Crop production is one of the most important agro-global issues, in particular questions of production under changing environmental conditions. This production needs to be increased to meet global needs for food, feed, fiber and fuel. Alfalfa is classified as "the queen of the forage crops" due to its high protein content and nutritional value as well as its unique availability during the summer compared with other forage crops. The production of alfalfa under different stressful environments is a great challenge due to several problems with alfalfa crop production, which represent a serious threat to global food security. These stresses may cause a decline in the global feed production from alfalfa due to harmful effects resulting from stresses at the physiological, biochemical and histological levels. To improve the production of alfalfa under these stresses, there is a crucial need to understand the response of alfalfa plants to stresses, the mechanisms of tolerance and the management options. The bio-organic fertilizers derived from alfalfa plants are a crucial and sustainable solution in particular under stressful environments. This review represents an attempt to highlight the positive sides of alfalfa production, particularly the sustainable use of this crop in bio-organic fertilizer production. The chemical and anatomical properties of this plant will also be reviewed. The histology of alfalfa plants under changing environments still needs further investigation.