Pedo-Transfer Functions to Estimate Kinetic Parameters for Anaerobic Soil Nitrogen Mineralization

Abstract

Knowledge of potential anaerobic soil N mineralization is important for nitrogen fertilizer application. Instead of time-consuming laboratory incubation, we attempt to use pedo-transfer functions (PTFs) approach to get this information. 27 soil samples with various soil depths were collected from paddy field, woodland and tea field in subtropical central China, anaerobically incubated at 35 ° C for 7 weeks to determine N mineralization, which was fitted by a modified double exponential model with two parameters (the fraction of active N pool ( f ) and mineralization rate constant ( k ) for active N pool). The PTFs for parameters were developed from significant soil properties using multiple stepwise regression method. Parameter f (range: 1.59% - 10.4%, mean: 5.2%) was mainly correlated with soil total N ( T N), organic C (SOC), sand and silt particle contents (r = - 0.59 - 0.69, p < 0.01), and parameter k (range: 0.027 - 0.155 d - 1 , mean: 0.97 d - 1 ) was significantly related to T N, SOC, clay content, C to N ratio and pH (r = - 0.6 - 0.71, p < 0.05). Three variables (SOC, silt and pH) could estimate parameter f (R 2 = 0.72, p < 0.01) well and two ( T N and pH) for parameter k (R 2 = 0.61, p < 0.01). The developed PTFs, integrating various land uses and soil depths, suggest that basic soil properties are helpful for estimation of anaerobic soil N mineralization.