Leaching of ammonium nitrate under field conditions: studies on kinetics of nitrification and nitrate reduction in an Ultisol profile
1991
Mishra, B.K. | Misra, C.
The simultaneous occurrence of nitrification and nitrate reduction was studied by leaching solution pulses of NH4NO3 through 9 cm long columns and natural field profile of Bhubaneswar sandy loam soil (Ultisol). Employing known analytical solutions of transport equations relevant to conditions induced for the leaching experiments, the nitrate reduction rate constant, k2, was estimated to be 0.072 h-1 at 28 degrees C based on the breakthrough curve (BTC) of NO3(-1)-N stemming from the soil column through which Ca(NO3)2 was leached. Using this value of k2, the value of nitrification rate constant, k1 was estimated to be 0.06 h-1 by curve fitting the NO3(-1)-N BTC derived from NH4NO3 leaching in an equivalent soil column. Using values of k2 close to that derived from the laboratory column studies, k1 was evaluated to be 0.1 h-1 and 0.04 h-1 for 0-30 and 0-50 cm soil layers, respectively, under field situations.
显示更多 [+] 显示较少 [-]