Role of Soil Enzymes and Soil Nutrients on Soil Fertility of TN Soils

Long-term fertilizer experiment (LTFE) is in progress since 1972 in field No. 36 of Eastern Block Farm at Tamil Nadu Agricultural University, Coimbatore with a cropping sequence of finger millet - maize. In order to evaluate the long-term effects of different fertilizer schedules adopted over the years in the LTFE on the soil properties, fertility status, enzymes activity, microbial population and biomass production, studies were undertaken in monsoon fallow followed by 97th crop of hybrid maize. There were ten treatments each replicated four times in randomized block design. The results revealed that there was no significant change in pH and EC due to the different fertilizer schedules adopted over years. Significant positive correlation was observed between the yield, uptake of nutrients by the crop and soil fertility status. The nutrient use efficiency was higher for K (40.0-205.7) followed by N (8.7-41.5) and P (3.6-17.4). High K efficiencies may be due to the luxury consumption of K by the crop in K rich experimental soil.