ABSTRACT
Introduction ......................................................................................................................................88 What Is Soil Salinity and Sodicity? ................................................................................................. 89 Saline Soils.......................................................................................................................................90 Sodic Soils .......................................................................................................................................90 Saline Sodic Soils ............................................................................................................................90 Water Salinity and Sodicity.............................................................................................................. 91 Salinity and Global Climatic Changes ............................................................................................. 91 Causes, Origin, and Genesis of Soil Salinity in Oman and Other Gulf Countries ..........................93 Water Salinity in the Arab World (the Major Date Palm Areas) ......................................................93 Soil Salinity in the Major Date Palm-Growing Areas ......................................................................95 Salinity Effects on Plants .................................................................................................................95 Salinity Effects on Date Palm ..........................................................................................................96 Root Development of Date Palm under Salinity Stress ...................................................................96 Nutritional Imbalances and Ion Toxicities in Date Palm under Salinity ..........................................97 Effect on Growth of Date Palm ........................................................................................................98 Effect on Fruit Yield and Quality of Date Palm ............................................................................. 100 Indirect Effects of Sodicity on Date Palm ..................................................................................... 101 Salt Tolerance of Date Palm ........................................................................................................... 101 Management Techniques with Respect to Soil Salinity and Brackish Water Irrigation ................ 102 Improved Hydraulic Techniques .................................................................................................... 102 Leaching of Salts ............................................................................................................................ 103 Improvement of Soil Drainage ....................................................................................................... 104 Improved Irrigation Practices ......................................................................................................... 105 Appropriate Agronomic Practices .................................................................................................. 105 Appropriate Intercrops ................................................................................................................... 107 Application of Amendments .......................................................................................................... 107 Genetic Variability and Appropriate Selection of Varieties............................................................ 107 Future Research ............................................................................................................................. 108 Conclusions .................................................................................................................................... 108 Acknowledgments .......................................................................................................................... 108 References ...................................................................................................................................... 108
Date palm (Phoenix dactylifera) is considered as the oldest fruit tree in the Arabian Peninsula and perhaps all over the world. The earliest evidence of date palm cultivation has been reported in 4000 BC in Ur, lower Mesopotamia (now Iraq), while in the Nile Valley, date palm cultivation goes back to 3000 BC (Erskine et al., 2004). This plant is deeply rooted in the traditions, history, and culture of the Arabian Peninsula region since ancient times and has become an integral part of economy and Arab culture. Worldwide date production has been found to concentrate at four main regions: the Arabian Peninsula (Saudi Arabia, the UAE, Oman, Yemen, Bahrain, Qatar, and Kuwait), Al-Maghrab Arabian countries (Algeria, Morocco, Mauritania, Libya, and Tunisia), other Arab countries (Egypt, Iraq, and Sudan), and non-Arab Asian countries (Iran, Pakistan, and China). A few other countries of the world such as Israel, the United States, and Chad are included in the list. According to 2008 data (FAOSTAT), Arabian countries contributed 72.3% to the world production of dates (Gulf countries = 29.8%, Al-Maghrab Arab countries = 12.7%, and other Arab countries = 29.8%). Non-Arab Asian countries shared 25.7%, whereas the remaining 2.1% was produced in the rest of the world. When data of the last 48 years (1961-2008) is considered, it can be noticed that total world production of dates continued to increase, but merely due to an increase in the harvested area, because there has been no increase in yield ha−1 in any of the decades or years. The last 8 years (the beginning of the twenty-Ÿrst century that is claimed to bring innovative technologies) have been the most discouraging.
