The effects of phosphorus deficiency on citrus

Abstract

does not appear. First page follows. Introduction Information concerning the effects of mineral deficiencies and excesses on plants has proved of great value in the diagnosis of nutritional disorders in the field and has also provided many clues as to the function and interrelation of elements in plant metabolism and nutrition. In the case of citrus, knowledge of this subject, though extensive, is far from complete. Certain deficiencies, for example, have never been seen or produced on bearing trees; nor is it known, in many instances, which of the effects of a deficiency are primary and which secondary. Investigations concerned with various phases of citrus nutrition have led to the realization that a more thorough understanding of this subject is indispensable—is, in fact, a necessary cornerstone for further effective work. There are indications, too, that certain obscure physiological disorders affecting fruit production and fruit quality may be related to nutrition. Hence considerable experimental work has been carried out and is under way to extend our knowledge of the incipient andacute effects of deficiencies and excesses of mineral elements on the various species of citrus. In connection with a soil-fertilizer experiment with young nave-lorange trees in large containers (55-gallon oil drums), acute phosphorus deficiency developed in one of the soils used. Since, to the knowledge of the authors, the effects of a lack of this element on bearing orange trees have never been described, an account of the onset and progressive stages of this disorder is set forth herein.