Status of iodine in soil and vegetables crops grown in different agro climatic zones of Assam

Iodine is one of the most important essential trace elements not only for plant but for human being and animal also. Plant derive iodine from soil but animal kingdom uptake it through food crops. North eastern region of India especially Assam is identified as iodine deficient state. It has been divided in six agro-climatic zones on basis of rainfall, temperature, humidity and soil. Three sites from each zone were selected for the study. The present investigation was carried out to evaluate total and available iodine content in soil and to explore the accumulation of iodine in edible part of Kharif and Rabi crops under agroforestry in different zones. Highest iodine content in soil was recorded in upper Brahmaputra valley (3.24 mg kg-1) followed by lower Brahmaputra valley (2.84 mg kg-1). Among the Kharif crops, highest iodine content was found in lady’s finger (7.09 mg kg-1) while in Rabi crops it was recorded in cabbage (11.10 mg kg-1). Iodine content was found comparatively more in Rabi crops than Kharif crops. Least amount of iodine content was recorded in crops as well as soil in hill zone of Assam. Foliar vegetable was found to have more iodine accumulating capability than fruit vegetables. Observation concluded that uptake of iodine by crop dependent on the availability of iodine content in soil.