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  • Author or Editor: John O'Sullivan x
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Abstract

The effects of soil fumigation with Telone C-17 on yield, petiole NO3-N levels and verticillium wilt (incited by Verticillium albo-atrum Reinke & Berth and V. dahliae Kleb.) of potatoes (Solanum tuberosum L.) grown continuously and in a 2-year rotation with corn since 1972 at 8 rates of nitrogen were studied in 1978 and 1979. Soil fumigation resulted in significant yield increases where potatoes were grown continuously. Potatoes grown in rotation responded to fumigation only in 1979. Continuous culture of potatoes resulted in reduced yields in both years. Nitrate-N levels were substantially lower in petioles from fumigated plots than in non-fumigated plots. Yield responses from fumigation and rotation were the result of reduced severity of verticillium wilt infestation. Soil fumigation and rotation had equal effects on yield and verticillium wilt, particularly in 1979.

Open Access

Abstract

An economic model involving simulation methodology was used, in conjunction with data from field experiments, to examine the economic effects of delayed or premature harvest of pickling cucumbers (Cucumis sativa L.) on yield and several measures of size grade distribution. It was shown that, for once-over harvesting of cucumbers, profitability of cucumber production was extremely sensitive to untimely harvesting. Profitability/ha was reduced on average by $1091 and $722 respectively for harvesting 3 days earlier or later than optimum. Harvest criteria which maximized profit were identified for both conventional cucumber production and production based on gynoecious cultivars and treatment with chlorflurenol. Substantial differences in the effect of harvest timing on profitability/ha and in optimum harvest criteria occurred between these production systems. Maximum margins occurred in production methods involving gynoecious cultivars and chlorflurenol when 54.6% of the fruit were classified as grade 1. The comparable value for conventional production methods was 27.3%.

Open Access

Abstract

Pickling cucumbers (Cucumis sativus L.) were harvested once-over at 24-hour intervals for periods of from 6-11 days over a 3-year period to study the effect of harvest date on yield, average crop value, and grade distributions, and to identify criteria that could be used to identify optimum harvest date in the field. The relationship between yield (MT/ha) and average crop value ($/MT) was linear (R2>.90) indicating that average crop value would be a satisfactory criterion to indicate optimum harvest date. The relationships between yield and grade 1 and grade 5 cucumbers (% by number and by weight) and grade 4 cucumbers (% by number) were also linear (R2>.68) indicating that these measures of grade distribution could also be used to indicate optimum harvest date. The relationship between yield and % by weight and by number of grade 2 and 3 cucumbers did not follow a consistent pattern and were not considered to be satisfactory indicators of optimum harvest date.

Open Access

Cucumber (Cucumis sativus L.) is grown using intensive tillage practices, which increase the cost of production and may lead to an increase in soil and water erosion. Research on alternative tillage practices for cucumber production has been limited primarily to exploring the benefits of no tillage. Alternative tillage practices, such as disking (one pass with a tandem disk) and zone tillage (one pass with a Trans-till) have not been investigated. Thus, the objective of this study was to compare the influence of reduced tillage practices on the growth, development, and yield of cucumbers. Seedling emergence varied between years, but was unaffected by a reduction in tillage, while cucumber leaf number, leaf area index, and vine growth were reduced by no tillage (P ≤ 0.05). Total dry matter accumulation and days to 50% open flower varied with tillage. No-tillage plots produced an average of 34 g·m-2 of dry matter compared to 47 g·m-2 for conventional tillage plots and took 1 day longer to reach 50% flower. Although growth differences were observed under all reduced tillage treatments, no reduction in total yield was observed when compared with conventional tillage yields. Alternative reduced tillage practices, such as disking or zone tillage, were found to be viable options for successful cucumber production. These alternative practices will reduce the cost of production, provide growers with greater time flexibility and ease of land preparation, and reduce the potential for water and wind erosion.

Free access

Abstract

The concept of genetic control of efficiency of nutrient utilization in tomatoes was investigated within naturally occurring variation among 146 strains. Under severe N stress (35 mg of N per plant) in nutrient culture solutions efficient strains produced as much as 45% more dry weight than inefficient strains. Efficiency in N utilization (NER) was defined as the mg of dry weight produced for each mg of N absorbed by a plant. Differences in N uptake and translocation by the root systems did not explain variations in efficiency. At equal total N concentrations in leaves, efficient plants produced larger lower leaves and maintained more normal tissues. High NER values for efficient strains also were associated with greater stem weights and lower total N concentrations. Inheritance studies showed that dominance and additive X additive gene effects made the major contributions to variation in both plant dry weight and N efficiency.

Open Access

Topramezone is a newly introduced herbicide for use in field corn (Zea mays L.) that may have potential for weed management in sweet corn. Tolerance of eight sweet corn hybrids to topramezone applied postemergence (POST) at 0, 50, 75, 100, 150, and 300 g a.i. ha 1 were studied at one Ontario location in 2000 and two locations in 2001 and 2002. Topramezone applied POST at 50, 75, 100, and 150 g·ha 1 did not cause any visual injury in Calico Belle, CNS 710, Delmonte 2038, FTF 222, FTF 246, GH 2684, Reveille, and Rival sweet corn hybrids at 7 days after treatment (DAT) and caused minimal injury (less than 5%) at 300 g·ha 1 in all hybrids. The initial sensitivity observed in these hybrids was minimal and transient with no effect on visual injury at 14 and 28 DAT. Topramezone applied POST did not reduce plant height, cob size, or marketable yield of the sweet corn hybrids included in this study. Based on these results, topramezone applied POST at the rates evaluated can be safely applied to Calico Belle, CNS 710, Delmonte 2038, FTF 222, FTF 246, GH 2684, Reveille, and Rival sweet corn.

Free access

Most administrators regard strategic planning as a structured process to produce fundamental decisions and actions shaping and guiding what their organization is, does, and why it does it. A concerted focus on the future is usually involved in the effort. In North Carolina, all Extension Agriculture and Natural Resource Agents, Specialists, Directors and State Staff recently utilized such a structured process in a 3-day conference entitled “The Summit”. The success of this strategic planning process can be measured by the degree to which the process lead to strategic management within NCCE. The Summit used a framework that fully explored forces affecting or impeding strategic thinking. That framework was a day of laying groundwork and with various keynote speakers helping to set the stage; a day of stakeholder direction and attendee active listening and debate; and a day of group reflection. The results of this conference were chronicled in “White Paper” written by a team representing all major in-house stakeholders. While many of the usual problems affecting Extension were reviewed, stakeholder input to both administration and staff is re-shaping the way NCCE uses resources and directs programs. Ten recommendations came out Action te Such an outcome is strategic management, and the framework of The Summit may allow other similar organizations to also have successful strategic planning meetings.

Free access

To foster development of Ontario commercial tigernut (Cyperus esculentus var. sativus) production, this study was conducted to identify cultural management practices that increase tuber yields. The agronomic practices of field preparation (hilled vs. not hilled), regular irrigation vs. natural rainfall, varying rates of nitrogen (N) fertility, and early season weed management were evaluated. Irrigation had no significant impact on total fresh weight, dry weight, and marketable yield over 2 growing seasons. Similarly, yields from plants grown in hilled rows vs. flat beds over two seasons showed no significant differences. Tigernut yields did not show a response to increasing rates of N up to 150 kg·ha−1. A critical weed-free period of 3 weeks resulted in an 844% yield increase over the nonweeded control. Overall, the results indicate that in general, tigernut requires few inputs to produce a viable commercial yield under Ontario growing conditions.

Open Access