the increase in soil organic carbon was due to widespread adaptation of several improved technologies including more general and increasing application rates of fossil fertilizers and returning crop residues to soil. The 102 increase in Total nitrogen was caused by gradual but constant increased application of N fertilizers by farmers to agricultural land. The average N input was only 54 kg ha (N)in 1980 but increased to 405 kg ha in 1999 an increase of 7.5 times. In contrast the coefficient of variation values for available phosphorus and available phosphorus increased rapidly from 1980-1999 most likely due to different P and K fertilizer usage in different understanding of nutrient balance and have not applied P and K fertilizers ass widely as N fertilizers.