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• 12

  Jan
  Gradual Fogging System for Cooling Greenhouses

  Vegetables

  by Avraham Arbel

  תחום או ענף אגרוטכנולוגיה
  תאריך עדכון 18/5/2010

  תיאור מלא Gradual Fogging System for Cooling Greenhouses

  Avraham Arbel, Mordechai Barak and Gia Lador – Institute for Agricultural Engineering, ARO
  Shabtai Cohen, Dudu Elkayam, Rivka Offenbach, Avi Osherovitz, Dorit Hashmonai, Israel Tzabari and Rami Golan – Central and Northern Arava R&D

  Email address of the writer: arbel@volcani.agri.gov.il

  Abstract
  Greenhouse crop production in Israel is based mainly on the export of agricultural products during the winter, due to the relative advantage of these products in the European market, this market is characterized by a high level of demand for quality products, that is, products that are free of pesticide residue and arrive in a regular, systematic manner. Lately, this market has been over-supplied with agricultural products, following the entrance of countries in southern Europe and North Africa, which compete for the same share of the market. As a result, the profitability of the crop has declined. The consistent supply of quality agricultural products throughout the year promises a noticeable market solution to growers and could help Israeli growers compete in the crowded marketplace. This requires growing and/or planting during the summer, when the ambient heat- is very high due to solar radiation and summer temperatures. To respond to this challenge, a fogging system was developed for cooling greenhouses. The system was used during the 2008-2009 growing season at the Yair Research Station in the Arava, in structures planted with peppers. The first year was mainly dedicated to testing the physical performance of the apparatus, which included a ventilation system, a fogging mechanism and controls. The system was programmed according to the conditions desired in the greenhouse (28°C and 80% relative humidity) during, extreme midday temperature, and installed according to the following specifications:
  Fogging – In order to supply water gradually, lines of nozzles were divided into three groups (one-sixth, one-third and one-half of the nozzles). This distribution, together with the partial and alternate activation of the supply lines and changes in the pressure (within the acceptable range), allows the gradual change in the water supply necessary to respond to the initial low demand during the night-time and morning hours, as well as the increased need for water corresponding to increased heat-loads during the day and night.
  Greenhouse ventilation – Roof openings allowed air to enter the greenhouse and fans were installed on the sides of the greenhouse. The fans were divided into two groups. One group of fans (the controlled group) was operated at a variable frequency. The desired air supply was obtained by installing a number of groups of fans, and also by timing the frequency in the controlled group.
  Control system – The desired conditions were achieved by timing the supplies of air and water, within the range of permitted deviation. In light of the promising results that were obtained, we can point to the following main conclusions: The actual conditions in the greenhouse corresponded closely to the desired conditions and the system of controls coped well with extreme situations in which the desired conditions could not be achieved. The control system operated effectively and without frequent changes in its activity. We recommend that this work be continued, with attention paid to the following issues: additional algorithms for the system of controls, and inclusion of additional operational controls, such as heating and natural ventilation.

  שפה English
  מחבר Avraham Arbel, Mordechai Barak, Gia Lador, Shabtai Cohen, Dudu Elkayam, Rivka Offenbach, Avi Osherovitz, Dorit Hashmonai, Israel Tzabari and Rami Golan
  שנה 2009
  שייכות yzvieli
  תאריך יצירה 18/5/2010
  תאריך עדכון 18/5/2010
• 9

  Jan
  Summer basil without Bemisia tabaci – Zohar Research Station 2009/10

  Plant Protection, Vegetables

  by Murad Ghanim, Prof.

  25 Summer basil without Bemisia tabaci Zohar Research Station 2009/10

  תחום או ענף הגה"צ; ירקות; תבלינים

  תאריך עדכון 1/10/2011

  Summer basil without Bemisia tabaci – Zohar Research Station 2009/10

  Murad Ghanim – Institute of Plant Protection, Volcani Center, Agricultural Research Organization
  Dafna Harari, Ami Maduel, Danit Parker, Uri Zairi – Central and Northern Arava R & D
  David Silverman, Svetlana Dobrinin – Extension Service, Ministry of Agriculture and Rural Development
  Iris Ben-David – Ein Tamar

  Email for correspondence: ghanim@volcani.agri.gov.il

  The whitefly Bemisia tabaci is a cosmopolitan pest with many hosts; it can develop on hundreds of plant species. This whitefly transmits viruses that cause damage in a number of crops. In herb crops, the main problem is that this pest is a quarantine pest that is unwanted in the countries to which these crops are generally exported. In herb crops such as basil, the damage caused by this pest is particularly serious because the whitefly is based in the parts of the plants that are not harvested. In recent years, an increase in the appearance of this whitefly and a decrease in the efficacy of some of the control measures used against it have been reported. This change is due to selection pressure on the whitefly populations. Most of the sprays used put selective pressure on the subspecies Q, which is known to be associated with the development of resistance to many classes of chemicals.
  The goal of the experiment that was carried out during the summer of 2010 was to evaluate different treatments, including greenhouse-type structures and sprays, in an effort to keep plants free of this whitefly for long periods of time. The experiment, which was carried out at the Yair Research Station in Sodom Valley, included four treatments and three replicates of each treatment. Each replicate was a polyethylene tunnel covered with shade netting. The ventilation openings and double entranceway of each tunnel were covered with insect netting. All of the tunnels were connected to a hallway with 50-mesh netting that had a dark, double entranceway. Basil cv. Pri was transplanted on May 7, 2010. The treatments included an unsprayed control, preventative sprays and reactive sprays based on scouting every two weeks in tunnels covered with regular polyethylene and UV-blocking polyethylene.
  Our scouting observations indicate that there is an advantage to using UV-blocking polyethylene and this advantage was clear in the reactive treatments with and without UV-blocking polyethylene. The preventative treatment was effective in that it kept the pest populations low and this type of treatment is preferred over a reactive treatment, in which the crop is treated after the first pests have been discovered. It appears that the initial resistance status of the populations that enter the building determines the level of the populations that will develop because, in this case when resistant populations are present, the efficacy of the spray treatments is doubtful. If the population that enters the building is made up of subspecies Q, we need to test for resistance if we want to only apply effective treatments. Otherwise, we may see the rapid development of populations that are not susceptible to spray treatments.

  Acknowledgements
  We would like to thank the Chief Scientist’s Fund of the Ministry of Agriculture of funding this research program as part of the Herb Initiative. We would also like to thank the management of the Vegetable Division of the Plant Board and the Herb Growers Association for helping to fund this experiment. We thank herb growers Eran Wein and Yoram Ozeri from Ein Tamar and the AdaFresh Company for their cooperation and for storing and transporting the basil for the shelf-life evaluation.

  שפה English
  מלות מפתח resistance, plant protection, insecticide, management
  מחבר Murad Ghanim, Dafna Harari, Ami Maduel, Danit Parker, Uri Zairi, David Silverman, Svetlana Dobrinin, Iris Ben-David
  שנה 2010
  שייכות yzvieli
  תאריך יצירה 1/10/2011
  תאריך עדכון 14/3/2012
• 12

  Dec
  Use of the Tisan Technology for Grafting Melon, as Compared to the Conventional Technology

  Vegetables

  by Shimshon Omer

  Use of the Tisan Technology for Grafting Melon, as Compared to the Conventional Technology

  תחום או ענף אגרוטכנולוגיה; הגה"צ; ירקות

  תאריך עדכון 9/4/2010

  תיאור מלא Abstract
  In order to improve the performance of grafted and trellised melon plants in the Arava, we tested two pumpkin rootstocks and two techniques for working with grafted plants during the 2008-2009 growing season. In an experiment conducted in a walk-in tunnel in the commercial area of Moshav Ein Yahav, we evaluated melon plants that had been grafted using the regular method and melon plants that had been grafted at a young age using the new Tisan machine. At the beginning of the season, the plants and roots in the Tisan treatment were more developed than those in the conventional grafting treatment. The two types of grafted young plants produced yields greater than those of the ungrafted control plants. The greatest yield of size 5 and size 6 fruit was recorded for those plants that were grafted onto rootstock 534 (Gad) using the conventional grafting method. While an advantage was observed for the plants in the Tisan grafting treatment at the beginning of the season, this early-season advantage did not seem to affect overall yield. The Tisan technology is advantageous for the earlier production of the desired fruit (sizes 5 and 6) on rootstock TZ148, but not on rootstock 534 (Gad). Throughout the experiment, the performance of the plants in the Tisan treatment was never inferior to the performance of the control. Future work in this area should include evaluations of the effect of the rootstocks on yield components, such as fruit size and overall yield.

  Email address of the writer: shiom@shaham.moag.gov.il

  שפה English
  מחבר Shimshon Omer, Roni Cohen, Carmela Horev, Menachem Edelstein, Yoram Zvieli, Rivka Offenbach, Itai Gal, Amnon Koren
  שנה 2010
  שייכות yzvieli
  תאריך יצירה 9/4/2010
  תאריך עדכון
• 12

  Dec
  Effect of an Endomycorrhiza (Glomus intraradices) on Water Use and Salt Tolerance in Peppers in the Arava

  Vegetables

  by Shabtai Cohen

  תחום או ענף ירקות
  תאריך עדכון 9/4/2010

  תיאור מלא Abstract
  In previous work, it was found that mycorrhizae significantly diminish the effects of abiotic stress, such as salinity and insufficient moisture, in pepper. The experimental results collected to date all came from crops grown on soil that had not been treated with compost. However, the spreading of compost is a widespread practice in the Arava. Therefore, in order to evaluate the effect of compost on the activity of mycorrhizae, three separate experiments were conducted at the Yair Research Station. The experiments were as follows: (1) growth on soil on which compost had never been spread; (2) growth on soil that had been treated with 7 m3 of compost in the previous season; and (3) growth on soil that had been treated with compost in two consecutive seasons, including the present season. For this study, seedlings were planted (on 19 August 2008) into net-houses covered with 25-mesh. Each of the three abovementioned experiments had two factors and the experiments were arranged in four randomized blocks. The examined variables were irrigation level and mycorrhiza level; three levels of irrigation (50, 75 and 100%) and two levels of mycorrhizae (1 – with mycorrhizae; 2 – without mycorrhizae) were tested. The results of the experiment indicate that the compost had a negative effect on the activity of the mycorrhizae. The compost masked the activity of the mycorrhizae and, as a result, we did not see significant differences between the treatment with the enhanced plants and the control treatment in which the plants were not enhanced with mycorrhizae. These results were obtained in experiments that were carried out against a background of compost applications in the present or previous season. In the experiment that was carried out on soil that had not been treated with compost, we noted increased yields in the enhanced treatments, as compared with the unenhanced control, in each of the different irrigation treatments. In all the three experiments, decreased irrigation corresponded to decreased yield.

  Email address of the writer: sab@inter.net.il

  שפה English
  מחבר Shabtai Cohen, Rivka Offenbach, Shimon Pivonia, Rachel Levite, Yoram Zvieli, Avi Osherovitz, Dorit Hashmonai, Eviatar Itiel, Alon Ben-Gal, Uri Yirmiyahu, Yoram Kapulnik
  שנה 2010
  שייכות yzvieli
  תאריך יצירה 9/4/2010
  תאריך עדכון 9/4/2010