Effect of Frost and Salts Dissolved after Heavy Rain on the Productivity of Olive Trees under Desert Growing Conditions
Due to the health benefits of olive oil and increasing demand on olive products in Saudi Arabia, cultivation of olive trees started in 1984 in the north-west regions of the country. Tabuk Agriculture Development Co. (TADCO) is one of the leading companies in Saudi Arabia in fruit crops production such as Stone fruits, Grapes, Pears and Olives. Over a period of more than 30 years of growing olives successfully at TADCO, olive trees of 1-4 years were subjected to severe salts toxicity following the sudden rainfall in the seasons 1994, 1997; leaching operations of the salts from the soil and pruning dry branches lead to the recovery of the trees for their normal growth after few months. TADCO reached maximum olive fruits productivity of 2305 M.T. in 2004 season after 20 years from the establishment.
Olive trees suffered frost damage in the winter seasons of 2000, 2007 and 2008, and a combined damage of frost and dissolved salts after heavy rainfall in January 2005. This led to the reduction of trees productivity for fruits by 25.4, 80.3. 39.9, 84.2% in the seasons 2000, 2005, 2007, 2008 respectively, and a reduction on olive oil productivity by 30.2, 85.1, 43.4, 88.9% respectively. Olive trees recovered their growth and productivity after frost damage in 2000, 2005 and 2007, but after the severe damage in 2008 the olive trees were unhealthy with low productivity and infested with neiroun insects which enforced TADCO to remove the damaged trees in 2009 to protect the remaining healthy trees. The productivity of olive trees was improved in 2011 which reached 2728 M.T. from 36.4% less number of olive trees. Cultivars Ayvalik, Jordan and Verdale were found relatively tolerant to frost in comparison to the cultivars Picual, Coratina, Improved Nebali, Surani, Frantioi and Manzanilla.
Ibrahim Naser*, Rodrigo Hermogino, Conrado Angeles and Abu Kashem A