Introducing the culture of foreign varieties of forage plants can not be made without prior testing in different pedological and climatic conditions comparatively to the origin countries in order to determine their value in terms of production and quality, so that the main purpose of the paper is establish which are the main characters that compete to achieve production yields per and what is the competition capacity of these species when are grown in mixture with other species. Knowing the biological particularities of forage plants is a first step in genetic researches in and amelioration, or in technology research to increase the quantity and quality of feed. Oproi Cristina (2005), claims that a simple calculation of the annual forage production can be done by multiplying the number of plants per hectar, with the number of shoots / plant, with weight of shoots at each harvest year. Of great importance are and some other characters: leaf surface, dry matter assimilation rate expressed phenotypically by a regeneration and rapid growth, rich sprout, stature high, diseases and unfavorable environmental conditions resistance. The same author says that the tiller is the basic element of fodder production. The tillers number on a plant is a fundamental attribute, related to force, photosynthetic capacity, the nutrition space and is a character with a strong variability. Referring to the term 'biological density ZAHONNE''(1985), says that optimmum achieve of this depends largely on the competitive value of the partner in the mixture, so that binary associations, when of one the partners may be replaced with other one more vigorously, the fodder production increases. As biological material we used a variety of Italian ryegrass var. westerwoldicum and three varieties of annual clovers: - Lolium multiflorum var. westerwoldicum - Wesley variety; - Trifolium alexandrinum - Miriam variety; - Trifolium incarnatum - variety Tardivo; - Trifolium resupinatum - Gorby variety. At these species were analyzed main quantitative elements which contribute to achieving the total plant production in two variants: unfertilized - N0P0K0 and fertilized - N100P50K50 and harvesting was done in phenophasa 69 (at full flowering). A special importance of this work is the fact that through these researches are brought significant contributions to the knowledge of main productivity elements, so that when these species will be cultivated, in determining the seeding density must be taken in account these characteristics to favorize a better plants development.

Lolium multilforum; Trifolium alexandrinum; Trifolium incarnatum; Trifolium resupinatum; production

Presentation: oral