Empirical models to predict soil nitrogen mineralization

Abstract

Empirical models are mathematical equations that can be fitted to experimental results. The use of these models aims to evaluate or predict observed phenomena or experimental data with the objective of helping the development of adequate soil management practices. Based on these considerations, eight mathematical models described in the literature are compared in the present work, using as experimental data the mineral N accumulated during 32 weeks of incubation in Southern Brazilian soils. To obtain mineralization values experimentally, an incubation-washing procedure with 0.01mol L-1 CaCl2 was used. Mineral N was determined at the beginning of the incubation and in the 2nd, 4th, 8th, 16th and 32nd weeks. Among the models, the best fit was obtained with the simple exponential model to describe the mineralization of organic N in the soils. The double exponential models showed quite good fit, but may be superparametrized. In addition, the hypothesis on which these models are based, i.e., the presence of two forms of organic N susceptible to mineralization, cannot be sustained in this study.

Keywords

• potentially mineralizable N
• mathematical models
• simple and double exponential
• N pools