Brief Papers: Chlorosis in Sudan Grass.

Introduction Sudan grass is one of the most important forage crops in the Rio Grande Valley, Texas. Growth is luxuriant and rapid, and the high yields suggest that the nutrients in the soil are eminently satisfactory for the growth of this species. Repeated cuttinigs may be made, often at intervals as short as 8 to 10 days, until 3 to 10 crops have been harvested. The leaves from the latter crops, however, become progressively more chlorotic until they become almost devoid of chlorophyll. Sometimes chlorosis appears in the second cutting, in which case the planits rarely survive more thani 3 harvests. Other plantings do not become chlorotic until the third or eveni the fourth harvest, and in these instalnces the plants survive for a longer period. This chlorosis is one of the most serious diseases of Sudan grass in this area, and it often becomes a limiting factor in its production. For the past 3 years, the author has carried out field experiments in the vicinity of Elsa, Hidalgo County, Texas, in an effort to discover the cause of this nutritional disturbance. These experiments were designed particularly to test the validity of several current theories concerning the causes of this disease. The study is incomplete, but the imminence of the writer's induction into military service and the importance of the problem itself has induced him to publish a brief statement of the present status of the study in the hope that it will aid students of the general problem of nutritionally induced chlorosis.