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Research

Found 55 matching results.(Clear)
  • 17
    Dec
    Pepper cultivar trail in a walk in tunnel, Zohar research station, Sodom Valley 2007/8
    Vegetables

    תחום או ענף ירקות
    תאריך עדכון 24/1/2009

    תיאור מלא In the 2007/8 growing season, pepper production in walk-in tunnels covered an area of 2,000 dunams (200 hectares) in the central Arava and Sodom Valley, among the 16,000 dunams of pepper production in this area. Most of the tunnels were located in Sodom Valley. This area occupies a unique niche, with a climate that is well-suited to pepper production. The particularly mild winters in this area allow for continued vegetative growth and fruit setting. This year, as every year, a cultivar trial was conducted at the Zohar Research Station in Sodom Valley, which included cultivars developed in Israel as well as cultivars from foreign companies. The pepper cultivars were transplanted (10 September 2007) in a walk-in tunnel (with a 6.40 m opening) covered with polyethylene. The tunnel was covered with an additional shade net for the first month after transplanting. The experiment included 29 red cultivars, 10 yellow cultivars and 4 orange cultivars. The plants in the tunnel were arranged in individual rows along the length of the side walls and in three pairs of internal rows. Harvesting began on 23 December 2007 and continued through 13 May 2008; there were 12 harvests in all, and 142 harvest days. The fruit was sorted according to the accepted export standards. Export-quality fruit was stored at the Quality Laboratory at the Yair Research Situation, in a situation that simulated the conditions under which exported fruit is stored and transported. The fruit was stored for 17 days at 7ºC and 95% relative humidity and for three days at 20ºC. The fruit was then re-examined to determine its shelf-life and quality after storage. The overall yield of the cultivars in the trial ranged from 8.0 to 11.6 kg/m2, with no clear differences between cultivars. The yield of export-quality fruit ranged from 3.7 to 6.8 kg/m2, with clear differences between some of the cultivars. Of the yellow cultivars that were examined, Ballet 4405 (Limona), which is an early-ripening cultivar, had a high yield, produced good quality fruit and had a low rate of old fruit. High yields and good quality were also noted for the red cultivar 14511 Bungee, which displayed an intermediate level of early ripening, showed no defects at sorting and had no old fruit following the storage period; and the red cultivar 1097. Of the yellow cultivars, notable results were recorded for 2125 - which displayed a lot of early ripening (50% of the fruit for export was harvested in January), had no old fruit and produced large and uniform fruit – and the cultivar TOP 79, which displayed an intermediate level of early-ripening (only 10% of the fruit for export was harvested in January), produced medium-sized fruit and had no old fruit in the storage test. We propose that these cultivars be included in an additional cultivar trial.

    שפה English
    מחבר Yoram Zvieli, Ami Maduel, Moran Kapon Patel, Rivka Offenbach, Israel Tzabari, Rami Golan, Eviater Itiel, Itzik Posalsky
    שנה 2009
    שייכות yzvieli
    תאריך יצירה 24/1/2009
    תאריך עדכון 25/1/2009

  • 16
    Dec
    Use of of a Fan and Pad Evaporative Cooling System
    Vegetables

    Use of a Fan and Pad Evaporative Cooling System

    תחום או ענף אגרוטכנולוגיה; ירקות

    תאריך עדכון 24/1/2009

    A fan and pad evaporative cooling system based on sprinklers and black shading nets was evaluated during the 2007/8 growing season (third season) in a greenhouse planted with pepper at the Zohar Research Station in Sodom Valley. A cooling system made of four nets, which were tightly bound together with the weave facing outward to slow the falling water and increase the cooling efficiency, was installed in the greenhouse. In this experiment, pepper plants (cultivars Celica, 7187, Copla, Sairus, 35131 and 117) were transplanted in the greenhouse on 15 August 2007. Pole trellising was used. Harvesting began on 25 November 2007. There was significant early-fruit setting of export-quality fruit under the conditions prevailing in Sodom Valley. The red cultivars, Celica, 7187 and Sairus, yielded 2.4 kg/m2 of export-quality fruit in November and December. The yellow, early cultivar 117 yielded 3.5 kg/m2 of export-quality fruit. Of the red cultivars, cv. Copla excelled in the production of fruit that was suitable for export even after a storage period. The quality of the fruit produced by cv. Sairus was particularly low, with an overall quality score of 0.5 as compared to the other red cultivars. The yellow cultivar 117 scored very well in terms of fruit quality following storage. The transplanting date used in this study was particularly early (15 August), as compared to the standard local practice. Local pepper crops are generally transplanted into walk-in tunnels during the first and second weeks of September, with the first harvest taking place in late December or early January. These results indicate the potential that a fan and pad evaporative cooling system made of sprinklers and nets holds for those interested in early transplanting in Sodom Valley and marketing fruit beginning in November, as is standard for the central Arava.

    שפה English
    מחבר Rivka Offenbach, Ami Maduel, Yoram Zvieli, Israel Tzabari, Rami Golan, Yitzhak Askira
    שנה 2008
    שייכות yzvieli
    תאריך יצירה 24/1/2009
    תאריך עדכון 9/2/2012

  • 13
    Dec
    Use of Energy-Saving Systems in Greenhouses at the Yair Research Station, Arava Valley (2008-2009)
    Vegetables

    45
    Use of Energy-Saving Systems in Greenhouses at the Yair Research Station, Arava Valley (2008-2009)

    Use of Energy-Saving Systems in Greenhouses at the Yair Research Station, Arava Valley (2008-2009)

    תחום או ענף אגרוטכנולוגיה; ירקות; פרחים; תבלינים

    תאריך עדכון 27/12/2009

    תיאור מלא Background – To facilitate the continuation and prosperity of agriculture in the Arava, particularly against the background of global economic and climatic change, we must concern ourselves with the use of advanced, innovative technologies to protect crops against damage caused by inclement weather, while allowing continuous fruiting and optimizing fruiting per unit area, to preserve and increase the quality of the fruit or other crop product produced on each unit of cultivated area.
    Goals – The testing and comparison of technologies will allow for energy savings, through the use of integrated systems that make possible improvements in the crop’s growing conditions, by heating and by reducing the relative humidity (RH) inside the greenhouses, as compared with the conventional methods in use today.
    Methods – The experiments were conducted in four cropping structures at the Yair Research Station in the Arava Valley in southern Israel. Each of these cropping structures had an area of 900 m2. The following technologies were tested: 1. Control greenhouse (GH 5). The roof of this greenhouse was covered with polyethylene and the sides were covered with 50-mesh screens. 2. The greenhouse that was equipped with a thermal screen only (GH 2) was constructed of impermeable, reflective sheeting that provided 50% shade. 3. A greenhouse equipped with a thermal screen and the Agam system (GH 3). The Agam system is based on a heat converter that can lower the RH in the greenhouse and supply the additional energy needed to heat the greenhouse. The Agam system pumps the humid greenhouse air through a concentrated salt solution flowing through a matrix of pads. The moisture in the air is then pumped through a condenser, where the latent heat present in the humid air is released into the salt solution. The solution heats up and releases warm, dry air into the greenhouse. 4. Hot-water heating (GH 9). The heater, which has an output capacity of 150,000 kilocalories, includes a heat transfer device based on the flow of hot water through a metal pipe. The heater is powered by natural gas. In this greenhouse, we also installed a thermal screen like the ones installed in buildings 3 and 2. We installed a calorimeter in each of the heated greenhouses, in order to measure the energy demand in the greenhouses. The pepper cultivars Celica (Efal) and 7158 and 7182 (Zeraim Gedera) were transplanted into the greenhouses on 10 August 2008.
    Over the course of the experiment, the temperatures of two fruits from each building and the amount of moisture on the surface of the fruit were evaluated manually once a week. We evaluated green fruits approaching their final size. The evaluation was carried out before the thermal screens were rolled up, usually between 6:45 and 7:00 in the morning, and once an hour for the following three hours. The evaluation of the moisture on the surface of the fruit was done by hand and the moisture level was defined according to four levels: dry, moist, wet or very wet.
    Results and Conclusion- The thermal screen improved the night-time temperature balance and raised the night-time temperature in the greenhouses by an average of 2 to 3.5°C, without any additional energy input from any external (artificial) source. This contribution was accompanied by an increase in the amount of moisture in the building, which increased the cracking of the pepper fruit. The Agam system provided an average energy savings of 60%, as compared to the parallel heating system that used warm water to heat the greenhouse. Both of these systems involved the use of a thermal screen. The RH in the building heated using the Agam system was lower than that in the building heated using the conventional hot-water heating system. This difference between these two systems will increase the more tightly the buildings are sealed. Of the tested cultivars, cv. Celica is most resistant to cracking and cv. 7182 is most susceptible. The highest levels of cracking were observed in the greenhouse with the thermal screen (and no heater), and this corresponds to the wetness of the fruit and the high humidity observed in this building, as compared to the other buildings. The heating systems should be tested in an additional season, in order to characterize the distributions of heat and humidity associated with the different heating systems. The performance of the heating systems should also be tested over a colder winter, as this past winter was quite mild.

    שפה English
    מחבר Shabtai Cohen, Rivka Offenbach, Dorit Hashmonai, Dudu Elkayam, Avi Osherovitz, Gad Asaf, Moshe Maroko
    שנה 2009
    שייכות yzvieli
    תאריך יצירה 27/12/2009
    תאריך עדכון 9/2/2012

  • 18
    Dec
    The effects of soil-bedding methods, water quantity, and water quality on the performance and yield of sweet pepper
    Vegetables

    תאריך עדכון 18/2/2008

    תיאור מלא Sweet pepper is the largest and most successful agricultural sector in the Arava valley yet, it faces problems of availability of fertile soils and water restrict its farther expansion. Innovative soil-bedding methods are, therefore, sought, to which the irrigation regime should be re-adjusted. The objective of the present study was to test the response of sweet pepper yield to different soil-bedding methods at differential irrigation quantity at two levels of water quality.
    Three methods of soil-bedding were tested. For the first method, 'nutrition duct' (ND), 40 cm wide, 20 cm deep ducts were dug in the 'Hamada' soil at 1.6 meter intervals. Tuff (0-8, Tuff Merom Golan Company) was laid inside the ducts at a uniform volume of 50 liter/m3. The second soil-bedding method tested was the restricted root zone (RRZ) system, in which a thin layer of coarse Tuff that covered the bottom of the duct was coated with a thick technical cloth sheet (Agripal, Palrig), on top of which an equal volume of Tuff 0-8 was added. The third was the traditional method of sand-coating (40 cm sand layer on top of the Hamada soil). The experiment took place at Yair Station in the Arava. Sweet pepper seedlings (var. 7187) were planted (24/08/05) in a net-house (50 Mesh), distributed between the three soil-bedding treatments. The differential water quantities began 24 days after planting. The water quantities were adjusted once a week at four different levels according to refund indices of 0.5, 1, 1.5, and 2 of the current evaporation as recorded by a maximum lysimeter. At the end of the season, the water quantities accumulated to 350, 684, 962, and 1350 mm. The experiment structure was duplicated in order to allow two salinity levels of the water: 2.5 and 0.7 dS/m.
    The sand coating method produced the lowest fruit yield at all conditions. When desalinated water (0.7 dS/m) was used, the difference in yield between the sand and the RRZ method reached 20%. The RRZ method did well in the desalinated water, but was inferior to the nutrition duct when saline water (2.5 dS/m) water was used. This inferiority may be attributed to higher salinity in the RRZ rhizosphere. The yield response curve to the desalinated water saturated already at the second level of 684 mm per season at all three methods, whereas in the saline water yields increased along with the increment of water quantity throughout the range. A small advantage of the RRZ over the ND method is explained by a better water retention (25% increase) that was found at the three higher water quantity levels. In conclusion, net-house sweet pepper yields in the Arava valley can be increased by 20% using the RRZ method with 700 mm high quality water. However, when this water quality is unavailable, equal results can be obtained with at least 1400 mm of saline water (2.5 dS/m). These conclusions will be reassessed in the next seasons.

    שפה English
    מחבר Eviatar Itiel, Shai Aharon, Rivka Ofenbach, Rami Golan, Israel Tzabari, Yoram Zvieli, Alon Ben-Gal
    שנה 2007
    שייכות Israel Tsabari
    תאריך יצירה 18/2/2008
    תאריך עדכון 14/3/2012