RESPONSE OF QUACK GRASS TO DEFOLIATION AND FERTILIZATION

Studies of the response of many species of forage plants to variouis cutting and fertilization treatments have brought out certain general principles. In general, short and frequently repeated defoliation has been found to result in decreased root reserves and decreased yields of foliage. Heavy fertilization with nitrogen usually stimulates top growth, and is associated with decreased root growth. Frequent cutting in immature stages has been found to result in slower recovery after cutting. Rather extensive reviews of the literature pertaining to root reserves have been made by THOMAS (8), GRABER (1), HARRISON (2), and others. Quack grass, (Agropyron repens) is generally considered a noxious weed (3), particularly notable and objectionable because of its extreme vegetative persistence and its pronounced tendency to spread by means of rhizomes. The most superficial consideration of the attributes and the reputation of this species makes it evident that it is not easy to exhaust its reserves of organic food, nor to produce in it a condition in which it is extremely susceptible to injury by defoliation. The present paper describes experiments designed to study the response of this species to various degrees of defoliation and nitrogenous fertilization. The behavior induced in the above-ground parts of the plant as well as the condition of the rhizonles were studied. Experimentation GREENHOUSE EXPERIMENTS