SURVEY OF CITRUS ORCHARDS FOR MICRONUTRIENTS DEFICIENCY IN SWAT VALLEY OF NORTH WESTERN PAKISTAN

Abstract

Citrus (Citrus sinenesis L.) orchards in Swat were assessed for micronutrients (Zn, Cu, Fe, Mn, B) deficiency during 2006. Representative soil and leaf samples from 51 citrus orchards were collected and analyzed for micronutrients. The results on leaf analysis showed that Zn was deficient in 100%, Mn in 96%, B in 24% and Cu in 16% orchards. The soil analysis showed that Zn was deficient in 10-44%, Fe in 12-18%, and Mn in 4-14% orchards, whereas Cu and B were adequate in all 51 orchards. The soil pH of citrus orchards was between 7.5 and 8.5, and EC was below 4.0 dS m-1. These results suggested that the deficiency of Zn and Mn in citrus orchards of Swat were wide-spread but that of B and Cu were sparse. The soil and plant tests for diagnosing micronutrient deficiencies in citrus orchards were poorly correlated. However, the surface soil (0-15 cm) and cumulative micronutrients contents of the profile (0-45 cm) were strongly positively correlated. Thus, the surface soil analysis can be used to measure pattern in micronutrients fertility of the profile using the regression equations developed in this study. Further studies are needed to determine suitable dose of micronutrients application to citrus orchards in Swat in field experiments.