tomato biomass (dry weight of stems + leaves + fruits) and N uptake were greater with CP and MP than with NT from 40 to 118 days after transplanting (DAT) in 1996; greater with hairy vetch than with winter weeds at 82 DAT in 1997; and greater with 90 or 180 than with 0 kg·ha-1 N at 97 DAT in 1996 and at 82 DAT in 1997. Soil inorganic N was greater with NT or CP than with MP at 0- to 10-cm depth at 0 and 30 DAT in 1996; greater with hairy vetch than with winter weeds at 0- to 10-cm and at 10- to 30-cm at 0 DAT in 1996 and 1997, respectively; and greater with 90 or 180 than with 0 kg·ha-1 N from 30 to 116 DAT in 1996 and 1997. Levels of soil inorganic N and tomato N uptake indicated that N release from cover crop residues was synchronized with N need by tomato, and that N fertilization should be done within 8 weeks of transplanting. Similar tomato yield, biomass, and N uptake with CP vs. MP and with 90 vs. 180 kg·ha-1 N suggests that minimum tillage, such as CP, and 90 kg·ha-1 N can better sustain tomato yield and reduce potentials for soil erosion and N leaching than can conventional tillage, such as MP, and 180 kg·ha-1 N, respectively. Because of increased vegetative cover in the winter, followed by increased mulch and soil N in the summer, hairy vetch can reduce the potential for soil erosion and the amount of N fertilization required for tomato better than can winter weeds.
Christian A. Wyenandt, Richard M. Riedel, Landon H. Rhodes, Mark A. Bennett and Stephen G.P. Nameth
-long groundcover due to early senescence from summer heat, twospotted spider mite ( Tetranychus urticae ) damage, and defoliation caused by powdery mildew ( Erisiphe polygoni ). This is the first study that supports the relationship between cover crop biomass
Michael J. Costello
that of the grapevine, i.e., their dormant period is during the summer dry season when the vines are active. Therefore, they should provide the advantages of a perennial cover crop without the disadvantage of excessive competition with the vines for
Emily R. Vollmer, Nancy Creamer, Chris Reberg-Horton and Greg Hoyt
( Ashford and Reeves, 2003 ). Use of summer cover crops for no-till fall cropping is an option in climates warm enough for a fall production season. No-till vegetable production after a summer cover crop compared with tilled bare ground resulted in higher
S.D. Nelson, C. Riegel, L.H. Allen Jr., D.W. Dickson, J. Gan, S.J. Locascio and D.J. Mitchell
One of the proposed alternative chemicals for methyl bromide is 1,3-D. The most common forms of 1,3-D products are cis- or trans-isomers of 1,3-D with the fungicidal agent, chloropicrin, containing such mixtures as 65% 1,3-D and 35% chloropicrin (C-35). Soil fumigants are commonly applied under a polyethylene film in Florida raised bed vegetable production. Much of the research regarding cropping system effects of alternative fumigants to methyl bromide has focused primarily on plant growth parameters, with little regard to the atmospheric fate of these chemicals. The objective of this research was to determine both the atmospheric emission of 1,3-D under different plastic film treatments and to evaluate effects of application rates of 1,3-D and C-35 on plant pests, growth, and yield of Sunex 9602 summer squash (Cucurbita pepo L.). Results showed that use of a high barrier polyethylene film (or virtually impermeable film - VIF) greatly reduced fumigant emission compared to ground cover with conventional polyethylene films or uncovered soil. Summer squash seedling survival was a severe problem in several of the 1,3-D alone treatments where no fungicidal agent was added, whereas C-35 resulted in excellent disease control at both full and one-half of the recommended application rates for this chemical. Both 1,3-D and C-35 provided good plant stands and higher yields when applied at their recommended application rates. However, all squash yields were lower than typical squash production levels due to late planting and early winter frost kill. Chemical names used: 1,3-dichloropropene (1,3-D); trichloronitropropene (chloropicrin).