Barley is the world's fourth important cereal crop after wheat, rice and maize. Being the most dependable crop in areas where alkali, frost or drought situations occur, it is cultivated in almost all parts of the world. Barley also does well even with brackish/saline water. It is also more suited to dry land and 'diara land'. Barley is generally grown on marginal and sub-marginal lands with low inputs. In Rajasthan, it is mostly grown on light textured soils, low in nitrogen and organic matter content with poor moisture retentive capacity. The present investigation was carried out Comparative efficacy of herbicidal and mechanical weed control in barley (Hordeum vulgare L.) at different levels of nitrogen. This book would be for paramount importance for the students as well as research scholars of agronomy.