wAbstract
@Accurate prediction of soil nitrogen (N) mineralization in agricultural
soils is of major concern because uncertainty in making fertilizer
N recommendations can lead to economic losses and environmental
pollution. This study examined the suitability of three temperature
functions (Q10, Arrhenius, Logistic) as predictors
of the temperature dependence of soil N mineralization rate, k,
in soil using previously published data sets. Each function fits
k/k0, where k0 is the
reference mineralization rate, against soil temperature T, where
k/k0 = 1 at the reference temperature, T0. No single value of soil temperature was common
to all data sets, and consequently a series of various of T0 from 5 to 35 were tested. The influence of
the temperature zone, land use and soil textural class of soils
in the data set on the temperature response function was also
tested. Despite the different mathematical forms of the functions
evaluated, the fitted curves for each function were very similar
and choice of temperature response function had a limited effect
on prediction of soil N mineralization rate. An additional model,
the LogisticFixed M models proposed which
fits the data sets as well as the previous models, but also takes
into account the existence of optimal and maximal temperatures
in a reasonable temperature range for biological organisms. In
contrast, choice of T0 had a much more pronounced
impact on the k/k0 values, and thus on the
predicted N mineralization rate, than choice of temperature model.
A greater response of N mineralization rate (i.e. k/k0)
to changes in temperature was observed in soils originating from
colder climatic zones (mean annual temperature2) compared with
warmer climate zones (mean annual temperature6). There was also
a greater temperature response of soil N mineralization rate for
agricultural compared with forested soils. Among agricultural
soils, sand-loam soils had a greater temperature response compared
with clay soils. Overall, selection of temperature response model
did not appear to be critical to prediction of soil N mineralization
rate, and consequently a form of the model which best represents
the biological system is therefore preferable, whereas more attention
should be given to the choice of the appropriate T0
for field prediction of N mineralization.
Keywords: Nitrogen mineralization; Temperature response; Arrhenius
function; First-order kinetic; Logistic function; Q10
functionx
1. Introduction
2. Materials and methods
@2.1. Fitting the temperature response function
@2.2. N mineralization simulation exercise
@2.3. Influence of the temperature zone, land use and soil texture
on the temperature response function
3. Results
@3.1. Fitting of the temperature response functions
@3.2. N mineralization simulation
@3.3. Influence of the temperature zone on the temperature response
function
@3.4. Influence of the land use and soil texture on the temperature
response function
4. Discussion
@4.1. Choice of a temperature model
@4.2. Temperature zone, land use and soil texture effects on temperature
response
@4.3. Choice of the T0
6. Conclusion
Acknowledgements
References