Joint International Conference on Long-term Experiments ...

COMPARATIVE ANALYSIS OF CHEMICAL AND BIOLOGICAL SOIL
EXAMINATION TO DETERMINE THE PLANT AVAILABLE N CONTENT
OF SOIL IN THE NYÍRLUGOS LONG TERM FIELD EXPERIMENTS 1
Péter Tamás Nagy* – János Lazányi** – Jakab Loch*
* Department of Agricultural Chemistry and Soil Science, University of Debrecen,
Centre of Agricultural Sciences, Faculty of Agronomy
** Department of Rural Development and Land Use, University of Debrecen, Centre of
Agricultural Sciences, Faculty of Agroeconomics and Rural Development
ABSTRACT
Chemical and biological (incubation) analysis was carried out the acidic sandy soil of
“Nyírlugos” long term field experiment. For chemical analysis 0.01 M CaCl2 extractant
was used. From extractant mineral and organic nitrogen were determined.
For biological analyses a modified incubation technique was applied to determine the
easily soluble, above mentioned N fractions.
The chemical and biological analysis was carried out chosen samples from 1998
and 2001. From the results of chemical analysis it was evident that the amounts of
easily soluble N forms highly depend on the applied treatments. All treatments
increased the content of both mineral and organic N compared to the control. Moreover,
it was found that excess N doses (100-150 kg/ha) resulted significant yield-decrement.
Results of biological analysis were pointed out that logarithmic rate equation was
founded between the amount of mineralized N and time, during incubation. Our results
open the door to establish the potentially mineralizable N-contents (Npot) and the
constant of the mineralization (k) of soils of different treatments. It can be established
that the applied treatments has not remarkably effect on the values of Npot, but higher
constant rate of mineralization was achieved in the limed treatment group than the
treatments without lime. The lowest mineralization rate constant was established in the
control.
From the results it was evident that the used modified incubation method is a
reliable tool to plan and implement of professional N supplement.
Keywords: easily soluble N forms; incubation; long term field experiment;
INTRODUCTION
The balance between supplying sufficient nitrogen for optimal plant performance and
minimizing pollution from excessive nitrogen application is delicate and very important.
It is widely know that N misuse can lead to pollution of the environment but it effects
on soil productivity and yield is well-known. The availability of soil N to the crop is
therefore of great importance in agricultural systems.
The determination of actual N-supply are very important and obligate for sustainable
1 Authors are grateful to coo-workers of MTA-TAKI for making soil sampling possible
and for providing the yield data of the experiment.
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