Centella asiatica, the Asiatic pennywort, is an herbaceous perennial indigenous to the southeastern United States. In some Asian countries, it is valued as an important vegetable and is widely cultivated. In addition, it is considered an important medicinal herb due primarily to the pentacyclic phytochemical, asiaticoside, which effectively treats a variety of skin diseases. Information on the botany, photochemistry, medicinal, nutritional value, and cultivation of the crop is reviewed. This species may warrant preliminary field and consumer acceptance tests as a speciality vegetable in the United States.
Combinations ofvarious vegetable crop species grown in multiple-cropping sequences using microirrigation on a sandy soil were evaluated for production potential and changes in normal cultural management An initial fall-season fresh-market tomato crop was followed immediately by a winter-season crucifer crop (cauliflower, broccoli, or cabbage), which was followed by a spring-season cucurbit crop (cucumber, zucchini squash, or muskmelon). Studies were conducted over a 3-year period in southwestem Florida. Results showed that when cropping sequences were compared on a basis of a derived relative value index (RVI), the sequence of tomato-cauliflower-zucchini squash significantly outperformed other sequences. Several management concerns particular to the production system (crop residue removal and interference, plastic mulch deterioration and damage, and weed control) were identified and discussed. The potential savings when cropping sequences are compared to individual crop production resulted in net savings (dollar savings less additional production costs) that ranged from $565 to $1212/acre ($1396 to $2993/ha) and $614 to $1316/acre ($1516 to $3251/ha) for the 1986-87 and 1988-89 seasons, respectively.
Abstract
Weed control is essential for production of high quality vegetables with maximum yields. (±)-2-[4-[5-(trifluoromethyl)-2-pyridinyl]oxy]phenoxy]propanoic acid (fluazifop) is a systemic postemergence herbicide that selectively controls annual and perennial grasses in dicotylendonous crops. In the United States, fluazifop is registered for control of emerged grasses in soybeans, cotton, nonbearing trees, vines, and strawberries, dicotyledonous ornamentals, and fallow land (Imperial Chemical Industries, Inc. 1985; Fusilade-2000 product label I.C.I. Americas, Inc., Agr. Chem. Div., Wilmington, DE 19897). Research has dealt with the safe use of fluazifop in field-grown vegetables at various growth stages (4), but there are no data in the literature describing the effect of fluazifop on greenhouse grown transplants. Therefore, we determined the effect of two rates of fluazifop on the growth and development of five vegetables grown in a greenhouse for transplants.
Abstract
The response of 9 vegetable crops to P concn in the soil solution was determined in field studies on soils with a relatively high capacity for immobilizing P. Adjusted P concentration in the soil solution ranged from 0.003 ppm, doubling at each level, to 1.6 ppm. Most crops produced maximum yields at 0.2 to 0.3 ppm P in soil solution, although transplanted head cabbage (Brassica oleracea L. Capitata Group) and sweet potato (Ipomoea batatas (L.) Lam) produced maximum yields at 0.04 and 0.1 ppm, respectively. At suboptimal P concentration in soil solution, crop response varied greatly. Sweet potato produced about 70% of maximum yield, while lettuce (Lactuca sativa L.) produced about 1% of maximum yield. P levels in plant tissue at 95% of maximum yields ranged from 0.3% in lettuce to 0.7% in Chinese cabbage (Brassica campestris L. Pekinensis Group).
We thank the Organic Farming Research Foundation for funding this evaluation of summer cover crop species. We also thank Jane Frampton, Joe Difeo, and Tim Mathews for their technical support, and the staff at the Tidewater Research Station
Civil war and the hostilities which followed it in Cambodia from 1972 to 1979 resulted in a 20% reduction in the country's population and the near total destruction of its educational and agricultural research infrastructure. As if this were not enough, western governments embargoed humanitarian aid to Cambodia during its most critical period of need from 1981 until multiparty elections were held in 1993. During this period a handful of nongovernmental agencies helped the government begin rebuilding some of its agricultural production capacity. One NGO, together with its government counterparts, established the country's first research station for vegetable crops in 1985 at the request of the Ministry of Agriculture. The Kbal Koh Vegetable Crops Research Station was built and its staff received training from 1985 to 1987. The facility has continued its four-part mission with very limited outside funding and technical support since 1987. Numerous variety and seed production trials have been conducted at the station and in farmers' fields since 1985; practical training programs for agricultural technicians and students began in 1986 and today provide much of the salary and operating budget support for the station. Coinciding with the phase out of NGO assistance in 1995, their are great expectations for continuing support through the newly formed Cambodia–Laos–Vietnam vegetable production and research network, AVRDC, and the Asian Development Bank.
Funding for this project was provided in part by USDA NCR-SARE grant No. 25-6205-0042-027, PPRC MSU (Pickle and Pepper Research Committee for Michigan State University), PPI (Pickle Packers International Inc.), and the Michigan Vegetable Council
139 ORAL SESSION 38 (Abstr. 645–650) Sustainable Agriculture–Vegetables
Abstract
Sodium azide (NaN3) applied at 134.4 kg/ha as a soil fumigant did not drastically alter the quality of vegetable root crops grown on treated soil. Azide soil treatment had no influence on quality of beets (Beta vulgaris L.) or potatoes (Solanum tuberosum L.). Differences were noted in quality of turnips (Brassica rapa L.) during 1976; however, no differences were found during the 1977 growing season at 2 locations. Azide soil treatments resulted in differences in quality of carrots (Daucus carota L.). Some differences that occurred were beneficial such as increased size and carotenoid content of carrots.
Abstract
Research related to plant growth and development over the past 75 years has brought us to a point where the vegetable plants we grow today have been developed to fit the needs of the home gardener, the greenhouse grower, the large scale fresh market grower and the vegetable processing industry. Through this research, changes have come about that contribute to a better understanding of the basic genetic and physiological mechanisms that control plant habit, sex expression, flowering, and fruit type. These four broad areas will be covered to demonstrate the diversity and scope of knowledge concerning growth and development that has accumulated in the 20th century. This knowledge opens doors for further work on the major crops and for beginning work on crops that hold promise for the future. The flexibility and complexity of plants and plant processes allow us to look at plants the way we find them, envision them the way they can be changed to best serve us and plan our procedures for developing them for the future.