EVALUATION OF FACTORS AFFECTING YIELD REDUCTION IN MATURE ALFALFA (Medicago sativa L.)
Alfalfa (Medicago sativa L.) stand longevity continues to be a problem even though progressive management practices are followed. The following parameters were evaluated on mature alfalfa stands to determine what factors were responsible for stand thinning: forage production, stand density, foliar and crown-root diseases, root and crown tissue weights, and total nonstructural carbohydrate levels. Foliar diseases did not affect stand density; however, three of five anthracnose-resistant cultivars had denser stands than susceptible parents. Fusarium infection was quite high but did not appear to be related to stand density. Individual root weight, root mass, and total nonstructural carbohydrates were not good indicators of stand density.Key words: Alfalfa stand longevity, foliar diseases, crown and root rot, root and crown tissue weight, total nonstructural carbohydrates, forage production