Paper Title
Modeling Nitrogen Mineralization Kinetics in Soils treated with Farm Yard Manure (FYM)

An incubation experiment was conducted to study the effect of different treatment on N mineralization. The treatments comprised of Control (unfertilized), recommended fertilizers (RF), RF + 200 kg N ha-1 FYM (INM), 300 kg N ha-1 FYM (FYM 300 N) and 400 kg N ha-1 FYM (FYM 400 N) applied to wheat crop in rice-wheat cropping sequence. Triplicate samples were incubated at 15, 25 and 35oC for 0, 3, 5, 7, 14, 28, 42, 56, 70, 98, 126 days and analyzed for mineral N (NH4-N + NO3-N) at each incubation interval. At 15oC, rate of N mineralization in different soils followed the order INM > 400 kg N FYM > 300 kg N FYM > RF > control. Potentially mineralizable nitrogen (No) and rate constant were higher at 25oC than 15oC. The nitrogen mineralization potential in all soils increased with the increase in temperature of incubation. The highest value of No was recorded in soils where FYM was applied to supply 400 kg N ha-1, the potentially mineralizable N in different treatment soils followed the order, 400 kg N FYM > 300 kg N FYM > INM > RF > control. Nitrogen mineralization potential was higher in soils receiving organic manures while the nitrogen mineralization rate was highest in soil where the use of integrated nutrient management was made. Therefore, the combined use of organic manures along with chemical fertilizers can ensure the sustainable crop yields to meet the food requirements of ever increasing population besides maintaining the soil health. The R2 values increased from 0.44, 0.277 and 0.005 to 0.786, 0.761 and 0.664 in INM, 300 and 400 kg N ha-1 from FYM treated soils, respectively with the increase in temperature from 15 to 35oC. The increase in value of R2 indicates that the model gives a significantly better fit at 35oC than 25 and 15oC in amended soils than the unamended control soil.