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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
• 17

  Dec
  Winter collapse of pepper 2007/8

  Plant Protection, Vegetables

  by Shimon Pivonia, Ph.D.

  תאריך עדכון 14/1/2009

  תיאור מלא The phenomenon of winter collapse of pepper (Capsicum annuum L.), the wilting of mature plants from December through February, has been known in the Arava for many years. Over the years, the use of methyl bromide as a soil fumigant kept the phenomenon at negligible levels. Winter collapse of pepper appeared on a wider scale during the 2004/5 and 2006/7 growing seasons. The phenomenon is seen primarily in the cooler areas of the Arava, in Paran and Tzofar and, to a lesser extent, in Ein Yahav.
  In experiments that were conducted in controlled growth chambers at the Yair Research Station during the 2007/8 growing season, pepper plants were infected with pythium isolated from wilted plants. The plants were grown at average temperatures of 25, 14, 10.5 and 8.6ºC. At temperatures of 14 and 25ºC, no damage was observed on the infected plants, as compared with control plants. In contrast, at 8.6ºC, we observed the death of many plants, beginning two weeks after the infection date. At 10.5ºC, many plants were damaged, but not completely killed. This damage was not seen until many weeks after the inoculation date. The pythium isolate used in this study was sent to a laboratory abroad for identification. It was identified as a new species of Pythium, previously unknown to science. The results of this study provide a good explanation of the relationship between the appearance of the disease, the type of structure used in the cropping system (i.e., net-house or greenhouse) and environmental conditions. In the last decade, relatively high levels of collapse were observed in the 1999/2000, 2004/5 and 2006/7 growing seasons. In each of these seasons, temperatures during December and January were below average for extended periods of time. The move from net-houses to greenhouses in areas that have suffered from winter collapse in previous years has led to a noticeable decrease in the level of collapse. Measurements of soil temperature collected last season in greenhouses and net-houses explain this phenomenon. In areas with similar climates, minimal soil temperatures in greenhouses are higher than those in net-houses.

  שפה English
  מלות מפתח Capsicum
  מחבר Shimon Pivonia, Rachel Levite, Eviatar Etiel
  שנה 2008
  שייכות yzvieli
  תאריך יצירה 14/1/2009
  תאריך עדכון 14/3/2012

  OPEN
• 17

  Dec
  Evaluation of pepper rootstock lines 2007/8

  Vegetables

  by Rivka Offenbach

  תאריך עדכון 14/1/2009

  תיאור מלא The decreased use of chemical soil treatments, the decreased variety of chemicals applied, increased nematode damage and a lack of nematode-resistant cultivars have all increased the need for appropriate rootstock lines for commercial production of conventional and organic pepper. In an experiment that was conducted during the 2007/8 growing season in screen-houses in the organic section of the Yair Research Station (Arava region), we tested new rootstock lines, in comparison with the veteran rootstock line, 23, in an effort to identify pepper rootstock lines that exhibit vigorous vegetative growth under different growing conditions. In particular, we evaluated the performance of the plants in the presence of salinity, low winter temperatures, diseases and soil pests (nematodes). We examined the following new rootstock lines: Capital, 72001 and 72002. During the growing season, the plants from cultivars 7158 and Vergasa that had been grafted onto rootstock line 23 produced many side branches. These branches were removed at a late date, which damaged the yields of these graft combinations and this rootstock line. Overall, ungrafted 7158 yielded 8.9 kg/m2, as compared to the 7.7 kg/m2 produced by 7158 grafted onto rootstock line 23. The difference in these yields is due to the side branches mentioned above. A similar negative yield effect was observed for plants in which ‘Vergasa’ was grafted onto rootstock line 23. These grafted plants yielded 7.4 kg/m2, as compared to the 8.0 kg/m2 produced by ungrafted ‘Vergasa’ plants. The quantities of fruit suitable for export and the percentages of the total crop that were suitable for export were also similar. Grafts of 7158 onto the rootstock lines 72001 and 72002 produced overall yields of 8.4-8.6 kg/m2, similar to the yield of the ungrafted 7158 plants (8.9 kg/m2). The combination of 7158 grafted onto ‘Capital’ rootstock produced an overall yield that was less than 7.4 kg/m2. The results involving export quality were similar.

  In light of the problems that arose as a result of the rapid sprouting of side branches in rootstock line 23, it is difficult to make any conclusions regarding the grafts of 7158 and ‘Vergasa’ onto this control veteran rootstock line. Of the three new rootstock lines that were evaluated (Capital, 72001 and 72002), the lines 72001 and 72002 both performed well. We recommend continued evaluation of these two rootstock lines, in comparison with the outstanding control rootstock from previous years, 23. Following transplanting, it is important to diligently remove side branches as they are produced by the rootstock line. We recommend future evaluations of new rootstock lines with high levels of resistance to viruses, including resistance to the TSWV virus. It is important that the rootstock line and graft have similar virus resistance profiles, to prevent the collapse of grafted plants as a result of incompatible resistances, a phenomenon that is found in tomato grafts.

  שפה English
  מלות מפתח Grafted Capsicum
  מחבר Rivka Offenbach, Ariel Yafe, Israel Tzabari, Yoram Zvieli, Dudu Elkayam, Svetlana Gugiu,Rami Golan
  שנה 2008
  שייכות yzvieli
  תאריך יצירה 14/1/2009
  תאריך עדכון 14/3/2012

  OPEN
• 17

  Dec
  Effect of the Use of Tomato Transplants from a Nursery in Sussiya on Early Fruit setting 2007-8

  Vegetables

  by Rivka Offenbach

  תאריך עדכון 16/1/2009

  תיאור מלא The marketing period for exported tomato is short, from November until April. Growers usually transplant beginning in September, when the weather is warm and not conducive to fruit setting (average air temperature above 35ºC). Transplanting during this period is problematic because conditions for fruit setting (for the fruit intended for export) begin to prevail in mid-October. Early transplanting can lead to problems with fruit setting, and these plants are also exposed to a number of different pests which are very active during this period, particularly the virus vector whitefly and mites. In organic production systems, hormones can not be sprayed and the majority of the growing areas (for both the organic and conventional crop) are not equipped with cooling systems. During this short marketing season, the export crop is small and its profitability has declined from year to year.
  During the summer of 2006/7 season, a project was begun to evaluate the possibility of earlier transplanting in the Syro-African Rift Valley. This research found that earlier transplanting was only successful in structures that were physically cooled using a fan and pad evaporative cooling system. In light of this finding, a decision was made to evaluate the possibility of later transplanting of slightly older tomato plants at a later date. Fruit setting would be induced in the nursery under cooler conditions, prior to transplanting, to ensure the continuous setting of quality fruit and decreased production costs.

  The present work was conducted at the Yair Research Station during the 2007/8 season. When young tomato plants (cv. Shiran and Meital – Hazera Co.) from different cohorts from the Sussiya nursery in the Hebron Mountains, where temperatures are lower than those in the Arava, were transplanted into organic greenhouse plots 15 days later than usual (25 Sept. 2007. vs. 10 Sept.), there was no difference between the yields of the two cultivars. For cv. Meital, the overall yield and the yield of clusters for export were greater for the 45-day-old plants that were transplanted on 25 September than for the standard plants that were transplanted earlier. The plants transplanted at the later date produced fruits that were lighter (weight of individual fruits) than those of the plants transplanted at the earlier date. Early fruit setting, which allowed for a harvest in December, was only observed in the regular plants transplanted at the later date, and was less significant for the plants that were transplanted when they were 45 or more days old than for the control. There was no advantage to transplanting 60-day-old plants instead of 45-day-old plants. For 45-day-old transplants of cv. Meital, the overall yield for the later transplanting date was greater than the overall yield for the earlier transplanting date. However, the yields of clusters for export were similar for the two planting dates. No early fruit setting was observed for the second transplanting date.

  Delaying the transplanting of slightly older tomato plants raised in Sussiya (cv. Shiran and Meital) by 15 days did not lead to a significantly earlier harvest, had no negative effects on overall yield or yield quality and led to increased yields when the transplanted plants were 45 days old. There was no advantage to transplanting 60-day-old plants instead of 45-day-old plants.

  שפה English
  מחבר Rivka Offenbach, Ariel Yafe, Yoram Zvieli, Rami Golan, Israel Tzabari
  שנה 2009
  שייכות yzvieli
  תאריך יצירה 16/1/2009
  תאריך עדכון 14/3/2012

  OPEN