Magnesium Deficiency of the Hass Avocado Tree

The avocado grower is usually familiar with deficiency symptoms such as those caused by lack of sufficient iron (3), zinc (11), and nitrogen (4). Also excesses of certain elements produce characteristic symptoms which may be readily identified, e. g. chloride and sodium (2, 9). However, little information is available concerning the remaining elements absorbed by the tree, their symptoms along with leaf standards. The Department of Soils and Plant Nutrition initiated Project 1694, "The Basic Mineral Nutrition of Avocado Trees," in January, 1956, to develop specific information on the mineral nutrition of the avocado tree. During the winter 1955-1956, ten large sand culture units were developed on the Riverside campus for such studies. Although the present experiment involves magnesium, additional elements could be investigated with the same ease; accordingly plans are now being made to extend the investigation to manganese, phosphorus, potassium, etc.