Application of exploration geochemistry techniques in agriculture

Soil samples collected from Tarlac, Nueva Ecija, Pampanga, Bulacan, Laguna and Quezon provinces were analyzed for Zn, Mn, Cu, Fe, Co, Pb, and Ni using two analytical methods - Smith and Lynch (S and L) element extraction technique used in exploration geochemical survey and the International Rice Research Institute (IRRI) technique for determining zinc availability in soil. The analytical results were treated statistically using the method of Lepeltier to obtain the background values. The background, or average concentrations of the elements obtained by the S and L method were an order-higher than those computed for the IRRI method. The different metal value contour maps of northwestern Luzon were multiplied by its corresponding metal ratio, IRRI/S and L to produce the agri-geochemical maps or agri-maps that show approximate trace element levels available to the plant. The agri-maps of northwestern Luzon show a region wide deficiency in Cu, Zn, Mn, Pb, Co, and Ni, with the exception of Baguio Area. It has been recognized that excess deficiency in certain minor or trace elements in, particularly the essential micronutrient elements, is one of the important factors in agricultural productivity. It is therefore, recommended that in order to assure the necessary level of trace elements in northwestern Luzon, additions of at least copper, zinc and manganese be provided together with the needed fertilizer. (Author). 14 figs.; 14 refs.; 4 tabs