THE ROLE OF MAGENTIC IRON AND SODIUM SELENATE IN MINIMIZING SOIL SALT HAZARDS ON GROWTH AND QUALITY OF JACARANDA ACUTIFOLIA HUMB. & BONPL. SEEDLINGS

The purpose of this study is exploring the role of some chemicals, namely magnetic iron (Fe3O4) and sodium selenate (Na2SeO4) on avoiding or minimizing soil salt hazards on growth and quality of Jacaranda acutifolia Humb. & Bonpl. seedlings. Thus, a pot experiment was conducted under the full sun at the nursery of Hort. Res. Inst., ARC, Giza, Egypt during 2011 and 2012 seasons, where one-year-old seedlings of Jacaranda were planted in 30 cm diameter plastic pots filled with about 7 kg of sand and clay mixture (1:1, v:v) salinized with an equal mixture of NaCl and CaCl2 pure salts (1:1, w:w) at the concentrations of 0, 1000, 2000 and 4000 ppm. Magnetic iron was applied three times as soil drench at the rate of 4 g/pot, while sodium selenate was added 3 times as foliar spray at 2 ppm. The effect of a combination between Fe3O4 at 4 g/pot and Na2SeO4 at 2 ppm was also studied. The obtained results revealed that means of vegetative and root growth characters were progressively decreased with increasing soil salinity level with significant differences relative to control means in the two seasons, but they were significantly increased as a result of applying magnetic iron, selenate or both in the combined treatment. The best vegetative and root growth, however was attained by planting in unsalinized soil mixture with the addition of both Fe3O4 (4 g/pot) and Na2SeO4 (2 ppm), as this interaction treatment gave the tallest plants, the longest root, the highest number of leaves and the heaviest fresh and dry weights of aerial parts and roots compared to all other interactions in both seasons. It was also noticed that leaf content of chlorophyll a and b and percentage of nitrogen, phosphorus and potassium were gradually decreased as the soil salinity level was increased, while they were significantly increased by drenching the soil with magnetic iron or spraying the foliage with the sodium selenate solution, or by adding these two chemicals in together. The opposite was the right regarding leaf content of carotenoids, sodium %, chloride % and free proline, as these constituents were progressively increased with rising salinity level, but were decreased by the two used chemicals when applied either individually or in combination. In general, applying magnetic iron alone or combining with Naselenate gave better results than the sole application of Na-selenate, whereas the mastery in all previous measurements was for the interaction of planting in unsalinized soil plus application of Fe3O4 (4 g/pot) + Na2SeO4 (2 ppm) that recorded the utmost high means in both seasons. From these results, it is recommended to drench the soil mixture with 4 g/pot of magnetic iron, alone or plus spraying of Na-selenate 2 ppm on the foliage to get the best growth and quality of Jacaranda acutifolia seedlings planted in either salinized or unsalinized soil.