Selenium is an essential element for the animals and human. This element may have an essential role in plant growth, but this has not yet been substantiated. The nutritional minimum level for animals and humans is about 0.05- 0.1 mg/Kg of selenium in dry fodder/ food and intake below that may cause severe deficiency in them. The objectives of this study were to determine the effects of selenium on concentration, uptake and crop yield of plants. For this purpose, soil samples were taken from 10 point 0-30 cm depth of surface soil of Lavark experiment station located in Najaf Abad, Isfahan . The study was carried out in a greenhouse using a completely randomized experimant design as a split plot, with 3 replications. The treatments were 5 levels of 0, 15, 30, 60and 120 g Se ha -1 , plants including Bromus inermis and Onobrychis vicifolia . Soil samples were supplied with manure at the rate of 0 and 100 Kg/ ha. Selenium concentration in plants increased significantly with increasing amount of selenium in soil. Manure application to the soil decreased the selenium concentration and uptake of this element in the plants. But Manure application increased crop yield. The increase in selenium concentration in the soil didn’t affect on crop yield and plant growth. On the other hand, uptake of this element by plants increased with increasing selenium level in soil. The results of this study also showed that different levels of selenium and manure applied had significant effects on the concentration and uptake of this element by plants. However, under greenhouse condition the 60g selenite Se ha -1 produced sufficient Se ( 100 mg Kg -1 ) to meet the needs of livestock.
