Author: Shabtai Cohen

Shabtai Cohen

Departments

Contact



Recent Publications
  • 12
    years
    ago
    Improvement of vegetable crops in the Arava region: Development of a fertilization protocol for the management of pepper growth and fruit set
    Vegetables

    22
    Improvement of vegetable crops in the Arava region: Development of a fertilization protocol for the management of pepper growth and fruit set

    ירקות
    תאריך עדכון 23/2/2012

    Improvement of vegetable crops in the Arava region: Development of a fertilization protocol for the management of pepper growth and fruit set
    Shabtai Cohen, Rivka Offenbach, Yoram Zvieli, Avi Usherovitz, Dorit Hashmonai, Israel Tsabari, Rami Golan – Central and Northern Arava R&D
    Eviatar Ityel – Extension Service (Shaham) Ministry of Agriculture and Rural Development
    Pinhas Fine, Hagai Yashur – Environmental Physics and Irrigation, Gilat Research Center, Agricultural Research Organization (ARO)
    Yoni Elkind – Faculty of Agriculture, The Hebrew University of Jerusalem
    Yoel Masika, Hezi Kalo, Itai Miara – Zeraim Gedera
    E-mail address for correspondence: sab@inter.net.il

    Current fertilization recommendations were developed for use with older cultivars that are not very vigorous. In recent years, more vigorous cultivars have been developed. Among these newer cultivars, there is a phenomenon of plants showing an imbalance between flower development and vegetative growth. During the 2010/11 growing season, a study was conducted at the Yair Research Station in order to develop a fertilization protocol for use in pepper during the periods of its reproductive and vegetative growth. We aimed to develop a protocol in which changes in nitrogen applications would facilitate balanced fruit/canopy development for the optimal distribution of yield over the fruiting months and increased yields.
    The study was conducted in greenhouses in which plants were transplanted into the ground. Eight different cultivars Canon (7158), Sobek (7303), Mekina (7269), Collosso (7229), Miko (7182), Meltzur (7181), Teer (7849) and Rialto (7802) from Zeraim Gedera of young pepper plants were transplanted into the greenhouse on 13 September 2010. We evaluated the effects of ceasing nitrogen fertilization for limited periods of time (20, 25 and 30 days) and a control treatment in which fertilization was never ceased. The treatments were applied two weeks after transplanting (2 September) and a month after transplanting (17 September). Over the course of the study, we assayed the nitrogen content of the petioles as part of our effort to construct a decision-support protocol for ceasing nitrogen fertilization.
    The results of this study indicate that each of the fertilization-cessation treatments, when applied two weeks after transplanting or one month after transplanting, caused earlier fruiting. The use of fertilization-cessation treatments at two weeks after transplanting is risky and may cause long-term damage when applied in commercial fields/greenhouses. Fertilization-cessation treatments initiated at one month after transplanting contributed to yield increases of 13-27% relative to the control treatment in the cultivars Teer, Canon, Rialto and Collosso. The other cultivars reacted to the treatment by fruiting earlier, but their total yields over the course of the study were unchanged or, in some cases, decreased. The cultivars Teer and Kanun, which responded to the treatments with overall yields that were increased 22-25%, reacted to the level of stress that was imposed upon them in very different ways, as was observed through the assays of the N content of the petioles of these plants. The cultivar Teer needed 30 days without fertilization and a nitrogen level of less than 1,000 ppm, in order to reach its peak yield. In contrast, in cv. CANON, only 5 days at the abovementioned threshold nitrogen level in its petioles was sufficient for a 25% increase in total yield.
    The experiment conducted this season was designed to evaluate the reactions of a number of different pepper cultivars to different timings and durations of cessation of fertilization. Due to space constraints, this study was set up as an observational study, without replications. In the coming season, we would like to evaluate two commercial cultivars that are popular in the Arava in a more in-depth manner, with a number of replications, in order to confirm the results of this study and improve our ability to make evaluations based on examinations of the nutrient and mineral content of petioles.

    Acknowledgements
    We thank Yaelit Raz, plant protection inspector, for her efficient and devoted service and the staff of Zeraim Gedera for their help with this study.

    שפה English
    מחבר Shabtai Cohen, Rivka Offenbach, Yoram Zvieli, Avi Usherovitz, Dorit Hashmonai, Israel Tsabari, Rami Golan,Eviatar Ityel, Pinhas Fine, Hagai Yashur, Yoni Elkind, Yoel Masika, Hezi Kalo, Itai Miara
    שנה 2011
    שייכות yzvieli
    תאריך יצירה 23/2/2012
    תאריך עדכון 23/2/2012

  • 12
    years
    ago
    Identifying methods to improve the application of nitrogen containing solid organic fertilizer in organic pepper
    Vegetables

    9 תחום או ענף אורגני; ירקות

    תאריך עדכון 14/3/2012

    Identifying methods to improve the application of nitrogen containing solid organic fertilizer in organic pepper
    Shabatai Cohen, Rivka Ofenbach, Dorith Hashmonai, Avi Osheroviz, Yoram Zvieli – Central and Northern Arava R&D
    Itzik Coen – The Israel Bio Organic Agriculture Association
    E-mail address for correspondence: sab@inter.net.il

    Abstract
    In an experiment conducted at the Yair Research Station in the Arava during the 2010/11 growing season, we examined the effects of the rate, frequency and method of application of solid organic fertilizer (Organicum) on pepper yield and yield quality, with the goal of evaluating possibilities for decreasing production costs and improving profitability for growers. This was done with the understanding that the manual application of fertilizer is labor intensive and requires labor resources that are in short supply. For this reason, any method that will permit less frequent applications will significantly decrease growers’ costs. In an experiment conducted in a screen-house in an organic growing area, we evaluated the effects of Organicum fertilizer, which is processed poultry litter that has undergone a brief composting process under controlled conditions.
    Organicum is representative of a series of materials that have come into use in recent years as part of efforts to lower fertilizer costs in organic agriculture, take advantage of local waste materials and identify substitutes for imported organic nutritional materials, such as guano from the shores of Namibia and feather meal, which is also fed to animals and is currently imported from Europe since the local production of this material is not sufficient. Other alternatives for Organicum include liquid nutritional materials, such as Nugrow, Protomix, Nifert and others, that can be applied through an irrigation system. The disadvantages of these materials are their high cost and the fact that they are imported, with all the environmental significance of their transportation across large distances.
    This experiment included six treatments. Two of these were control treatments. One of the control treatments was treated with Tivon fertilizer for the first 20 days after transplanting. After that period, no supplemental fertilizer was applied. The other control treatment was treated with Tivon fertilizer with a nitrogen concentration of 50–70 ppm throughout the season. In three of the four Organicum treatments, the fertilizer was applied close to the plant roots every 20, 45 or 60 days. In the fourth Organicum treatment, the same amount of fertilizer was distributed on the soil surface instead of being applied to the root zone.
    The results of this study indicate that the Organicum treatments have an advantage over the control (Tivon) treatment even though the nitrogen in Tivon fertilizer is almost immediately available to the plants as ammonia or amino acids. This finding may reflect the fact that Organicum contains not only nitrogen, but also additional elements, such as potassium, phosphorous and trace elements; whereas Tivon contains only nitrogen.
    The yield of the treatment in which Organicum was applied every 20 days was higher than the yields of the other treatments. The largest amount of nitrogen was applied in this treatment, 60 units of nitrogen as opposed to half of that amount or even less in the other treatments. However, the observed results could be more indicative of the availability of the nutrients than the amount of nutritional material applied. This finding suggests that the nutritional treatment applied in this treatment about a month after transplanting greatly improved the nutritional balance of the plants during the critical period in which they began to set fruit. We know that a lack of essential nutrition during fruit development can cause increased fruit setting and the plants “getting stuck.” Therefore, in order to insure proper crop production, it is necessary to check the nutritional status of the crop relatively frequently (every 10 days) between Day 35 and Day 45 after transplanting. It is quite possible that after this critical period there is barely any need to fertilize the plants. That is, fertilizer applications could be concentrated during the necessary developmental period and not be continued through the further development of the crop, during which time the fertilizer does not appear to have much of an effect because the yield-determining events have already occurred.

    Acknowledgement
    We would like to thank the Fertilizers & Chemicals Ltd. Company for supplying the liquid fertilizers used in this experiment.

    שפה English
    מלות מפתח Capsicum
    מחבר Shabatai Cohen, Rivka Ofenbach, Dorith Hashmonai, Avi Osheroviz, Yoram Zvieli, Itzik Coen
    שנה 2011
    שייכות yzvieli
    תאריך יצירה 14/3/2012
    תאריך עדכון 14/3/2012

  • 12
    years
    ago
    Impact of the endomycorrhizal fungus (Glomus intraradices) on water balance and salt stress tolerance in pepper
    Vegetables

    ירקות
    תאריך עדכון 14/3/2012

    תיאור מלא Impact of the endomycorrhizal fungus (Glomus intraradices) on water balance and salt stress tolerance in pepper
    Shabtai Cohen, Rivka Offenbach, Yoram Zvieli, Israel Tsabari, Rami Golan – Central and Northern Arava R&D
    Uri Yermiyahu, Alon Ben-Gal, Ina Finegold, Ahmed Oshala – Environmental Physics and Irrigation, Gilat Research Center, Agricultural Research Organization (ARO)
    Yoram Kapulnik – Institute of Plant Science, The Volcani Center, Agricultural Research Organization
    Shoshana Soriano – Institute of Soil Sciences, The Volcani Center, Agricultural Research Organization
    E-mail address for correspondence: sab@inter.net.il

    Abstract
    Pepper is the main crop in the Arava. This crop is irrigated with saline water as the availability of water in the Arava is limited. The increase in the concentration of salts causes damage that is expressed as reduced canopy size, leaf burn, an increase in the appearance of black coloring on the tips of the fruit and decreased fruiting potential of the pepper plants. The goal of this research was to evaluate the effect of mycorrhizae on water use and salt tolerance in pepper plants, as a means of preventing damage to plants exposed to drought or salt stress and providing future water savings (decreased water consumption) in production areas. This research was based on two field experiments that were conducted at the Yair Research Station during the 2009/10 and 2010/11 growing seasons and three experiments involving potted plants that were conducted at the Gilat Research Center. In Field Experiment 1, we evaluated two levels of phosphorous fertilization (standard and low-level) at three different irrigation levels (50, 75 and 100% of the recommended level) and two levels of mycorrhizae (with and without).
    In Field Experiment 2, we evaluated the effects of mycorrhizal infection and the use of a barrier in a system in which compost was applied. This experiment included three levels of irrigation (50, 75 and 100% of the recommended level) and an examination of the effects of these different treatments on infection in plots with a sand barrier as compared to plots in which plants were transplanted directly into soil rich in compost.
    In the experiment involving potted plants, three factors were evaluated: salinity (five NaCl treatments, specifically 0, 7.5, 15, 25 and 35 mM NaCl), potassium level (two treatments, specifically 5 and 20 ppm) and mycorrhiza (two treatments, infected and uninfected).
    In the first year (2009/10), Field Experiment I was conducted on ground to which no compost had been applied in the past and no compost was applied during the experiment. The results indicate that the fertilizer treatments significantly affected yield. The yield in the treatment that received the standard level of phosphorous fertilizer was greater than the yield from the low-phosphorous treatment. In the low-phosphorous treatments, the mycorrhizae had a significant yield effect.
    In the experiment that was conducted in the 2010-2011season, we found that the application of compost inhibits the positive yield effect that was observed the year before. This was due to the mycorrhiza-suppressant effect of the compost.
    In the experiment with the potted plants, the presence of mycorrhizae did not improve growth under saline conditions when water and phosphorous levels were adequate. At this point, mycorrhizal fungi will not be applied to commercial plots because the majority of these plots are treated with large amounts of compost each year, in a manner that inhibits the ability of mycorrhizae to help alleviate abiotic stress, such as drought and salt stress.

    Acknowledgements
    We would like to thank Haji Yassour of the Gilat Research Center for his help carrying out the experiments. We thank Hishitl Nurseries for their fruitful cooperation involving the application of the fungus to young pepper plants

    שפה English
    KEYWORDS Capsicum, salinity
    AUTHERS: Shabtai Cohen, Rivka Offenbach, Yoram Zvieli, Israel Tsabari, Rami Golan, Uri Yermiyahu, Alon Ben-Gal, Ina Finegold, Ahmed Oshala, Yoram Kapulnik, Shoshana Soriano
    שנה 2011
    שייכות yzvieli
    תאריך יצירה 14/3/2012
    UPDETED 14/3/2012

More...