STUDIES ON COBALT IN SOILS OF SOME PASTURE REGIONS OF THE NORTH WESTERN COAST OF EGYPT

Abstract

The essentiality of cobalt for higher plants has not been definitely established, even though cobalt is required by rhizobia for nitrogen fixation and indirectly by leguminous and other plants. Soils greatly vary in their cobalt content at its deficiency occurs in sandy soil derived from acid igneous rocks or in highly calcareous or peaty soils. The chief importance of cobalt in agricultural soils, however, is connected with the fact that ruminants have an essential need for the element; cobalt deficiency in pasture soils has led to incidence of disease in sheep and cattle.

The present investigation was conducted to study:

0 Status and dynamics of cobalt in soils of representative areas of the northern western coast of Egypt. e Status of cobalt in two fodder crops grown on the selected sites of

the representative areas.

@ The cobalt soil test in relation to plant content and soil cobalt availability. O Response of barley to applied cobalt in a shmi-term experiment.

Series of experiments were carried out under controlled laboratory conditions to achieve the previous aims. Composite surface soil samples (0-20 cm) were collected from selected sites of the representative areas, which classified as calciorthids. Also, fodder plant samples of two crops (clover and barley) were collected from the same selected sites of the representative areas.