Changing dynamics of micronutrients in piedmont soil of Bangladesh

Abstract

A study was aimed to delineate the micronutrient status, their change directive with time and relationship with other soil variables in piedmont soils of Bangladesh. Northern and Eastern Piedmont Plains (AEZ 22) is one of the 30 agro-ecological zones (AEZs) of the country whose bench mark status of soil micronutrient has been used for comparing with the present status. There is an indication of zinc (Zn) and boron (B) depletion to some extent after a decade of time whereas the very high fertility status of copper (Cu), manganese (Mn) and iron (Fe) prevails as it was in the previous status. In general view, the micronutrient content of surface soil (0-15 cm) was higher than those of sub-surface soils (15-30 cm). In surface soil clay content showed significant correlation with soil Zn (r=0.403**), Cu (r=0.752**), Fe (r=0.501**) and Mn (r=0.340**). Cu content of soil exhibited positive relationship with all the soil parameters except soil pH and P content; there existed highly significant negative correlation of Cu with soil pH (r=-0.578**) and P (r=-0.420**). The availability of Fe in soil was strongly related with soil clay content (r=0.501**), soil pH (r=-0.686**) and organic matter content (r=0.527**). In surface soil, Fe content influenced significantly with the content of Zn, Cu and Mn. Accordingly in sub-surface soil, positive significant interaction of Zn-Fe, Cu-Fe, Cu-Mn and Fe-Mn was observed. The message revealed from this study concerning nutrient depletion, and interactions among different soil parameters and nutrient elements will pave the way for efficient use of soil resources in a sustainable way.