Effect of Irrigation Water Salinity, Potassium Silicate Levels and Their Interaction Treatments on Eucalyptus camaldulensis Dehn.

Abstract

A field experiment was carried out at the Experimental Farm in Faculty of Agriculture, Suez Canal University, Ismailia Governorate, Egypt, to study the effect of saline irrigation water, potassium silicate and their interaction treatments on growth and chemical contents of Eucalyptus camaldulensis Dehn. seedlings during the two successive seasons of 2013 and 2014. The seedlings were irrigated with tap water (control) one month after transplanting two times/week. The saline irrigation water was prepared from seawater obtained from Suez Canal in Ismailia region, included five treatments (control (tap water), 3000, 6000, 9000 and 12000 ppm),. Plants were irrigated with the treatments twice/week during 10 month starting 1 month after planting at the rate of 5 liters per plant. Seedlings were sprayed with potassium silicate levels (0, 2, 4, 6 and 8 cm 3 /l) one time every month during 10 months. The results showed that, vegetative growth characters (percent of plant height and stem diameter increment, fresh and dry weights of leaves, stem and roots/plant), chemical contents in the leaves (N, P, K, chlorophyll a, b and carotenoids) and some physical properties of wood [specific gravity (g/ml), lignin % and fiber length (mm)] were decreased with the high rates of saline irrigation water, but raised with the highest concentration of potassium silicate. However, the relative water content (RWC), sodium and proline contents in the leaves were increased by increasing the concentration of saline irrigation water but decreased when using the high rate of potassium silicate. The results revealed that, potassium silicate application alleviates the detrimental effect of salinity stress on vegetative growth, chemical content and physical properties of wood in this study.