During a pot experiment run in three series over 2002-2005 on light and heavy soils, the process of competition between spring barley and field peas was investigated for three periods determined by the development rhythm of barley as a single crop, i.e. during the stages of: seedling growth (Zadoks 10-13), tillering (25), stem elongation (32), heading (55) and ripening (87-91). Dry mass yield of both species (overground parts and roots) was used for computation of relative yields (RY), relative yield total (RYT), and competition ratio (CR). It was found that the competence between barley and peas on light soil began during the stage of seedling growth and on heavy soil during the tillering of barley. Its intensity increased until heading on heavy soil, and until the end of vegetation period on light soil. On light soil barley predominated over peas during seedling growth, and peas predominated over barley during stem elongation and heading. The interactions were balanced in the other periods of joint vegetation. On heavy soil barley predominated over peas during seedling growth and heading, while peas predominated over barley at stages of barley tillering and stem elongation. At the ripening stage both species interacted similarly. More intense interactions between the plants were recorded on heavy soil.

87-99