Effect of Seed Coating Methods on Germination Speed of Onobrychis sativa at Different Drought Stress Levels and Sowing Depths

Seed enhancement methods are applied to eliminate or decrease adverse environmental stresses effects and increase seed germination rate and vigor of rangeland plants. The aim of this study was to assess different methods of seed coating effects on germination speed of Onobrychis sativa at different sowing depths and soil moisture levels. The experiment was conducted at growth chamber to apply a better control on environmental factors. So the intact effects of different seed coating treatments were better distinguished by eliminating the interfering environmental factors. The treatments were set up in factorial arrangement based on a Randomized Complete Block (RCB) design with three replications. Factor A: treatment of drought stress treatment at three levels of 9%, 14% and 21% of soil moisture content and factor B: sowing depths of range plants at two levels of leaving the on soil surface and sowing the seed in the soil at 3 times of its thickness and finally factor C: seed coating material with four levels of control (no coating), organic coating, hydro gel coating and mineral coating. Parameter such as germination speed parameter were measured. Results showed that range species seeds coated with different coating materials created in this experiment, significantly performed better germination speed in both normal and drought stressed situations