Lint yields of Acala 4–42 are highest (despite some lodging) when plants receive only adequate supplies of nitrogen and water, according to Palo Verde Valley tests reported here. When the nitrogen fertility level is adequate for maximum yields, excessive irrigations can produce such rank cotton with large amounts of boll rot that resulting yields are lower than those obtained under nitrogen deficiency conditions. Deltapine Smooth Leaf variety also grew more rank when given extra amounts of both water and nitrogen, but boll rot was not severe and yields were not depressed. Deltapine Smooth Leaf performed better than Acala 4–42 under all conditions tested and required less strict attention to irigation and nitrogen fertilizer for maximum lint yields than Acala 4–42.

These tests were conducted at Fisher Ranches, Blythe, with the cooperation of D. Fisher, Manager.