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• 12

  Dec
  Effect of a pause in nitrogen fertilization early in the growing season on the rate of fruit yield in pepper cultivar 7158

  Vegetables

  by Shabtai Cohen

  תחום או ענף ירקות
  תאריך עדכון 29/9/2011

  תיאור מלא Effect of a pause in nitrogen fertilization early in the growing season on the rate of fruit yield in pepper cultivar 7158

  Shabatai Chohen, Rivka Ofenbach, Dorith Hashmonai, Avi Osheroviz, Yoram Zvieli - Central and Northern Arava R&D
  Eviatar Ityel – Extension Service, Ministry of Agriculture and Rural Development

  Email for correspondence: sab@inter.net.il

  Pepper cultivar 7158 (Zeraim Gedera) is widely planted in the central Arava. This cultivar is characterized by its strong resistance to different types of abiotic stress. One of the characteristics of this cultivar is its vigorous growth, which allows it to successfully withstand arid and saline conditions. However, this vigorous growth is also responsible for the fact that, sometimes, there is no fruit-setting on the first internodes; the flowers remain and never develop into fruit. The main reason for this is that the high temperatures during the growing season in the Arava sometimes cause vigorous growth together with vigorous respiration, which, in turn, cause the plant’s resources to be directed more toward the production of leaves and less toward the production of flowers and fruit. In cultivars that are particularly vigorous for genetic reasons, such as 7158, the phenomenon of a lack of fruit-setting at the beginning of the cropping season is particularly notable. The combination of excessive fertilization, vigorous growth and extreme climatic conditions intensifies the problem of fruit-setting at the beginning of the cropping season, which can significantly delay fruit production.
  Goals: 1) To test the effect of ceasing nitrogen fertilization for a limited period on the number of immature fruits, yield and yield quality in pepper grown in artificial potting material. 2) Development of field indices, based on the examination of nitrate levels in petioles, to be used in decision-support systems for stopping and starting fertilization as a way to improve fruit-setting in pepper.
  In an experiment conducted at the Yair Research Station during the 2009-2010 season, cv. 7158 was transplanted (August 15, 2009) into a greenhouse structure that was covered with 50-mesh netting at the beginning of the cropping season. In November, the structure was covered with sheets of polyethylene. The crop was grown in artificial potting material containing Perlite 2. We evaluated a control treatment (continuous fertilization as is the common practice) and treatments in which nitrogen fertilization was stopped for 15, 20 or 25 days. Fertilization with potassium, phosphorous and microelements continued in the different experimental treatments exactly as it continued in the control treatment. The treatments were initiated approximately 25 days after transplanting. Afterwards, fertilization was returned to the level of the control. The experiment was carried out in random blocks with five replicates of each treatment. The results of this experiment show that temporarily stopping fertilization led to changes in the rate of fruit production. Stopping fertilization for 15 days led to significantly advanced fruit production in the first month. In contrast, stopping fertilization for 25 days did not lead to any changes in the timing of fruit production, relative to the control.
  The fertilization-stopping treatments did not lead to significant changes in the overall yield or export-quality yield, as compared to the control, through the end of the experiment. In addition, the treatments were not associated with any significant differences in average fruit weight. The results of this experiment indicate that it is possible to eliminate 20-25 days of nitrogen fertilization, for a savings of 250 shekels per dunam or 1250 shekels per 50 dunams, without negatively affecting the yield of cv. 7158, which is currently the leading pepper cultivar in the central Arava.
  When nitrogen values in the petioles fall to 500 ppm NO3- for a period of 10 days, that stress allows for the early ripening of cv. 7158. This parameter is important as we begin to learn how to induce directed and quantified abiotic stress that will, in the future, allow us to direct fruit-production potential.

  שפה English
  מלות מפתח Capsicum
  מחבר Shabatai Chohen, Riveka Ofenbach, Dorith Hashmonai, Avi Osheroviz, Yoram Zvieli, Eviatar Ityel
  שנה 2010
  שייכות yzvieli
  תאריך יצירה 29/9/2011
  תאריך עדכון 29/9/2011
• 12

  Dec
  Effect of different types of nitrogen fertilizer on the yield and fruit quality of pepper

  Vegetables

  by Shabtai Cohen

  תחום או ענף ירקות
  תאריך עדכון 29/9/2011

  תיאור מלא Effect of different types of nitrogen fertilizer on the yield and fruit quality of pepper
  Shabatai Cohen, Rivka Ofenbach, Dorith Hashmonai, Avi Osheroviz, Yoram Zvieli - Central and Northern Arava R&D

  Email for correspondence: sab@inter.net.il

  Fertilizer is an important component of crop calculations. In a period in which the price of fertilizer is increasing following increasing energy prices, we need to test old axioms and whether cheaper forms of nitrogen can be used without sacrificing yield or fruit quality. Today in the Arava, 50-80 units of nitrogen are applied per season in pepper crops and the use of a cheaper form of nitrogen could decrease each season’s fertilizer bill noticeably. In order to study the effect of the type of nitrogen fertilizer (urea, ammonium or nitrate) on pepper yield and yield quality at the time of harvest and following storage, as well as whether a (cheaper) form of nitrogen whose source is urea could be used without any associated crop damage or crop loss, a study was conducted during the 2009/10 growing season at the Yair Research Station in the Arava. The experiment was carried out in a greenhouse structure in which the crop was planted directly into the ground. Soil preparation was the same for all of the treatments and included the application of 7 m3 of compost per dunam. Irrigation was identical across all of the treatments. We tested four treatments that included different nitrogen compounds. The nitrogen concentration was 90 ppm in each treatment. The treatments were: Meirav 13:7:20, which is based on ammonium and potassium chloride (100% ammonium); Novsid 18:9:20, which is based on urea (100% urea); Idit 6:3:9, a liquid product based on ammonium nitrate (50% ammonium, 50% nitrate) and Raviv 4:2:6 (30% nitrate, 70% ammonium).
  We did not observe any significant differences between the treatments in terms of export-quality yield or overall yield. The fertilizers based on urea or ammonium nitrate did not decrease yields, but the Raviv fertilizer, which contained the highest level of nitrate, led to a significant delay in fruit production, particularly during the second month of fruit production. However, we also observed an increase in fruit production in this treatment during the fourth month of harvest. That is, the delay in fruit production was compensated for during the last month of harvest. The root of this phenomenon is not clear and merits further study. In the storage test that was carried out after the fruits were harvested, we did not observe any differences in the shelf-lives of the produce from the different treatments. In order to expand on these results, we will repeat this experiment in the coming season.

  Acknowledgements
  We would like to thank the Fertilizers and Chemicals Company Ltd' for helping us with this experiment.

  שפה English
  מלות מפתח Capsicum, nitrate, ammonium, urea
  מחבר Shabatai Cohen, Rivka Ofenbach, Dorith Hashmonai, Avi Osheroviz, Yoram Zvieli
  שנה 2010
  שייכות yzvieli
  תאריך יצירה 29/9/2011
  תאריך עדכון 29/9/2011
• 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
• 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