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- Author or Editor: Daniel Cantliffe x
Abstract
Cucumbers, [Cucumis sativus L. cvs. Triple Cross (pickling) and Gemini (slicing)], were grown in the field in the spring and fall under conditions of normal pollination (uncaged) and conditions precluding pollination (caged). When about 5 pistillate flowers were open, some plants from both treatments were sprayed with 100 ppm methyl-2-chloro-9-hydroxyfluorene (chlorflurenol). Very few fruit were produced by either cultivar unless plants were pollinated or treated with chlorflurenol. The most fruit per plant were produced on pollinated, chlorflurenol-treated plants. Numbers of fruit from chlorflurenol-treated plants equalled that of pollinated plants. Chlorflurenol application reduced fruit size in ‘Triple Cross’. No viable seeds developed in fruit from unpollinated plants and chlorflurenol reduced seed number in pollinated fruits.
Extension gained strength from its inception in the early 1900s until the early 1980s. Then things changed—trends led to the notion that extension should get out of social programs and let producers pay their own way. These were the Reagan/Thatcher years. England, New Zealand, Australia, and Canada largely dismantled their extension services. This was supposedly due to financial reasons. They let the private sector take up whatever was released. In the U.S. during the 1980s the Extension Service came under similar attacks and some erosion of the services took place in various states. This has led to a reorganization of the extension service at the federal level, bringing the ARS and Extension Service closer together. I believe that this is the future for Extension—to bind and to build with research to improve and promote continued transfer of new technology. I see this as very difficult for the private sector to do. The ARS and university researchers have to be intimately involved with extension personnel. Program development must be two-fold and must begin to cross state lines both at the state and county levels. Extension workers are doing many of the research jobs of the 1960s and 1970s. For example, our Florida county agents are now doing demonstration and applied research studies that the experiment station personnel did up until 1980. For survival, county operations will need further combining and refining. The basis of the future lies in accountability of extension programs to the public and continued public relationships to express the good job that extension does for all Americans.
Transplants are grown and shipped locally or over long distances. Shipping conditions and time in transit depend on the distance travelled. Local growers may receive transplants in trays they were grown in while those shipped long distances are pulled and packed in boxes. Plant field performance is directly correlated with seedling vigor at the time of transplanting. Factors which can affect transplant vigor during growing and shipping include the plant hardening techniques employed, mechanical injury at any stage of plant growing, shipping and planting, length and conditions of transit, and storage prior to transplanting. Mechanical injury begins as soon as the plants are removed from the tray, while reduced watering and/or nutrition during hardening may have a long term effect on plant productivity. High temperature during shipping, packing plants too densely, and prolonged storage in the dark can reduce subsequent yields. Knowledge of proper conditions for transplant pre- and post-harvest handling and shipping are not clearly understood by many transplant producers and growers. Such knowledge can greatly improve transplant vigor and potentially give growers better yields.
Abstract
Different preplant and sidedress N fertilizer rates from NH4NO3 or urea were applied to pickling cucumbers (Cucumis sativus L.) grown for once-over harvest to determine the effect of N rate, source and time of application on cucumber yield, sex expression, and fruit quality. Nitrogen preplant rates of 67 or 134 kg/ha resulted in greater yields ($/ha and MT/ha) than no N preplant fertilizer. Preplant rates of 201 or 268 kg N/ha gave lower yields. The preplant source of N, NH4NO3 or urea had no effect on yield. Sidedress N as NH4NO3 or urea generally did not influence yields ($ and MT) when preplant N was used at rates of 67 or 134 kg/ha. The addition of preplant N fertilizer up to 134 kg/ha resulted in a slightly greater number of pistillate flowers per plant. The percentages of off-shape fruit were higher for the highest rate (268 kg/ha) of preplant N. Fruit quality evaluation (shape and color) and length:diameter ratios were generally not influenced by preplant N fertilizer.
Abstract
Pickling cucumbers (Cucumis sativus L.) were grown at high plant population (250,000 plants/ha) for once-over harvest. Nitrogen was applied preplant, 0 to 268 kg/ha, and sidedress, 0 to 112 kg/ha, from 2 N sources, NH4NO3 and urea. The effects of N fertilization practices on mineral nutrient composition of the tissue was studied. The concentration of NO3-N in leaf blade and petiole tissue rapidly decreased during the last 2 to 3 weeks before harvest (fruit sizing period). Preplant and sidedress N fertilizer applications led to increased tissue concentration of NO3-N and total N. Petiole tissue concentration less than 0.8% NO3-N or greater than 1.5% at harvest usually reflected reduced yields. Optimum yields generally occurred when blades contained 4 to 5% total N. The source of N fertilizer used had little influence on tissue concentration of NO3-N and total N. Nitrogen fertilization practices had a direct influence on the mineral nutrient composition of the leaf tissue at harvest. Tissue concentration of K, Ca, Mg, Fe and Mn were higher in tissue that received preplant fertilizer N rates from 67 to 201 kg/ha compared to plants that received no preplant N, while the Na concn was reduced. Sidedressing N fertilizer had little influence on cation and anion accumulation in the tissue.
Abstract
Nitrate accumulated in spinach plants that did not receive additional fertilizer N when temp was increased above 15°C. When 50 mg N/kg soil was added the NO3 concn increased above 10°C and with 200 mg N/kg soil NO3 increased with temp increments above 5°C. When N fertilizer was added the NO3 concn decreased with a subsequent increment in temp from 25°C to 30°C. The effect of N fertilizer on NO3 accumulation became more apparent with each 5°C rise in temp to 25°C. Either N fertilizer or a temp rise from 5°C to 25°C led to a significant increase in the total N concn of the plants. Changes in total N were correlated with changes in NO3-N when N fertilizer was added to the soil or when the temp was changed. Nitrite did not accumulate appreciably at any of 6 temp or 3 N fertilizer levels used.
Abstract
‘Winter Bloomsdale’ spinach plants were grown in a growth chamber with a light intensity of 2400 ft-c until 2 weeks before harvest when light intensity treatments of 600, 1600, 2400, and 3500 ft-c were imposed. The total N and NO3 concn of the leaves were increased by the addition of N to the soil and by reduction of light intensity. At 600 ft-c the plants accumulated NO3-N and total N at all soil N levels, but response to soil increments of N was greater at higher light intensities. The concn of K in the tissue increased with a reduction in the light intensity from 2400 to 600 ft-c or application of N fertilizer to 200 mg/kg of soil. Less P was found in spinach leaves as N fertilizer was added to 100 mg/kg of soil. The P content was variable with light intensity.
Abstract
No NO3 accumulated at any photoperiod in leaves or roots of table beets when N was not added to the soil. When N was applied at rates from 100 to 400 lb./acre less NO3 accumulated in both plant parts as photoperiod was extended from 8 to 20 hr. Addition of N to the soil increased the total N content of leaves and roots. Larger total N concn were observed in plants grown under an 8-hr photoperiod than in plants grown under longer photoperiods.
Various radish, spinach, and snap bean cultivars were grown at different soil N rates and harvested 0, 6, and 12 hr after the initiation of the light period. Radish leaves and snap bean pods contained less NO3-N as the plants were harvested further into the light period. Nitrate concn of radish roots and spinach leaves were not changed by harvesting at 6 AM, 12 noon or 6 PM. The addition of N fertilizer increased the NO3-N concn of radish and spinach but decreased the NO3-N concn of snap bean pods. Cultivars differed in their capacity to accumulate NO3 in all 3 species. Nitrite accumulation was proportional to the quantity of NO3 in the tissue.