Hoda M. Mohamed and Faten A. Al- Kamar ( 2018). Effects of salicylic acid and potassium silicate foliar sprays on growth and yield of Valencia orange trees growing in soil influenced by salinity under El-Bustan conditionMiddle East Journal of Agriculture Research ISSN 2077-4605
Volume : 07 | Issue : 04 | Oct.-Dec. | 2018
Abstract: In Egypt, the area of agricultural land affected by salts is increasing as a result of climate change, water shortage and scarcity of rainfall. Under soil conditions affected by salinity, (where EC was 3.40 ds/m) at El Bustan district, El Behera Governorate, Olinda Valencia orange (Citrus sinensis) trees were sprayed with salicylic acid and potassium silicate (as a source of silicon) at full bloom stage and two weeks later during two seasons ( 2016 and 2017) . The study included seven treatments as follow: Salicylic acid at concentrations (200,400 and 600 ppm), potassium silicate at (1000, 2000 and 3000ppm) and untreated tree (control treatment). The best treatments were salicylic acid at 400 ppm and potassium silicate at 2000 ppm, which showed an increase in the average yield of the two seasons than the control by 32.74% and 42.36%, respectively, where these treatments increased the resistance of the plant to tolerate the adverse effects of salinity. The results indicated that the use of potassium silicate at 2000ppm produced higher concentration of leaf total chlorophyll, increased leaf mineral content especially the ratio between K+ and Na+ in the leaves (where, lower Na+ is a good indicator of salt tolerance in plants), improved fruit peel quality, where, (the peel firmness and thickness increased, fruit peel was more lightness and had good rind color), so it seemed more attractive and had high quality. Potassium silicate treatments could earlier the harvest dates by increasing fruit T.S.S/ acid ratio and decreasing juice acidity. On the other hand, leaf total proline content was decreased due to applied treatments. Also, all treatments slightly reduced soil electrical conductivity (EC) and pH. It could be recommended to spray Olinda Valencia orange trees by either potassium silicate at 2000 ppm or salicylic acid at 400 ppm, according to the available material and the economic return.
Keywords: (Salicylic acid, Potassium silicate, Yield, Fruit quality Valencia orange trees.)
