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Ramat Yishay, Israel

Raviv M.,Newe Yaar Research Center
Acta Horticulturae | Year: 2013

In the last decades the fraction of fresh produce and cut flowers that are grown in soilless media are constantly growing due to the inherent advantages of substrates over soils. Peat moss is being used for many years as a main component of soilless media, mainly due to its excellent physical properties. Recently peat is frequently replaced by a variety of recycled, aerobically-stabilized materials, also known as composts. This trend is driven by the societal need to recycle organic wastes in an environmentally-sensitive manner, by the rising cost of peat and by peat conduciveness to several soil-borne diseases. Proper composting of many types of organic wastes achieves a number of important objectives. It should eliminate phytotoxicity, pathogens and weed seeds, and stabilize the material with respect to N and oxygen demand of microorganisms. In addition, some composts are suppressive against several soil-borne diseases. Compost maturity is a crucial characteristic in relation to its use in growing media. It ensures minimal medium shrinkage, oxygen consumption, nitrogen immobilization and phytotoxicity. Feedstocks for composts include bark, sawdust, spent mushroom compost, grape marc, composted green wastes, rice hulls, animal manures, biowaste and others. Limitations to the use of composts in growing media are their physical properties (high bulk density, low content of easily available water), salinity, high pH and rate of residual degradation with time. As a result, normally the fraction of the compost in the mixture should not exceed 50%, although some exceptions exist. Advantages of composts as ingredients of growing media include their low cost, nutritional contribution and suppressiveness against soil-borne diseases. A clear advantage of composts used in substrates is that most of them can be further recycled, after the end of the growing cycle, by soil application. Required future research includes the effect of composting techniques and feedstocks on compost characteristics and predicted performance. The effect of compost storage on the shelf life of its desirable properties should also be studied. Source


Aly R.,Newe Yaar Research Center
Weed Research | Year: 2013

Parasitic plants have evolved various methods of invading host plants. Some invade aerial parts, whereas others invade the roots to obtain necessary nutrients for their development. Phelipanche and Orobanche spp. (broomrapes) and Cuscuta spp. (dodders) are holoparasitic plants that subsist on roots and shoots, respectively, of a variety of agricultural crops. These weeds are able to connect directly with the vascular system of the host, thereby acquiring the water, minerals and carbohydrates necessary for their own growth and reproduction. This exploitation by parasitic plants often causes severe losses in yield quality and quantity of host crops. The key to an effective means for controlling parasitic plants lies in the development of resistant crops, supported by an improved understanding of broomrape and dodder biology. The haustoria formed at the junctions of parasite and host open the way for translocation of a variety of molecules and macromolecules from the host to the parasite. At the same time, however, the haustoria also open opportunities for the development of methods to control parasitic plants. This review will summarise the current knowledge on translocation of siRNAs, mRNAs, viruses, sugars, proteins and herbicides from host to parasitic plants and the potential significance of such molecules to the parasite. Improved understanding of the molecular exchange between host plants and their parasites is expected to lead to the development of state-of-the-art, effective approaches to parasitic weed management. © 2013 European Weed Research Society. Source


Paris H.S.,Newe Yaar Research Center
Genetic Resources and Crop Evolution | Year: 2012

The snake melon, Cucumis melo subsp. melo Flexuosus Group, is a cucurbit crop that was grown and esteemed in Mediterranean lands in antiquity and classical times. Images of snake melons appear in ancient Egyptian wall paintings and sculptures and in mosaics from the Roman Empire. The sikyos of Greek, the cucumis of Latin, and the qishu'im of Hebrew, thought by many to be cucumbers, Cucumis sativus, have now been identified as snake melons. Less iconographic and written evidence exists concerning the appreciation of snake melons during the medieval period. The present work focuses on some philologically based evidence of the importance of snake melons leading into and including the medieval period, with two specific objectives. One was to trace the records of the Hebrew epithet piqqus, which applied to removal of the hairs of young cucurbit fruits, and the Arabic epithet faqqous, used historically and to the present day to designate snake melons. Another objective was to re-affirm how piqqus was actually conducted, as mandated in the second-century code of Jewish Oral Law known as the Mishna. Various conjugational forms of the Hebrew word piqqus were found in writings dating from 200 CE to approximately 600 CE. Evidence is presented that further establishes the exact meaning of piqqus as the rubbing off of the hairs of young cucurbit fruits. The Arabic word faqqous was found in writings dating from the beginning of the tenth century and through to the end of the medieval period in the fifteenth century, the writers hailing from Andalusia in the west to Iraq in the east. These writings suggest that the snake melon was a familiar vegetable across a wide geographic belt throughout the medieval period. © 2011 Springer Science+Business Media B.V. Source


Plaut Z.,Institute of Soil, Water and Environmental Sciences | Edelstein M.,Newe Yaar Research Center | Ben-Hur M.,Institute of Soil, Water and Environmental Sciences
Critical Reviews in Plant Sciences | Year: 2013

Salinity is a major problem in arid and semi-arid regions, where irrigation is essential for crop production. Major sources of salinity in these regions are salt-rich irrigation water and improper irrigation management. The effects of salinity on crops include inhibition of growth and production, and ultimately, death. There are two main approaches to alleviating the adverse effects of salinity on agricultural crops: (i) development of salt-tolerant cultivars by screening, conventional breeding or genetic engineering, and (ii) the traditional approach dealing with treatments and management of the soil, plants, irrigation water, and plant environment. The success of the first approach is limited under commercial growing conditions, because salt-tolerance traits in plants are complex. The present paper reviews, analyzes, and discusses the following traditional approaches: (i) improving the plant environment, (ii) exploiting interactions between plant roots and bacteria and fungi, and (iii) treating the plant directly. With respect to improving the plant environment, we review the possibilities of decreasing salt content and concentration and improving the nutrient composition and concentration in the root zone, and controlling the plant's aerial environment. The interactions between salt-tolerant bacteria or mycorrhizal fungi and root systems, and their effects on salt-tolerance, are demonstrated and discussed. Discussed treatments aimed at alleviating salinity hazard by treating the plant directly include priming of seeds and young seedlings, using proper seed size, grafting onto tolerant rootstocks, applying non-enzymatic antioxidants, plant growth regulators or compatible solutes, and foliar application of nutrients. It can be concluded from the present review that the traditional approaches provide promising means for alleviating the adverse effects of salinity on agricultural crops. © 2013 Copyright Taylor and Francis Group, LLC. Source


Raviv M.,Newe Yaar Research Center
Acta Horticulturae | Year: 2011

Horticulturists have long used various organic materials as components of potting substrates. Since the 1950s, peat moss replaced most of these materials due to its superior physical properties. More recently the trend has changed again as a result of the need to recycle organic wastes in an environmentally-sensitive manner, the rising cost of peat and the understanding of the crucial role that peat bogs play in the global carbon cycle. Most organic materials require controlled composting before they can be used as growing medium components. The composting process should be aerobic and the compost should be exposed to thermophilic conditions. The composting process should achieve a number of important objectives. It should eliminate phytotoxicity, pathogens and weed seeds, and stabilise the material with respect to N and oxygen demand of micro-organisms. The end product is an easy-tohandle material that can be used as a component of growing media. Compost maturity is an important characteristic in relation to its use in growing media. If active decomposition continues after incorporation into a growing medium, it will negatively affect plant growth due to medium shrinkage, reduced oxygen level, nitrogen immobilization and the presence of phytotoxic compounds. Sources for composts as ingredients of growing media include bark, sawdust, plant wastes (spent mushroom compost, grape marc, composted green wastes, rice hulls, etc.), animal manures, bio-waste and others. Limitations to the use of composts as ingredients of growing media are their physical properties (high bulk density and low amount of easily available water), salinity, residual phytotoxicity, high biological oxygen demand, pH and rate of residual degradation with time. As a result, normally the fraction of the compost in the mixture should not exceed 50%, although some exceptions exist. Advantages of composts as ingredients of growing media include their low cost, nutritional contribution and suppressiveness against soil-borne diseases. The above-mentioned considerations suggest a bright future for the use of composts in growing media. Required future research is highlighted. It is of paramount importance to study the linkage between composting techniques and compost characteristics and predicted performance. The effect of compost storage on the shelf life of its desirable properties should also be studied. Source

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