Abstract

A pot experiment was conducted with four heterogeneous soils of Tamil Nadu State to determine the effect of continuous cropping and fertilization on Micronutrient availability in soils. Crops were grown continuously, following a fixed crop rotation under four levels of fertility representing low. medium, high and very high levels classi- fied in accordance with the amounts of fertilizers added. An assessment of micronutrient balance was determined after ten crops and the data revealed increasing rate of depletion of micronutrients from the total reserve with increasing doses of fertilizers for all the four heterogeneous soils. This established that the use of high levels of fertilizers tended to cause faster tate of depletion of micro- nutrient elements. irrespective of the nature of soils studied. The rate of depletion of micronutrients followed a set pattern with reference to soils and the sequences of the rate of depletion were arrived at for each one of the micronutrient elements and with reference to soil groups and crops.

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