The monograph summarizes data on the productivity of grass ecosystems. Primary production of ecosystems is its most important characteristic, the assessment of free energy, which ensures the flow of the biological cycle. Knowledge of this value is necessary both for understanding the functioning of ecosystems and for assessing the production potential of hayfields and pastures. Estimates of primary production of grass ecosystems vary extremely widely, as they are obtained by various methods. For the first time, the parameters of biological productivity obtained by one method are given by authors working from the northern to the southern boundary of the steppe zone with all types of grass ecosystems. New geographical structures of plant matter and primary production of grass ecosystems have been identified . The book is of interest to ecologists, botanists, soil scientists and specialists in hay and pastures.