Plant Stages and Environment Requirements
Alfalfa is a legume perennial plant, with a powerful root system which can reach several meters in depth, stems are 90-100 centimeters tall and they sprout from the basal portion of the plant (crown). Leaves are trifoliate, flowers are united in racemes, color is from violet to yellow, fruits are pods spiral-like. Seeds are yellow brownish, very small, about 500 seeds in a gram. Main growth stages are: Germination, is a biochemical process by which reserve compounds as sugars and proteins are transferred from cotyledons to embryo, which evolves in seedling: cotyledons, as in all legume, are pulled out of soil. First knot is formed above cotyledons and then the first leaf appears. At this stage, the plant begins photosynthesis and is not more dependent on seeds reserves. Moisture and water are critical for germination as well as a proper soil texture in order to avoid crust formation, which hinder the emergence of cotyledons out of soil. Vegetative growth Defined below are the stages of Alfalfa growth (adapted from Alfalfa Management /Diagnostic Guide, 1990, Pioneer Hi-Breed International).