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• 12

  Dec
  Evaluating Different Irrigation Volumes in Preparation for Use of recycled Irrigation Water

  Vegetables

  by Shabtai Cohen

  תחום או ענף ירקות
  תאריך עדכון 9/4/2010

  תיאור מלא Abstract
  In recent years, the water reserves in the Arava have been relatively small compared to the increase in cultivated area. In order to conserve water and increase the efficiency of fertilizer use, two model cropping systems were established at Moshav Paran (Be'eri Farm and Stieglitz Farm), with the goal of conserving irrigation water and fertilizer by collecting and recycling of drainage water. The model systems were based on the use of detached substrate, from which drainage water is collected and recycled. A third of the total area was dedicated to detached substrateand two-thirds of the total area was dedicated to pepper grown in the ground. Crop relations were determined in order to allow for high irrigation volumes, to rinse the salts from the crop’s root zone and allow for the use of an irrigation regime with the standard water pressures required in detached substrate systems. The use of these water pressures is based on the fact that the root zone area in these systems is smaller than that of a crop planted in the ground, as well as the need for the necessary absorption area for volumes of water that are sufficient, yet no larger than necessary. All of this was done to ensure optimal performance of the growth medium.
  The volumes of water used today are generally three times the evapotranspiration level (E3). This volume ensures the proper rinsing of salts from the growth medium, but also creates a demand for sufficientarea for absorption of the liquid drained from the growth medium. The smaller the ratio between the area in the soil-less growth medium system and the area in the cultivated-ground system, the greater the efficiency of the system. The necessary rinsing volumes (drainage) will also vary with the quality of the water. Today, the water that reaches the cultivated areas (before fertilization) has an electrical conductivity between 2.5 and 3.5 dS/m. When higher quality irrigation water is used, smaller volumes are necessary to rinse away the salts. Goal of the Experiment: Evaluation of the quality and quantity of drainage water recovered from different volumes of irrigation water. Evaluation of crop performance, in order to prepare a collection of data for use in making decisions regarding the use of recycled water.
  The experiment was conducted at the Zohar Research Station in Sodom Valley, in a plastic-covered greenhouse. Pepper seedlings (cv. Celica, EZ Holland, Efal Israel) were planted in the greenhouse on 15 September 2008. Seedlings were planted into Perlite 2 growth medium in large, 80-L, 1-m-long growing containers, or about 53 L/m2 growing area. There were five replicates of each treatment; each treatment covered an area of 300 m2. Drainage water was collected in a hidden container that had a submerged pump. The collected water was then moved into an accumulation container, using double water meters. The examined variable was irrigation level; irrigation levels were determined according to the ET MAX (maximal evapotranspiration) observed. This amount was used to allocate the water, and was also used as the basis for the irrigation levels in all of the treatments. Four irrigation levels were evaluated in the experiment: ET1, ET2, ET3 and ET4.
  In this experiment, the only treatment in which there was a yield difference was the ET1 irrigation treatment; this treatment received the smallest amount of water. The plants in the different irrigation treatments produced fruit at different times. The plants in the treatments that received smaller amounts of water produced fruit significantly earlier than those in the treatments that received the two highest levels of irrigation. The water drained from the ET1 and ET2 treatments had electrical conductivity levels between 6 and 8 dS/m. These levels indicate that this water is not suitable for use in recycled water systems. An attempt to dilute this water with regular water from the main supply was ineffective and wasteful. The ET3 treatment was the best, in terms of the use of recycled water, based on both the electrical conductivity of the drainage water and the levels of leaching, which were only 30% more than those of the ET2 treatment. (The water that was recovered from the ET2 treatment was not suitable for recycling). The best, recommended treatment from this experiment is also the current accepted practice in the model plots at Moshav Paran.

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

  שפה English
  מחבר Shabtai Cohen, Ami Maduel, Moran Kapun Patel, Rivka Offenbach, Yoram Zvieli, Israel Tzabari, Rami Golan, Eviatar Itiel, Alon Ben-Gal, Naftali Lazarovich
  שנה 2010
  שייכות yzvieli
  תאריך יצירה 9/4/2010
  תאריך עדכון 9/4/2010
• 12

  Dec
  AGROTECHNIQUES FOR PRODUCTION OF TABLE GRAPES IN AN ORGANIC VINEYARD

  Orchard

  by Dafna Harari

  תחום או ענף מטעים
  תאריך עדכון 9/4/2010

  תיאור מלא Dafna Harari and Omer Galor – Central and Northern Arava R&D
  Baruch Luzon – Negev Region, Extension Service, Ministry of Agriculture
  Eyal Raban – Orchard Department, Extension Service, Ministry of Agriculture
  Etty Or – Orchard Department, Volcani Center, ARO

  Abstract
  In the Arava, there is little use of pesticides for the control of pests and diseases. This fact makes it possible to evaluate the organic production of table grapes. Together with the increasing public awareness of the issue of pesticide residues, the Yair Research Station was allocated an organic vineyard. In 2007, there was a severe outbreak of powdery mildew in this vineyard and none of the produce from that year could be marketed. In 2008-2009, we tested a treatment program for the control of powdery mildew that was appropriate for an organic vineyard. This program was based on a preliminary treatment following pruning to ensure early and uniform emergence from dormancy, as well as the use of polyethylene sheets on the rows of the vineyard. The pruned vines in the plots that had been covered with polyethylene sheets emerged from dormancy earlier and in a more uniform fashion than the vines in the uncovered plots. The grape yield was relatively high as compared to that observed in a conventional vineyard of cv. SBS (‘Early Sweet’), approximately 3 tons/dunam of high quality grapes and an additional 0.75 tons/dunam of lower quality grapes. Research efforts toward a preventative treatment for powdery mildew should be continued.

  Email address of the writrer: dafnahr@arava.co.il

  שפה English
  מחבר Dafna Harari, Omer Galor, Baruch Luzon, Eyal Raban, Etty Or
  שנה 2010
  שייכות yzvieli
  תאריך יצירה 10/4/2010
  תאריך עדכון 10/4/2010
• 17

  Dec
  Lighting in Ranunculus

  Flowers

  by Maayan Plaves Kitron

  תאריך עדכון 7/1/2009

  תיאור מלא The production of geophyte crops in Israel has increased in recent years and benefits from a seasonal marketing advantage. Following a survey of a number of bulb and corm cut-flower crops, which was conducted by Central and North Arava R&D, it became clear that it is possible to move up the flowering and harvest season relative to that in other regions of the country, yielding positive results that have transformed geophytes into an additional crop in the portfolio of flower crops produced in the Arava. Taking advantage of, and adapting existing cropping infrastructure, such as greenhouses, soil-less culture, and supplemental heating and lighting, has allowed geophytes to become a worthwhile alternative to declining large-scale crops. In work we performed in ranunculus, we found that increasing day-length led to slightly earlier flowering and encouraged the production of longer stems, but adversely affected flower quality and quantity. The ‘Elegance’ cultivars were brought into commercial production as cultivars possessing economical potential, despite their late-ripening flowers. In work that was conducted at the Yair Research Station in the Arava over a period of three growing seasons (2005/6 through 2007/8), we examined the effect of 16 hours of daylight (achieved through the use of supplemental lighting during night-time hours) on the flowering of ranunculus, specifically ‘Elegance’ cultivars. Ranunculus was planted in the ground and in tuff at the end of October, with a planting density of 20 corms per m2. Supplemental lighting was first supplied approximately one month after planting. We found that the cyclical lighting regimen of two weeks of supplemental lighting and two weeks without supplemental lighting, under natural (winter) day-length conditions, caused earlier flowering with minimal damage to flower quantity or quality. Additionally, we found that supplemental lighting with fluorescent bulbs was not as effective as supplemental lighting with incandescent bulbs.

  שפה English
  מחבר Maayan Plaves Kitron, Avi Osherovitz, Keren Elbaz, Dorit Hashmonai, Iris Yedidya, Gidon Luria, Amnon Navon, Yair Nishri
  שנה 2008
  שייכות yzvieli
  תאריך יצירה 7/1/2009
  תאריך עדכון 7/1/2009

  OPEN
• 17

  Dec
  Lisianthus shading

  Flowers

  by Maayan Plaves Kitron

  תאריך עדכון 7/1/2009

  תיאור מלא Lisianthus production in Israel is primarily directed to the winter and spring, which is when European lisianthus production is reduced and prices are high. For this reason, there is an interest in transplanting young plants as early in the season as possible (until October), while air temperatures are still high. This causes a significant delay in the development of the plants and delayed flowering, which is problematic. In order to facilitate the establishment of the transplanted plants and decrease the temperature around the crop, growers shade production plots from the time that the plants are transplanted. The shading material is left in place for different periods of time, the durations of which have been determined empirically. To date, there have been no in-depth investigations into the effects of shading on quality and yield of lisianthus in the Arava. The primary goals of this investigation were: (1) to test the effects of shade treatments on the development of lisianthus plants, particularly on the timing of differentiation for flowering, the timing of flowering and flower quality; and (2) to set up a system to chart the biochemical factors that contribute to flowering in lisianthus. The study was conducted at the Yair Research Station in the Arava during the 2004/5, 2005/6, 2006/7 and 2007/8 growing seasons. In the first year of the research, we saw that heavy shading negatively affected both the quality and quantity of flowering branches in the cultivar ‘Echo White’. In this season, the shading was in place for long periods of time; the plants spent 58 days under a 75% shade net. In the second season, we shortened the periods of time that the plants were shaded, and found that the best treatments were those in which the plants spent five weeks under a 50% shade net or three weeks under a 75% shade net. In this season, the tested cultivar was ‘Mariachi White’. The actual shading treatments ranged from 67 to 88%. In the third year, we examined a combination of different shading treatments and transplanting dates. None of the shading periods exceeded five weeks. In terms of transplanting dates, for two cultivars, the development of plants transplanted on September 28 was generally one week faster than that of plants transplanted on October 16. Shading delayed differentiation to flowering in all of the cultivars. The amount of amylin was noticeably reduced in all of the plants, indicating that lisianthus plants are dependent on the constant supply of assimilates from the process of photosynthesis.
  In the fourth year, we transplanted plants without any shade and, only after differentiation, spread 90% shade nets, which were left in place for three weeks. From the results of the fourth year’s experiment, we learned that shading after differentiation also has a negative effect on the amount of flowering branches available for harvest, as well as the timing of the harvest of the first crop wave.

  שפה English
  מחבר Maayan Plaves Kitron, Avi Osherovitz, Keren Elbaz, Dorit Hashmonai, Amnon Navon, Yair Nishri, Michelle Zakai, Maya Lugasi, Rivka Ophir
  שנה 2008
  שייכות yzvieli
  תאריך יצירה 7/1/2009
  תאריך עדכון 7/1/2009

  OPEN