MINERAL CONCENTRATIONS OF FORAGES AND SOILS IN BENUE STATE, NIGERIA .2. TRACE MINERALS, SOIL-PH AND ORGANIC-MATTER

Trace mineral concentrations of forages and soils and soil pH and orga nic matter in three agricultural zones in Benue State were studied. Th e zones consisted of Northern zone (A), Eastern zone (B), and Central zone (C) corresponding to Tiv, Igala and Idoma territorial districts, respectively. Each zone was divided into three grazing environments. I n each of the study environments, grazing animals were closely followe d during grazing and forages corresponding to that consumed by the ani mals and their corresponding soil samples were collected and analyzed for nutrient concentrations. Deficiencies in forage copper (Cu) and zi nc (Zn) were found in all classes of forages in each of the zones. Mea n soil pH was similar at all sites in each zone, ranging from 6.4 to 8 .7. In Tiv Zone, soils from leguminous forages contained the highest ( 8.9 ppm) amount of Fe which was higher (P < 0.05) than soils collected at tree leaf sites. At all sites, forage Cu and Zn were deficient in Tiv and Idoma Zones in regard to critical requirements of these minera ls. In Igala Zone, deficiencies in both forage Zn and Cu were observed in migration routes, Zn in home sites, and soil iron (Fe) in grazing reserves. Selenium (Se) was deficient in legumes in Zone A and crop wa stes in Zone B, while results of analyses by site indicated a deficien cy of Se only in home sites. Selenium concentrations were not affected (P > 0.05) by forage class or site of study. Results obtained indicat ed low correlation coefficients between forage and soil trace minerals . Supplementation of Cu and Zn and in some locations Se would seem mos t important for optimum productivity of grazing animals during the dry season.