Several crops of “Fidelio” greenhouse cucumbers were grown in an integrated system with tilapia fish throughout a year. Cucumbers were irrigated with water containing fish waste, that was filtered through the 0.3 m deep sand and returned to the fish tank 8 times daily. Biofilter to fish tank volume ratios of 0.67 to 2.25 were compared. As biofilter volume increased fish growth increased and yield per plant and plant weight decreased. Larger biofilter systems required more water and less pH adjustment because they contained more plants and filter area.
The following should be considered when installing and maintaining a drip irrigation system for vegetable crops: water source (surface or ground water); water quality (salinity, particulate matter, contaminants); size of area to be irrigated; pump size; soil type; drip tape type; crop to be irrigated; management skill of the operator; automation needs; water meter and budget. Use a professional designer.
Because drip irrigation systems are very susceptible to clogging, maintenance revolves around flushing the system. Both primary and secondary filters and main and lateral lines and drip tubes require flushing on a regular basis. Chlorination and use of acid often are necessary for keeping lines clear of contaminants. Rubber gaskets and diaphragms should be replaced every 2 years. A water meter will assist in assuring that desired application rates are being obtained. The use of air vents assures that air locks do not reduce system efficiency. The calibration of injector pumps should be verified at least two times per season.
D. C. Sanders
Land Grant Universities have undergone tremendous change during the late 1980's and early 1990's. These changes are due to declining resources, changing social needs, the decreasing agricultural components of society, and globalization. Faculty and support positions have been reduced. Research programs have embraced more complex areas of study, leaving adoption of new technologies to extension faculty. The Agricultural Industry has declined in political power as fewer farmers feed more people. All of these conditions lead to many changes in `THE LAND GRANT UNIVERSITY'. These changes have been the subject of extensive and intensive, previous and continuing study, because of Land Grants' dramatic influence on both American and global society. Representatives of various institutions within and on the periphery of these institutions will provide their vision for the future of this great American institution. The objectives of this workshop are as follows: Articulate and illuminate the major changes that face The Land Grant Universities and provide a glimpse of these institutions in the future. How these institutions will and should deal with and respond to these challenges will be discussed in order to provide a picture of the future that will affect all of our membership at the very core. The impact of these changes on various aspects of these universities will be presented as follows: Research and science, by Representative of National Academy of Sciences; Outreach/extension and regional cooperation, Representative of The New England Consortium; Private foundations, Representative of Kellogg Foundation; The greater university view, Chancellor Emeritus UCD. The observations of these speakers should generate important discussions that will affect our society, its members, and American society, as we come face to face with major changes in the paradigm of the Land Grant University.
D. C. Sanders
We instituted a series of on-farm trials to introduce vegetable growers to plasticulture systems. Initial trials were large areas where all combinations of plastic mulch, soil fumigation with methyl bromide, and drip irrigation were compared. As the system developed 0.4 Ha trials were instituted to show system potentials. Later 0.1 Ha trials were used to reduce resource demand. Low volume wells were used as a water source for drip irrigation. Often a simple venturi was used to apply fertilizer. Sand filters were made portable by placing them on a trailer and other equipment was made more portable. As more growers adopted the system demonstration became more complex and the focus changed to developing a total, intensive cropping system. In 10 year 50 demonstrations were conducted with a high of 18, and the hectarage of plasticulture increased from 100 Ha to 3500 Ha or from 0.1% to 8% of the appropriate crops. Yields were increase 2 to 6 times with similar improvements in quality.
Douglas C. Sanders and Jennifer D. Cure
The efficacy of undercutting as a technique to control bolting of two short-day onion cultivars was studied in controlled-environment chambers. `Buffalo' and `Granex 33' onions were grown to the third, fifth, and seventh visible leaf stages in a 10-hour photoperiod at 22/18 °C (day/night) and then exposed to 30, 40, 50, 60, or 70 days of vernalizing temperatures (10/10 °C). Half of the plants were undercut at the initiation of the vernalizing treatment. After vernalizing treatments, plants were returned to 14-hour photoperiods at 22/18 °C. `Buffalo', which is resistant to bolting, did not flower significantly under any of these conditions. The flowering response of `Granex 33' increased with leaf number at vernalization and as the duration of vernalization increased. Undercutting `Granex 33' increased the days of vernalization required for flowering and reduced the proportion of flowering relative to controls. Overall dry-matter accumulation was unaffected by leaf number at vernalization or the duration of vernalization but was reduced ≈30% by undercutting. In both cultivars, fresh mass per bulb decreased with increasing leaf stage of vernalization and number of vernalizing days. Undercutting also decreased fresh mass per bulb, but through its effect on bolting, undercutting increased marketable yield for plants vernalized and undercut at the fifth and seventh leaf stages.
D.C. Sanders and W.R. Jester
During 2 years, `Takinogawa Long' gobo was seeded with two, three, or four rows per 1.5-m bed at in row spacings of 7.5, 15, 21.5, and 30 cm. Total and marketable yield increased with in-row spacing and marketable yield increased with row number, with greatest yields occurring at 15 cm regardless of row number. Average root weight and yield of forked roots were not affected by row number but increased with in row spacing. Similarly, percent forked roots decreased with more rows per bed. The 15-cm in-row spacing had the greatest yield, but also the greatest weight of culled roots, but none of the populations affected percentage culls. In another study, in-row subsoiling (SS) and in-row banded phosphorus (P) were evaluated. Marketable yield was increased by both SS and P but did not interact. P increased average root weight. Neither SS or P affected forked root yield or cull root yield, but SS decreased forked roots and increased cull production.
C.S. Kousik, D.C. Sanders, and D.F. Ritchie
The impact of a single hail storm injury in combination with bacterial spot caused by Xanthomonas campestris pv. vesicatoria was assessed on three commercial pepper (Capsicum annuum) cultivars—King Arthur, Jupiter, and Rebell. In addition, the effectiveness of copper plus maneb sprays on hail-damaged plants to suppress bacterial spot was evaluated. A hail storm of ≈5-min duration severely damaged and defoliated the pepper plants. Severe bacterial spot was observed 10 days later on all plants. Disease ratings taken 2 weeks after the hail storm were significantly greater than ratings before the storm. Unsprayed plots of all three cultivars had the greatest disease and the least yield. Plots sprayed weekly (7-day schedule) had a significantly greater yield and less disease compared to unsprayed and biweekly sprayed (14-day schedule) plots for all three cultivars. The combination of hail damage and bacterial spot resulted in a 6-fold reduction in yield in the absence of copper plus maneb sprays and a 2-fold reduction with weekly sprays when compared to the previous season with no hail injury, but similar levels of bacterial spot disease. Disease ratings were less and yields were greater for `King Arthur', than for `Jupiter' and `Rebell'. A judicious copper plus maneb spray program can suppress bacterial spot and help recovery of a young pepper crop when hail damage occurs.